Config::Model::Loader(3pm)

NAME
Config::Model::Loader - Load serialized data into config tree

VERSION
version 2.166

SYNOPSIS
 use Config::Model;

 # define configuration tree object
 my $model = Config::Model->new;
  $model->create_config_class(
    name    => "Foo",
    element => [
        foo => {
            type       => 'leaf',
            value_type => 'string'
        },
        bar => '*foo',
    ]
 );

 $model ->create_config_class (
    name => "MyClass",

    element => [

        foo => {
            type       => 'leaf',
            value_type => 'string'
        },
        bar => '*foo',
        hash_of_nodes => {
            type       => 'hash',     # hash id
            index_type => 'string',
            cargo      => {
                type              => 'node',
                config_class_name => 'Foo'
            },
        },
        lista => {
            type => 'list',
            cargo =>  {
                type => 'leaf',
                value_type => 'string'
            }
        },
        listb => '*lista',
    ],
 ) ;

 my $inst = $model->instance(root_class_name => 'MyClass' );

 my $root = $inst->config_root ;

 # put data
 my $steps = 'foo=FOO hash_of_nodes:fr foo=bonjour -
   hash_of_nodes:en foo=hello
   ! lista=foo,bar lista:2=baz
     listb:0=foo listb:1=baz';
 $root->load( steps => $steps );

 my $s = $root->fetch_element_value('foo');      # => is 'FOO'
 $s = $root->grab_value('hash_of_nodes:en foo'); # => is 'hello'
 $s = $root->grab_value('lista:1');              # => is 'bar'
 $s = $root->grab_value('lista:2');              # => is 'baz'

 # delete some data
 $root->load( steps => 'lista~2' );

 $s = $root->grab_value('lista:2');              # => is undef

 # append some data
 $root->load( steps => q!hash_of_nodes:en foo.=" world"! );

 $s = $root->grab_value('hash_of_nodes:en foo'); # => is 'hello world'

DESCRIPTION
This module is used directly by Config::Model::Node to load serialized configuration data into the configuration tree.

Serialized data can be written by the user or produced by Config::Model::Dumper while dumping data from a configuration tree.

CONSTRUCTOR

  new
The constructor should be used only by Config::Model::Node.

Parameters:

start_node
    node ref of the root of the tree (of sub-root) to start the load from. Stored as a weak reference.

load string syntax
The string is made of the following items (also called "actions") separated by spaces. These actions can be divided in 4 groups:

•   navigation: moving up and down the configuration tree.

•   list and hash operation: select, add or delete hash or list item (also known as "id" items)

•   leaf operation: select, modify or delecte leaf value

•   annotation: modify or delete configuration annotation (aka comment)

  navigation

-   Go up one node

!   Go to the root node of the configuration tree.

xxx Go down using "xxx" element. (For "node" type element)

/xxx
    Go up until the element "xxx" is found. This search can be combined with one of the command specified below, e.g "/a_string="foo bar""

  list and hash operation

xxx:yy
    Go down using "xxx" element and id "yy" (For "hash" or "list" element with "node" cargo_type). Literal "\n" are replaced by real "\n" (LF in Unix).

xxx:.foreach_match(yy) or xxx:~yy
    Go down using "xxx" element and loop over the ids that match the regex specified by "yy". (For "hash" only. This does not apply to "list" elements).

    For instance, with "OpenSsh" model, you could do

     Host:~"/.*.debian.org/" user='foo-guest'

    to set "foo-user" users for all your debian accounts.

    The leading and trailing '/' may be omitted. Be sure to surround the regexp with double quote if space are embedded in the regex.

    Note that the loop ends when the load command goes above the element where the loop is executed. For instance, the instruction below tries to execute "DX=BV" and "int_v=9" for all elements of "std_id" hash:

     std_id:~/^\w+$/ DX=Bv int_v=9

    In the examples below only "DX=BV" is executed by the loop:

     std_id:~/^\w+$/ DX=Bv - int_v=9
     std_id:~/^\w+$/ DX=Bv ! int_v=9

    The loop is done on all elements of the hash when no value is passed after "":~"" (mnemonic: an empty regexp matches any value).

xxx:.rm(yy) or xxx:-yy
    Delete item referenced by "xxx" element and id "yy". For a list, this is equivalent to "splice xxx,yy,1". This command does not go down in the tree (since it has just deleted the element). I.e. a '"-"' is generally not needed afterwards.

xxx:.rm_value(yy) or xxx:-=yy
    Remove the element whose value is "yy". For list or hash of leaves. Does not not complain if the value to delete is not found.

xxx:..rm_match(yy) or xxx:-~/yy/
    Remove the element whose value matches "yy". For list or hash of leaves. Does not not complain if no value were deleted.

xxx:.substitute(/yy/zz/) or xxx:=~s/yy/zz/
    Substitute a value with another. Perl switches can be used(e.g. "xxx:=~s/yy/zz/gi")

xxx:<yy or xxx:.push(yy)
    Push "yy" value on "xxx" list

xxx:>yy or xxx:.unshift(yy)
    Unshift "yy" value on "xxx" list

xxx:@ or xxx:.sort
    Sort the list

xxx:.insert_at(yy,zz)
    Insert "zz" value on "xxx" list before index "yy".

xxx:.insert_before(yy,zz)
    Insert "zz" value on "xxx" list before value "yy".

xxx:.insert_before(/yy/,zz)
    Insert "zz" value on "xxx" list before value matching "yy".

xxx:.insort(zz)
    Insert "zz" value on "xxx" list so that existing alphanumeric order is preserved.

xxx:.insort(zz)
    For hash element containing nodes: creates a new hash element with "zz" key on "xxx" hash so that existing alphanumeric order of keys is preserved. Note that all keys are sorted once this instruction is called. Following instructions are applied on the created element. I.e. putting key order aside, "xxx:.insort(zz)" has the same effect as "xxx:zz" instruction.

xxx:.insort(zz,vv)
    For hash element containing leaves: creates a new hash element with "zz" key and assing value "vv" so that existing alphanumeric order of keys is preserved. Note that all keys are sorted once this instruction is called. Putting key order aside, "xxx:.insort(zz,vv)" has the same effect as "xxx:zz=vv" instruction.

xxx:.ensure(zz,...)
    Ensure that list "xxx" contains value "zz". If value "zz" is already stored in "xxx" list, this function does nothing. In the other case, value "zz" is inserted in alphabetical order. This function accepts a list of values separated by a comma.

xxx:=z1,z2,z3
    Set list element "xxx" to list "z1,z2,z3". Use ",," for undef values, and "" for empty values.

    I.e, for a list "('a',undef,'','c')", use "a,,"",c".

xxx:yy=zz
    For "hash" element containing "leaf" cargo_type. Set the leaf identified by key "yy" to value "zz".

    Using "xxx:~/yy/=zz" is also possible.

xxx:.copy(yy,zz)
    copy item "yy" in "zz" (hash or list).

xxx:.rename(yy,zz)
    rename item "yy" in "zz" (hash).

xxx:.move(yy,zz)
    Alias to rename.

xxx:.json("path/to/file.json/foo/bar")
    Store "bar" content in array or hash. This should be used to store hash or list of values.

    You may store deep data structure. In this case, make sure that the structure of the loaded data matches the structure of the model. This won't happen by chance.

    Note that JSON module must be installed to use this function.

xxx:.clear
    Clear the hash or list.

  leaf operation

xxx=zz
    Set element "xxx" to value "yy". load also accepts to set elements with a quoted string. (For "leaf" element) Literal "\n" are replaced by real "\n" (LF in Unix). Literal "\\" are replaced by "\".

    For instance "foo="a quoted string"" or "foo="\"bar\" and \"baz\""".

xxx=~s/foo/bar/
    Apply the substitution to the value of xxx. "s/foo/bar/" is the standard Perl "s" substitution pattern.

    Patterns with white spaces must be surrounded by quotes:

      xxx=~"s/foo bar/bar baz/"

    Perl pattern modifiers are accepted

      xxx=~s/FOO/bar/i

xxx~
    Undef element "xxx"

xxx.=zzz
    Appends "zzz" value to current value (valid for "leaf" elements).

xxx=.set_to_standard_value()
    Set to standard value. Standard value is like a suggested value which requires an action from user to be set. "set_to_std_value" is also accepted.

xxx=.file(yyy)
    Store the content of file "yyy" in element "xxx".

    Store STDIN in value xxx when "yyy" is '-'.

xxx=.json(path/to/data.json/foo/bar)
    Open file "data.json" and store value from JSON data extracted with "foo/bar" subpath.

    For instance, if "data.json" contains:

     {
        "foo": {
           "bar": 42
        }
     }

    The instruction "baz=.json(data.json/foo/bar)" stores 42 in "baz" element.

xxx=.yaml(path/to/data.yaml/0/foo/bar)
    Open file "data.yaml" and store value from YAML data extracted with "0/foo/bar" subpath.

    Since a YAML file can contain several documents (separated by "---" lines, the subpath must begin with a number to select the document containing the required value.

    For instance, if "data.yaml" contains:

      ---
      foo:
        bar: 42

    The instruction "baz=.yaml(data.yaml/0/foo/bar)" stores 42 in "baz" element.

    Note that YAML::PP module must be installed to use this function.

xxx=.ini(path/to/data.ini/foo/bar)
    Open file "data.ini" and store value from INI data extracted with "foo/bar" subpath. INI files contains sections and parameter, so the subpath must contains at most 2 elements.

    For instance, if "data.ini" contains:

      [foo]
        bar = 42

    The instruction "baz=.ini(data.ini/foo/bar)" stores 42 in "baz" element.

    Note that Config::INI::Reader module must be installed to use this function.

xxx=.env(yyy)
    Store the content of environment variable "yyy" in element "xxx".

  annotation

xxx#zzz or xxx:yyy#zzz
    Element annotation. Can be quoted or not quoted. Note that annotations are always placed at the end of an action item.

    I.e. "foo#comment", "foo:bar#comment" or "foo:bar=baz#comment" are valid. "foo#comment:bar" is not valid.

  Quotes
You can surround indexes and values with single or double quotes. E.g.:

  a_string='"foo" and "bar"'

Single quotes were added in version 2.153.

Examples
You can use cme to modify configuration with "cme modify" command.

For instance, if Config::Model::Ssh is installed, you can run:

 cme modify ssh 'ControlMaster=auto ControlPath="~/.ssh/master-%r@%n:%p"'

To delete "Host *" entry:

 cme modify ssh 'Host:-"*"'

To specify 2 "Host" with a single command:

 cme modify ssh 'Host:"foo* bar*" ForwardX11=yes HostName="foo.com" - Host:baz HostName="baz.com"'

Note the '"-"' used to go up one node before ""Host:baz"". In this case, "up one node" leads to the "root node", so ""!"" could also be used instead of ""-"":

 cme modify ssh 'Host:"foo* bar*" ForwardX11=yes HostName="foo.com" ! Host:baz HostName="baz.com"'

Let's modify now the host name of using a ".org" domain instead of ".com". The ":~" operator uses a regexp to loop over several Host entries:

 cme modify ssh 'Host:~/ba[rz]/ HostName=~s/.com$/.org/'

Now that ssh config is mucked up with dummy entries, let's clean up:

 cme modify ssh 'Host:-"baz" Host:-"foo* bar*"'

Methods

  load
Load data into the node tree (from the node passed with "node") and fill values as we go following the instructions passed with "steps". ("steps" can also be an array ref).

Parameters are:

steps (or step)
    A string or an array ref containing the steps to load. See "load string syntax" in above for a description of the string.

check
    Whether to check values while loading. Either "yes" (default), "no" or "skip". Bad values are discarded when "check" is set to "skip".

caller_is_root
    Change the target of the "!" command: when set, the "!" command go to caller node instead of going to root node. (default is false)

AUTHOR
Dominique Dumont, (ddumont at cpan dot org)

SEE ALSO
Config::Model,Config::Model::Node,Config::Model::Dumper

AUTHOR
Dominique Dumont

COPYRIGHT AND LICENSE
This software is Copyright (c) 2005-2022 by Dominique Dumont.

This is free software, licensed under:

  The GNU Lesser General Public License, Version 2.1, February 1999