/ 
Config-Model-2.104
River stage two • 11 direct dependents • 11 total dependents
/ Config::Model::Backend::IniFile

NAME

Config::Model::Backend::IniFile - Read and write config as a INI file

VERSION

version 2.104

SYNOPSIS

use Config::Model;

my $model = Config::Model->new;
$model->create_config_class (
   name    => "IniClass",
   element => [
       [qw/foo bar/] => {
           type => 'list',
           cargo => {qw/type leaf value_type string/}
       }
   ]
);

# model for free INI class name and constrained class parameters
$model->create_config_class(
   name => "MyClass",

   element => [
       ini_class => {
           type   => 'hash',
           index_type => 'string',
           cargo => {
               type => 'node',
               config_class_name => 'IniClass'
           },
       },
   ],

  read_config  => [
       {
           backend => 'IniFile',
           config_dir => '/tmp',
           file  => 'foo.conf',
           store_class_in_hash => 'ini_class',
           auto_create => 1,
       }
   ],
);

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

$root->load('ini_class:ONE foo=FOO1 bar=BAR1 - 
             ini_class:TWO foo=FOO2' );

$inst->write_back ;

Now /tmp/foo.conf contains:

## file written by Config::Model
[ONE]
foo=FOO1

bar=BAR1

[TWO]
foo=FOO2

DESCRIPTION

This module is used directly by Config::Model to read or write the content of a configuration tree written with INI syntax in Config::Model configuration tree.

This INI file can have arbitrary comment delimiter. See the example in the SYNOPSIS that sets a semi-column as comment delimiter. By default the comment delimiter is '#' like in Shell or Perl.

Note that undefined values are skipped for list element. I.e. when a list element contains ('a',undef,'b'), the data structure contains 'a','b'.

Limitations

Structure

Structure of the Config::Model must be very simple. Either:

  • A single class with hash of leaves elements.

  • 2 levels of classes. The top level has nodes elements. All other classes have only leaf elements.

Comments in Ini file

This backend tries to read and write comments from configuration file. The comments are stored as annotation within the configuration tree. Comments extraction is based on best estimation as to which parameter the comment may apply. Wrong estimations are possible.

CONSTRUCTOR

new ( node => $node_obj, name => 'inifile' ) ;

Inherited from Config::Model::Backend::Any. The constructor is called by Config::Model::BackendMgr.

Parameters

Optional parameters declared in the model:

comment_delimiter

Change the character that starts comments in the INI file. Default is '#'.

Some Ini files allows comments to begin with several characters (e.g. # or ;). In this case, set comment_delimiter to the possible characters (e.g "#;"). The first character is used to write back comments. (In the example above, comment ; blah is written back as # blah.

store_class_in_hash

See "Arbitrary class name"

section_map

Is a kind of exception of the above rule. See also "Arbitrary class name"

force_lc_section

Boolean. When set, sections names are converted to lowercase.

force_lc_key

Idem for key name

force_lc_value

Idem for all values.

split_list_value

Some INI values are in fact a list of items separated by a space or a comma. This parameter specifies the regex to use to split the value into a list. This applies only to list elements.

join_list_value

Conversely, the list element split with split_list_value needs to be written back with a string to join them. Specify this string (usually ' ' or ', ') with join_list_value.

split_check_list_value

Some INI values are in fact a check list of items separated by a space or a comma. This parameter specifies the regex to use to split the value read from the file into a list of items to check. This applies only to check_list elements.

join_check_list_value

Conversely, the check_list element split with split_list_value needs to be written back with a string to join them. Specify this string (usually ' ' or ', ') with join_check_list_value.

write_boolean_as

Array ref. Reserved for boolean value. Specify how to write a boolean value. Default is [0,1] which may not be the most readable. write_boolean_as can be specified as ['false','true'] or ['no','yes'].

assign_char

Character used to assign value in INI file. Default is =.

assign_with

String used write assignment in INI file. Default is " = ".

Mapping between INI structure and model

INI file typically have the same structure with 2 different conventions. The class names can be imposed by the application or may be chosen by user.

Imposed class name

In this case, the class names must match what is expected by the application. The elements of each class can be different. For instance:

foo = foo_v
[ A ]
bar = bar_v
[ B ]
baz = baz_v

In this case, class A and class B do not use the same configuration class.

The model has this structure:

Root class 
|- leaf element foo
|- node element A of class_A
|  \- leaf element bar
\- node element B of class_B
   \-  leaf element baz

Arbitrary class name

In this case, the class names can be chosen by the end user. Each class has the same elements. For instance:

foo = foo_v
[ A ]
bar = bar_v1
[ B ]
bar = bar_v2

In this case, class A and class B do not use the same configuration class. The model has this structure:

Root class 
|- leaf foo
\- hash element my_class_holder
   |- key A (value is node of class_A)
   |  \- element-bar
   \- key B (value is node of class_A)
      \- element-bar

In this case, the my_class_holder name is specified in read_config with store_class_in_hash parameter:

read_config  => [
    { 
        backend => 'IniFile',
        config_dir => '/tmp',
        file  => 'foo.ini',
        store_class_in_hash => 'my_class_holder',
    }
],

Of course they are exceptions. For instance, in Multistrap, the [General] INI class must be mapped to a specific node object. This can be specified with the section_map parameter:

read_config  => [
    { 
        backend => 'IniFile',
        config_dir => '/tmp',
        file  => 'foo.ini',
        store_class_in_hash => 'my_class_holder',
        section_map => { 
            General => 'general_node',
        }
    }
],

section_map can also map an INI class to the root node:

read_config => [
    {
        backend => 'ini_file',
        store_class_in_hash => 'sections',
        section_map => {
            General => '!'
        },
    }
],

Handle key value files

This backend is able to handle simple configuration files where the values are written as key value pairs like:

foo = bar

or

foo: bar

The option assign_char is used to specify which character is used to assign a value in the file (white spaces are ignored). assign_char is "=" (the default) in the first example, and ":" in the second.

The assign_with is used to control how the file is written back. E.g:

foo=bar   # the default
foo= bar  # assign_with is "= "
foo = bar # assign_with is " = "
foo:bar   # assign_char is ':', assign_with is the default
foo: bar  # assign_char is ':', assign_with is ": "
foo : bar # assign_char is ':', assign_with is " : "

Methods

read ( io_handle => ... )

Of all parameters passed to this read call-back, only io_handle is used. This parameter must be IO::File object already opened for read.

It can also be undef. In this case, read() returns 0.

When a file is read, read() returns 1.

write ( io_handle => ... )

Of all parameters passed to this write call-back, only io_handle is used. This parameter must be IO::File object already opened for write.

write() returns 1.

AUTHOR

Dominique Dumont, (ddumont at cpan dot org); Krzysztof Tyszecki, (krzysztof.tyszecki at gmail dot com)

SEE ALSO

Config::Model, Config::Model::BackendMgr, Config::Model::Backend::Any,

AUTHOR

Dominique Dumont

COPYRIGHT AND LICENSE

This software is Copyright (c) 2005-2017 by Dominique Dumont.

This is free software, licensed under:

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