## Chapter 14. Scripting Implementations

## 14.1. I. Select a scripting implementation

Level: Beginner

Red5 includes interpreters for the following scripting languages:

- Javascript - version 1.6 (Mozilla Rhino version 1.6 R7)

- JRuby - version 1.0.1 (Ruby version 1.8.5)

- Jython - version 2.2 (Python version 2.1)

- Groovy - version 1.0

- Beanshell - version 2.0b4

Future versions may include:

- JudoScript

- Scala

- PHP (This one is non-trivial, I may just provide a bridge)

- Actionscript (Maybe SSAS)

The scripting implementation classes are pre-specified in the following locations depending upon your Java version:

Java5 - js-engine.jar, jython-engine.jar, groovy-engine.jar
Java6 - resources.jar

File location: /META-INF/services/javax.script.ScriptEngineFactory

It is most likely that the classes read from the jdk or jre will be prefered over any specified elsewhere.

## 14.2. II. Configuring Spring

Level: Intermediate

Step one is to locate your web applications red5-web.xml file. Within the xml config file the web.scope bean definition must supply a web.handler, this handler is your Red5 application (An application must extend the org.red5.server.adapter.ApplicationAdapter class).

The application provides access to the Red5 server and any service instances that are created. The service instances and the application itself may be scripted. Bean definitions in Spring config files may not have the same id, here are some web handler definition examples:

- Java class implementation

    <bean id="web.handler" class="org.red5.server.webapp.oflaDemo.MultiThreadedApplicationAdapter" />

- Javascript implementation

    <bean id="web.handler" class="org.red5.server.script.rhino.RhinoScriptFactory">
      <constructor-arg index="0" value="classpath:applications/main.js"/>
      <constructor-arg index="1">
        <list>
         <value>org.red5.server.api.IScopeHandler</value>
         <value>org.red5.server.adapter.IApplication</value>
        </list>
    </constructor-arg>
    <constructor-arg index="2">
     <value>org.red5.server.adapter.ApplicationAdapter</value>
    </constructor-arg>
    </bean>

- Ruby implementation

    <bean id="web.handler" class="org.springframework.scripting.jruby.JRubyScriptFactory">
    <constructor-arg index="0" value="classpath:applications/main.rb"/>
    <constructor-arg index="1">
     <list>
      <value>org.red5.server.api.IScopeHandler</value>
      <value>org.red5.server.adapter.IApplication</value>
     </list>
    </constructor-arg>
    </bean>

- Groovy implementation

    <bean id="web.handler" class="org.red5.server.script.groovy.GroovyScriptFactory">
    <constructor-arg index="0" value="classpath:applications/main.groovy"/>
    <constructor-arg index="1">
     <list>
      <value>org.red5.server.api.IScopeHandler</value>
      <value>org.red5.server.adapter.IApplication</value>
     </list>
    </constructor-arg>
    </bean>

- Python implementation

    Red5 Open Source
    Flash Server (0.7.1) 51
    <bean id="web.handler" class="org.red5.server.script.jython.JythonScriptFactory">
     <constructor-arg index="0" value="classpath:applications/main.py"/>
     <constructor-arg index="1">
      <list>
          <value>org.red5.server.api.IScopeHandler</value>
          <value>org.red5.server.adapter.IApplication</value>
    Scripting Implementations
      </list>
     </constructor-arg>
            <constructor-arg index="2">
      <list>
                <value>One</value>
                <value>2</value>
                <value>III</value>
            </list>
        </constructor-arg>
    </bean>

In general the configuration using scripted classes is defined using the constructor arguments (see interpreter section) in the following order:

- Argument 1 - Location of the script source file

- Argument 2 - Java interfaces implemented by the script.

The interfaces for the code which extends an Application are basically boilerplate as seen in the examples above; You do not have to use those interfaces in all your script definitions.

- Argument 3 - Java classes extended by the script.

The extended class is not always necessary, it depends upon the scripting engine implementation.

The example location starts with classpath:applications which in physical disk terms for the "oflaDemo" application equates to webapps/oflaDemo/WEB-INF/applications

## 14.3. III. Creating an application script

### 14.3.1. 1. Application adapter

Scripting an application adapter is more difficult in some languages than it is in others, because of this I present the Ruby example which works really well and is easy to write and integrate. The application services are easily written in any of the supported languages, but they require a Java interface at a minimum.

i. JRuby application adapter implementation

# JRuby
require 'java'
module RedFive
include_package "org.red5.server.api"
include_package "org.red5.server.api.stream"
include_package "org.red5.server.api.stream.support"
include_package "org.red5.server.adapter"
include_package "org.red5.server.stream"
end
#
# application.rb - a translation into Ruby of the ofla demo application, a red5 example.
#
# @author Paul Gregoire
#
class Application &lt; RedFive::ApplicationAdapter
attr_reader :appScope, :serverStream
attr_writer :appScope, :serverStream
def initialize
#call super to init the superclass, in this case a Java class
super
puts "Initializing ruby application"
end
def appStart(app)
puts "Ruby appStart"
@appScope = app
return true
end
def appConnect(conn, params)
puts "Ruby appConnect"
measureBandwidth(conn)
puts "Ruby appConnect 2"
if conn.instance_of?(RedFive::IStreamCapableConnection)
puts "Got stream capable connection"
sbc = RedFive::SimpleBandwidthConfigure.new
sbc.setMaxBurst(8388608)
sbc.setBurst(8388608)
sbc.setOverallBandwidth(8388608)
conn.setBandwidthConfigure(sbc)
end
return super
end
def appDisconnect(conn)
puts "Ruby appDisconnect"
if appScope == conn.getScope &amp;&amp; @serverStream != nil
@serverStream.close
end
super
end
def toString
return "Ruby toString"
end
def setScriptContext(scriptContext)
puts "Ruby application setScriptContext"
end
def method_missing(m, *args)
super unless @value.respond_to?(m)
return @value.send(m, *args)
end
end

### 14.3.2. 2. Application services

Here is an example of a Java interface (Yes, the methods are supposed to be empty) which is used in the examples to provide a template for applications which will gather a list of files and return them as a "Map" (key-value pairs) to the caller.

i. Simple Java interface for implementation by scripts

    package org.red5.server.webapp.oflaDemo;

    import java.util.Map;
    public interface IDemoService {
            /**
         * Getter for property 'listOfAvailableFLVs'.
         *
         * @return Value for property 'listOfAvailableFLVs'.
         */
        public Map getListOfAvailableFLVs();
        public Map getListOfAvailableFLVs(String string);
    }

ii. Spring bean definition for a script implementation of the interface

    <bean id="demoService.service" class="org.springframework.scripting.jruby.JRubyScriptFactory">
       <constructor-arg index="0" value="classpath:applications/demoservice.rb"/>
       <constructor-arg index="1">
          <list>
             <value>org.red5.server.webapp.oflaDemo.IDemoService</value>
          </list>
       </constructor-arg>
    </bean>

iii.JRuby script implementing the interface

# JRuby - style
require 'java'
module RedFive
include_package "org.springframework.core.io"
include_package "org.red5.server.webapp.oflaDemo"
end
include_class "org.red5.server.api.Red5"
include_class "java.util.HashMap"
#
# demoservice.rb - a translation into Ruby of the ofla demo application, a red5 example.
#
# @author Paul Gregoire
#
class DemoService &lt; RedFive::DemoServiceImpl
attr_reader :filesMap
attr_writer :filesMap
def initialize
puts "Initializing ruby demoservice"
super
@filesMap = HashMap.new
end
def getListOfAvailableFLVs
puts "Getting the FLV files"
begin
dirname = File.expand_path('webapps/oflaDemo/streams').to_s
Dir.open(dirname).entries.grep(/\.flv$/) do |dir|
dir.each do |flvName|
fileInfo = HashMap.new
stats = File.stat(dirname+'/'+flvName)
fileInfo["name"] = flvName
fileInfo["lastModified"] = stats.mtime
fileInfo["size"] = stats.size || 0
@filesMap[flvName] = fileInfo
print 'FLV Name:', flvName
print 'Last modified date:', stats.mtime
print 'Size:', stats.size || 0
print '-------'
end
end
rescue Exception =&gt; ex
puts "Error in getListOfAvailableFLVs #{errorType} \n"
puts "Exception: #{ex} \n"
puts caller.join("\n");
end
return filesMap
end
def formatDate(date)
return date.strftime("%d/%m/%Y %I:%M:%S")
end
def method_missing(m, *args)
super unless @value.respond_to?(m)
return @value.send(m, *args)
end
end

iv.Java application implementing the interface, upon which the Ruby code was based (This code is NOT needed when using the script)

    package org.red5.server.webapp.oflaDemo;
    import java.io.File;
    import java.io.IOException;
    import java.text.SimpleDateFormat;
    import java.util.Date;
    import java.util.HashMap;
    import java.util.Locale;
    import java.util.Map;
    import org.apache.commons.logging.Log;
    import org.apache.commons.logging.LogFactory;
    import org.red5.server.api.IScope;
    import org.red5.server.api.Red5;
    import org.springframework.core.io.Resource;
    public class DemoService {
            protected static Log log = LogFactory.getLog(DemoService.class.getName());

     /**
         * Getter for property 'listOfAvailableFLVs'.
    Scripting Implementations
         *
         * @return Value for property 'listOfAvailableFLVs'.
         */
        public Map getListOfAvailableFLVs() {
                    IScope scope = Red5.getConnectionLocal().getScope();
                    Map&lt;String, Map&gt; filesMap = new HashMap&lt;String, Map&gt;();
                    Map&lt;String, Object&gt; fileInfo;
                    try {
                            log.debug("getting the FLV files");
                            Resource[] flvs = scope.getResources("streams/*.flv");
                            if (flvs != null) {
                                    for (Resource flv : flvs) {
                                            File file = flv.getFile();
                                            Date lastModifiedDate = new Date(file.lastModified());
                                            String lastModified = formatDate(lastModifiedDate);
                                            String flvName = flv.getFile().getName();
                                            String flvBytes = Long.toString(file.length());
                                            if (log.isDebugEnabled()) {
                                                    log.debug("flvName: " + flvName);
                                                    log.debug("lastModified date: " + lastModified);
                                                    log.debug("flvBytes: " + flvBytes);
                                                    log.debug("-------");
                                            }
                                            fileInfo = new HashMap&lt;String, Object&gt;();
                                            fileInfo.put("name", flvName);
                                            fileInfo.put("lastModified", lastModified);
                                            fileInfo.put("size", flvBytes);
                                            filesMap.put(flvName, fileInfo);
                                    }
    }
                            Resource[] mp3s = scope.getResources("streams/*.mp3");
                            if (mp3s != null) {
                                    for (Resource mp3 : mp3s) {
                                            File file = mp3.getFile();
                                            Date lastModifiedDate = new Date(file.lastModified());
                                            String lastModified = formatDate(lastModifiedDate);
                                            String flvName = mp3.getFile().getName();
                                            String flvBytes = Long.toString(file.length());
                                            if (log.isDebugEnabled()) {
                                                    log.debug("flvName: " + flvName);
                                                    log.debug("lastModified date: " + lastModified);
                                                    log.debug("flvBytes: " + flvBytes);
                                                    log.debug("-------");
                                            }
                                            fileInfo = new HashMap&lt;String, Object&gt;();
                                            fileInfo.put("name", flvName);
                                            fileInfo.put("lastModified", lastModified);
                                            fileInfo.put("size", flvBytes);
                                            filesMap.put(flvName, fileInfo);
                                    }
                            }
                    } catch (IOException e) {
                            log.error(e);
                    }
                    return filesMap;
            }

            private String formatDate(Date date) {
                    SimpleDateFormat formatter;
                    String pattern = "dd/MM/yy H:mm:ss";
                    Locale locale = new Locale("en", "US");
                    formatter = new SimpleDateFormat(pattern, locale);
                    return formatter.format(date);
            }
    }

v. Flex AS3 method calling the service

[Bindable]
public var videoList:ArrayCollection;
public function catchVideos():void{
// call server-side method
// create a responder and set it to getMediaList
var nc_responder:Responder = new Responder(getMediaList, null);
// call the server side method to get list of FLV's
nc.call("demoService.getListOfAvailableFLVs", nc_responder);
}
public function getMediaList(list:Object):void{
// this is the result of the server side getListOfAvailableFLVs
var mediaList:Array = new Array();
for(var items:String in list){
mediaList.push({label:items, size:list[items].size, dateModified:list[items].lastModifi
}
// videoList is bindable and the datagrid is set to use this for it's dataprovider
// wrap it in an ArrayCollection first
videoList = new ArrayCollection(mediaList);
}

## 14.4. Creating your own interpreter

Level: Advanced

Lets just open this up by saying that I attempted to build an interpreter for PHP this last weekend 02/2007 and it was a real pain; after four hours I had to give up. So what I learned from this is that you must first identify scripting languages which operate as applications, not as http request processors. Heres a test: Can X language be compiled into an executable or be run on the command-line? If yes then it should be trivial to integrate.

## 14.5. Links with scripting information

Spring scripting

- http://static.springframework.org/spring/docs/2.0.x/reference/dynamic-language.html

- http://rhinoinspring.sourceforge.net/

Java scripting

- http://java.sun.com/developer/technicalArticles/J2SE/Desktop/scripting/

- http://blogs.sun.com/sundararajan/

- https://scripting.dev.java.net/

- http://today.java.net/pub/a/today/2006/04/11/scripting-for-java-platform.html

- http://www.javaworld.com/javaworld/jw-03-2005/jw-0314-scripting_p.html

- http://www.oreillynet.com/onjava/blog/2004/01/java_scripting_half_the_size_h.html

- http://www.robert-tolksdorf.de/vmlanguages.html

Javascript

- http://www.mozilla.org/rhino/

- http://www.mozilla.org/rhino/ScriptingJava.html

Ruby

- http://jruby.codehaus.org/

BeanShell

- http://www.beanshell.org/

Python

- http://www.jython.org/Project/

- http://www.onjava.com/pub/a/onjava/2002/03/27/jython.html

- http://jepp.sourceforge.net/

- http://jpe.sourceforge.net/

- http://jpype.sourceforge.net/

Groovy

- http://groovy.codehaus.org/

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