Table of Contents
*****************

Ada Web Server
1 Introduction
2 Building AWS
  2.1 Requirements
  2.2 AWS.Net.Std
  2.3 Building
  2.4 Building on cross-platforms
  2.5 Demos
  2.6 Installing
3 Using AWS
  3.1 Setting up environment
    3.1.1 Using environment variables
    3.1.2 Using GNAT Project Files
  3.2 Basic notions
    3.2.1 Building an AWS server
    3.2.2 Callback procedure
    3.2.3 Form parameters
    3.2.4 Distribution of an AWS server
  3.3 Building answers
    3.3.1 Redirection
    3.3.2 New location for a page
    3.3.3 Authentication required
    3.3.4 Sending back an error message
    3.3.5 Response from a string
    3.3.6 Response from a Stream_Element_Array
    3.3.7 Response from a file
    3.3.8 Response from a stream
    3.3.9 Response from a on-disk stream
    3.3.10 Response from a on-disk once stream
    3.3.11 Response from a memory stream
    3.3.12 Response from a compressed memory stream
    3.3.13 Split page
    3.3.14 Response a from pipe stream
  3.4 Configuration options
  3.5 Session handling
  3.6 HTTP state management
  3.7 Authentication
  3.8 File upload
  3.9 Communication
    3.9.1 Communication - client side
    3.9.2 Communication - server side
  3.10 Hotplug module
    3.10.1 Hotplug module - server activation
    3.10.2 Hotplug module - creation
  3.11 Server Push
  3.12 Working with Server sockets
  3.13 Server Log
  3.14 Secure server
    3.14.1 Initialization
    3.14.2 Creating a test certificate
    3.14.3 Protocol
  3.15 Unexpected exception handler
  3.16 Socket log
  3.17 Client side
4 High level services
  4.1 Directory browser
  4.2 Dispatchers
    4.2.1 Callback dispatcher
    4.2.2 Method dispatcher
    4.2.3 URI dispatcher
    4.2.4 Virtual host dispatcher
    4.2.5 Transient pages dispatcher
    4.2.6 Timer dispatcher
    4.2.7 Linker dispatcher
    4.2.8 SOAP dispatcher
  4.3 Static Page server
  4.4 Transient Pages
  4.5 Split pages
  4.6 Download Manager
  4.7 Web Elements
    4.7.1 Installation
    4.7.2 Ajax
      4.7.2.1 Steps to do Ajax
      4.7.2.2 Basic Ajax support
      4.7.2.3 XML based Ajax
      4.7.2.4 Advanced Ajax
  4.8 Web Blocks
    4.8.1 Web Block example
    4.8.2 Web Block and Ajax
    4.8.3 Web Block and templates2ada
  4.9 Web Cross-References
5 Using SOAP
  5.1 SOAP Client
  5.2 SOAP Server
    5.2.1 Step by step instructions
    5.2.2 SOAP helpers
6 Using WSDL
  6.1 Creating WSDL documents
    6.1.1 Using ada2wsdl
    6.1.2 Ada mapping to WSDL
    6.1.3 ada2wsdl
    6.1.4 `ada2wsdl' limitations
  6.2 Working with WSDL documents
    6.2.1 Client side (stub)
    6.2.2 Server side (skeleton)
    6.2.3 wsdl2aws
    6.2.4 wsdl2aws behind the scene
    6.2.5 wsdl2aws limitations
  6.3 Using ada2wsdl and wsdl2aws together
7 Working with mails
  7.1 Sending e-mail
  7.2 Retrieving e-mail
8 LDAP
9 Jabber
  9.1 Jabber presence
  9.2 Jabber message
10 Resources
  10.1 Building resources
  10.2 Using resources
  10.3 Stream resources
  10.4 awsres tool
11 Status page
Appendix A References
Appendix B AWS API Reference
  B.1 AWS
  B.2 AWS.Attachments
  B.3 AWS.Client
  B.4 AWS.Client.Hotplug
  B.5 AWS.Communication
  B.6 AWS.Communication.Client
  B.7 AWS.Communication.Server
  B.8 AWS.Config
  B.9 AWS.Config.Ini
  B.10 AWS.Config.Set
  B.11 AWS.Containers.Tables
  B.12 AWS.Cookie
  B.13 AWS.Default
  B.14 AWS.Dispatchers
  B.15 AWS.Dispatchers.Callback
  B.16 AWS.Exceptions
  B.17 AWS.Headers
  B.18 AWS.Headers.Values
  B.19 AWS.Jabber
  B.20 AWS.LDAP.Client
  B.21 AWS.Log
  B.22 AWS.Messages
  B.23 AWS.MIME
  B.24 AWS.Net
  B.25 AWS.Net.Buffered
  B.26 AWS.Net.Log
  B.27 AWS.Net.Log.Callbacks
  B.28 AWS.Net.SSL
  B.29 AWS.Net.SSL.Certificate
  B.30 AWS.Parameters
  B.31 AWS.POP
  B.32 AWS.Resources
  B.33 AWS.Resources.Embedded
  B.34 AWS.Resources.Files
  B.35 AWS.Resources.Streams
  B.36 AWS.Resources.Streams.Disk
  B.37 AWS.Resources.Streams.Disk.Once
  B.38 AWS.Resources.Streams.Memory
  B.39 AWS.Resources.Streams.Memory.ZLib
  B.40 AWS.Resources.Streams.Pipe
  B.41 AWS.Response
  B.42 AWS.Server
  B.43 AWS.Server.Hotplug
  B.44 AWS.Server.Log
  B.45 AWS.Server.Push
  B.46 AWS.Server.Status
  B.47 AWS.Services.Callbacks
  B.48 AWS.Services.Directory
  B.49 AWS.Services.Dispatchers
  B.50 AWS.Services.Dispatchers.Linker
  B.51 AWS.Services.Dispatchers.Method
  B.52 AWS.Services.Dispatchers.URI
  B.53 AWS.Services.Dispatchers.Virtual_Host
  B.54 AWS.Services.Download
  B.55 AWS.Services.Page_Server
  B.56 AWS.Services.Split_Pages
  B.57 AWS.Services.Split_Pages.Alpha
  B.58 AWS.Services.Split_Pages.Alpha.Bounded
  B.59 AWS.Services.Split_Pages.Uniform
  B.60 AWS.Services.Split_Pages.Uniform.Alpha
  B.61 AWS.Services.Split_Pages.Uniform.Overlapping
  B.62 AWS.Services.Transient_Pages
  B.63 AWS.Services.Web_Block
  B.64 AWS.Services.Web_Block.Context
  B.65 AWS.Services.Web_Block.Registry
  B.66 AWS.Session
  B.67 AWS.SMTP
  B.68 AWS.SMTP.Client
  B.69 AWS.Status
  B.70 AWS.Templates
  B.71 AWS.Translator
  B.72 AWS.URL
  B.73 SOAP
  B.74 SOAP.Client
  B.75 SOAP.Dispatchers
  B.76 SOAP.Dispatchers.Callback
  B.77 SOAP.Message
  B.78 SOAP.Message.XML
  B.79 SOAP.Parameters
  B.80 SOAP.Types
Index


Ada Web Server
**************

1 Introduction
**************

`AWS' stand for Ada Web Server. It is an Ada implementation of the
`HTTP/1.1' protocol as defined in the RFC 2616 from June 1999.

The goal is not to build a full Web server but more to make it possible
to use a Web browser (like Internet Explorer, or Netscape Navigator) to
control an Ada application. As we'll see later it is also possible to
have two Ada programs exchange informations via the `HTTP' protocol.
This is possible as `AWS' also implement the client side of the HTTP
protocol.

Moreover with this library it is possible to have more than one server
in a single application. It is then possible to export different kind
of services by using different `HTTP' ports, or to have different ports
for different services priority. Client which must be served with a
very high priority can be assigned a specific port for example.

As designed, `AWS' big difference with a standard `CGI' server is that
there is only one executable. A `CGI' server has one executable for
each request or so, this becomes a pain to build and to distribute when
the project gets bigger. We will also see that it is easier with `AWS'
to deal with session data.

`AWS' support also `HTTPS' (secure `HTTP') using `SSL'. This is based
on `OpenSSL' a very good and Open Source SSL implementation.


Major supported features are:

   * HTTP implementation

   * HTTPS (Secure HTTP) implementation based on SSLv3

   * Template Web pages (separate the code and the design)

   * Web Services - SOAP based

   * WSDL support (generate stub/skeleton from WSDL documents)

   * Basic and Digest authentication

   * Transparent session handling (server side)

   * HTTP state management (client side cookies)

   * File upload

   * Server push

   * SMTP / POP (client API)

   * LDAP (client API)

   * Embedded resources (full self dependant Web server)

   * Complete client API, including HTTPS

   * Web server activity log


2 Building AWS
**************

2.1 Requirements
================

`AWS' has been mainly developed with `GNAT' on Windows.  It is built
and tested regularly on `GNU/Linux' and `Solaris', it should be fairly
portable across platforms. To build `AWS' you need:

   * GNU/Ada (GNAT compiler) ; 

     To build this version you need at least `GNAT GPL 2009 Edition' or
     `GNAT Pro 6.2' as some Ada 2005 fearures (`Ada.Containers',
     interfaces, overriding keyword) are used. The code should be
     fairly portable but has never been tested on another compiler than
     `GNAT'.

   * OpenSSL (optional) ; 

     OpenSSL is an Open Source toolkit implementing the Secure Sockets
     Layer (SSL v2 and v3) and much more. You'll find libraries for
     Win32 into this distribution. For other platforms just download
     the OpenSSL source distribution from `http://www.openssl.org' and
     build it.

   * OpenLDAP (optional) ; 

     OpenLDAP is an Open Source toolkit implementing the Lightweight
     Directory Access Protocol.  If you want to use the `AWS/LDAP' API
     on UNIX based systems, you need to install properly the `OpenLDAP'
     package. On Windows you don't need to install it as the
     `libldap.a' library will be built by `AWS' and will use the
     standard Windows `LDAP DLL' `wldap32.dll'.

     You can download OpenLDAP from `http://www.openldap.org'.


2.2 AWS.Net.Std
===============

This package is the standard (non-SSL) socket implementation. It exists
different implementations of this package:

IPv4
     Version based on `GNAT.Sockets'. This is the default implementation
     used.

IPv6
     As above but supporting IPv6 protocol. To select this
     implementation just do when building (see below):

          $ make IPv6=true


2.3 Building
============

Before building be sure to edit `makefile.conf', this file contains
many settings important for the build. Note that it is important to run
`make setup' each time you edit this file.

When you have built and configured all external libraries you must set
the ADA_PROJECT_PATH variable to point to the GNAT Project files for
the different packages. For `XML/Ada' support, you also need to set
XMLADA to TRUE in `makefile.conf'.

At this point you can build `AWS' with:

     $ make setup build

Note that some demos require that `AWS' be built with `SSL' support. If
you want to activate `SSL' on UNIX (in this case you must have
`libssl.a' and `libcrypto.a' available on your platform), open
`makefile.conf' and set the SOCKET variable to `openssl'. Then rebuild
with: 

     $ make setup build

It is is possible to build `AWS' in debug mode by setting DEBUG make's
variable in `makefile.conf', or just:

     $ make DEBUG=true setup build

Note that by default `AWS' is configured to use the `GNAT' compiler.
So, if you use `GNAT' you can build `AWS' just with:

     $ make setup build

If you want to build only the `AWS' libraries and tools and do not want
to build the demos you can set `DEMOS' to "false" as in:

     $ make DEMOS=false setup

2.4 Building on cross-platforms
===============================

To build for a cross platform the TARGET makefile variable must be set
with the cross toolchain to be used. The value must be the triplet of
the toolchain to use.

For example, to build on VxWorks:

     $ make TARGET=powerpc-wrs-vxworks setup build

2.5 Demos
=========

`AWS' comes with some ready to use demos. The demos are a good way to
learn how to use `AWS'.

Here are a short description of them:

`agent'
     A program using the `AWS' client interface. This simple tool can
     be used to retrieve Web page content. It supports passing through
     a proxy with authentication and basic authentication on the Web
     site.

`auth'
     A simple program to test the Web Basic and Digest authentication
     feature.

`com'
     Two simples program that uses the `AWS' communication service.

`dispatch'
     A simple demo using the dispatcher facility. *note URI
     dispatcher::.

`hello_world'
     The famous Hello World program. This is a server that will always
     return a Web page saying "Hello World!".

`hotplug'
     A simple test for the hotplug feature.

`interoplab'
     A WSDL based demo that test most of the `SOAP' features.

`jabber_demo'
     A simple Jabber command line client to check the presence of a JID
     (Jabber ID). This uses the Jabber API, *note AWS.Jabber::.

`multiple_sessions'
     A demo of two embedded servers using different sessions.

`res_demo'
     A demo using the resource feature. This Web Server embedded a `PNG'
     image and an `HTML' page. The executable is self contained.

`runme'
     An example that test many `AWS' features.

`soap_demo'
     A simple client/server program to test the `SOAP' protocol.

`soap_disp'
     Like above but use a `SOAP' dispatcher.

`soap_vs'
     A client and server that implement seven `SOAP' procedures for
     testing purpose.

`split'
     A demo for the transient pages and page splitter `AWS''s feature.
     Here a very big table is split on multiple pages. A set of links
     can be used to navigate to the next or previous page or to access
     directly to a given page.

`test_ldap'
     A simple `LDAP' demo which access a public `LDAP' server and
     display some information.

`test_mail'
     A simple application that send a set of `SMTP' messages with
     different kind of attachments.

`text_input'
     A simple demo which handle textarea and display the content.

`vh_demo'
     Two servers on the same machine... virtual hosting demo.  *note
     Virtual host dispatcher::.

`web_block'
     A simple Web Bock based counter.

`web_block_ajax'
     As above but using also `Ajax'.

`web_block_ajax_templates'
     As above but using also the `templates2ada' tool which create a
     tight coupling between the web templates and the `Ada' code.

`web_elements'
     A driver to browse the Web Elements library and see some examples.

`web_mail'
     A simple Web Mail implementation that works on a `POP' mailbox.

`wps'
     A very simple static Web page server based on
     `AWS.Services.Page_Server'.  *note Static Page server::.

`ws'
     A static Web page server and push enabled server.

`zdemo'
     A simple demo of the Gzip content encoding feature.


For build instructions see `demos/README'.

2.6 Installing
==============

When the build is done you must install `AWS' at a specific location.
The target directory is defined with the PREFIX `makefile.conf'
variable. The default value is set to the compiler root directory. Note
that the previously installed version is automatically removed before
installing the new one. To install:

     $ make install

To install `AWS' into another directory you can either edit
`makefile.conf' and set PREFIX to the directory you like to install
`AWS' or just force the make PREFIX variable:

     $ make prefix=/opt install

Alternatively, with `GNAT' 5.03 and above it is possible to install
`AWS' into the GNAT Standard Library location. In this case `AWS' is
ready-to-use as there is no need to set ADA_PROJECT_PATH, just set
PREFIX to point to `GNAT' root directory:

     $ make prefix=/opt/gnatpro/6.1.1 install

Now you are ready to use `AWS' !

3 Using AWS
***********

3.1 Setting up environment
==========================

3.1.1 Using environment variables
---------------------------------

After installing `AWS' you must set the build environment to point the
compiler to the right libraries. First let's say that `AWS' has been
installed in `awsroot' directory.

   Following are the instructions to set the environment yourself. Note
that the preferred solution is to use project files. In this case there
is no manual configuration.

spec files
     The spec files are installed in `<awsroot>/include/aws'. Add this
     path into ADA_INCLUDE_PATH or put it on the command line
     `-aI<awsroot>/include/aws'.

components
     `AWS' uses some components they are installed in
     `<awsroot>/include/aws/components'. Add this path into
     ADA_INCLUDE_PATH or put it on the command line
     `-I<awsroot>/include/aws/components'.

libraries
     The GNAT library files (`.ali') and the `AWS' libraries
     (`libaws.a') are installed into `<awsroot>/lib/aws/static'. Add
     this path into ADA_OBJECTS_PATH or put it on the command line
     `-aO<awsroot>/lib/aws/static'. Furthermore for `gnatlink' to find
     the libraries you must add the following library path option on the
     `gnatmake' command line `-largs -L<awsroot>/lib/aws/static -laws'.

     Note that to build SSL applications you need to add `-lssl
     -lcrypto' on gnatmake's `-largs' section.

external libraries
     You must do the same thing (setting ADA_INCLUDE_PATH and
     ADA_OBJECTS_PATH) for all external libraries that you will be
     using.


3.1.2 Using GNAT Project Files
------------------------------

The best solution is to use the installed GNAT Project File `aws.gpr'.
This is supported only for `GNAT 5.01' or above. You must have
installed `XML/Ada' with project file support too.

   If this is the case just set the ADA_PROJECT_PATH variable to point
to the `AWS' and `XML/Ada' install directories. From there you just
have to with the `AWS' project file in your GNAT Project file, nothing
else to set.

     with "aws";

     project Simple is

        for Main use ("prog.adb");

        for Source_Dirs use ("src");

        for Object_Dir use "obj";

     end Simple;

See the GNAT User's Guide for more information about GNAT Project Files.

3.2 Basic notions
=================

`AWS' is not a Web Server like IIS or Apache, it is a component to
embedded HTTP protocol in an application. It means that it is possible
to build an application which can also answer to a standard browser like
Internet Explorer or Netscape Navigator. Since `AWS' provides support
client and server HTTP protocol, applications can communicate through
the HTTP channel. This give a way to build distributed applications,
*Note AWS.Client::.

An application using `AWS' can open many `HTTP' channels. Each channel
will use a specific port. For example, it is possible to embedded many
`HTTP' and/or many `HTTPS' channels in the same application.

3.2.1 Building an AWS server
----------------------------

To build a server you must:

  1. declare the HTTP Web Server 

          WS  : AWS.Server.HTTP;

  2. Start the server 

     You need to start the server before using it. This is done by
     calling `AWS.Server.Start' (*Note AWS.Server::.)

          procedure Start
            (Web_Server                : in out HTTP;
             Name                      : in     String;
             Callback                  : in     Response.Callback;
             Max_Connection            : in     Positive     := Def_Max_Connect;
             Admin_URI                 : in     String       := Def_Admin_URI;
             Port                      : in     Positive     := Def_Port;
             Security                  : in     Boolean      := False;
             Session                   : in     Boolean      := False;
             Case_Sensitive_Parameters : in     Boolean      := True;
             Upload_Directory          : in     String       := Def_Upload_Dir);
          -  Start the Web server. It initialize the Max_Connection connections
          -  lines. Name is just a string used to identify the server. This is used
          -  for example in the administrative page. Admin_URI must be set to enable
          -  the administrative status page. Callback is the procedure to call for
          -  each resource requested. Port is the Web server port. If Security is
          -  set to True the server will use an HTTPS/SSL connection. If Session is
          -  set to True the server will be able to get a status for each client
          -  connected. A session ID is used for that, on the client side it is a
          -  cookie. Case_Sensitive_Parameters if set to False it means that the CGI
          -  parameters name will be handled without case sensitivity. Upload
          -  directory point to a directory where uploaded files will be stored.

     `Start' takes many parameters:

    Web_Server
          this is the Web server to start.

    Name
          This is a string to identify the server. This name will be
          used for example in the administrative status page.

    Callback
          This is the procedure to call for each requested resources.
          In this procedure you must handle all the possible URI that
          you want to support.  (see below).

    Max_Connection
          This is the maximum number of simultaneous connections. It
          means that Max_Connection client's browsers can gets answer
          at the same time. This parameter must be changed to match
          your needs. A medium Web server will certainly need something
          like 20 or 30 simultaneous connections.

    Admin_URI
          This is a special URI recognized internally by the server. If
          this URI is requested the server will return the
          administrative page. This page is built using a specific
          template page (default is `aws_status.thtml') *note Status
          page::.

          The administrative page returns many information about the
          server. It is possible to configure the server via two
          configuration files *Note Configuration options::.

    Port
          This is the port to use for the Web server. You can use any
          free port on your computer. Note that on some OS specific
          range could be reserved or needs specials privileges (port 80
          on Linux for example).

    Security
          If Security is set to True the server will use an HTTPS/SSL
          connection. This part uses the `OpenSSL' library.

    Session
          If Session is set to true the server will keep a session ID
          for each client. The client will be able to save and get
          variables associated with this session ID.

    Case_Sensitive_Parameters
          If set to True the CGI name parameters will be handled
          without using the case.


     Note that there is other `Start' routines which support other
     features.  For example there is a `Start' routine which use a
     dispatcher routine instead of the simple callback procedure. *note
     AWS.Server::. And there is also the version using a
     `Config.Object' which is the most generic one.

  3. provides a callback procedure

     The callback procedure has the following prototype:

          function Service (Request : in AWS.Status.Data) return AWS.Response.Data;

     This procedure receive the request status. It is possible to
     retrieve information about the request through the `AWS.Status' API
     (*Note AWS.Status::.).

     For example, to know what URI has been asked:

          URI : constant String := AWS.Status.URI (Request);

          if URI = "/whatever" then
             ...
          end if;

     Then this function should return an answer using one of the
     constructors in `AWS.Response' (*Note AWS.Response::.). For
     example, to return an `HTML' message:

          AWS.Response.Build (Content_Type => "text/html",
                              Message_Body => "<p>just a demo");

     It is also possible to return a file. For example, here is the way
     to return a PNG image:

          AWS.Response.File (Content_Type => "image/png",
                             Filename     => "adains.png");


Note that the main procedure should exit only when the server is
terminated.  For this you can use the `AWS.Server.Wait' service.

A better solution is to use a template engine like Templates_Parser to
build the `HTML' Web Server answer. Templates_Parser module is
distributed with this version of AWS.

3.2.2 Callback procedure
------------------------

The callback procedure is the user's code that will be called by the AWS
component to get the right answer for the requested resource. In fact
AWS just open the HTTP message, parsing the HTTP header and it builds
an object of type `AWS.Status.Data'. At this point it calls the user's
callback procedure, passing the object. The callback procedure must
returns the right response for the requested resources. Now AWS will
just build up the HTTP response message and send it back to user's
browser.

But what is the resource ?  

Indeed in a standard Web development a resource is either a static
object - an `HTML' page, an `XML' or `XSL' document - or a `CGI'
script. With `AWS' a resource is just a string to identify the
resource, it does not represent the name of a static object or `CGI'
script.

So this string is just an internal representation for the resource. The
callback procedure must be implemented to handle each internal resource
and return the right response.

Let's have a small example. For example we want to build a Web server
that will answer "Hello World" if we ask for the internal resource
/hello, and must answer "Hum..." otherwise.

     with AWS.Response;
     with AWS.Server;
     with AWS.Status;

     procedure Hello_World is

        WS : AWS.Server.HTTP;

        function HW_CB (Request : in AWS.Status.Data)
          return AWS.Response.Data
        is
           URI : constant String := AWS.Status.URI (Request);
        begin
           if URI = "/hello" then
              return AWS.Response.Build ("text/html", "<p>Hello world !");
           else
              return AWS.Response.Build ("text/html", "<p>Hum...");
           end if;
        end HW_CB;

     begin
        AWS.Server.Start
           (WS, "Hello World", Callback => HW_CB'Unrestricted_Access);
        delay 30.0;
     end Hello_World;

Now of course the resource internal name can represent a file on disk.
It is not mandatory but it is possible. For example it is perfectly
possible to build with `AWS' a simple page server.

As an example, let's build a simple page server. This server will
returns files in the current directory. Resources internal name
represent an `HTML' page or a `GIF' or `PNG' image for example. This
server will return a 404 message (Web Page Not Found) if the file does
not exist. Here is the callback procedure that implements such simple
page server:

     function Get (Request : in AWS.Status.Data) return AWS.Response.Data is
        URI      : constant String := AWS.Status.URI (Request);
        Filename : constant String := URI (2 .. URI'Last);
     begin
        if Utils.Is_Regular_File (Filename) then
           return AWS.Response.File
             (Content_Type => AWS.MIME.Content_Type (Filename),
              Filename     => Filename);

        else
           return AWS.Response.Acknowledge
             (Messages.S404,
              "<p>Page '" & URI & "' Not found.");
        end if;
     end Get;

3.2.3 Form parameters
---------------------

Form parameters are stored into a table of key/value pair. The key is
the form input tag name and the value is the content of the input field
as filled by the user.

     Enter your name

     <FORM METHOD=GET ACTION=/get-form>"
     <INPUT TYPE=TEXT NAME=name VALUE="<default>" size=15>
     <INPUT TYPE=SUBMIT NAME=go VALUE="Ok">
     </FORM>

Note that as explained above *note Callback procedure::, the resource
described in `ACTION' is just an internal string representation for the
resource.

In this example there is two form parameters:

name
     The value is the content of this text field as filled by the
     client.

go
     The value is "Ok".

There is many functions (in `AWS.Parameters') to retrieve the tag name
or value and the number of parameters. Here are some examples:

     function Service (Request : in AWS.Status.Data)
       return AWS.Response.Data
     is
        P : constant AWS.Parameters.List := AWS.Status.Parameters (Request);
        ...

`AWS.Parameters.Get (P, "name")'
     Returns the value for parameter named name

`AWS.Parameters.Get_Name (P, 1)'
     Returns the string "name".

`AWS.Parameters.Get (P, 1)'
     Returns the value for parameter named name

`AWS.Parameters.Get (P, "go")'
     Returns the string "Ok".

`AWS.Parameters.Get_Name (P, 2)'
     Returns the string "go".

`AWS.Parameters.Get (P, 2)'
     Returns the string "Ok".

`Request' is the `AWS' current connection status passed to the callback
procedure. And `P' is the parameters list retrieved from the connection
status data. For a discussion about the callback procedure *Note
Building an AWS server::.

3.2.4 Distribution of an AWS server
-----------------------------------

The directory containing the server program must contain the following
files if you plan to use a status page *Note Status page::.

`aws_status.thtml'
     The template `HTML' file for the `AWS' status page.

`aws_logo.png'
     The `AWS' logo displayed on the status page.

`aws_up.png'
     The `AWS' hotplug table up arrow.

`aws_down.png'
     The `AWS' hotplug table down arrow.


Note that these filenames are the current `AWS' default. But it is
possible to change those defaults using the configuration files *note
Configuration options::.

3.3 Building answers
====================

We have already seen, in simple examples, how to build basic answers
using `AWS.Response' API. In this section we present all ways to build
answers from basic support to the more advanced support like the
compressed memory stream response.

3.3.1 Redirection
-----------------

A redirection is a way to redirect the client's browser to another URL.
Client's won't notice that a redirection has occurs. As soon as the
browser has received the response from the server it will retrieve the
page as pointed by the redirection.

     return Response.URL (Location => "/use-this-one");

3.3.2 New location for a page
-----------------------------

User will receive a Web page saying that this page has moved and
eventually pointing to the new location.

     return Response.Moved
       (Location => "/use-this-one";
        Message  => "This page has moved, please update your reference");

3.3.3 Authentication required
-----------------------------

For protected pages you need to ask user to enter a password.  *note
Authentication::.

3.3.4 Sending back an error message
-----------------------------------

`Acknowledge' can be used to send back error messages. There is many
kind of status code, see `Message.Status_Code' definition. Together
with the status code it is possible to pass textual error message in
`Message_Body' parameter.

     return Response.Acknowledge
       (Status_Code  => Messages.S503,
        Message_Body => "Can't connect to the database, please retry later.",
        Content_Type => MIME.Text_Plain);

3.3.5 Response from a string
----------------------------

This is the simplest way to build a response object. There is two
constructors in `AWS.Response', one based on a standard string and one
for Unbounded_String.

     return Response.Build (MIME.Text_HTML, "My answer");

The Build routine takes also a status code parameter to handle errors.
By default this code is `Messages.S200' which is the standard HTTP
status (no error encountered). The other parameter can be used to
control caches. *note AWS.Response::.

3.3.6 Response from a Stream_Element_Array
------------------------------------------

This is exactly as above but the Build routine takes a
`Stream_Element_Array' instead of a string.

3.3.7 Response from a file
--------------------------

To build a `File' response there is a single constructor named `File'.
This routine is very similar to the one above except that we specify a
filename as the response.

     return Response.File (MIME.Text_HTML, "index.html");

Again there parameters to control the status code and cache. No check
on the filename is done at this point, so if `index.html' does not exit
no exception is raised. The server is responsible to check for the file
and to properly send back the 404 message if necessary.

Note that this routine takes an optional parameter named `Once' that is
to be used for temporary files created on the server side for the
client. With `Once' set to `True' the file will be deleted by the
server after sending it (this includes the case where the download is
suspended).

3.3.8 Response from a stream
----------------------------

Sometimes it is not possible (or convenient) to build the response in
memory as a string object for example. Streams can be used to
workaround this. The constructor for such response is again very
similar to the ones above except that instead of the data we pass an
handle to a `Resources.Streams.Stream_Type' object.

The first step is to build the stream object. This is done by deriving
a new type from `Resources.Streams.Stream_Type' and implementing three
abstract procedures.

`Read'
     Must return the next chunk of data from the stream. Note that
     initialization if needed are to be done there during the first
     call to read.

`End_Of_File'
     Must return True when there is no more data on the stream.

`Close'
     Must close the stream and for example release all memory used by
     the implementation.

The second step is to build the response object:

     type SQL_Stream is new Resources.Streams.Stream_Type;

     Stream_Object : SQL_Stream;

     procedure Read (...) is ...
     function End_Of_File (...) return Boolean is ...
     procedure Close (...) is

     ...

     return Response.Stream (MIME.Text_HTML, Stream_Object);

Note that in some cases it is needed to create a file containing the
data for the client (for example a tar.gz or a zip archive). But there
is no way to properly remove this file from the file system as we
really don't know when the upload is terminated when using the
`AWS.Response.File' constructor. To solve this problem it is possible
to use a stream as the procedure `Close' is called by the server when
all data have been read. In this procedure it is trivial to do the
necessary clean-up.

3.3.9 Response from a on-disk stream
------------------------------------

An ready-to-use implementation of the stream API described above where
the stream content is read from an on-disk file.

3.3.10 Response from a on-disk once stream
------------------------------------------

An ready-to-use implementation of the stream API described above where
the stream content is read from an on-disk file. When the transfer is
completed the file is removed from the file system.

3.3.11 Response from a memory stream
------------------------------------

This is an implementation of the standard stream support described
above. In this case the stream is in memory and built by adding data to
it.

To create a memory stream just declare an object of type
`AWS.Resources.Streams.Memory.Stream_Type'. When created, this memory
stream is empty, using the `Streams.Memory.Append' routines it is
possible to add chunk of data to it. It is of course possible to call
`Append' as many times as needed. When done just return this object to
the server.

     Data : AWS.Resources.Streams.Memory.Stream_Type;

     Append (Data, Translator.To_Stream_Element_Array ("First chunk"));
     Append (Data, Translator.To_Stream_Element_Array ("Second chunk..."));

     ...

     return Response.Stream (MIME.Text_HTML, Data);

Note that you do not have to take care of releasing the allocated
memory, the default `Close' routine will do just that.

3.3.12 Response from a compressed memory stream
-----------------------------------------------

This is a slight variant of the standard memory stream described above.
In this case the stream object must be declared as a
`AWS.Resources.Streams.Memory.ZLib.Stream_Type'.

The ZLib stream object must be initialized to enable the compression
and select the right parameters. This is done using the
`AWS.Resources.Streams.Memory.ZLib.Deflate_Initialize' routine which
takes many parameters to select the right options for the compression
algorithm, all of them have good default values. When initialized the
compressed stream object is used exactly as a standard stream.

     Data : AWS.Resources.Streams.Memory.ZLib.Stream_Type;

     Deflate_Initialize (Data);

     Append (Data, Translator.To_Stream_Element_Array ("First chunk"));
     Append (Data, Translator.To_Stream_Element_Array ("Second chunk..."));

     ...

     return Response.Stream (MIME.Text_HTML, Data);

Note that there is the reverse implementation to decompress a stream.
*note AWS.Resources.Streams.Memory.ZLib::. It's usage is identical.

3.3.13 Split page
-----------------

`AWS' has a specific high level service to split a large response into
a set of pages. For more information *note Split pages::.

3.3.14 Response a from pipe stream
----------------------------------

The response sent to the server is read from the output of an external
application. This kind of stream can be used to avoid writing a
temporary file into the hard disk. For example it is possible to return
an archive created with the `tar' tool without writting the
intermediate tar achive on the disk.

3.4 Configuration options
=========================

To configure an `AWS' server it is possible to use a configuration
object. This object can be set using the `AWS.Config.Set' API or
initialized using a configuration file.

Configuration files are a way to configure the server without
recompiling it. Each application can be configured using two
configurations files:

`aws.ini'
     This file is parsed first and corresponds to the configuration for
     all AWS server runs in the same directory.

`<program_name>.ini'
     This file is parsed after `aws.ini'. It is possible with this
     initialization file to have specific settings for some servers.
     `program_name.ini' is looked first in the application's directory
     and then in the current working directory. This is only supported
     on platforms where `Ada.Command_Line' is implemented. So, on
     VxWorks only `aws.ini' is parsed.


Furthermore, it is possible to read a specific configuration file using
the `AWS.Config.Ini.Read' routine. *note AWS.Config.Ini::.

Current supported options are:

`Accept_Queue_Size (positive)'
     This is the size of the queue for the incoming requests. Higher
     this value will be and less "connection refused" will be reported
     to the client. The default value is 64.

`Admin_Password (string)'
     This is the password used to call the administrative page. The
     password can be generated with `aws_password' (the module name
     must be ADMIN)

          $ aws_password admin <password>

`Admin_URI (string)'
     This is the URI to call the administrative page. This can be used
     when calling `AWS.Server.Start'. The default is `'.

`Certificate (string)'
     Set the certificate file to be used with the secure servers. The
     default is `cert.pem'. A single certificate or a certificate chain
     is supported. The certificates must be in `PEM' format and the
     chain must be sorted starting with the subject's certificate,
     followed by intermediate CA certificates if applicable and ending
     at the highest level (root) CA certificate. If the file contains
     only a single certificate, it can be followed by a private key. In
     this case the Key parameter (see below) must empty.

`Case_Sensitive_Parameters (boolean)'
     If set to `True' the `HTTP' parameters are case sensitive. The
     default value is TRUE.

`Check_URL_Validity (boolean)'
     Server have to check URI for validity. For example it checks that
     an URL does not reference a resource above the Web root. The
     default is TRUE.

`Cleaner_Wait_For_Client_Timeout (duration)'
     Number of seconds to timeout on waiting for a client request. This
     is a timeout for regular cleaning task. The default is 80.0
     seconds.

`Cleaner_Client_Header_Timeout (duration)'
     Number of seconds to timeout on waiting for client header. This is
     a timeout for regular cleaning task. The default is 7.0 seconds.

`Cleaner_Client_Data_Timeout (duration)'
     Number of seconds to timeout on waiting for client message body.
     This is a timeout for regular cleaning task. The default is
     28800.0 seconds.

`Cleaner_Server_Response_Timeout (duration)'
     Number of seconds to timeout on waiting for client to accept
     answer. This is a timeout for regular cleaning task. The default is
     28800.0 seconds.

`Directory_Browser_Page (string)'
     Specify the filename for the directory browser template page. The
     default value is `aws_directory.thtml'.

`Down_Image (string).'
     The name of the down arrow image to use in the status page. The
     default is `aws_down.png'.

`Error_Log_Filename_Prefix (string)'
     This is to set the filename prefix for the log file. By default the
     log filename prefix is the program name (without extension)
     followed by "_error".

`Error_Log_Split_Mode [None/Each_Run/Daily/Monthly]'
     It indicates how to split the error logs. Each_Run means that a
     new log file is used each time the process is started. Daily and
     Monthly will use a new log file each day or month. The default is
     NONE.

`Exchange_Certificate (boolean)'
     If set to True it means that the client will be asked to send its
     certificate to the server. The default value is FALSE.

`Force_Wait_For_Client_Timeout (duration)'
     Number of seconds to timeout on waiting for a client request. This
     is a timeout for urgent request when resources are missing. The
     default is 2.0 seconds.

`Force_Client_Header_Timeout (duration)'
     Number of seconds to timeout on waiting for client header. This is
     a timeout for urgent request when resources are missing. The
     default is 2.0 seconds.

`Force_Client_Data_Timeout (duration)'
     Number of seconds to timeout on waiting for client message body.
     This is a timeout for urgent request when resources are missing.
     The default is 10800.0 seconds.

`Force_Server_Response_Timeout (duration)'
     Number of seconds to timeout on waiting for client to accept
     answer. This is a timeout for urgent request when resources are
     missing. The default is 10800.0 seconds.

`Free_Slots_Keep_Alive_Limit (positive)'
     This is the minimum number of remaining free slots to enable
     keep-alive HTTP connections. For heavy-loaded HTTP servers, the
     Max_Connection parameter should be big enough, and
     Free_Slots_Keep_Alive_Limit should be about 1-10% of the
     Max_Connection parameter depending on the duration of the average
     server response. Longer is the average time to send back a
     response bigger Free_Slots_Keep_Alive_Limit should be.  The
     default is 1.

`Hotplug_Port (positive)'
     This is the hotplug communication port needed to register and
     un-register an hotplug module. The default value is 8888.

`Key (string)'
     Set the RSA key file to be used with the secure servers. The
     default file is `'.

`Line_Stack_Size (positive)'
     The HTTP lines stack size. The stack size must be adjusted for each
     applications depending on the use of the stack done by the callback
     procedures. The default is 1376256.

`Log_Extended_Fields (string list)'
     Comma separated list of the extended log field names. If this
     parameter is empty, the HTTP log would be in the apache
     compartible format, otherwise log file would be in Extended
     format. For more information *note Server Log::.

`Log_File_Directory (string)'
     This is to set the directory where log file must be written. This
     parameter will be used automatically by `AWS.Log' if logging
     facility is enabled. By default log files are written in the
     current directory. The default is `./'.

`Log_Filename_Prefix (string)'
     This is to set the filename prefix for the log file. By default the
     log filename prefix is the program name (without extension).

`Log_Split_Mode [None/Each_Run/Daily/Monthly]'
     It indicates how to split the logs. Each_Run means that a new log
     file is used each time the process is started. Daily and Monthly
     will use a new log file each day or month. The default is NONE.

`Logo_Image (string).'
     The name of the logo image to use in the status page. The default
     is `aws_logo.png'.

`Max_Concurrent_Download (positive)'
     Control the maximum number of parallel downloads accepted by the
     download manager. The default value is 25.

`Max_Connection (positive)'
     This is the maximum number of simultaneous connections for the
     server. This can be used when calling the `AWS.Server.Start'. The
     default is 5.

     Note that the total number of threads used by a server is:

          N = <main server thread> + <max connections> [+ <session>]

            Note: [...] means optional value
                  Add 1 only if the session feature is activated. This is
                  due to the session cleaner task.

`MIME_Types (string)'
     The name of the file containing the MIME types associations. The
     default file name is `aws.mime'.

`Receive_Timeout (duration)'
     Number of seconds to timeout when receiving chunk of data. The
     default is 30.0 seconds.

`Reuse_Address (boolean)'
     Set the socket reuse address policy. If set to True the server
     will be able to bind to a socket that has just been released
     without the need of waiting. Enabling this feature is not secure
     and should probably used only for debugging purpose. The default
     is FALSE.

`Security_Mode (string)'
     Set the security mode to use for the secure connections. The
     default mode is "SSLv23". *note AWS.Net.SSL::.

`Send_Buffer_Size (positive)'
     This is the socket internal buffer used for sending data to the
     clients. The default is 32768.

`Send_Timeout (duration)'
     Number of seconds to timeout when sending chunk of data. The
     default is 40.0 seconds.

`Server_Host (string)'
     The name of the host machine. This can be used if a computer has
     more than one IP address, it is possible to have two servers at
     the same port on the same machine, both being binded on different
     IP addresses.

`Server_Name (string)'
     The name of the server. This can be used when calling
     `AWS.Server.Start'. The default is "AWS Module".

`Server_Port (integer)'
     The port where server will wait for incoming connections requests.
     This can be used when calling `AWS.Server.Start'. The default is
     8080.

`Session (boolean)'
     Whether the session support must be activated or not. The default
     is FALSE.

`Session_Name (string)'
     The name of the cookie session. This can be used to support
     sessions for multiple servers embedded into the same executable.
     The default is "AWS".

`Session_Lifetime (duration)'
     Number of seconds to keep session information. After this period a
     session is obsoleted and will be removed at next cleanup. The
     default is 600.0 seconds.

`Session_Cleanup_Interval (duration)'
     Number of seconds between each run of the session cleanup task.
     This task will remove all session data that have been obsoleted.
     The default is 300.0 seconds.

`Status_Page (string)'
     The name of the status page to used. The default is
     `aws_status.thtml'.

`Transient_Cleanup_Interval (positive)'
     Specify the number of seconds between each run of the cleaner task
     to remove transient pages. The default value is 180.0 seconds.

`Transient_Lifetime'
     Specify the number of seconds to keep a transient page. After this
     period the transient page is obsoleted and will be removed during
     next cleanup. The default value is 300.0 seconds.

`Up_Image (string)'
     The name of the up arrow image to use in the status page. The
     default is `aws_up.png'.

`Upload_Directory (string)'
     This is to set the directory where upload files must be stored. By
     default uploaded files are written in the current directory. The
     default is `'.

`WWW_Root (string)'
     This option sets the Web Server root directory. All Web resources
     are referenced from this root directory. The default value is "./".

Each option value can be retrieved using the `AWS.Config' unit or set
using `AWS.Config.Set'.

For example to build a server where the port and the maximum number of
connection can be changed via a configuration file (either `aws.ini' or
`<program_name>.ini'):

     WS   : AWS.Server.HTTP;

     Conf : constant AWS.Config.Object := AWS.Config.Get_Current;

     Server.Start (WS, Service'Access, Conf);

3.5 Session handling
====================

`AWS' provides a way to keep session data while users are browsing. It
works by creating transparently a session ID where it is possible to
insert, delete and retrieve session data using a standard Ada API
(*Note AWS.Session::.). Session data are key/value pair each of them
being strings. These sessions data are kept on the server, for client
side state management see *Note HTTP state management::.

   * First you declare and start an HTTP channel with session enabled:

          WS : AWS.Server.HTTP;

          Server.Start (WS,
                        Port     => 1234,
                        Callback => Service'Access,
                        Session  => True);

     Here we have built an HTTP channel with a maximum of 3 simultaneous
     connections using the port 1234. A session ID will be created and
     sent inside a cookie to the client's browser at the first request.
     This session ID will be sent back to the server each time the
     client will ask for a resource to the server.

   * Next, in the Service callback procedure that you have provided you
     must retrieve the Session ID. As we have seen, the callback
     procedure has the following prototype:

          function Service (Request : in AWS.Status.Data) return AWS.Response.Data;

     The Session ID is kept in the Request object and can be retrieved
     using:

          Session_ID  : constant AWS.Session.ID := AWS.Status.Session (Request);

   * From there it is quite easy to get or set some session data using
     the provided API. For example:

          declare
             C : Integer;
          begin
             C := AWS.Session.Get (Session_ID, "counter");
             C := C + 1;
             AWS.Session.Set (Session_ID, "counter", C);
          end;

     This example first get the value (as an Integer) for session data
     whose key is "`counter'", increment this counter and then set it
     back to the new value.


It is also possible to save and restore all session data. It means that
the server can be shutdown and launched some time after and all client
data are restored as they were at shutdown time. Client will just see
nothing. With this feature it is possible to shutdown a server to
update its look or because a bug has been fixed for example. It is then
possible to restart it keeping the complete Web server context.

3.6 HTTP state management
=========================

`AWS' provides a full implementation of RFC 2109 via the `AWS.Cookie'
package. Using this package you set, get and expire client-side HTTP
cookies.

First we set a cookie:

     declare
        Content : AWS.Response.Data;
     begin
        AWS.Cookie.Set (Content,
                        Key      => "hello",
                        Value    => "world",
                        Max_Age  => 86400);
     end;

Here we set the cookie `hello' with the value `world', and we tell the
client to expire the cookie 86400 seconds into the future.

Getting the cookie value back is equally simple:

     declare
        Request : AWS.Status.Data
        --  Assume that this object contain an actual HTTP request.
     begin
        Put_Line (AWS.Cookie.Get (Request, "hello"));
        --  Output 'world'
     end;

Had the cookie `hello' not existed, an empty `String' would've been
returned.

In some cases it might be of value to know if a given cookie exists,
and for that we have the `Exists' function available.

     declare
        Request : AWS.Status.Data
        --  Assume that this object contain an actual HTTP request
     begin
        if AWS.Cookie.Exists ("hello") then
           Put_Line ("The 'hello' cookie exists!");
        end if;
     end;

   Note that `Exists' doesn't care if the cookie contains an actual
value or not. If a cookie with no value exists, `Exists' will return
`True'.

And finally we might wish to tell the client to expire a cookie:

     declare
        Content : AWS.Response.Data;
     begin
        AWS.Cookie.Expire (Content,
                           Key  => "hello");
     end;

The Cookie package provide `Get' functions and `Set' procedures for
`String', `Integer', `Float' and `Boolean' types, but since cookies are
inherently strings, it's important to understand what happens when the
cookie `String' value can't be converted properly to either `Integer',
`Float' or `Boolean'.

So if either conversion fails or the cookie simply doesn't exist, the
following happens:

   * For `Integer', the value 0 is returned

   * For `Float', the value 0.0 is returned.

   * For `Boolean', the value `False' is returned. Note that only the
     string "True" is `True'. Everything else is `False'.


   For more information, *Note AWS.Cookie::.

3.7 Authentication
==================

`AWS' supports Basic and Digest authentication. The authentication
request can be sent at any time from the callback procedure. For this
the `AWS.Response.Authenticate' message must be returned.

The authentication process is as follow:

  1. Send authentication request

     From the callback routine return an authentication request when
     needed.

          function Service (Request : in Status.Data) return Response.Data is
             URI  : constant String := Status.URI (Request);
             User : constant String := Status.Authorization_Name (Request);
          begin
             -  URI starting with "/prot/" are protected
             if URI (URI'First .. URI'First + 5) = "/prot/"
               and then User = ""
             then
                return Response.Authenticate ("AWS", Response.Basic);

     The first parameter is the Realm, it is just a string that will be
     displayed (on the authentication dialog box) by the browser to
     indicate for which resource the authentication is needed.

  2. Check authentication

     When an authentication as been done the callback's request data
     contain the user and password. Checks the values against an ACL for
     each protected resources.

          function Protected_Service
            (Request : in AWS.Status.Data)
             return AWS.Response.Data
          is
             User : constant String := Status.Authorization_Name (Request);
             Pwd  : constant String := Status.Authorization_Password (Request);
          begin
             if User = "xyz" and then Pwd = "azerty" then
                return ...;


Note that the Basic authentication is not secure at all. The password
is sent unencoded by the browser to the server. If security is an issue
it is better to use the Digest authentication and/or an SSL server.

3.8 File upload
===============

File upload is the way to send a file from the client to the server. To
enable file upload on the client side the Web page must contain a FORM
with an INPUT tag of type FILE. The FORM must also contain the enctype
attribute set to multipart/form-data.

     <FORM enctype="multipart/form-data" ACTION=/whatever METHOD=POST>
     File to process: <INPUT NAME=filename TYPE=FILE>
     <INPUT TYPE=SUBMIT NAME=go VALUE="Send File">
     </FORM>

On the server side, `AWS' will retrieve the file and put it into the
upload directory. `AWS' add a prefix to the file to ensure that the
filename will be unique on the server side. The upload directory can be
changed using the configuration options. *Note Configuration options::.

The uploaded files are removed after the user's callback. This is done
for security reasons, if files were not removed it would be possible to
fill the server hard disk by uploading large files to the server. This
means that uploaded files must be specifically handled by the users by
either copying or renaming them.

`AWS' will also setup the form parameters as usual. In the above example
there is two parameters (*Note Form parameters::.)

filename
     This variable contains two values, one with the client side name
     and one with the server side name.

    First value : Parameters.Get (P, "filename")
          The value is the full pathname of the file on the server.
          (i.e. the upload directory catenated with the prefix and
          filename).

    Second value : Parameters.Get (P, "filename", 2)
          The value is the simple filename (no path information) of the
          file on the client side.

go
     The value is "Send File"

3.9 Communication
=================

This API is used to do communication between programs using the HTTP
GET protocol. It is a very simple API not to be compared with `GLADE'
or `SOAP'. This communication facility is to be used for simple request
or when a light communication support is needed. For more complex
communications or to achieve inter-operability with other modules it is
certainly a good idea to have a look at the `AWS/SOAP' support, *note
SOAP::.

In a communication there is a Client and a Server. Here is what is to be
done on both sides to have programs talking together.

3.9.1 Communication - client side
---------------------------------

On the client side it is quite simple. You just have to send a message
using `AWS.Communication.Client.Send_Message'.

     function Send_Message
       (Server     : in String;
        Port       : in Positive;
        Name       : in String;
        Parameters : in Parameter_Set := Null_Parameter_Set)
        return Response.Data;

The message is sent to the specified server using the given port. A
message is composed of a name which is a string and a set of
parameters. There is a parameter set constructor in
`AWS.Communication'. This function return a response as for any
callback procedure.

3.9.2 Communication - server side
---------------------------------

On the server side things are a bit more complex but not that
difficult. You must instantiate the `AWS.Communication.Server' generic
package by providing a callback procedure. This callback procedure will
must handle all kind of message that a client will send.

During instantiation you must also pass a context for the communication
server. This context will be passed back to the callback procedure.

     generic

        type T (<>) is limited private;
        type T_Access is access T;

        with function Callback
          (Server     : in String;
           Name       : in String;
           Context    : in T_Access;
           Parameters : in Parameter_Set := Null_Parameter_Set)
           return Response.Data;

     package AWS.Communication.Server is
        ...

     A complete example can be found in the demos directory. Look for
     `com_1.adb' and `com_2.adb'.

Note that this communication API is used by the Hotplug module facility
*Note Hotplug module::.

3.10 Hotplug module
===================

An Hotplug module is a module that can by dynamically binded to a
running server. It is a Web server and the development process is very
similar to what we have seen until now *Note Building an AWS server::.
The Hotplug module will register itself into a Web server by sending a
message using the communication API. The Hotplug module send to the
server a regular expression and an URL. The main server will redirect
all URL matching the regular expression to the Hotplug module.

Note that the main server will redirect the URL to the first matching
regular expression.

3.10.1 Hotplug module - server activation
-----------------------------------------

The first step is to properly create the main server hotplug module
registration file. This file must list all hotplug modules that can
register into the main server. Each line have the following format:

     hotplug_module_name:password:server:port

hotplug_module_name
     The name of the hotplug module. You can choose any name you want.
     This name will be use during the registration process and to
     generate the password.

password
     The MD5 password, see below.

server
     The name of the server where the redirection will be made. This is
     for security reasons, main server will not permit to redirect
     requests to any other server.

port
     The port to use for the redirection on `server'.


You must create a password for each hotplug modules. The generated
password depends on the hotplug module name. A tool named
`aws_password' is provided with `AWS' to generate such password. Usage
is simple:

     $ aws_password <hotplug_module_name> <password>

Then, after starting the main server you must activate the Hotplug
feature:

     AWS.Server.Hotplug.Activate (WS'Unchecked_Access, 2222, "hotplug_conf.ini");

`hotplug_conf.ini' is the hotplug module registration file described
above.

3.10.2 Hotplug module - creation
--------------------------------

Here is how to create an Hotplug module:

  1. First you create a standard Web server *Note Building an AWS
     server::.

          WS : AWS.Server.HTTP
            (3, 1235, False, Hotplug_CB.Hotplug'Access, False);

     Here we have a server listening to the port 1235. This server can
     be used alone if needed as any Server developed with AWS.

  2. Then you register the Hotplug module to the main server *Note
     AWS.Client.Hotplug::.

          Response := AWS.Client.Hotplug.Register
            (Name     => "Hotplug_Module_Demo",
             Password => "my_password",
             Server   => "http://dieppe:2222",
             Regexp   => ".*AWS.*",
             URL      => "http://omsk:1235/");

     The hotplug module `Hotplug_Module_Demo' must have been declared
     on the main server, the password and redirection must have been
     properly recorded too for security reasons *note Hotplug module -
     server activation::.  This command register `Hotplug_Module_Demo'
     into the server running on the machine `dieppe' and ask it to
     redirect all `URL' containing `AWS' to the server running on
     machine `omsk' on port `1235'.

  3. When the Hotplug module is stopped, you must unregister it

          Response := AWS.Client.Hotplug.Unregister
            (Name     => "Hotplug_Module_Demo",
             Password => "my_password",
             Server   => "http://dieppe:2222",
             Regexp   => ".*AWS.*");

     Here we ask to unregister `Hotplug_Module_Demo' from server
     `dieppe'. As for the registration process a proper password must
     be specified *note Hotplug module - server activation::.


     A complete example can be found in the demos directory. Look for
     `main.adb' and `hotplug.adb'.

3.11 Server Push
================

Server Push is a feature that let the Web Server send continuously data
to client's  Web Browser or client applications. The client does not
have to reload at periodic time (which is what is called client pull)
to have the data updated, each time the server send a piece of data it
gets displayed on the client.

To build a push server you need to build an instance of the
`AWS.Server.Push' package. This package takes a set of formal
parameters. Here are the step-by-step instructions to build a Push
Server:

  1. The data to be sent

     First you must create a type that will contains the data to be
     sent to client's browser except if it is a standard Ada type. See
     `Client_Output_Type' formal parameter.

  2. The data that will be streamed

     This is the representation of the data that will be sent to
     client's browser. This will be either a `String' for Web pages or
     `Stream_Element_Array' for binary data like pictures. See
     `Stream_Output_Type' formal parameter.

  3. The context

     It is often nice to be able to configure each client with different
     parameters if needed. This can be achieved with the Context data
     type that will be passed as parameter of the conversion function
     described below. See `Client_Environment' formal parameter.

  4. Provides a function to convert from the data type to be sent to
     the data that will be streamed.

     This is a function that will transform the data described on point
     1 above to the form described on point 2 above. See
     `To_Stream_Output' formal parameter.

  5. Build the Push Server

     To do so you just need to instantiate `AWS.Server.Push' with the
     above declarations.

  6. Registering new clients

     In the standard `AWS' procedure callback it is possible to
     register a client if requested. This is done by calling
     `AWS.Server.Push.Register'. It is possible to unregister a client
     using `AWS.Server.Push.Unregister'. Each client must be identified
     with a unique client ID. After registering a new client from the
     callback procedure you must return the `AWS.Response.Socket_Taken'
     message. This is very important, it tells the server to not close
     this socket.

  7. Sending the data

     At this point it is possible to send data to clients. To do so two
     routines are available.

    `AWS.Server.Push.Send_To'
          To send a piece of data to a specific client identified by
          its client ID.

    `AWS.Server.Push.Send'
          To send a piece of data to all clients registered on this
          server.



Very large Internet applications should use this feature carefully. A
push server keeps a socket reserved for each registered clients and the
number of available sockets per process is limited by the OS.

3.12 Working with Server sockets
================================

With `AWS' is is possible to take out a socket from the server and give
it back later. This feature must be used carefully but it gives a lot
of flexibility. As the socket is taken away, the connection line (or
slot) is released, `AWS' can then use it to handle other requests.

This can be used to better support heavy loaded servers when some
requests need a long time to complete. Long time here means longer than
most of the other requests which should be mostly interractives for a
Web server. Of course in such a case a keep-alive connection is kept
open.

The usage in such a case is to take out the socket and put it in a
waiting line. This releases the connection for the server. When the
data to prepare the answer is ready you give back the socket to the
server.

   * Take a socket from the server

     This first step is done form the callback function. A user instead
     of replying immediatly decides to take away the socket from the
     server. The first step is to record the connection socket socket by
     calling `AWS.Status.Socket'. The second step is to tell the server
     to not release this socket by returning `AWS.Response.Socket_Taken'
     from the callback function. At this point the server will continue
     to serve other clients.

     Note that this feature is used by the server push implementation
     *note Server Push::.

   * Give back the socket to the server

     Calling `AWS.Sever.Give_Back_Socket' will register the socket for
     reuse. This socket will be placed into a spool, next time the
     server will check for incoming requests it will be picked up.


3.13 Server Log
===============

It is possible to have the server activity logged into the file
`<progname>-Y-M-D.log'. To activate the logging you must call the
`AWS.Server.Log.Start', and it is possible to stop logging by calling
`AWS.Server.Log.Stop'. Note that `AWS.Server.Log.Start' have a
parameter named `Auto_Flush' to control output buffering. This
parameter is False by default. If set to True, the log file will be
automatically flushed after each data. If the server logging is not
buffered, i.e. Auto_Flush is False, the log can still be flushed by
calling the `AWS.Server.Log.Flush' routine. *Note AWS.Log::, for more
information especially about the way rotating logs can be setup. Using
this feature it is possible to have automatic split of the log file
each day, each month or at every run. See `AWS.Log' spec. This is very
useful to avoid having very big log files.

The log format depend on Log_Extended_Fields configuration parameter.
If this parameter is empty, the HTTP log would have fixed apache
compartible format:

     <client IP> - <auth name> - [<date and time>] "<request>" <status code> <size>

     For example:

     100.99.12.1 -  - [22/Nov/2000:11:44:14] "GET /whatever HTTP/1.1" 200 1789

   If the extended fields list is not empty, the log file format would
have user defined fields set:

     #Version: 1.0
     #Date: 2006-01-09 00:00:01
     #Fields: date time c-ip cs-method cs-uri cs-version sc-status sc-bytes
     2006-01-09 00:34:23 100.99.12.1 GET /foo/bar.html HTTP/1.1 200 30

   Fields in the comma separated Log_Extended_Fields list could be:
date
     Date at which transaction completed

time
     Time at which transaction completed

time-taken
     Time taken for transaction to complete in seconds

c-ip
     Client side connected IP address

c-port
     Client side connected port

s-ip
     Server side connected IP address

s-port
     Server side connected port

cs-method
     HTTP request method

cs-username
     Client authentication username

cs-version
     Client supported HTTP version

cs-uri
     Request URI

cs-uri-stem
     Stem portion alone of URI (omitting query)

cs-uri-query
     Query portion alone of URI

sc-status
     Responce status code

sc-bytes
     Length of response message body

cs(<header>)
     Any header field name sent from client to server

sc(<header>)
     Any header field name sent from server to client

x-<appfield>
     Any application defined field name

`AWS' also support error log files. If activated every internal error
detected by `AWS' will gets logged into this special file.  Log file
for errors would be in simple apache compartible format.  See
`AWS.Server.Log.Start_Error' and `AWS.Server.Log.Stop_Error'.

For the full set of routines supporting the log facility *note
AWS.Server.Log:: .

3.14 Secure server
==================

It is not much difficult to use a secure server (`HTTPS') than a
standard one. Here we describe only what is specific to an HTTPS server.

Before going further you must check that `AWS' has been configured with
`SSL' support. *note Building::. You must also have installed the
`OpenSSL' library on your system. If this is done, you can continue
reading this section.

3.14.1 Initialization
---------------------

A server is configured as using the HTTPS protocol at the time it is
started. The only thing to do is to set the Start's Security parameter
to True. This will start a server and activate the `SSL' layer by
default. A secure server must use a valid certificate, the default one
is `cert.pem'. This certificate has been created by the openssl tool
and is valid until year 2008. Yet, this certificate has not been
signed. To build a secure server user's can rely on, you must have a
valid certificate signed by one of the Certificate Authorities.

The certificate to be used must be specified before starting the secure
server with `AWS.Server.Set_Security'.

     AWS.Server.Set_Security (WS, Certificate_Filename => "/xyz/aws.pem");

3.14.2 Creating a test certificate
----------------------------------

The goal here is not to replace the `OpenSSL' documentation but just to
present one way to create a certificate for an `HTTPS' test server.

The RSA key
          $ openssl genrsa -rand <filename> -out ca-key.pem

     Filename must be point to any file, this is used to initialized the
     random seed.

The Certificate
          $ openssl req -new -x509 -days 730 -key ca-key.pem -out ca-cert.pem

Create a single self contained file
          $ cat ca-key.pem ca-cert.pem > aws.pem


A this point you can use `aws.pem' with your server.

3.14.3 Protocol
---------------

There are different security options, either `SSLv2', `SSLv3' or
`TLSv1'. `SSLv2' and `SSLv3' are supported by most if not all Web
browsers. These are the default protocol used by `AWS'.

`TLSv1' is not supported at this point.

3.15 Unexpected exception handler
=================================

When `AWS' detects an internal problem, it calls a specific handler.
This handler can be used to log the error, send an alert message or
build the answer to be sent back to the client's browser.

Here is the spec for this handler:

     type Unexpected_Exception_Handler is access
       procedure (E      : in     Ada.Exceptions.Exception_Occurrence;
                  Log    : in out AWS.Log.Object;
                  Error  : in     Data;
                  Answer : in out Response.Data);

The handler can be called in two modes:

Non fatal error (Error.Fatal is False)
     In this case `AWS' will continue working without problem. A bug
     has been detected but it was not fatal to the thread (slot in
     `AWS''s terminology) handling. In this case it is possible to send
     back an application level message to the client's browser. For
     that you just have to fill the unexpected handler's ANSWER
     parameter with the right response message. The ERROR parameter
     receive information about the problem, *note AWS.Exceptions::.

Fatal error (Error.Fatal is True)
     In this case `AWS' will continue working but a thread (slot number
     ERROR.SLOT in `AWS''s terminology) will be killed. It means that
     `AWS' will have lost one the simultaneous connection handler. The
     server will continue working unless it was the last slot handler
     available. Note that a Fatal error means an `AWS' internal bug and
     it should be reported if possible. In this mode there is no way to
     send back an answer to the client's browser and ERROR value must
     be ignored.


The default handler for unexpected exceptions send a message to
standard error for fatal errors. For non fatal errors it log a message
(if the error log is activated for the server) and send back a message
back to the client. The message is either a built-in one or, if present
in the server's directory, the content of the `500.tmplt' file.  This
templates can used the following tags:

AUTH_MODE
     The authorization mode (Either NONE, BASIC or DIGEST).

EXCEPTION
     Exception information with traceback if activated.

HTTP_VERSION
     Either HTTP/1.0 or HTTP/1.1

METHOD
     The request method (Either GET, HEAD, POST or PUT)

PAYLOAD
     The full `XML' payload for `SOAP' request.

PEERNAME
     The IP address of the client

SOAP_ACTION
     Either True or False. Set to True for a `SOAP' request.

URI
     The complete URI

For more information *note AWS.Server:: and *note AWS.Exceptions::.

3.16 Socket log
===============

To ease `AWS' applications debugging it is possible to log all data
sent/received to/from the sockets. For this you need to call the
`AWS.Net.Log.Start' routine by passing a write procedure callback. You
have to create such procedure or use one read-to-use provided in
`AWS.Net.Log.Callbacks' package.

   For more information *note AWS.Net.Log:: and *note
AWS.Net.Log.Callbacks::.

3.17 Client side
================

`AWS' is not only a server it also implement the HTTP and HTTPS
protocol from the client side. For example with `AWS' it is possible to
get a Web page content using the `AWS.Client' API, *Note AWS.Client::.

It also support client Keep-Alive connections. It is then possible to
request many URI from the same server using the same connection (i.e.
the same sockets).

`AWS' client API also support proxy, proxy authentication and Web server
authentication. Only basic (and not digest) authentication is supported
at this time.

Let's say that you want to retrieve the `contrib.html' Web page from
Pascal Obry's homepage which is `http://perso.wanadoo.fr/pascal.obry'.
The code to do so is:

     Data := Client.Get
       (URL => "http://perso.wanadoo.fr/pascal.obry/contrib.html");

From there you can ask for the result's content type:

     if Response.Content_Type (Data) = "text/html" then
        ...
     end if;

Or using the MIME types defined in `AWS.MIME' unit:

     if Response.Content_Type (Data) = MIME.Text_HTML then
        ...
     end if;

And display the content if it is some kind of text data:

     Text_IO.Put_Line (Response.Message_Body (Data));

If the content is some kind of binary data (executable, PNG image, Zip
archive...), then it is possible to write the result to a file for
example. Look at the `agent' program in the `demos' directory.

If the Web page is protected and you must pass the request through an
authenticating proxy, the call will becomes:

     Data := Client.Get
       (URL        => "http://www.mydomain.net/protected/index.html"
        User       => "me",
        Pwd        => "mypwd",
        Proxy      => "192.168.67.1",
        Proxy_User => "puser",
        Proxy_Pwd  => "ppwd");

The client upload protocol is implemented. Using `AWS.Client.Upload' it
is possible to send a file to a server which support the file upload
protocol.

4 High level services
*********************

Here you will find a description of high level services. These services
are ready to use with AWS and can be used together with user's
callbacks.

Refer to the Ada spec for a complete API and usage description.

4.1 Directory browser
=====================

This service will help building a Web directory browser. It has a lot
of options to sort directory entries and is based on the templates
interface *note AWS.Templates::. This means that you can use the
default directory template or provide your own.

   *note AWS.Services.Directory:: for complete spec and services
descriptions.

4.2 Dispatchers
===============

In many AWS applications it is needed to check the URI to give the
right answer. This means that part of the application is a big if/elsif
procedure. Also, in standard callback it is not possible to have user
data. Both of these restrictions are addressed with the Dispatchers
facilities.

Working with a dispatcher is quite easy:

  1. Create a new dispatcher by inheriting from the service you want to
     build.

  2. Register a set of action based on rules (strings, regular
     expressions depending on the service)

4.2.1 Callback dispatcher
-------------------------

This is a wrapper around the standard callback procedure. It is needed
to mix dispatcher based callback and access to procedure callback. Note
that it is not in the `AWS.Services.Dispatchers' hierarchy but in
`AWS.Dispatchers.Callback' because this is a basic service needed for
the server itself. It is referenced here for documentation purpose but
an AWS server can be built with using it.

   *note AWS.Dispatchers.Callback:: for complete spec description.

4.2.2 Method dispatcher
-----------------------

This is a dispatcher based on the request method. A different callback
procedure can be registered for the supported request methods: GET,
POST, PUT, HEAD.

   *note AWS.Services.Dispatchers.Method:: for complete spec
description.

4.2.3 URI dispatcher
--------------------

This is a dispatcher based on the request resource. A different callback
procedure can be registered for specific resources. The resource is
described either by its full name (string) or a regular expression.

   *note AWS.Services.Dispatchers.URI:: for complete spec description.

4.2.4 Virtual host dispatcher
-----------------------------

This is a dispatcher based on the host name. A different callback
procedure can be registered for specific host. This is also known as
virtual hosting.

The same computer can be registered into the DNS with different names.
So all names point to the same machine. But in fact you want each name
to be seen as a different Web server. This is called virtual hosting.
This service will just do that, call different callback procedures or
redirect to some machine/port based on the host name in the client's
request.

   *note AWS.Services.Dispatchers.Virtual_Host:: for complete spec
description.

4.2.5 Transient pages dispatcher
--------------------------------

This is a dispatcher that calls a user's callback and if the resource
requested is not found (i.e. the user's callback returns status code
404) it checks if this resource is known as a transient page. *note
Transient Pages::.

4.2.6 Timer dispatcher
----------------------

A timer dispatcher can be used to call different callback routines
depending on the current date and time. Such dispatcher is composed of
a set of `Period' activated. When the current date and time is inside a
`Period' the corresponding callback is called. A `Period' can
eventually be repeated. Here are the different kind of `Period'
supported by `AWS':

Once
     A unique period in time. The boundaries are fully described using a
     year, month, day, hour, minute and second.

Yearly
     A period that repeats each year. The boundaries are described
     using a month, day, hour, minute and second.

Monthly
     A period that repeats each month. The boundaries are described
     using a day, hour, minute and second.

Weekly
     A period that repeats each week. The boundaries are described
     using a day name, hour, minute and second.

Daily
     A period that repeats each day. The boundaries are described using
     an hour, minute and second.

Hourly
     A period that repeats each hour. The boundaries are described
     using a minute and second.

Minutely
     A period that repeats each minute. The boundaries are described
     using a second.


4.2.7 Linker dispatcher
-----------------------

A dispatcher that can be used to chain two dispatchers. The response of
the first dispatcher is returned except if it is a 404 (Not Found)
error. In this case, the response of the second dispatcher is returned.

4.2.8 SOAP dispatcher
---------------------

`AWS' provides also a `SOAP' specific dispatcher. This is a way to
automatically route HTTP requests or `SOAP' requests to different
callback routines.

   *note SOAP helpers:: for more information.

   *note SOAP.Dispatchers.Callback:: for complete spec description.

4.3 Static Page server
======================

This service is a ready to use static page server callback. Using it is
possible to build a simple static page server, as simple as:

     with AWS.Server;
     with AWS.Services.Page_Server;

     procedure WPS is
        WS : AWS.Server.HTTP;
     begin
        AWS.Server.Start
          (WS, "Simple Page Server demo",
           Port           => 8080,
           Callback       => AWS.Services.Page_Server.Callback'Access,
           Max_Connection => 5);

        AWS.Server.Wait (AWS.Server.Q_Key_Pressed);

        AWS.Server.Shutdown (WS);
     end WPS;

Build this program and launch it, it will server `HTML' pages and images
in the current directory.

It is possible to activate the directory browsing facility of this
simple page server. This is not activated by default. This feature is
based on the directory browsing service *note Directory browser::.

Note that this service uses two template files:

aws_directory.thtml
     The template page used for directory browsing. See *note
     AWS.Services.Directory:: for a full description of this template
     usage.

404.thtml
     The Web page returned if the requested page is not found. This is a
     template with a single tag variable named PAGE. It will be
     replaced by the ressource which was not found.

     Note that on Microsoft IE this page will be displayed only if the
     total page size is bigger than 512 bytes or it includes at least
     one image.


   *note AWS.Services.Page_Server:: for a complete spec description.

4.4 Transient Pages
===================

A transient page is a resource that has a certain life time on the
server. After this time the resource will be released and will not be
accessible anymore.

Sometimes you want to reference, in a Web page, a resource that is built
in memory by the server. This resource can be requested by the client
(by clicking on the corresponding link) or not, in both cases the page
must be released after a certain amount of time to free the associated
memory.

This is exactly what the transient pages high level service do
automatically. Each transient page must be registered into the service,
a specific routine named `Get_URI' can be used to create a unique `URI'
on this server. *note AWS.Services.Transient_Pages::.

A transient pages dispatcher can be used to build a transient pages
aware server. *note Transient pages dispatcher::.

4.5 Split pages
===============

It not not very convenient to send back a Web page with a large table.
In such a case it is better to split the table in chunks (20 lines or
so) and to send only the first page. This page reference the next pages
and can also contains an index of the pages.

The `AWS''s split page feature can automatically do that for you. Given
template `Translate_Table' or `Translate_Set' and the max line per page
it returns the first page and create a set of transient pages for all
other pages. A set of template tags are used to reference the previous
and next page and also to build the page index.

There is different ways to split a set of pages and ready-to-use
splitters are available:

Alpha
     Split in (at most) 28 pages, one for empty fields, one for all
     fields that start with a digit, and one for each different initial
     letter.  *note AWS.Services.Split_Pages.Alpha::.

Alpha.Bounded
     Same as the alpha splitter, but pages larger than a Max_Per_Page
     value are further splitted.  A secondary index is generated that
     gives the various pages for a given letter. *note
     AWS.Services.Split_Pages.Alpha.Bounded::.

Uniform
     Split in pages of length Max_Per_Page (except the last one). This
     corresponds to the default service in Split_Pages package.  *note
     AWS.Services.Split_Pages.Uniform::.

Uniform.Alpha
     Same as the uniform splitter, but builds in addition an
     alphabetical secondary index from a key field.  *note
     AWS.Services.Split_Pages.Uniform.Alpha::.

Uniform.Overlapping
     Same as the uniform splitter, but pages (except the first one)
     repeat Overlap lines from the previous page in addition to the
     Max_Per_Page lines. *note
     AWS.Services.Split_Pages.Uniform.Overlapping::.

Using the spliter abstract interface it is possible to build a
customized splitter algorithm. *note AWS.Services.Split_Pages::.

4.6 Download Manager
====================

A server that need to handle lot of large downloads can run out of
connection to answer the standard Web pages. A solution is to increase
the number of simultaneous connections, but this is not really efficient
as a task is created for each connection and does not ensure that all
the connections will be used for the downloads anyway.

The download manager can be used for that, and provides the following
feature:

   * use a single task for all downloads

   * can be configured to limit the number of simultaneous connections

   * downloads past this limit are queued

   * send messages to the client with the position in the waiting line

   * send messages to the client when the download is about to start

The server must be configured to use dispatchers (standard callbacks
are not supported, note that it is possible to create a dispatcher for
standard callbacks. *note AWS.Dispatchers.Callback::).

To start the download manager you need to pass the main server
dispatcher object. The start routine will return a new dispatcher,
linked with the download server specific dispatcher, that must be used
to start the standard Web server. See comment in *note
AWS.Services.Download::.

To queue a download request in the download manager you just need to
create a stream object (can be any kind of stream, see
`AWS.Resources.Streams.*') for the resource to download.

The download manager needs two templates files:

`aws_download_manager_waiting.thtml'
     This template is used for sending a message to the client when the
     request is on the waiting line. The tags defined in this template
     file are:

    NAME
          the name of the resource to download (the filename), this is
          the default filename used for the client side save dialog.

    RES_URI
          the URI used to access the resource.

    POSITION
          the position in the waiting line (not counting the current
          served clients).

`aws_download_manager_start.thtml'
     This template is used for sending a message to the client when the
     download is about to start (the request is out of the waiting
     line). The tags defined in this template file are:

    NAME
          as above

    RES_URI
          as above

It is important to note that those templates must be reloaded
periodically. The best way to do that in the context of an `HTML'
document is to use a meta-tag. For example to refresh the page every
two seconds:

     <meta http-equiv="refresh" content="2">

The templates could look like:

`aws_download_manager_waiting.thtml'
          <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
                  "http://www.w3.org/TR/html4/strict.dtd">

            Download Manager - waiting

            <p>Waiting for downloading @_NAME_@
            <p>Position in the waiting line @_POSITION_@

`aws_download_manager_start.thtml'
          <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
                  "http://www.w3.org/TR/html4/strict.dtd">

            Download Manager - waiting

            <p>Waiting for downloading @_NAME_@
            <p>The download will start in a moment

4.7 Web Elements
================

`AWS' provides some components to help creating nice looking Web
interfaces. It is possible to browse those Web Elements using the
`web_elements' demo. Just launch this Web application from the demos
directory and turn your Web browser to `http://localhost:2400'.

   Currently `AWS' provides:

   * Notebooks (based on CSS)

   * CSS Menu

   * Rounded boxes

   * Ajax

All of them are based on templates to be easily reused in other
applications. The three first are best described by the Web Elements
demos as they are 100% design. The `Ajax' one is a bit more complex, we
will present its use in the following section.

4.7.1 Installation
------------------

To ease integration we have used the following design:

   * Sub-directories found in the `AWS''s web_elements directory are
     self contained. The content must be copied into the project. Note
     that the icons and javascripts directories contain the icons and
     javascripts code shared by all web elements and must also be
     copied, see below.

   * Each graphic elements (icons) is referenced into the templates
     with the alias `/we_icons/<icon_name>'. So users must provide the
     right alias ("`/we_icons/'") in the  Web server.

   * Each JavaScripts code is referenced into the templates with the
     alias `/we_js/<script>'. So users must provide the right alias
     (`"/we_js/"') in the  Web server.

4.7.2 Ajax
----------

First of all, `Ajax' stand for Asynchronous JavaScript language and
XML, and is not well defined at the moment. `Ajax' is on one side able
to send HTTP requests to the Web server and on the other side able to
manipulate directly the Web browser's `DOM' tree. On the `DOM' it can
add, remove or replace `XML' nodes. So, it is possible to change the
content of a Web page without reloading it from the server.

Most importantly, `Ajax' changes the way Web applications are thought
from page based to event based.

As implemented into `AWS', `Ajax' support comes as a set of
`JavaScript' templates. Using those templates there is no need to know
`JavaScript' (except for the `JavaScript' event names) and it makes
`Ajax' programming lot easier. Two actions are provided, one for
replacing another for clearing part of the web page content.

4.7.2.1 Steps to do Ajax
........................

What are the steps to do `Ajax' ?

Remember, do not think about the Web page but about a specific widget
(`HTML' fragments) with the associated event and action.

  1. Include the AWS/Ajax support file

     This is the `AWS/Ajax' runtime, it contains `JavaScript' code
     needed for the `AWS/Ajax' support.

  2. Create the Web widgets/forms

     There is nothing special here, use your favorite Web designer tool.

  3. Create Web area

     Using some `HTML' <div> tags we create areas where we will place
     `HTML' fragments later. For example when clicking on a button
     (described above) in our Web interface we want to display a new
     form in this area.

  4. Name the widgets/forms/area using id="name" attribute

     Give a different name to the widgets using id="name". This name
     will be later used to identify the widgets on which the envent and
     corresponding action must be placed. We do not want to clutter the
     Web design with `JavaScript' code like `onclick="dothis()"' or
     `onchange="dothat()"'.

  5. Add the proper event/action to the widgets using the AWS/Ajax
     templates

     This is the interresting part. At this point we link events/actions
     to the widgets and specify in which area the results sent by the
     server will be placed.


This is not the only way to do `Ajax', we just presented here a simple
approach that works well with the `AWS/Ajax' templates.

4.7.2.2 Basic Ajax support
..........................

This section describes the `AWS/Ajax' support where the answer from the
server is an `HTML' fragment. This basic support is designed to be used
for migration of a Web server to `Ajax'. For new applications, it is
worth considering using the XML based Ajax support, *note XML based
Ajax::.

Let's have a very simple example:

   * The AWS/Ajax runtime support

          @@INCLUDE@@ aws.tjs

     Must be included in every Web pages into the `<head>' tag.

   * The widget: a button

          <input id="clickme" type="button" value="Clik Me">

   * The result area: a div

          <div id="placeholder">... result here ...</div>

   * The AWS/Ajax

          @@INCLUDE@@ aws_action_replace.tjs onclick clickme placeholder

     Basically it places an onclick attribute (the event) in the `HTML'
     `<input>' identified as clickme (the action) above. Here is what
     happen when the button is clicked:

        * send the "/onclick$clickme" HTTP request to the server

        * asynchronously wait for the answer, when received place the
          message body into the `<div>' placeholder.


On the server side the code would look like this:

     function Callback (Request : in Status.Data) return Response.Data is
        URI : constant String := Status.URI (Request);
     begin
        if URI = "/clickme" then
           return Response.Build (MIME.Text_HTML, "you click me!");
        ...

So when the button is clicked the string "you click me!" will replace
the "... result here ..." string of the place holder div above.

This is a simple and very limited example as there is no parameter
passed to the `HTTP' request. In real Web applications it is necessary
to send a context with the request. This can be either the value of
other widgets or all values of widgets' form.

References to widgets or forms can be passed to the
`aws_action_replace.tjs' template starting with the 5th parameter.

     <input id="field" type="text" value="default value">

     ...

     @@INCLUDE@@ aws_action_replace.tjs (onclick clickme placeholder 5=>field)

   or

     <form id="small_form" name="small_form">
     ...
     </form>

     @@INCLUDE@@ aws_action_replace.tjs (onclick clickme placeholder 5=>small_form)

Note that the `onclick' event is only one of the possible `JavaScript'
event on a `button'. It is possible to used any supported event, for
example on an `HTML' `<select>' widget it is common to map the action
to the `onchange' event.

`AWS' also provides support for clearing an area or a widget content
(like an input).

     @@INCLUDE@@ aws_action_clear.tjs (onclick, clear, field)

This simple action adds the onclick event to the clear button to erase
the content of the field widget.

4.7.2.3 XML based Ajax
......................

In many cases you'll like to update and/or clear multiple areas in your
Web interface. With the templates above only a single action is
possible. `AWS' provides support for `XML' based answers. In this `XML'
documents it is possible to:

   * replace an area with a new content

          <replace id="item_id">new text</replace>

   * clear an area

          <clear id="item_id"/>

   * add an item into a select widget

          <select action="add" id="item_id"
          option_value="value" option_content="content"/>

   * remove an item from a select widget

          <select action="delete" id="item_id" option_value="value"/>

   * select a specific item in a select widget

          <select action="select" id="item_id" option_value="value"/>

   * clear a select widget (remove all items)

          <select action="clear" id="item_id"/>

   * select a radio button

          <radio action="select" id="item_id"/>

   * check a checkbox

          <check action="select" id="item_id"/>

   * clear a checkbox

          <check action="clear" id="item_id"/>

   * call another URL

          <get url="http://thishost/action">
             <parameters value="name=Ajax"/>
             <field id="input1"/>
          </get>

     This will send the following request:

          http://thishost/action?name=Ajax&input1=<val_input1>

     Where val_input1 is the current value of the input1 input widget.
     The result must be an `XML/Ajax' document that will be parsed.

   * make a list sortable

          <make_sortable>
             <list id="firstlist"/>
             <list id="secondlist"/>
          </make_sortable>

     Here firstlist and secondlist are id of `UL' elements. It is
     possible to specified as many list id as needed. A drag and drop is
     then possible for all elements in those lists. It is then possible
     to reference such list by passing the list id as a field to the
     template. Items on those list will be serialized and passed to the
     `AWS' callback. Note that for the serialization to work properly,
     each `LI' elements must be given the id of the list and then the
     value we want to pass.

          <ul id="firstlist">
             <li id="firstlist_red">Red</li>
             <li id="firstlist_green">Green</li>
             <li id="firstlist_blue">Blue</li>
          </ul>

     The serialization will send each value on this list using a
     multi-valued parameter named firstlist[].

          http://server?firstlist[]=red&firstlist[]=green&firstlist[]=blue

   * make a list not sortable

          <destroy_sortable>
             <list id="firstlist"/>
             <list id="secondlist"/>
          </destroy_sortable>

     Remove the sortable properly from the specified lists.

   * redirect to another URL

          <location url="http://thishost/go_there"/>

     Redirect the browser to the specified URL.

   * refresh the current page

          <refresh/>

     Refresh the current page as if the Web Browser refresh button was
     pressed.

   * add a CSS style to a given node

          <apply_style id="node_id">
             <attribute id="display" value="none"/>
          </apply_style>

     Add the CSS style `display:none' to the node_id element. It is
     possible to specify multiple attributes if needed.

   * make an entry disabled or enabled

          <disabled id="item_id" value="true/false"/>

   * make an entry read-only or writable

          <read_only id="item_id" value="true/false"/>

   * reset a form

          <reset id="form_id"/>


Here is an example of such XML document:

     <response>
        <replace id="xml_status_bar">Fill Widgets...</replace>
        <replace id="text1">Response from XML</replace>
        <replace id="text2">Another response for text2</replace>
        <replace id="input1">tag is input1</replace>
        <replace id="input2">tag is input2</replace>
        <select action="add" id="xmlsel" option_value="one" option_content="1"/>
        <select action="add" id="xmlsel" option_value="two" option_content="2"/>
        <select action="add" id="xmlsel" option_value="three" option_content="3"/>
        <select action="select" id="xmlsel" option_value="two"/>
        <radio action="select" id="radio1"/>
        <check action="select" id="check1"/>
        <check action="select" id="check3"/>
        <check action="clear" id="check2"/>
     </response>

To register an `Ajax' action to a specific tag id a macro can be used.
It is named `JS_ACTION' and defined in `ajax_api.tjs'.  The usage is
similar to what is described in the previous section (*note Basic Ajax
support::) except that in this case we use a macron instead of an
include file and we do not have to pass the placeholder.

Let's revisit the first example above to use the `XML' `Ajax' support.

   * The AWS/Ajax runtime support

          @@INCLUDE@@ aws.tjs

     Must be included in every Web pages into the `<head>' tag.

   * The AWS/Ajax API

          @@INCLUDE@@ ajax_api.tjs

     Must be included at least once during an application life-time. It
     gives access to the `JS_ACTION' macro.

   * The widget: a button

          <input id="clickme" type="button" value="Clik Me">

   * The result area: a div

          <div id="placeholder">... result here ...</div>

   * The AWS/Ajax

          @_JS_ACTION(onclick, clickme)_@

     Basically it places an onclick attribute (the event) in the `HTML'
     `<input>' identified as clickme (the action) above. Here is what
     happen when the button is clicked:

        * send the "/onclick$clickme" HTTP request to the server

        * asynchronously wait for the XML answer, when received parse
          the answer and perform the actions according to the `XML'
          content.


To set the placeholder with "new text", the `XML' document returned by
the server must be:

     <response>
        <replace id="placeholder">new text</replace>
     </response>

If we want also to clear the input field named field and to select the
radio button named radio1 we must return:

     <response>
        <replace id="placeholder">new text</replace>
        <clear id="field"/>
        <radio action="select" id="radio1"/>
     </response>

This is by far the most flexible solution as it is possible to return,
from the server, a structured answer.

A final comment, if the text returned by the server to replace a
specific area is an `HTML' fragment, the content must be placed into a
`CDATA' tag:

     <response>
        <replace id="item_id">
           <![CDATA[ HTML CODE HERE ]]>
        </replace>
     </response>

4.7.2.4 Advanced Ajax
.....................

Finally, if this is not enough because you need to use some specific
`JavaScript' code, `AWS' provides a macro named `BIND_JS' to add an
event to a specific widget, the action being the name of a `JavaScript'
routine.

This macro together with the `aws_func_replace.tjs',
`aws_func_clear.tjs' templates and the `JS_ACTION' macro can be used to
chain multiple actions. Those templates are the function body used by
the corresponding templates `aws_action_replace.tjs',
`aws_action_clear.tjs'.

Let say you want to clear a widget, change the content of another one
and calling one of your specific `JavaScript' routine when clicking on
a button. It is not possible to have mutiple `onclick' events on the
same widget, the solution is the following:

   * Create the JavaScript routine to do the job

     For this in the the body of the `clear_replace()' JavaScript
     routine we place:

     function clear_replace()
     {
          @@INCLUDE@@ aws_func_replace.tjs (clickme placeholder 4=>field)
          @@INCLUDE@@ aws_func_clear.tjs (area)
          call_this_routine();

     }

     Then to add the event on the widget:

          @_BIND_JS(onclick, clickme clear_replace)_@


Furthermore, it is possible to pass (as the parameter number 20) a
routine to call after a specific action to all templates and to the
`JS_ACTION' macro. This is another way to chain multiple actions for a
single event.

Note that all `AWS/Ajax' templates and the `ajax_api.tjs' file have a
set of comments at the start explaining in details the usage of each
parameter.

4.8 Web Blocks
==============

The `AWS.Services.Web_Block' hierarchy contains an API useful for
keeping context on Web pages. It has been designed to be able to split
a Web application into a set of independent blocks that can be put
together in the same Web page. The context is then useful as it is
passed and known by each individual block. Note that this is different
than the session as a session is global to the current Web browser
whereas the context can be different for each individual web pages
opened.

Instead of parsing a whole page using `AWS.Templates' API the web blocks
are registered independently using `AWS.Services.Web_Block.Registry'.
The block is registered together with its templates and a callback to
use to get user's data for this specific block with the given context.

So using this API, instead of having a set of callbacks returning an
`AWS.Response.Data' and where the final rendering is to be done by the
client code, we have a set of callbacks that returns a `Translate_Set'.
The client just have to fill the set with the data corresponding to the
actual request and possibly using the context. The final rendering is
done by the provided services in `Web_Block.Registry'.

Note that all Web pages must also be registered into the registry to
ensure that the context identification is properly kept. The context
identification is injected into the Web pages transparently for the
end-user when using `Ajax'.

4.8.1 Web Block example
-----------------------

Let's have a simple example, a page containing a single block with a
tag (@_COUNTER_@) which is incremented by one each time it is used. The
code can be found in `demos/web_block'.

First create the following HTML fragment and place it into
`counter.thtml'.

     <p>@_COUNTER_@</p>

Then create the main page and place it into `page.thtml'. The important
part is the @_CTX_WB_@ tag which is passed to the link. This tag is the
context identifier, it must be passed to each request. Note that this
is automatically done when using the `Ajax' framework (*note Web Block
and Ajax::).

     <html>
        <head>
           <title>Main Page</title>
        </head>
        <body>
           <p>This is the main page, bellow is a simple counter</p>
           <p>@_COUNTER_@</p>
           <a href="/?CTX_WB=@_CTX_WB_@>Next</a>
        </body>
     </html>

The `Web_Callbacks' package contains the application callbacks.

     with AWS.Response;
     with AWS.Status;
     with AWS.Templates;
     with AWS.Services.Web_Block.Context;

     package Web_Callbacks is

        use AWS;
        use AWS.Services;

        function Main (Request : in Status.Data) return Response.Data;
        --  Main callback which handle the home page

        procedure Counter
          (Request      : in              Status.Data;
           Context      : not null access Web_Block.Context.Object;
           Translations : in out          Templates.Translate_Set);
        --  The callback handling the counter web block

     end Web_Callbacks;

Last part is to actually implement the `Counter' callback. Here is a
possible implementation making use of the context to keep the counter
state.

     with AWS.Utils;
     with AWS.Messages;
     with AWS.MIME;
     with AWS.Services.Web_Block.Registry;

     package body Web_Callbacks is

        -------------
        -- Counter --
        -------------

        procedure Counter
          (Request      : in              Status.Data;
           Context      : not null access Web_Block.Context.Object;
           Translations : in out          Templates.Translate_Set)
        is
           N : Natural := 0;
        begin
           if Context.Exist ("N") then
              N := Natural'Value (Context.Get_Value ("N"));
           end if;

           N := N + 1;
           Context.Set_Value ("N", Utils.Image (N));

           Templates.Insert
             (Translations,
              AWS.Templates.Assoc ("COUNTER", N));
        end Counter;

        ----------
        -- Main --
        ----------

        function Main (Request : in Status.Data) return Response.Data is
           URI : constant String := Status.URI (Request);
        begin
           return Web_Block.Registry.Build
             (Key          => URI,
              Request      => Request,
              Translations => Set);
        end Main;

     end Web_Callbacks;

Finally, we write the main procedure:

     with Ada.Text_IO;

     with AWS.Server;
     with AWS.Services.Web_Block.Registry;

     with Web_Callbacks;

     procedure Web_Block is

        use Ada;
        use AWS;
        use AWS.Services;

        HTTP : AWS.Server.HTTP;

     begin
        --  First we register the main page and the counter block

        Services.Web_Block.Registry.Register
          ("/", "page.thtml", null);

        Services.Web_Block.Registry.Register
          ("COUNTER", "counter.thtml",
           Web_Callbacks.Counter'Access, Context_Required => True);

        --  Then we just start the server

        Server.Start (HTTP, "web_block", Web_Callbacks.Main'Access);

        Text_IO.Put_Line ("Press Q to terminate.");

        Server.Wait (Server.Q_Key_Pressed);

        Server.Shutdown (HTTP);
     end Web_Block;

Compile and run the server. Then connect to the server and click on
next. The counter will be incremented by one each time.

4.8.2 Web Block and Ajax
------------------------

The Web Block framework has really been designed to be used with
`Ajax'. It is the only way to gain the full power of the Web Block
framework.

For the complete code, see `demos/web_block_ajax'.

When using `Ajax' it is not needed to explicitly pass the context
identification to every link. This is done automatically by the
framework. So the main page will look like this:

     @@INCLUDE@@ ../../web_elements/javascripts/ajax_api.tjs
     <html>
        <head>
           <title>Main Page</title>
           @@INCLUDE@@ ../../web_elements/javascripts/aws.tjs
        </head>
        <body>
           <p>This is the main page, bellow is a simple counter</p>
           @_WIDGET_COUNTER_@
        </body>
     </html>

The counter widget is on `widget_counter.thtml':

     <!-- implementation of a simple counter widget -->
     <p><div id="counter">@_COUNTER_@</div></p>
     <a id="next" href="/">Next</a>
     @_JS_ACTION(onclick, next)_@

   For the `Ajax' part, *note Ajax::.

We now have one more register call for registering the `next' button
`Ajax' callback, and a callback named `Widget_Counter' for displaying
the block:

     Services.Web_Block.Registry.Register
       ("WIDGET_COUNTER", "widget_counter.thtml",
        Web_Callbacks.Widget_Counter'Access);

     Services.Web_Block.Registry.Register
       ("/onclick$next", "r_widget_counter.txml",
        Web_Callbacks.Onclick_Next'Access,
        Content_Type     => MIME.Text_XML,
        Context_Required => True);

The `next' `Ajax' button is using an XML based response which is
defined in `r_widget_counter.txml':

     <response>
        <replace id="counter">@_COUNTER_@</replace>
     </response>

The `Widget_Counter' callbacks just have to set the `COUNTER' tag
variable to the corresponding value. This is used to display the block.
The `Ajax' callback `Onclick_Next' has to increment the counter and set
the `COUNTER' tag variable, a simple implementation is:

     procedure Onclick_Next
       (Request      : in              Status.Data;
        Context      : not null access Web_Block.Context.Object;
        Translations : in out          Templates.Translate_Set)
     is
        N : Natural := 0;
     begin
        if Context.Exist ("N") then
           N := Natural'Value (Context.Get_Value ("N"));
        end if;

        N := N + 1;

        Context.Set_Value ("N", Utils.Image (N));

        Templates.Insert
          (Translations, Templates.Assoc ("COUNTER", N));
     end Onclick_Next;

The framework will then call `Onclick_Next' when pressing the `Next'
button. This routine increments N by one sending back a response based
on `r_widget_counter.txml'. Finally, the client browser will parse this
XML response and do the corresponding actions.

4.8.3 Web Block and templates2ada
---------------------------------

For the complete code, see `demos/web_block_ajax_templates'.

It is possible to use the `Templates_Parser's templates2ada' tool for
generating the callbacks register calls. This ensures that all tags on
the application Web Pages have a corresponding callback.

The code is almost identical to the standard `Ajax' example above. The
main difference is that we need to use a naming convention for the
blocks. This way we can generate automatically the corresponding
callbacks using a template. A common convention is to add `LAZY_' as
prefix for the name of the blocks. With this convention the main page
template is:

     @@INCLUDE@@ ../../web_elements/javascripts/ajax_api.tjs
     <html>
        <head>
           <title>Main Page</title>
           @@INCLUDE@@ ../../web_elements/javascripts/aws.tjs
        </head>
        <body>
           <p>This is the main page, bellow is a simple counter</p>
           @_LAZY_WIDGET_COUNTER_@
        </body>
     </html>

We need also modify the standard `templates.tads' as distributed with
the `Templates_Parser'. Here is the interesting part:

     @@SET@@ PACKAGE = WBlocks

     ...

     with AWS.MIME;
     with AWS.Services.Web_Block.Registry;
     with Web_Callbacks;

     @@TABLE@@
     with @_PACKAGE_@.@_CAPITALIZE:REPLACE_ALL(./_):BASENAME_@;
     @@END_TABLE@@

     package body @_PACKAGE_@ is

        use AWS;

        package body Lazy is

           --------------
           -- Register --
           --------------

           procedure Register is
              use AWS.Services;
           begin
              --  Register blocks
     @@TABLE@@
        @@IF@@ @_UPPER:SLICE(1..5):VARIABLE_LIST_@ = "LAZY_"
              Web_Block.Registry.Register
                ("@_VARIABLE_LIST_@",
                 "@_LOWER:REPLACE_ALL(LAZY_/):VARIABLE_LIST_@.thtml",
                 Web_Callbacks.@_CAPITALIZE:REPLACE_ALL(LAZY_/):VARIABLE_LIST_@'Access);
        @@END_IF@@
     @@END_TABLE@@
              --  Register Ajax
     @@TABLE@@
        @@TABLE@@
           @@IF@@ not @_IS_EMPTY:AJAX_EVENT_@
              Services.Web_Block.Registry.Register
                 ("/@_AJAX_EVENT_@$@_AJAX_ACTION_@",
                  @_PACKAGE_@.R_@_CAPITALIZE:REPLACE_ALL(./_):AJAX_FILE_@.Template,
                  Web_Callbacks.@_CAPITALIZE:AJAX_EVENT_@_@_CAPITALIZE:AJAX_ACTION_@'Access,
                  Content_Type     => MIME.Text_XML,
                  Context_Required => True);
           @@END_IF@@
        @@END_TABLE@@
     @@END_TABLE@@
           end Register;
        end Lazy;

     end @_PACKAGE_@;

Basically this is to write a register call for every template's tag
starting with `LAZY_'. The second section is to write a register call
for every `Ajax' event. All callbacks are expected to be in a package
named `Web_Callbacks'. It is of course possible to change this template
to reference callbacks for blocks and `Ajax' in separate packages. The
use of a template here is very flexible.

Now let's parse the application HTML and XML templates and create the
corresponding Ada specs and register calls:

     $ templates2ada -d . -o code.ada -t templates.tada -e .thtml -e .txml
     $ gnatchop code.ada

Look at the generated code below, it properly register the
`Widget_Counter' callback to be used for rendering
`LAZY_WIDGET_COUNTER' using the `widget_counter.thtml'. So we have a
tight coupling between the code and the template file. If the tag is
renamed in the template file the application will not compile anymore.
The same is true for `Ajax' callbacks, every `Ajax' action put in a
template file needs a corresponding callback in Ada. This greatly helps
keeping the application code synchronized.

     procedure Register is
        use AWS.Services;
     begin
        Web_Block.Registry.Register
           ("LAZY_WIDGET_COUNTER",
            "widget_counter.thtml",
            Web_Callbacks.Widget_Counter'Access);
        Services.Web_Block.Registry.Register
           ("/onclick$next",
            WBlocks.R_Widget_Counter.Template,
            Web_Callbacks.Onclick_Next'Access,
            Content_Type     => MIME.Text_XML,
            Context_Required => True);
     end Register;

In the main, it is just now required to register the Web pages and to
call the generated `Register' procedure:

     Services.Web_Block.Registry.Register ("/", "page.thtml", null);

     WBlocks.Lazy.Register;

Moreover, an Ada spec containing reference for the tag names is
generated for every HTML and XML template file. All tags can be
referenced using those specs, it is not needed to use string literal in
the application. Again, this ensures that a tag which is renamed or
deleted is detected at compilation time. For example the
`Widget_Counter' callback can be rewritten as follow:

     procedure Widget_Counter
       (Request      : in              Status.Data;
        Context      : not null access Web_Block.Context.Object;
        Translations : in out          Templates.Translate_Set)
     is
        N : Natural := 0;
     begin
        if Context.Exist ("N") then
           N := Natural'Value (Context.Get_Value ("N"));
        end if;

        Templates.Insert
          (Translations, Templates.Assoc (WBlocks.Widget_Counter.COUNTER, N));
     end Widget_Counter;

4.9 Web Cross-References
========================

When building an `Ajax' Web applications it is required to give ids to
web elements to be able to reference them. It is also quite common to
use CSS to give such and such item a specific style. After some time it
is quite difficult to keep track of all those ids. Are they all used ?
Don't we reference an id that does not exist anymore ?

`webxref' has been designed to help finding such problems.

The files kinds handled are:

`.css'

`.tcss'
     A CSS (or template CSS file). Ids and classes inside are recorded
     as CSS definitions.

`.xml'

`.html'

`.thtml'
     A meta-language document. Ids and classes inside are recorded as
     referencing a CSS definition and meta-language definition.

`.txml'
     An `Ajax' response file. Ids declared inside are recorded as
     referencing a meta-language definition.


The features are:

cross-references
     By default `webxref' output all the references to ids and classes.

finding unused items
     Output the ids/classes that are defined but not used. For example
     an id declared in a CSS but never referenced into an HTML document
     or an HTML id never referenced in an `Ajax' response file `.txml'
     document.

finding undeclared items
     Output ids/classes that are referenced but never defined. This is
     for example an id inside an `Ajax' response file which is never
     defined into an HTML document.

enforcing a naming scheme for ids and classes
     It can enforce a specific prefix for ids and classes. The id prefix
     can be based on the filename (using filename's first character and
     all character before an underscore). This make it less likely to
     find the same id on multiple files.


Note that all references are in a format recognized by tools like `GPS'
and `Emacs'. It is then possible to navigate inside them easily.

All `webxref' options are listed using the `-h' option.

5 Using SOAP
************

`SOAP' can be used to implements Web Services. The `SOAP'
implementation uses `AWS HTTP' as the transport layer. `SOAP' is
platforms and languages independent, to ensure a good
inter-operability, `AWS/SOAP' implementation has been validated through
`http://validator.soapware.org/', the version number listed on this
server corresponds to the AWS version string (`AWS.Version') catenated
with the `SOAP' version string (`SOAP.Version').

This `SOAP' implementation is certainly one with the higher level of
abstraction. No need to mess with a serializer, to know what is a
payload or be an `XML' expert. All the low level stuffs are completely
hidden as the `SOAP' type system has been binded as much as possible to
the Ada type system.

The `SOAP' type system has been relaxed to be compatible with `WSDL'
based `SOAP' implementation. In these implementations, types are
generally (as in the Microsoft implementation) not part of the payload
and should be taken from the `WSDL' (Web Services Description
Language). `AWS/SOAP' is not `WSDL' compliant at this stage, all such
types are binded into the Ada type system as strings. It is up to the
programer to convert such strings to the desired type.

5.1 SOAP Client
===============

The `SOAP' client interface is quite simple. Here are the step-by-step
instructions to call a `SOAP' Web Service:

  1. Build the `SOAP' parameters

     As for the `SOAP' servers, the `SOAP' parameters are built using a
     `SOAP.Parameters.List' object.

          Params : constant Parameters.List
            := +I (10, "v1") & I (32, "v2");

  2. Build the `SOAP' Payload

     The Payload object is the procedure name and the associated
     parameters.

          declare
             Payload : Message.Payload.Object;
          begin
             Payload := Message.Payload.Build ("Add", Params);

  3. Call the `SOAP' Web Service

     Here we send the above Payload to the Web Server which handles the
     Web Service. Let's say that this server is named `myserver', it is
     listening on port `8082' and the `SOAPAction' is `soapdemo'.

          Resp : constant Message.Response.Object'Class :=
             SOAP.Client.Call ("http://myserver:8082/soapdemo", Payload);

  4. Retrieve the result

     Let's say that the answer is sent back into the parameter named
     "myres", to get it:

          My_Res : constant Integer := SOAP.Parameters.Get (Params, "myres");


In the above example we have called a Web Service whose spec could be
described in Ada as follow:

     function Add (V1, V2 : in Integer) return Integer;
     -  Add V1 and V2 and returns the result. In SOAP the result is named "myres"

5.2 SOAP Server
===============

A `SOAP' server implementation must provides a callback procedure as for
standard Web server *note Callback procedure::. This callback must
checks for the `SOAP' Action URI to handle both standard Web requests
and `SOAP' ones. The `SOAPAction' is sent with the HTTP headers and can
be retrieved using `AWS.Status.SOAPAction'.

5.2.1 Step by step instructions
-------------------------------

Here are the step-by-step instructions to be followed in the `SOAP'
callback procedure:

  1. Retrieve the `SOAP' Payload 

     The `SOAP' Payload is the `XML' message, it contains the procedure
     name to be called and the associated parameters.

          function SOAP_CB (Request : in AWS.Status.Data)
            return AWS.Response.Data
          is
             use SOAP.Types;
             use SOAP.Parameters;

             Payload : constant SOAP.Message.Payload.Object
               := SOAP.Message.XML.Load_Payload (AWS.Status.Payload (Request));

     `AWS.Status.Payload' returns the `XML' Payload as sent by the
     `SOAP' Client. This `XML' Payload is then parsed using
     `SOAP.Message.XML.Load_Payload' which returns a
     `SOAP.Message.Payload.Object' object.

  2. Retrieve the `SOAP' Parameters

     The `SOAP' procedure's parameters.

          Params  : constant SOAP.Parameters.List
            := SOAP.Message.Parameters (Payload);

     `SOAP.Parameters.List' is a structure which holds the `SOAP'
     parameters. Each parameter can be retrieved using a
     `SOAP.Parameters' API, *note SOAP.Parameters::. For example to get
     the parameter named `myStruc' which is a `SOAP' struct:

          My_Struct : constant SOAP_Record
            := SOAP.Parameters.Get (Params, "myStruct");

     Another example, to get the parameter named `myInt' which is a
     `SOAP' integer:

          My_Int : constant Integer := SOAP.Parameters.Get (Params, "myInt");

  3. Implements the Web Service

     This is the real job, as for any procedure you can do whatever is
     needed to compute the result.

  4. Build the `SOAP' answer

     This is the procedure answer. A `SOAP' answer is built from the
     `SOAP' Payload and by setting the returned parameters.

          declare
             Resp        : SOAP.Message.Response.Object;
             Resp_Params : SOAP.Parameters.List;
          begin
             Resp := SOAP.Message.Response.From (Payload);

             Resp_Params := +I (My_Int * 2, "answer");

             SOAP.Message.Set_Parameters (Resp, Resp_Params);

     This build a response which is a single integer value named
     `answer' with the value `My_Int * 2'.

  5. Returns the answer back to the client

     This last step will encode the response object in `XML' and will
     returns it as the body of an `HTTP' message.

          return SOAP.Message.Response.Build (Resp);


5.2.2 SOAP helpers
------------------

There is two ways to help building the `SOAP' callbacks. `AWS' provides
a `SOAP' specific callback, the spec is :

     function SOAP_Callback
       (SOAPAction : in String;
        Payload    : in Message.Payload.Object;
        Request    : in AWS.Status.Data)
        return AWS.Response.Data;

With both solutions exposed below, `AWS' retrieve the `SOAPAction' and
the Payload from the `SOAP' request. This is transparent to the user.

  1. Using Utils.SOAP_Wrapper 

     It is possible to dispatch to such callback by using the
     `SOAP.Utils.SOAP_Wrapper' generic routine.

          generic
             with function SOAP_CB
               (SOAPAction : in String;
                Payload    : in Message.Payload.Object;
                Request    : in AWS.Status.Data)
                return AWS.Response.Data;
          function SOAP_Wrapper
            (Request : in AWS.Status.Data)
             return AWS.Response.Data;
          -  From a standard HTTP callback call the SOAP callback passed as generic
          -  formal procedure. Raise Constraint_Error if Request is not a SOAP
          -  request.

     For example, from the standard HTTP callback `CB' we want to call
     `SOAP_CB' for all `SOAP' requests:

          function SOAP_CB
            (SOAPAction : in String;
             Payload    : in Message.Payload.Object;
             Request    : in AWS.Status.Data)
             return AWS.Response.Data
          is
          begin
             -  Code here
          end SOAP_CB;

          procedure SOAP_Wrapper is new SOAP.Utils.SOAP_Wrapper (SOAP_CB);

          function CB (Request : in AWS.Status.Data)
            return AWS.Response.Data
          is
             SOAPAction : constant String := Status.SOAPAction (Request);
          begin
             if SOAPAction /= "" then
                SOAP_Wrapper (Request);
             else
                ...

  2. Using a SOAP Dispatcher 

     `AWS' provides also a `SOAP' specific dispatcher. This dispatcher
     will automatically calls a standard `HTTP' or `SOAP' callback
     depending on the request. If `SOAPAction' is specified (i.e. it is
     a `SOAP' request), the dispatcher will call the `SOAP' callback
     otherwise it will call the standard `HTTP' callback. This is by
     far the easiest integration procedure. Using dispatcher the above
     code will be written:

          function SOAP_CB
            (SOAPAction : in String;
             Payload    : in Message.Payload.Object;
             Request    : in AWS.Status.Data)
             return AWS.Response.Data
          is
          begin
             -  Code here
          end SOAP_CB;

          function CB (Request : in AWS.Status.Data)
            return AWS.Response.Data
          is
             SOAPAction : constant String := Status.SOAPAction (Request);
          begin
             -  Code here
          end CB;

          -  In the main procedure

          begin
             AWS.Server.Start
               (WS,
                Dispatcher =>
                  SOAP.Dispatchers.Callback.Create (CB'Access, SOAP_CB'Access),
                Config     =>
                  AWS.Config.Default_Config);

     The dispacther is created using `SOAP.Dispatchers.Callback.Create'.
     This routine takes two parameters, one is the standard HTTP
     callback procedure and the other is the `SOAP' callback procedure.

6 Using WSDL
************

`WSDL' (Web Service Definition Language) is an `XML' based document
which described a set of Web Services either based on `SOAP' or
`XML/RPC'.  By using a `WSDL' document it is possible to describe, in a
formal way, the interface to any Web Services. The `WSDL' document
contains the end-point (URL to the server offering the service), the
`SOAPAction' (needed to call the right routine), the procedure names
and a description of the input and output parameters.

`AWS' provides two tools to work with `WSDL' documents:

`ada2wsdl'
     which creates a `WSDL' document from an Ada package spec.

`wsdl2aws'
     which create the interfaces to use a Web Service or to implement
     Web Services. With this tool the `SOAP' interface is completely
     abstracted out, users will deal only with `Ada' API. All the
     `SOAP' marshaling will be created automatically.

6.1 Creating WSDL documents
===========================

Note that this tool is based on `ASIS'.

6.1.1 Using ada2wsdl
--------------------

`ada2wsdl' can be used on any Ada spec file to generated a `WSDL'
document. The Ada spec is parsed using `ASIS'.

The simplest way to use it is:

     $ ada2wsdl simple.ads

Given the following Ada spec file:

     package Simple is
        function Plus (Value : in Natural) return Natural;
     end Simple;

It will generate the following `WSDL' document:

     <?xml version="1.0" encoding="UTF-8"?>
     <definitions name="Simple"
        targetNamespace="urn:aws:Simple"
        xmlns:tns="urn:aws:Simple"
        xmlns="http://schemas.xmlsoap.org/wsdl/"
        xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/"
        xmlns:soap-enc="http://schemas.xmlsoap.org/soap/encoding/"
        xmlns:wsdl="http://schemas.xmlsoap.org/wsdl/"
        xmlns:xsi="http://www.w3.org/1999/XMLSchema-instance"
        xmlns:xsd="http://www.w3.org/2001/XMLSchema">

        <message name="Plus_Request">
           <part name="Value" type="xsd:int"/>
        </message>

        <message name="Plus_Response">
           <part name="Result" type="xsd:int"/>
        </message>

        <portType name="Simple_PortType">
           <operation name="Plus">
              <input message="tns:Plus_Request"/>
              <output message="tns:Plus_Response"/>
           </operation>
        </portType>

        <binding name="Simple_Binding" type="tns:Simple_PortType">
           <soap:binding style="rpc"
              transport="http://schemas.xmlsoap.org/soap/http"/>

           <operation name="Plus">
              <soap:operation soapAction="Plus"/>
              <input>
                 <soap:body
                    encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"
                    namespace="urn:aws:Simple"
                    use="encoded"/>
              </input>
              <output>
                 <soap:body
                    encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"
                    namespace="urn:aws:Simple"
                    use="encoded"/>
              </output>
           </operation>
        </binding>

        <service name="Simple_Service">
           <port name="Simple_Port" binding="tns:Simple_Binding">
              <soap:address location="http://.../"/>
           </port>
        </service>
     </definitions>

In bold are marked the important parts from a spec point of view. The
first item is the name of the `WSDL' document (the name of the Ada spec
package). On the `portType' section we have the description of the Ada
Plus function. Something important to note is that in Ada a function
does not have a named return parameter, `ada2wsdl' use Result for the
response. Both the input and output parameter are mapped to `SOAP'
`xsd:int' type.

Note that the `SOAP' address generated by default (http://.../) must be
edited manually or specified using `ada2wsdl''s -a option.

This is of course a very simple example. `ada2wsdl' does support lot
more complex specs and will map Ada records, arrays, enumerations,
derived types to a corresponding `XML' schema definition. See section
below for a description of the mapping.

6.1.2 Ada mapping to WSDL
-------------------------

`ada2wsdl' parse Ada records, arrays, derived types, enumerations,
procedures and functions and generate the corresponding `WSDL'
document. In this section we describe the mapping between Ada and
`WSDL'.

Integer
     Mapped to xsd:int.

Float
     Mapped to xsd:float.

Long_Float
     Mapped to xsd:double

Long_Long_Float
     Mapped to xsd:double, not supported by SOAP, mapped for
     convenience but precision cannot be guaranteed.

Boolean
     Mapped to xsd:boolean

String
     Mapped to xsd:string

Unbounded_String
     Mapped to xsd:string, note that Unbounded_String should be used
     only inside a record for full interoperability. This is a current
     limitation.

Character
     Mapped to a Character schema definition.

          <simpleType name="Character">
             <restriction base="xsd:string">
                <length value="1"/>
             </restriction>
          </simpleType>

SOAP.Utils.SOAP_Base64
     Mapped to xsd:base64Binary. `SOAP.Utils.SOAP_Base64' is a subtype
     of string which is is recognized by `ada2wsdl' to generate the
     proper SOAP type.

SOAP.Types.Byte
     Mapped to xsd:byte. `SOAP.Types.Byte' is a type which is
     recognized by `ada2wsdl' to generate the proper SOAP type.

SOAP.Types.Short
     Mapped to xsd:short. `SOAP.Types.Short' is a type which is
     recognized by `ada2wsdl' to generate the proper SOAP type.

SOAP.Types.Long
     Mapped to xsd:long. `SOAP.Types.Long' is a type which is
     recognized by `ada2wsdl' to generate the proper SOAP type.

SOAP.Types.Unsigned_Byte
     Mapped to xsd:unsignedByte. `SOAP.Types.Unsigned_Byte' is a type
     which is recognized by `ada2wsdl' to generate the proper SOAP type.

SOAP.Types.Unsigned_Short
     Mapped to xsd:unsignedShort. `SOAP.Types.Unsigned_Short' is a type
     which is recognized by `ada2wsdl' to generate the proper SOAP type.

SOAP.Types.Unsigned_Int
     Mapped to xsd:unsignedInt. `SOAP.Types.Unsigned_Int' is a type
     which is recognized by `ada2wsdl' to generate the proper SOAP type.

SOAP.Types.Unsigned_Long
     Mapped to xsd:unsignedLong. `SOAP.Types.Unsigned_Long' is a type
     which is recognized by `ada2wsdl' to generate the proper SOAP type.

Derived types
     Mapped to a type schema definition.

          type Number is new Integer;

     is defined as:

          <simpleType name="Number"
                  targetNamespace="http://soapaws/WSDL_C_pkg/">
             <restriction base="xsd:int"/>
          </simpleType>

User's types
     Mapped to a type schema definition.

          type Small is range 1 .. 10;

     is defined as:

          <simpleType name="Small"
                  targetNamespace="http://soapaws/WSDL_C_pkg/">
             <restriction base="xsd:byte"/>
          </simpleType>

Enumerations
     Mapped to an enumeration schema definition. For example:

          type Color is (Red, Green, Blue);

     is defined as:

          <simpleType name="Color">
             <restriction base="xsd:string">
                <enumeration value="Red"/>
                <enumeration value="Green"/>
                <enumeration value="Blue"/>
             </restriction>
          </simpleType>

Records
     Mapped to a struct schema definition. For example:

          type Rec is record
             A : Integer;
             B : Float;
             C : Long_Float;
             D : Character;
             E : Unbounded_String;
             F : Boolean;
          end record;

     is defined as:

          <complexType name="Rec">
             <all>
                <element name="A" type="xsd:int"/>
                <element name="B" type="xsd:float"/>
                <element name="C" type="xsd:double"/>
                <element name="D" type="tns:Character"/>
                <element name="E" type="xsd:string"/>
                <element name="F" type="xsd:boolean"/>
             </all>
          </complexType>

Arrays
     Mapped to an array schema definition. For example:

          type Set_Of_Rec is array (Positive range <>) of Rec;

     is defined as:

          <complexType name="Set_Of_Rec">
             <complexContent>
                <restriction base="soap-enc:Array">
                   <attribute ref="soap-enc:arrayType" wsdl:arrayType="tns:Rec[]"/>
                </restriction>
             </complexContent>
          </complexType>

Array inside a record
     This part is a bit delicate. A record field must be constrained
     but a `SOAP' arrays is most of the time not constrained at all. To
     support this `AWS' use a safe access array component. Such a type
     is built using a generic runtime support package named
     `SOAP.Utils.Safe_Pointers'. This package implements a reference
     counter for the array access and will release automatically the
     memory when no more reference exists for a given object.

     For example, let's say that we have an array of integer that we
     want to put inside a record:

          type Set_Of_Int is array (Positive range <>) of Integer;

     The first step is to create the safe array access support:

          type Set_Of_Int_Access is access Set_Of_Int;

          package Set_Of_Int_Safe_Pointer is
             new SOAP.Utils.Safe_Pointers (Set_Of_Int, Set_Of_Int_Access);

     Note that the name `Set_Of_Int_Safe_Pointer' (<type>_Safe_Pointer)
     is mandatory (and checked by `ada2wsdl') to achieve
     interoperability with `wsdl2aws'. *note Working with WSDL
     documents::.

     From there the safe array access can be placed into the record:

          type Complex_Rec is record
             SI : Set_Of_Int_Safe_Pointer.Safe_Pointer;
          end record;

     To create a Safe_Pointer given a `Set_Of_Int' one must use
     `Set_Of_Int_Safe_Pointer.To_Safe_Pointer' routine. Accessing
     individual items is done with `SI.Item (K)'.

     These Ada definitions are fully recognized by `ada2wsdl' and will
     generate standard array and record `WSDL' definitions as seen
     above.

          <complexType name="Set_Of_Int">
             <complexContent>
                <restriction base="soap-enc:Array">
                   <attribute ref="soap-enc:arrayType" wsdl:arrayType="xsd:int[]"/>
                </restriction>
             </complexContent>
          </complexType>

          <complexType name="Complex_Rec">
             <all>
                <element name="SI" type="tns:Set_Of_Int"/>
             </all>
          </complexType>


6.1.3 ada2wsdl
--------------

     Usage: ada2wsdl [options] ada_spec

`ada2wsdl' options are:

-a url
     Specify the `URL' for the Web Server address. Web Services will be
     available at this address. A port can be specified on the `URL',
     `http://server[:port]'. The default value is `http://.../'.

-f
     Force creation of the `WSDL' file. Overwrite exiting file with the
     same name.

-I path
     Add path option for the `ASIS' compilation step. This option can
     appear any number of time on the command line.

-noenum
     Do not generate `WSDL' representation for Ada enumerations, map
     them to standard string. *note Ada mapping to WSDL::.

-o file
     Generate the `WSDL' document into file.

-q
     Quiet mode (no output)

-s name
     Specify the Web Service name for the `WSDL' document, by default
     the spec package's name is used.

-v
     Verbose mode, display the parsed spec.


6.1.4 `ada2wsdl' limitations
----------------------------

   * Do not handle constraint arrays into a records.

   * Unbounded_String are supported with full interoperability only
     inside a record.

   * Only unconstraint arrays are supported

   * Arrays with multiple dimentions not supported

6.2 Working with WSDL documents
===============================

6.2.1 Client side (stub)
------------------------

This section describe how to use a Web Service. Let's say that we want
to use the Barnes & Noble Price Quote service. The WSDL document for
this service can be found at
`http://www.xmethods.net/sd/2001/BNQuoteService.wsdl'. In summary this
document says that there is a service named `getPrice' taking as input
a string representing the ISBN number and returning the price as
floating point.

   The first step is to generate the client interface (stub):

     $ wsdl2aws -noskel http://www.xmethods.net/sd/2001/BNQuoteService.wsdl

This will create many files, the interesting one at this point is
`bnquoteservice-client.ads', inside we have:

     function getPrice
       (isbn : in String)
        return Float;
     --  Raises SOAP.SOAP_Error if the procedure fails

Let's call this service to find out the price for The Sword of Shannara
Trilogy book.

     with Ada.Text_IO;
     with BNQuoteService.Client;

     procedure Price is
        use Ada;

        ISBN : constant String := "0345453751";
        --  The Sword of Shannara Trilogy ISBN

        package LFIO is new Text_IO.Float_IO (Float);

     begin
        Text_IO.Put_Line ("B&N Price for The Sword of Shannara Trilogy");
        LFIO.Put (BNQuoteService.Client.getPrice (ISBN), Aft => 2, Exp => 0);
     end Price;

That's all is needed to use this Web Service. This program is fully
functional, It is possible to build it and to run it to get the answer.

6.2.2 Server side (skeleton)
----------------------------

Building a Web Service can also be done from a `WSDL' document. Let's
say that you are Barnes & Noble and that you want to build Web Service
`getPrice' as described in the previous section.

You have created the `WSDL' document to specify the service spec.  From
there you can create the skeleton:

     $ wsdl2aws -nostub http://www.xmethods.net/sd/2001/BNQuoteService.wsdl

This will create many files, the interesting one here is
`bnquoteservice-server.ads', inside we have:

     Port : constant := 80;

     generic
       with function getPrice
       (isbn : in String)
        return Float;
     function getPrice_CB
       (SOAPAction : in String;
        Payload    : in SOAP.Message.Payload.Object;
        Request    : in AWS.Status.Data)
        return AWS.Response.Data;

This is a `SOAP AWS''s callback routine that can be instantiated with
the right routine to retrieve the price of a book given its ISBN
number. A possible implementation of such routine could be:

     function getPrice
       (isbn : in String)
        return Float is
     begin
        if isbn = "0987654321" then
           return 45.0;
        elsif ...
     end getPrice;

     function SOAP_getPrice is new BNQuoteService.Server.getPrice_CB (getPrice);

`SOAP_getPrice' is a `SOAP AWS''s callback routine (i.e. it is not a
standard callback). To use it there is different solutions:

Using SOAP.Utils.SOAP_Wrapper
     This generic function can be used to translate a standard callback
     based on `AWS.Status.Data' into a `SOAP' callback routine.

          function getPrice_Wrapper is new SOAP.Utils.SOAP_Wrapper (SOAP_getPrice);

     The routine `getPrice_Wrapper' can be used as any other AWS's
     callback routines. Note that inside this wrapper the `XML' payload
     is parsed to check the routine name and to retrieve the `SOAP'
     parameters. To call this routine the payload needs to be parsed (we
     need to know which routine has be invoked). In this case we have
     parsed the `XML' payload twice, this is not efficient.

Building the wrapper yourself
     This solution is more efficient if there is many `SOAP' procedures
     as the payload is parsed only once.

          function CB (Request : in Status.Data) return Response.Data is
             SOAPAction : constant String := Status.SOAPAction (Request);
             Payload    : constant SOAP.Message.Payload.Object
               := SOAP.Message.XML.Load_Payload (AWS.Status.Payload (Request));
             Proc       : constant String
               := SOAP.Message.Payload.Procedure_Name (Payload);
          begin
             if SOAPAction = "..." then

                if Proc = "getPrice" then
                   return SOAP_getPrice (SOAPAction, Payload, Request);
                elsif ...
                   ...
                end if;

             else
                ...
             end if;


Note that the port to be used by the AWS server is described into the
server spec.

6.2.3 wsdl2aws
--------------

     Usage: wsdl2aws [options] <file|URL>

   It is possible to pass a `WSDL' file or direct `wsdl2aws' to a
`WSDL' document on the Web by passing it's `URL'.

`wsdl2aws' options are:

-q
     Quiet mode (no output)

-d
     Generate debug code. Will output some information about the
     payload to help debug a Web Service.

-a
     Generate using Ada style names. For example `getPrice' will be
     converted to `Get_Price'. This formatting is done for packages,
     routines and formal parameters.

-f
     Force creation of the file. Overwrite any exiting files with the
     same name.

-e
     Specify the default endpoint to use instead of the one found in the
     WSDL document.

-s
     Skip non supported `SOAP' routines. If `-s' is not used,
     `wsdl2aws' will exit with an error when a problem is found while
     parsing the `WSDL' document. This option is useful to skip
     routines using non supported types and still be able to compile the
     generated files.

-o name
     Specify the name of the local `WSDL' document. This option can be
     used only when using a Web `WSDL' document (i.e. passing an URL to
     `wsdl2aws').

-doc
     Handle document style binding as RPC ones. This is sometimes needed
     because some `WSDL' document specify a document style binding even
     though it is really an RPC one.

-v
     Verbose mode, display the parsed spec.

-v -v
     Verbose mode, display the parsed spec and lot of information while
     parsing the `WSDL' document tree.

-wsdl
     Add `WSDL' document as comment into the generated root unit.

-cvs
     Add CVS Id tag in every generated file.

-nostub
     Do not generated stubs, only skeletons are generated.

-noskel
     Do not generated skeletons, only stubs are generated.

-cb
     Generate a `SOAP' dispatcher callback routine for the server. This
     dispatcher routine contains the code to handle all the operations
     as described in the `WSDL' document. You need also to specify the
     `-spec' and/or `-types' options, see below.

-x operation
     Add `operation' to the list of `SOAP' operations to skip during the
     code generation. It is possible to specify multiple `-x' options
     on the command line.

-spec spec
     Specify the name of the spec containing the Ada implementation of
     the `SOAP' routines. This is used for example by the `-cb' option
     above to instantiate all the server side `SOAP' callbacks used by
     the main `SOAP' dispatcher routine. If `-types' is not specified,
     the type definitions are also used from this spec.

-types spec
     Specify the name of the spec containing the Ada types (record,
     array) used by `SOAP' routines specified with option `-spec'. If
     `-spec' is not specified, the spec definitions are also used from
     this spec.

-main filename
     Specify the name of the server's procedure main to generate. If
     file `<filename>.amt' (Ada Main Template) is present, it uses this
     template file to generate the main procedure. The template can
     reference the following variable tags:

    SOAP_SERVICE
          The name of the service as described into the `WSDL'
          document. This tag can be used to include the right units

               with @_SOAP_SERVICE_@.Client;
               with @_SOAP_SERVICE_@.CB;

    SOAP_VERSION
          The AWS's SOAP version.

    AWS_VERSION
          The AWS's version.

    UNIT_NAME
          The name of the generated unit. This is the name of the
          procedure that will be created.

               procedure @_UNIT_NAME_@ is
               begin
                  ...


-proxy name|IP
     Use this proxy to access the `WSDL' document and generate code to
     access to these Web Services via this proxy. The proxy can be
     specified by its DNS name or IP address.

-pu name
     User name for the proxy if proxy authentication required.

-pp password
     User password for the proxy if proxy authentication required.

-timeouts [timeouts | connect_timeout,send_timeout,receive_timeout ]
     Set the timeouts for the SOAP connection. The timeouts is either a
     single value used for the connect, send and receive timeouts or
     three values separated by a colon to set each timeout
     independently.

6.2.4 wsdl2aws behind the scene
-------------------------------

The `wsdl2aws' tool read a `WSDL' document and creates a root package
and a set of child packages as described below:

<root>
     This is the main package, it contains eventually the full `WSDL' in
     comment and the description of the services as read from the `WSDL'
     document.

<root>.Types
     This package contains the definitions of the types which are not
     `SOAP' base types. We find here the definitions of the `SOAP'
     structs and arrays with routines to convert them between the Ada
     and `SOAP' type model. A subtype definition is also created for
     every routine's returned type.  In fact, all definitions here are
     only alias or renaming of types and/or routines generated in other
     packages. The real definitions for structs, arrays, enumerations
     and derived types are generated into a package whose name depends
     on the name space used for these entities. This package act as a
     container for all definitions and it is the only one used in the
     other generated packages.

<root>.Client
     All spec to call Web Services.

<root>.Server
     All spec to build Web Services. These specs are all generic and
     must be instantiated with the right routine to create the web
     services.

<root>.CB
     The `SOAP' dispatcher callback routine.

6.2.5 wsdl2aws limitations
--------------------------

It is hard to know all current limitations as the `WSDL' and `SOAP'
world is quite complex. We list there all known limitations:

   * Some `SOAP' base types are not supported : date, time,
     xsd:hexBinary, decimal. All these are easy to add (except
     decimal), it is just not supported with the current version.

   * Multi-dimension arrays are not supported.

   * abstract types are not supported.

   * SOAP MIME attachments are not supported.

   * WSDL type inheritance not supported.

   * Only the RPC/Encoded SOAP messages' style is supported (the
     Document/Literal is not)


6.3 Using ada2wsdl and wsdl2aws together
========================================

Using both tools together is an effective way to build rapidely a `SOAP'
server. It can be said that doing so is quite trivial in fact. Let's
take the following spec:

     package Graphics is

        type Point is record
           X, Y : Float;
        end record;

        function Distance (P1, P2 : in Point) return Float;
        --  Returns the distance between points P1 and P2

     end Graphics;

We do not show the body here but we suppose it is implemented. To build
a server for this service it is as easy as:

     $ ada2wsdl -a http://localhost:8787 -o graphics.wsdl graphics.ads

The server will be available on localhost at port 8787.

     $ wsdl2aws -cb -main server -types graphics graphics.wsdl
     $ gnatmake server -largs ...

Options

`-cb'
     is to create the `SOAP' dispatcher callback routine,

`-main server'
     to generate the main server procedure in `server.adb',

`-types graphics'
     to use `graphics.ads' to get references from user's spec
     (reference to `Graphics.Point' for example).

7 Working with mails
********************

7.1 Sending e-mail
==================

`AWS' provides a complete API to send e-mail using `SMTP' protocol. You
need to have access to an SMTP server to use this feature. The API
covers sending simple mail with text message and/or with `MIME'
attachments (base64 encoded). Here are the steps to send a simple
e-mail:

   * Initialize the SMTP server

          SMTP_Server : SMTP.Receiver
             := SMTP.Client.Initialize ("smtp.hostname");

     Here `AWS' uses the default SMTP port to create an SMTP mail
     server but it is possible to specify a different one. The hostname
     specified must be a valid SMTP server.

   * Send the e-mail

     To send an e-mail there is many different API. Let's send a simple
     text mail.

          Status : SMTP.Status;

          SMTP.Client.Send
            (SMTP_Server,
             From    => SMTP.E_Mail ("Pascal Obry", "p.obry@wanadoo.fr"),
             To      => SMTP.E_Mail ("John Doe", "john.doe@here.com"),
             Subject => "About AWS SMTP protocol",
             Message => "AWS can now send mails",
             Status  => Status);

     Here Status will contain the SMTP returned status.

   * Check that everything is ok

     Using above status data it is possible to check that the message
     was sent or not by the server. The status contain a code and an
     error message, both of them can be retrieved using specific
     routines, *Note AWS.SMTP::. It is also possible to check that the
     call was successful with `SMTP.Is_Ok' routine.

          if not SMTP.Is_Ok (Status) then
             Put_Line ("Can't send message: " & SMTP.Status_Message (Status));
          end if;


In the above example, the message content was given as a string but it
is possible to specify a disk file. `AWS' can also send MIME messages
either from disk files or with in memory base64 encoded binary data.
The API provides also a way to send messages to multiple recipients at
the same time and to send messages with alternative contents (text and
HTML for example). These features are not described here, complete
documentation can be found on the spec *note AWS.SMTP:: and *note
AWS.SMTP.Client::.

7.2 Retrieving e-mail
=====================

`AWS' provides an API to retrieve e-mails from a `POP' mailbox. `POP'
stands for Post Office Protocol and is the main protocol used by
Internet Service Providers around the world. `IMAP' is another well
known protocol in this area but it is not supported by `AWS'.

We describes here the `POP' API. For a complete description see *note
AWS.POP::.

   * Opening the mailbox

     The first step is to authenticate using a user name and password.
     `AWS' supports two methods one called `Clear_Text' which is the
     most used and another one `APOP' which is more secure but almost
     not supported by `ISP' for the moment (and will probably never be
     supported as a more secure protocol named `SPA' -Secure Password
     Authentication- could be used instead).

          Mailbox : POP.Mailbox
             := POP.Initialize ("pop.hostname", "john.does", "mysuperpwd");

     The default Authentication method is `Clear_Text'.

   * Getting mailbox information

     When the connection is opened it is possible to get information
     about the mailbox like the number of messages or the total number
     of bytes in the mailbox.

          N     : constant Natural := POP.Message_Count (Mailbox);

          Bytes : constant Natural := POP.Size (Mailbox);

   * Retreiving individual e-mail

     Each message is numbered starting from 1. A function named `Get'
     will return a message given its mailbox's number.

          Message : constant POP.Message := POP.Get (Mailbox, 2, Remove => True);

     Remove can be set to `False' for the message to stay on the
     mailbox. The default value is `False'.

   * Iterating through the mailbox content

     Another way to retreive message is by using an iterator.

          procedure Print_Subject
            (Message : in     POP.Message
             Index   : in     Positive;
             Quit    : in out Boolean) is
          begin
             Text_IO.Put_Line (POP.Subject (Message));
          end Print_Message;

          procedure Print_All_Subjects is new POP.For_Every_Message (Print_Subject);

          ...

          Print_All_Subjects (Mailbox, Remove => True);

     It exists a set of routines on a `POP.Message' object to get the
     subject the content, the date or any headers. It is also possible
     to work with attachments. See point below.

   * Working with attachments

     A message can have a set of `MIME' attachments. The number of
     attachments can be retrieved using `Attachment_Count'.

          Message : constant POP.Message := ...;

          A_Count : constant Natural := POP.Attachment_Count (Message);

     As for messages it is possible to get a single attachment using its
     index in the message or by using an iterator.

          First_Attachment : constant POP.Attachment := POP.Get (Message, 1);

          procedure Write_Attachment
            (Attachment : in     POP.Attachment
             Index      : in     Positive;
             Quit       : in out Boolean) is
          begin
             POP.Write (Attachment, Directory => ".");
          end Print_Message;

          procedure Write_All_Attachments is new POP.For_Every_Attachment (Write_Attachment);

          ...

          Write_All_Attachments (Message);

     It is also possible to retrieve the attachment's filename, the
     content as a memory stream. *note AWS.POP::.

   * Closing the connection

          POP.Close (POP_Server);


8 LDAP
******

`AWS' provides a complete API to retrieve information from LDAP servers.
Note that there is no support for updating, modifying or deleting
information only to read information from the server.

The `AWS/LDAP' implementation is based on `OpenLDAP'. To build an LDAP
application you need to link with the `libldap.a' library. This library
is built by `AWS' on Windows based system and will use the
`wldap32.dll' as provided with Windows NT/2000/XP. On UNIX based
systems, you must install properly the `OpenLDAP' package.

The steps required to read information from an LDAP server are:

Initialize the LDAP directory
          declare
             Directory : LDAP.Client.Directory;
          begin
             Directory := LDAP.Client.Init (Host);

     Host is the hostname where the LDAP directory is running. It is
     possible to specify the port if the LDAP server does not use the
     default one.

Bind to the LDAP server
     This step is the way to pass a login/password if the LDAP server
     required an authentication. If not, the login/password must be
     empty strings.

          LDAP.Client.Bind (Directory, "", "");

Do the search
     For the search you must specify the base name, a filter, the scope
     and a set of attributes to retrieve.

          Response_Set := LDAP.Client.Search
            (Directory, Base_DN, Filter, LDAP.Client.LDAP_Scope_Subtree,
             LDAP.Client.Attributes
               ("cn", "sn", "telephonenumber"));

    Attributes
          The set of attributes to retrieve from the directory.

    Filter
          A set of values for some attributes. A filter is
          <attribute_name>=<value> where value can contain '*' at the
          end. For example "(cn=DUPON*)" will look for all entries
          where the common name is starting by the string "DUPON".

    Scope
          Define how far in the hierarchical directory the search will
          operate. It is either one level, all subtrees or on the base
          of the tree.

     For more information *note AWS.LDAP.Client::.

Iterate through the response set
     For this there is two iterators. `First_Entry'/`Next_Entry' or the
     generic high level iterator `For_Every_Entry'.

          declare
             Message : LDAP.Client.LDAP_Message;
          begin
             Message := LDAP.Client.First_Entry (Directory, Response_Set);

             while Message /= LDAP.Client.Null_LDAP_Message loop

                Do_Job (Message);

                Message := LDAP.Client.Next_Entry (Directory, Message);
             end loop;
          end;

Read attributes for each entry
     Each entry has an associated set of attributes. To retrieve
     attributes values there is two iterators. `First_Attribute' /
     `Next_Attribute' or the generic high level iterator
     `For_Every_Attribute'.

          declare
             BER : aliased LDAP.Client.BER_Element;

             Attr : constant String := LDAP.Client.First_Attribute
               (Directory, Message, BER'Unchecked_Access);
          begin
             Do_Job (Attr);

             loop
                declare
                   Attr : constant String := LDAP.Client.Next_Attribute
                    (Directory, Message, BER);
                begin
                   exit when Attr = "";
                   Do_Job (Attr);
                end;
            end loop;
          end;

Cleanup
     At the end of the processing it is important to release memory
     associated with LDAP objects.

          LDAP.Client.Free (Message);
          LDAP.Client.Unbind (Directory);


*note AWS.LDAP.Client:: for all high level supported API and
documentation.

Note that for complete information about `AWS/LDAP' you you should read
an LDAP API description. `AWS/LDAP' is only a binding and follow the
LDAP API closely.

9 Jabber
********

`AWS' support part of the Jabber protocol. At this stage only two kind
of messages are supported:

  1. Presence

     To check the presence status of a specific JID (Jabber ID)

  2. Message

     To send messages to a specific JID (Jabber ID)


Note that if you want an application to check the presence or send
message to users it is recommended to create a specific Jabber ID on the
server for this application and ask users to accept this specific user
to check their presence status.

9.1 Jabber presence
===================

To check for the presence of another JID you must first have the right
to do so. The jabber server won't let you see presence of another JID
unless the JID have permitted you to see its presence.

   * First declare the server and status objects

          Server : AWS.Jabber.Server;
          Status : AWS.Jabber.Presence_Status;

   * Connect to the server, you must have an account created and must
     know the login and password

          AWS.Jabber.Connect
            (Server, "jabber.domain.org", "joe", "mysuperpwd");

   * Then, to check the presence of user "john"

          AWS.Jabber.Check_Presence
            (Server, "john@jabber.domain.org", Status);

   * Then, you just have to close the server

          AWS.Jabber.Close (Server);


9.2 Jabber message
==================

To send a message to a specific JID, you must connect to the server as
above and close the server when you don't need to communicate with it
anymore. The only different part is to send the message, here is an
example:

     Send_Message
        (Server,
         JID     => "john@jabber.domain.org",
         Subject => "Hello there!",
         Content => "Are you using AWS ?");

It is as simple as that !

10 Resources
************

`AWS' support embedded resources. It means that it is possible to build
a fully self dependent executable. This is useful when distributing a
server. The server program contains the code but also the images (`PNG',
`JPEG', `GIF'), the templates, the `HTML' pages... more generally any
file the Web Server must serve to clients.

10.1 Building resources
=======================

To embbed the files into the executable you must build a resource tree.
This task is greatly simplified using `AWSRes' tool. For example let's
say that you want to build a simple server with a single page
containing some text and one PNG image. The text is handled directly in
the callback procedure and contain a reference to the image `logo.png'.
To build the resource tree:

     $ awsres logo.png

This will create a set of packages whose root is the unit `res' by
default. The resource tree is created. *note awsres tool:: for the
complete AWS's usage description.

`awsres' can also compress the resource files. This can be done by
using `awsres''s `-z' option. Compressed resources are handled
transparently. If the Web client supports compression the resource is
sent as-is otherwise a decompression stream will be created for the
resource to be decompressed on-the-fly while sending it.

10.2 Using resources
====================

This is really the simplest step. The resource tree must be linked with
your executable, to do so you just have to "with" the resource tree
root into one of your program unit. This will ensure that the resource
tree will be compiled and linked into the executable. `AWS' and
`Templates_Parser know' about resource files and will pick them up if
available.

Note that this is transparent to users. It is possible to build the
very same server based on standard files or resources files. The only
change in the code is to "with" or not the resource tree.

Note that `AWS' supports only a single resource tree. If more than one
resource tree is included into a program only one will be seen.

10.3 Stream resources
=====================

Users can build a response directly from a stream. In this case the
callback answer is built using `AWS.Response.Stream'. It creates a
resource object whose operations have been inherited from
`AWS.Resource.Stream.Stream_Type' and redefined by the user. So the
`Read' operation can dynamically create the result stream data, the
`End_Of_File' operation must returns `True' when the stream data is out
and so on. This feature is useful to let users completely create and
control dynamically `AWS''s response content.

   *note AWS.Resources.Streams::.

10.4 awsres tool
================

`AWSRes' is a tool to build resource files. It creates a root package
named `res' by default and a child package for each resource file.

Usage: awsres [-hrquz] file1 [-uz] [file2...]

`-h'
     Display help message.

`-q'
     Quiet mode.

`-r name'
     Set the root unit name. Default is `res'.

`-u'
     Add following files as uncompressed resources.

`-z'
     Add following files as compressed resources.


11 Status page
**************

The status page gives information about the `AWS' internal status. For
example it returns the server socket ID, the number of simultaneous
connection, the number of time a connection has been used...

To display the information `AWS' use a template file. The template file
(default is `aws_status.thtml') is an `HTML' file with some specific
tags recognized by the parser. For more information about how the
template parser works, please look for the template parser
documentation distributed with `AWS'.

Here are the tag variables recognized by `AWS' status page:

ABORTABLE_V (vector tag)
     A list of boolean. One for each connection. True means that this
     connection can be aborted if none is available. This is to be
     inserted in a template table.

ACCEPT_QUEUE_SIZE
     *note Configuration options::.

ACCEPTOR_LENGTH
     Number of sockets in the internal socket set.

ACTIVITY_COUNTER_V (vector tag)
     A list of natural. One for each connection. This is the number of
     request the connection has answered. This counter is reset each
     time the connection is closed. In other word this is the number of
     request a keep-alive connection has processed.

ACTIVITY_TIME_STAMP_V (vector tag)
     A list of date. One for each connection. This is the time of the
     latest request answered.

ADMIN
     URI to the administrative page.

CASE_SENSITIVE_PARAMETERS
     *note Configuration options::.

CHECK_URL_VALIDITY
     *note Configuration options::.

CLEANER_CLIENT_DATA_TIMEOUT
     *note Configuration options::.

CLEANER_CLIENT_HEADER_TIMEOUT
     *note Configuration options::.

CLEANER_SERVER_RESPONSE_TIMEOUT
     *note Configuration options::.

CLEANER_WAIT_FOR_CLIENT_TIMEOUT
     *note Configuration options::.

CURRENT_CONNECTIONS
     Number of current connections to the server.

ERROR_LOG (boolean tag)
     This is set to true if error logging is active.

ERROR_LOG_FILE
     The error log file full pathname.

ERROR_LOG_FILENAME_PREFIX
     *note Configuration options::.

ERROR_LOG_SPLIT_MODE
     *note Configuration options::.

FORCE_CLIENT_DATA_TIMEOUT
     *note Configuration options::.

FORCE_CLIENT_HEADER_TIMEOUT
     *note Configuration options::.

FORCE_SERVER_RESPONSE_TIMEOUT
     *note Configuration options::.

FORCE_WAIT_FOR_CLIENT_TIMEOUT
     *note Configuration options::.

FREE_SLOTS_KEEP_ALIVE_LIMIT
     *note Configuration options::.

LINE_STACK_SIZE
     *note Configuration options::.

KEYS_M (matrix tag)
     A list of set of keys (for each key correspond a value in the tag
     VALUES_L, see below). Each key in the vector tag start with an
     `HTML' "<td>" tag. This is to be able to display the key/value in
     column.

LOG (boolean tag)
     This is set to true if logging is active.

LOG_FILE
     The log file full pathname.

LOG_FILENAME_PREFIX
     *note Configuration options::.

LOG_FILE_DIRECTORY
     *note Configuration options::.

LOG_MODE
     The rotating log mode, this is either `NONE', `DAILY', `MONTHLY'
     or `EACH_RUN'.

LOGO
     A string to be placed in an img `HTML' tag. This is the name of
     the `AWS' logo image.

MAX_CONCURRENT_DOWNLOAD
     *note Configuration options::.

MAX_CONNECTION
     *note Configuration options::.

PEER_NAME_V (vector tag)
     A list of peer name. One for each connection. This is the name of
     the last peer connected to the slot.

PHASE_V (vector tag)
     What is the slot currently doing, for example Server_Processing or
     Closed.

RECEIVE_TIMEOUT
     *note Configuration options::.

REUSE_ADDRESS
     *note Configuration options::.

SECURITY
     A boolean set to True if this is a secure socket (HTTPS/SSL).

SECURITY_MODE
     *note Configuration options::.

SEND_TIMEOUT
     *note Configuration options::.

SERVER_HOST
     *note Configuration options::.

SERVER_NAME
     *note Configuration options::.

SERVER_PORT
     *note Configuration options::.

SERVER_SOCK
     Server socket ID.

SESSION
     *note Configuration options::.

SESSION_CLEANUP_INTERVAL
     Number of seconds between each run of the session cleanup task.
     This task will remove all session data that have been obsoleted.

SESSION_LIFETIME
     Number of seconds to keep session information. After this period a
     session is obsoleted and will be removed at next cleanup.

SESSION_NAME
     *note Configuration options::.

SESSIONS_TERMINATE_V (vector tag)
     A list of time. Each item correspond to the time when the session
     will be obsoleted.

SESSIONS_TS_V (vector tag)
     A list of time stamp. Each item correspond to a session last
     access time.

SESSIONS_V (vector tag)
     A list of session ID.

SLOT_ACTIVITY_COUNTER_V (vector tag)
     A list of natural. One for each connection. This is the total
     number of requests the slot has answered. This counter is never
     reseted.

SOCK_V (vector tag)
     A list of sockets ID. One for each connection.

STATUS_PAGE
     *note Configuration options::.

START_TIME
     A timestamp in YYYY-MM-DD HH:MM:SS format. When the server was
     started.

TRANSIENT_CLEANUP_INTERVAL
     *note Configuration options::.

TRANSIENT_LIFETIME
     *note Configuration options::.

UPLOAD_DIRECTORY
     *note Configuration options::.

UPLOAD_SIZE_LIMIT
     *note Configuration options::.

VALUES_M (matrix tag)
     A list of set of values (for each value correspond a key in the
     vector tag KEYS_L, see above). Each key in the vector tag start
     with an `HTML' "<td>" tag. This is to be able to display the
     key/value in column.

VERSION
     `AWS' version string.

WWW_ROOT
     *note Configuration options::.


There is also all `Templates_Parser' specific tags. This is not listed
here please have a look at the `Templates_Parser' documentation
distributed with `AWS'.

Appendix A References
*********************

Here is a list of documents used to implement `AWS', the `SOAP' support
and associated services:

RFC 0821
                               SIMPLE MAIL TRANSFER PROTOCOL

                                     Jonathan B. Postel
                                        August 1982

                               Information Sciences Institute
                             University of Southern California
                                     4676 Admiralty Way
                             Marina del Rey, California  90291

RFC 1867
          Network Working Group                                           E. Nebel
          Request For Comments: 1867                                   L. Masinter
          Category: Experimental                                 Xerox Corporation
                                                                     November 1995


                               Form-based File Upload in HTML

RFC 1939
          Network Working Group                                           J. Myers
          Request for Comments: 1939                               Carnegie Mellon
          STD: 53                                                          M. Rose
          Obsoletes: 1725                             Dover Beach Consulting, Inc.
          Category: Standards Track                                       May 1996


                              Post Office Protocol - Version 3

RFC 1945
          Network Working Group                                     T. Berners-Lee
          Request for Comments: 1945                                       MIT/LCS
          Category: Informational                                      R. Fielding
                                                                         UC Irvine
                                                                        H. Frystyk
                                                                           MIT/LCS
                                                                          May 1996


                          Hypertext Transfer Protocol -- HTTP/1.0

RFC 2049
          Network Working Group                                          N. Freed
          Request for Comments: 2049                                     Innosoft
          Obsoletes: 1521, 1522, 1590                               N. Borenstein
          Category: Standards Track                                 First Virtual
                                                                    November 1996


                           Multipurpose Internet Mail Extensions
                                     (MIME) Part Five:
                             Conformance Criteria and Examples

RFC 2109
          Network Working Group                                         D. Kristol
          Request for Comments: 2109        Bell Laboratories, Lucent Technologies
          Category: Standards Track                                    L. Montulli
                                                           Netscape Communications
                                                                     February 1997


                              HTTP State Management Mechanism

RFC 2195
          Network Working Group                                       J. Klensin
          Request for Comments: 2195                                    R. Catoe
          Category: Standards Track                                 P. Krumviede
          Obsoletes: 2095                                                    MCI
                                                                  September 1997


                 IMAP/POP AUTHorize Extension for Simple Challenge/Response

RFC 2554
          Network Working Group                                           J. Myers
          Request for Comments: 2554                       Netscape Communications
          Category: Standards Track                                     March 1999


                                   SMTP Service Extension
                                     for Authentication

RFC 2616
          Network Working Group                                      R. Fielding
          Request for Comments: 2616                                   UC Irvine
          Obsoletes: 2068                                              J. Gettys
          Category: Standards Track                                   Compaq/W3C
                                                                        J. Mogul
                                                                          Compaq
                                                                      H. Frystyk
                                                                         W3C/MIT
                                                                     L. Masinter
                                                                           Xerox
                                                                        P. Leach
                                                                       Microsoft
                                                                  T. Berners-Lee
                                                                         W3C/MIT
                                                                       June 1999


                          Hypertext Transfer Protocol -- HTTP/1.1

RFC 2617
          Network Working Group                                          J. Franks
          Request for Comments: 2617                       Northwestern University
          Obsoletes: 2069                                          P. Hallam-Baker
          Category: Standards Track                                 Verisign, Inc.
                                                                      J. Hostetler
                                                                   AbiSource, Inc.
                                                                       S. Lawrence
                                                             Agranat Systems, Inc.
                                                                          P. Leach
                                                             Microsoft Corporation
                                                                       A. Luotonen
                                               Netscape Communications Corporation
                                                                        L. Stewart
                                                                 Open Market, Inc.
                                                                         June 1999


                HTTP Authentication: Basic and Digest Access Authentication

draft 302
          Transport Layer Security Working Group                  Alan O. Freier
          INTERNET-DRAFT                                 Netscape Communications
          Expire in six months                                    Philip Karlton
                                                         Netscape Communications
                                                                  Paul C. Kocher
                                                          Independent Consultant
                                                               November 18, 1996


                                    The SSL Protocol
                                      Version 3.0

SOAP (W3C Note 08 May 2000)
          Simple Object Access Protocol (SOAP) 1.1

          W3C Note 08 May 2000

          This version:
             http://www.w3.org/TR/2000/NOTE-SOAP-20000508

          Latest version:
             http://www.w3.org/TR/SOAP

          Authors (alphabetically):
             Don Box, DevelopMentor
             David Ehnebuske, IBM
             Gopal Kakivaya, Microsoft
             Andrew Layman, Microsoft
             Noah Mendelsohn, Lotus Development Corp.
             Henrik Frystyk Nielsen, Microsoft
             Satish Thatte, Microsoft
             Dave Winer, UserLand Software, Inc.

          Copyright 2000 DevelopMentor, International Business Machines Corporation,
          Lotus Development Corporation, Microsoft, UserLand Software

     `http://www.w3.org/TR/SOAP/'

A Busy Developer's Guide to SOAP 1.1
          By Dave Winer, Jake Savin, UserLand Software, 4/2/01.

     `http://www.soapware.org/bdg'


Appendix B AWS API Reference
****************************

B.1 AWS
=======


B.2 AWS.Attachments
===================


B.3 AWS.Client
==============


B.4 AWS.Client.Hotplug
======================


B.5 AWS.Communication
=====================


B.6 AWS.Communication.Client
============================


B.7 AWS.Communication.Server
============================


B.8 AWS.Config
==============


B.9 AWS.Config.Ini
==================


B.10 AWS.Config.Set
===================


B.11 AWS.Containers.Tables
==========================


B.12 AWS.Cookie
===============


B.13 AWS.Default
================


B.14 AWS.Dispatchers
====================


B.15 AWS.Dispatchers.Callback
=============================


B.16 AWS.Exceptions
===================


B.17 AWS.Headers
================


B.18 AWS.Headers.Values
=======================


B.19 AWS.Jabber
===============


B.20 AWS.LDAP.Client
====================


B.21 AWS.Log
============


B.22 AWS.Messages
=================


B.23 AWS.MIME
=============


B.24 AWS.Net
============


B.25 AWS.Net.Buffered
=====================


B.26 AWS.Net.Log
================


B.27 AWS.Net.Log.Callbacks
==========================


B.28 AWS.Net.SSL
================


B.29 AWS.Net.SSL.Certificate
============================


B.30 AWS.Parameters
===================


B.31 AWS.POP
============


B.32 AWS.Resources
==================


B.33 AWS.Resources.Embedded
===========================


B.34 AWS.Resources.Files
========================


B.35 AWS.Resources.Streams
==========================


B.36 AWS.Resources.Streams.Disk
===============================


B.37 AWS.Resources.Streams.Disk.Once
====================================


B.38 AWS.Resources.Streams.Memory
=================================


B.39 AWS.Resources.Streams.Memory.ZLib
======================================


B.40 AWS.Resources.Streams.Pipe
===============================


B.41 AWS.Response
=================


B.42 AWS.Server
===============


B.43 AWS.Server.Hotplug
=======================


B.44 AWS.Server.Log
===================


B.45 AWS.Server.Push
====================


B.46 AWS.Server.Status
======================


B.47 AWS.Services.Callbacks
===========================


B.48 AWS.Services.Directory
===========================


B.49 AWS.Services.Dispatchers
=============================


B.50 AWS.Services.Dispatchers.Linker
====================================


B.51 AWS.Services.Dispatchers.Method
====================================


B.52 AWS.Services.Dispatchers.URI
=================================


B.53 AWS.Services.Dispatchers.Virtual_Host
==========================================


B.54 AWS.Services.Download
==========================


B.55 AWS.Services.Page_Server
=============================


B.56 AWS.Services.Split_Pages
=============================


B.57 AWS.Services.Split_Pages.Alpha
===================================


B.58 AWS.Services.Split_Pages.Alpha.Bounded
===========================================


B.59 AWS.Services.Split_Pages.Uniform
=====================================


B.60 AWS.Services.Split_Pages.Uniform.Alpha
===========================================


B.61 AWS.Services.Split_Pages.Uniform.Overlapping
=================================================


B.62 AWS.Services.Transient_Pages
=================================


B.63 AWS.Services.Web_Block
===========================


B.64 AWS.Services.Web_Block.Context
===================================


B.65 AWS.Services.Web_Block.Registry
====================================


B.66 AWS.Session
================


B.67 AWS.SMTP
=============


B.68 AWS.SMTP.Client
====================


B.69 AWS.Status
===============


B.70 AWS.Templates
==================


B.71 AWS.Translator
===================


B.72 AWS.URL
============


B.73 SOAP
=========


B.74 SOAP.Client
================


B.75 SOAP.Dispatchers
=====================


B.76 SOAP.Dispatchers.Callback
==============================


B.77 SOAP.Message
=================


B.78 SOAP.Message.XML
=====================


B.79 SOAP.Parameters
====================


B.80 SOAP.Types
===============


Index
*****

ABORTABLE_V:                                   See 11.       (line 4933)
ACCEPT_QUEUE_SIZE:                             See 11.       (line 4938)
Accept_Queue_Size:                             See 3.4.      (line 1136)
ACCEPTOR_LENGTH:                               See 11.       (line 4941)
ACTIVITY_COUNTER_V:                            See 11.       (line 4944)
ACTIVITY_TIME_STAMP_V:                         See 11.       (line 4950)
ada2wsdl <1>:                                  See 6.1.      (line 3777)
ada2wsdl:                                      See 6.        (line 3766)
ada2wsdl limitations:                          See 6.1.4.    (line 4116)
ADMIN:                                         See 11.       (line 4954)
Admin_Password:                                See 3.4.      (line 1141)
Admin_URI <1>:                                 See 3.4.      (line 1148)
Admin_URI:                                     See 3.2.1.    (line  651)
Ajax:                                          See 4.7.2.    (line 2619)
authentication:                                See 3.7.      (line 1537)
AWS:                                           See B.1.      (line 5323)
AWS.Attachments:                               See B.2.      (line 5327)
AWS.Client:                                    See B.3.      (line 5331)
AWS.Client.Hotplug:                            See B.4.      (line 5335)
AWS.Communication:                             See B.5.      (line 5339)
AWS.Communication.Client:                      See B.6.      (line 5343)
AWS.Communication.Server:                      See B.7.      (line 5347)
AWS.Config:                                    See B.8.      (line 5351)
AWS.Config.Ini:                                See B.9.      (line 5355)
AWS.Config.Set:                                See B.10.     (line 5359)
AWS.Containers.Tables:                         See B.11.     (line 5363)
AWS.Cookie:                                    See B.12.     (line 5367)
AWS.Default:                                   See B.13.     (line 5371)
AWS.Dispatchers:                               See B.14.     (line 5375)
AWS.Dispatchers.Callback:                      See B.15.     (line 5379)
AWS.Exceptions:                                See B.16.     (line 5383)
AWS.Headers:                                   See B.17.     (line 5387)
AWS.Headers.Values:                            See B.18.     (line 5391)
aws.ini:                                       See 3.4.      (line 1118)
AWS.Jabber:                                    See B.19.     (line 5395)
AWS.LDAP.Client:                               See B.20.     (line 5399)
AWS.Log:                                       See B.21.     (line 5403)
AWS.Messages:                                  See B.22.     (line 5407)
AWS.MIME:                                      See B.23.     (line 5411)
AWS.Net:                                       See B.24.     (line 5415)
AWS.Net.Buffered:                              See B.25.     (line 5419)
AWS.Net.Log:                                   See B.26.     (line 5423)
AWS.Net.Log.Callbacks:                         See B.27.     (line 5427)
AWS.Net.SSL:                                   See B.28.     (line 5431)
AWS.Net.SSL.Certificate:                       See B.29.     (line 5435)
AWS.Net.Std:                                   See 2.2.      (line  307)
AWS.Parameters:                                See B.30.     (line 5439)
AWS.POP:                                       See B.31.     (line 5443)
AWS.Resources:                                 See B.32.     (line 5447)
AWS.Resources.Embedded:                        See B.33.     (line 5451)
AWS.Resources.Files:                           See B.34.     (line 5455)
AWS.Resources.Streams:                         See B.35.     (line 5459)
AWS.Resources.Streams.Disk:                    See B.36.     (line 5463)
AWS.Resources.Streams.Disk.Once:               See B.37.     (line 5467)
AWS.Resources.Streams.Memory:                  See B.38.     (line 5471)
AWS.Resources.Streams.Memory.ZLib:             See B.39.     (line 5475)
AWS.Resources.Streams.Pipe:                    See B.40.     (line 5479)
AWS.Response:                                  See B.41.     (line 5483)
AWS.Server:                                    See B.42.     (line 5487)
AWS.Server.Hotplug:                            See B.43.     (line 5491)
AWS.Server.Log:                                See B.44.     (line 5495)
AWS.Server.Push:                               See B.45.     (line 5499)
AWS.Server.Status:                             See B.46.     (line 5503)
AWS.Services.Callbacks:                        See B.47.     (line 5507)
AWS.Services.Directory:                        See B.48.     (line 5511)
AWS.Services.Dispatchers:                      See B.49.     (line 5515)
AWS.Services.Dispatchers.Linker:               See B.50.     (line 5519)
AWS.Services.Dispatchers.Method:               See B.51.     (line 5523)
AWS.Services.Dispatchers.URI:                  See B.52.     (line 5527)
AWS.Services.Dispatchers.Virtual_Host:         See B.53.     (line 5531)
AWS.Services.Download:                         See B.54.     (line 5535)
AWS.Services.Page_Server:                      See B.55.     (line 5539)
AWS.Services.Split_Pages:                      See B.56.     (line 5543)
AWS.Services.Split_Pages.Alpha:                See B.57.     (line 5547)
AWS.Services.Split_Pages.Alpha.Bounded:        See B.58.     (line 5551)
AWS.Services.Split_Pages.Alpha.Uniform:        See B.59.     (line 5555)
AWS.Services.Split_Pages.Alpha.Uniform.Alpha:  See B.60.     (line 5559)
AWS.Services.Split_Pages.Alpha.Uniform.Overlapping:See B.61. (line 5563)
AWS.Services.Transient_Pages:                  See B.62.     (line 5567)
AWS.Services.Web_Block:                        See B.63.     (line 5571)
AWS.Services.Web_Block.Context:                See B.64.     (line 5575)
AWS.Services.Web_Block.Registry:               See B.65.     (line 5579)
AWS.Session:                                   See B.66.     (line 5583)
AWS.SMTP:                                      See B.67.     (line 5587)
AWS.SMTP.Client:                               See B.68.     (line 5591)
AWS.Status:                                    See B.69.     (line 5595)
AWS.Templates:                                 See B.70.     (line 5599)
AWS.Translator:                                See B.71.     (line 5603)
AWS.URL:                                       See B.72.     (line 5607)
aws_action_clear.tjs:                          See 4.7.2.    (line 2619)
aws_action_replace.tjs:                        See 4.7.2.    (line 2619)
awsres:                                        See 10.4.     (line 4896)
basic:                                         See 3.7.      (line 1537)
Building <1>:                                  See 2.4.      (line  363)
Building:                                      See 2.3.      (line  324)
Building resources:                            See 10.1.     (line 4843)
Callback <1>:                                  See 3.2.2.    (line  729)
Callback:                                      See 3.2.1.    (line  639)
Callback procedure:                            See 3.2.2.    (line  729)
Callback, dispatcher:                          See 4.2.1.    (line 2244)
Callback, dispatcher API:                      See B.15.     (line 5379)
CASE_SENSITIVE_PARAMETERS:                     See 11.       (line 4957)
Case_Sensitive_Parameters <1>:                 See 3.4.      (line 1162)
Case_Sensitive_Parameters:                     See 3.2.1.    (line  677)
certificate <1>:                               See 3.14.2.   (line 2038)
certificate:                                   See 3.14.1.   (line 2021)
Certificate (string):                          See 3.4.      (line 1152)
CHECK_URL_VALIDITY:                            See 11.       (line 4960)
Check_URL_Validity:                            See 3.4.      (line 1166)
CLEANER_CLIENT_DATA_TIMEOUT:                   See 11.       (line 4963)
Cleaner_Client_Data_Timeout:                   See 3.4.      (line 1180)
CLEANER_CLIENT_HEADER_TIMEOUT:                 See 11.       (line 4966)
Cleaner_Client_Header_Timeout:                 See 3.4.      (line 1176)
CLEANER_SERVER_RESPONSE_TIMEOUT:               See 11.       (line 4969)
Cleaner_Server_Response_Timeout:               See 3.4.      (line 1185)
CLEANER_WAIT_FOR_CLIENT_TIMEOUT:               See 11.       (line 4972)
Cleaner_Wait_For_Client_Timeout:               See 3.4.      (line 1171)
client HTTP:                                   See 3.17.     (line 2150)
Client protocol:                               See 3.17.     (line 2150)
Communication:                                 See 3.9.      (line 1629)
Communication, Client:                         See 3.9.1.    (line 1643)
Communication, Server:                         See 3.9.2.    (line 1662)
Configuration options:                         See 3.4.      (line 1109)
Cookies:                                       See 3.6.      (line 1459)
cross-platforms:                               See 2.4.      (line  363)
CURRENT_CONNECTIONS:                           See 11.       (line 4975)
digest:                                        See 3.7.      (line 1537)
Directory browser:                             See 4.1.      (line 2216)
Directory_Browser_Page:                        See 3.4.      (line 1190)
Dispatchers:                                   See 4.2.      (line 2227)
Dispatchers callback:                          See 4.2.1.    (line 2244)
Dispatchers Linker:                            See 4.2.7.    (line 2339)
Dispatchers method:                            See 4.2.2.    (line 2256)
Dispatchers SOAP:                              See 4.2.8.    (line 2346)
Dispatchers Timer:                             See 4.2.6.    (line 2300)
Dispatchers Transient pages:                   See 4.2.5.    (line 2292)
Dispatchers URI:                               See 4.2.3.    (line 2266)
Dispatchers virtual host:                      See 4.2.4.    (line 2275)
Distributing:                                  See 3.2.4.    (line  869)
Down_Image:                                    See 3.4.      (line 1194)
Download Manager:                              See 4.6.      (line 2474)
draft 302:                                     See Appendix A.
                                                             (line 5273)
ERROR_LOG:                                     See 11.       (line 4978)
ERROR_LOG_FILE:                                See 11.       (line 4981)
ERROR_LOG_FILENAME_PREFIX:                     See 11.       (line 4984)
ERROR_LOG_SPLIT_MODE:                          See 11.       (line 4987)
exception handler:                             See 3.15.     (line 2068)
Exceptions, Unexpected exceptions, Exceptions handler:See B.16.
                                                             (line 5383)
Exchange_Certificate:                          See 3.4.      (line 1209)
File upload:                                   See 3.8.      (line 1586)
FORCE_CLIENT_DATA_TIMEOUT:                     See 11.       (line 4990)
Force_Client_Data_Timeout:                     See 3.4.      (line 1223)
FORCE_CLIENT_HEADER_TIMEOUT:                   See 11.       (line 4993)
Force_Client_Header_Timeout:                   See 3.4.      (line 1218)
FORCE_SERVER_RESPONSE_TIMEOUT:                 See 11.       (line 4996)
Force_Server_Response_Timeout:                 See 3.4.      (line 1228)
FORCE_WAIT_FOR_CLIENT_TIMEOUT:                 See 11.       (line 4999)
Force_Wait_For_Client_Timeout:                 See 3.4.      (line 1213)
Form parameters:                               See 3.2.3.    (line  810)
FREE_SLOTS_KEEP_ALIVE_LIMIT:                   See 11.       (line 5002)
Free_Slots_Keep_Alive_Limit:                   See 3.4.      (line 1233)
GNAT:                                          See 2.1.      (line  276)
GNU/Ada:                                       See 2.1.      (line  276)
Hello world:                                   See 3.2.2.    (line  754)
hotplug:                                       See 3.10.     (line 1694)
Hotplug_Port:                                  See 3.4.      (line 1243)
HTML File Upload:                              See Appendix A.
                                                             (line 5161)
HTTP Authentication:                           See Appendix A.
                                                             (line 5253)
HTTP declaration:                              See 3.2.1.    (line  597)
HTTP state:                                    See 3.6.      (line 1459)
HTTP/1.0:                                      See Appendix A.
                                                             (line 5180)
HTTP/1.1:                                      See Appendix A.
                                                             (line 5233)
HTTPS:                                         See 3.14.     (line 2010)
IMAP/POP:                                      See Appendix A.
                                                             (line 5214)
ini file:                                      See 3.4.      (line 1118)
Installing:                                    See 2.6.      (line  483)
Jabber:                                        See 9.        (line 4770)
Jabber Binding:                                See B.19.     (line 5395)
Jabber message:                                See 9.2.      (line 4818)
Jabber presence:                               See 9.1.      (line 4790)
Key:                                           See 3.4.      (line 1247)
KEYS_M:                                        See 11.       (line 5008)
LDAP:                                          See 8.        (line 4656)
LDAP Binding:                                  See B.20.     (line 5399)
LDAP Directory:                                See 8.        (line 4656)
libcrypto.a:                                   See 2.3.      (line  341)
libssl.a:                                      See 2.3.      (line  341)
Lightweight Directory Access Protocol:         See 8.        (line 4656)
LINE_STACK_SIZE:                               See 11.       (line 5005)
Line_Stack_Size:                               See 3.4.      (line 1251)
linker, dispatcher:                            See 4.2.7.    (line 2339)
LOG:                                           See 11.       (line 5014)
Log.Flush:                                     See 3.13.     (line 1912)
Log.Start:                                     See 3.13.     (line 1912)
Log.Start_Error:                               See 3.13.     (line 1912)
Log.Stop:                                      See 3.13.     (line 1912)
Log.Stop_Error:                                See 3.13.     (line 1912)
Log_Extended_Fields:                           See 3.4.      (line 1256)
LOG_FILE:                                      See 11.       (line 5017)
LOG_FILE_DIRECTORY:                            See 11.       (line 5023)
Log_File_Directory:                            See 3.4.      (line 1262)
LOG_FILENAME_PREFIX:                           See 11.       (line 5020)
Log_Filename_Prefix:                           See 3.4.      (line 1198)
LOG_MODE:                                      See 11.       (line 5026)
Log_Split_Mode:                                See 3.4.      (line 1203)
LOGO:                                          See 11.       (line 5030)
Logo_Image:                                    See 3.4.      (line 1277)
logs:                                          See 3.13.     (line 1912)
MAX_CONCURRENT_DOWNLOAD:                       See 11.       (line 5034)
Max_Concurrent_Download:                       See 3.4.      (line 1281)
MAX_CONNECTION:                                See 11.       (line 5037)
Max_Connection <1>:                            See 3.4.      (line 1285)
Max_Connection:                                See 3.2.1.    (line  644)
method, dispatcher:                            See 4.2.2.    (line 2256)
MIME:                                          See Appendix A.
                                                             (line 5192)
MIME_Types:                                    See 3.4.      (line 1298)
OpenLDAP:                                      See 2.1.      (line  292)
OpenSSL:                                       See 2.1.      (line  284)
Page server <1>:                               See 4.3.      (line 2357)
Page server:                                   See 3.2.2.    (line  784)
pages, split:                                  See 4.5.      (line 2427)
pages, transient:                              See 4.4.      (line 2406)
Parameters:                                    See 3.2.3.    (line  810)
Parameters Get:                                See 3.2.3.    (line  844)
Parameters Get_Name:                           See 3.2.3.    (line  847)
Payload:                                       See 5.2.1.    (line 3582)
PEER_NAME_V:                                   See 11.       (line 5040)
PHASE_V:                                       See 11.       (line 5044)
POP <1>:                                       See Appendix A.
                                                             (line 5170)
POP:                                           See 7.2.      (line 4553)
Port:                                          See 3.2.1.    (line  662)
Post Office Protocol:                          See 7.2.      (line 4553)
program_name.ini:                              See 3.4.      (line 1122)
Push:                                          See 3.11.     (line 1797)
RECEIVE_TIMEOUT:                               See 11.       (line 5048)
Receive_Timeout:                               See 3.4.      (line 1302)
References:                                    See Appendix A.
                                                             (line 5146)
Resources:                                     See 10.       (line 4834)
resources:                                     See 3.2.2.    (line  738)
Retrieving e-mail:                             See 7.2.      (line 4553)
REUSE_ADDRESS:                                 See 11.       (line 5051)
Reuse_Address:                                 See 3.4.      (line 1306)
RFC 0821:                                      See Appendix A.
                                                             (line 5150)
RFC 1867:                                      See Appendix A.
                                                             (line 5161)
RFC 1939:                                      See Appendix A.
                                                             (line 5170)
RFC 1945:                                      See Appendix A.
                                                             (line 5180)
RFC 2049:                                      See Appendix A.
                                                             (line 5192)
RFC 2109:                                      See Appendix A.
                                                             (line 5204)
RFC 2195:                                      See Appendix A.
                                                             (line 5214)
RFC 2554:                                      See Appendix A.
                                                             (line 5224)
RFC 2616:                                      See Appendix A.
                                                             (line 5233)
RFC 2617:                                      See Appendix A.
                                                             (line 5253)
Secure server:                                 See 3.14.     (line 2010)
SECURITY:                                      See 11.       (line 5054)
Security:                                      See 3.2.1.    (line  668)
SECURITY_MODE:                                 See 11.       (line 5057)
Security_Mode:                                 See 3.4.      (line 1313)
Self dependant:                                See 10.       (line 4834)
Send:                                          See 3.11.     (line 1861)
Send_Buffer_Size:                              See 3.4.      (line 1317)
SEND_TIMEOUT:                                  See 11.       (line 5060)
Send_Timeout:                                  See 3.4.      (line 1321)
Send_To:                                       See 3.11.     (line 1857)
Sending e-mail:                                See 7.1.      (line 4496)
Sending message:                               See 3.9.      (line 1629)
Server Push:                                   See 3.11.     (line 1797)
SERVER_HOST:                                   See 11.       (line 5063)
Server_Host:                                   See 3.4.      (line 1325)
SERVER_NAME:                                   See 11.       (line 5066)
Server_Name:                                   See 3.4.      (line 1331)
SERVER_PORT:                                   See 11.       (line 5069)
Server_Port:                                   See 3.4.      (line 1335)
SERVER_SOCK:                                   See 11.       (line 5072)
SESSION:                                       See 11.       (line 5075)
Session <1>:                                   See 3.5.      (line 1400)
Session <2>:                                   See 3.4.      (line 1340)
Session:                                       See 3.2.1.    (line  672)
SESSION_CLEANUP_INTERVAL:                      See 11.       (line 5078)
Session_Cleanup_Interval (duration):           See 3.4.      (line 1354)
SESSION_LIFETIME:                              See 11.       (line 5082)
Session_Lifetime (duration):                   See 3.4.      (line 1349)
SESSION_NAME:                                  See 11.       (line 5086)
Session_Name:                                  See 3.4.      (line 1344)
SESSIONS_TERMINATE_V:                          See 11.       (line 5089)
SESSIONS_TS_V:                                 See 11.       (line 5093)
SESSIONS_V:                                    See 11.       (line 5097)
Simple Mail Transfer Protocol:                 See 7.1.      (line 4496)
Simple Object Access Protocol:                 See 5.        (line 3498)
Simple Page server:                            See 4.3.      (line 2357)
Simple server:                                 See 3.2.2.    (line  784)
SLOT_ACTIVITY_COUNTER_V:                       See 11.       (line 5100)
SMTP <1>:                                      See Appendix A.
                                                             (line 5150)
SMTP:                                          See 7.1.      (line 4496)
SMTP Authentication:                           See Appendix A.
                                                             (line 5224)
SOAP:                                          See 5.        (line 3498)
SOAP (API):                                    See B.73.     (line 5611)
SOAP 1.1:                                      See Appendix A.
                                                             (line 5286)
SOAP Client:                                   See 5.1.      (line 3523)
SOAP Dispatcher:                               See 5.2.2.    (line 3710)
SOAP Server:                                   See 5.2.      (line 3570)
SOAP, dispatcher:                              See 4.2.8.    (line 2346)
SOAP.Client:                                   See B.74.     (line 5615)
SOAP.Dispatchers:                              See B.75.     (line 5619)
SOAP.Dispatchers.Callback <1>:                 See B.76.     (line 5623)
SOAP.Dispatchers.Callback:                     See 5.2.2.    (line 3748)
SOAP.Message:                                  See B.77.     (line 5627)
SOAP.Message.XML:                              See B.78.     (line 5631)
SOAP.Parameters:                               See B.79.     (line 5635)
SOAP.Types:                                    See B.80.     (line 5639)
SOAPAction:                                    See 5.2.      (line 3570)
SOCK_V:                                        See 11.       (line 5105)
Socket log:                                    See 3.16.     (line 2138)
split pages:                                   See 4.5.      (line 2427)
SSL <1>:                                       See Appendix A.
                                                             (line 5273)
SSL:                                           See 3.14.3.   (line 2059)
START_TIME:                                    See 11.       (line 5111)
starting server:                               See 3.2.1.    (line  601)
Static Page server:                            See 4.3.      (line 2357)
Status:                                        See 11.       (line 4920)
STATUS_PAGE:                                   See 11.       (line 5108)
Status_Page:                                   See 3.4.      (line 1359)
Stream resources:                              See 10.3.     (line 4882)
timer, dispatcher:                             See 4.2.6.    (line 2300)
TLS:                                           See 3.14.3.   (line 2059)
transient pages:                               See 4.4.      (line 2406)
transient pages, dispatcher:                   See 4.2.5.    (line 2292)
TRANSIENT_CLEANUP_INTERVAL:                    See 11.       (line 5115)
Transient_Cleanup_Interval:                    See 3.4.      (line 1363)
TRANSIENT_LIFETIME:                            See 11.       (line 5118)
Transient_Lifetime:                            See 3.4.      (line 1367)
Up_Image:                                      See 3.4.      (line 1372)
upload, client:                                See 3.17.     (line 2200)
upload, server:                                See 3.8.      (line 1586)
UPLOAD_DIRECTORY:                              See 11.       (line 5121)
Upload_Directory:                              See 3.4.      (line 1376)
UPLOAD_SIZE_LIMIT:                             See 11.       (line 5124)
URI, dispatcher:                               See 4.2.3.    (line 2266)
Using resources:                               See 10.2.     (line 4865)
Utils.SOAP_Wrapper:                            See 5.2.2.    (line 3667)
VALUES_M:                                      See 11.       (line 5127)
VERSION:                                       See 11.       (line 5133)
virtual host, dispatcher:                      See 4.2.4.    (line 2275)
we_icons:                                      See 4.7.1.    (line 2600)
we_js:                                         See 4.7.1.    (line 2600)
Web Blocks:                                    See 4.8.      (line 3034)
web cross-references:                          See 4.9.      (line 3438)
Web Elements:                                  See 4.7.      (line 2577)
Web Service Definition Language <1>:           See 6.        (line 3755)
Web Service Definition Language:               See 5.        (line 3512)
Web_Server:                                    See 3.2.1.    (line  632)
webxref:                                       See 4.9.      (line 3438)
Working with Server sockets:                   See 3.12.     (line 1873)
WSDL <1>:                                      See 6.        (line 3755)
WSDL:                                          See 5.        (line 3512)
WSDL, Client:                                  See 6.2.1.    (line 4131)
WSDL, Server:                                  See 6.2.2.    (line 4176)
wsdl2aws <1>:                                  See 6.2.3.    (line 4261)
wsdl2aws:                                      See 6.        (line 3769)
wsdl2aws limitations:                          See 6.2.5.    (line 4431)
WWW_ROOT:                                      See 11.       (line 5136)
WWW_Root:                                      See 3.4.      (line 1381)
