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CPAN::Meta(3)                        User Contributed Perl Documentation                       CPAN::Meta(3)



NAME
       CPAN::Meta - the distribution metadata for a CPAN dist

VERSION
       version 2.120921

SYNOPSIS
         my $meta = CPAN::Meta->load_file('META.json');

         printf "testing requirements for %s version %s\n",
           $meta->name,
           $meta->version;

         my $prereqs = $meta->requirements_for('configure');

         for my $module ($prereqs->required_modules) {
           my $version = get_local_version($module);

           die "missing required module $module" unless defined $version;
           die "version for $module not in range"
             unless $prereqs->accepts_module($module, $version);
         }

DESCRIPTION
       Software distributions released to the CPAN include a META.json or, for older distributions,
       META.yml, which describes the distribution, its contents, and the requirements for building and
       installing the distribution.  The data structure stored in the META.json file is described in
       CPAN::Meta::Spec.

       CPAN::Meta provides a simple class to represent this distribution metadata (or distmeta), along with
       some helpful methods for interrogating that data.

       The documentation below is only for the methods of the CPAN::Meta object.  For information on the
       meaning of individual fields, consult the spec.

METHODS
   new
         my $meta = CPAN::Meta->new($distmeta_struct, \%options);

       Returns a valid CPAN::Meta object or dies if the supplied metadata hash reference fails to validate.
       Older-format metadata will be up-converted to version 2 if they validate against the original stated
       specification.

       It takes an optional hashref of options. Valid options include:

       •   lazy_validation -- if true, new will attempt to convert the given metadata to version 2 before
           attempting to validate it.  This means than any fixable errors will be handled by
           CPAN::Meta::Converter before validation.  (Note that this might result in invalid optional data
           being silently dropped.)  The default is false.

   create
         my $meta = CPAN::Meta->create($distmeta_struct, \%options);

       This is same as "new()", except that "generated_by" and "meta-spec" fields will be generated if not
       provided.  This means the metadata structure is assumed to otherwise follow the latest
       CPAN::Meta::Spec.

   load_file
         my $meta = CPAN::Meta->load_file($distmeta_file, \%options);

       Given a pathname to a file containing metadata, this deserializes the file according to its file
       suffix and constructs a new "CPAN::Meta" object, just like "new()".  It will die if the deserialized
       version fails to validate against its stated specification version.

       It takes the same options as "new()" but "lazy_validation" defaults to true.

   load_yaml_string
         my $meta = CPAN::Meta->load_yaml_string($yaml, \%options);

       This method returns a new CPAN::Meta object using the first document in the given YAML string.  In
       other respects it is identical to "load_file()".

   load_json_string
         my $meta = CPAN::Meta->load_json_string($json, \%options);

       This method returns a new CPAN::Meta object using the structure represented by the given JSON string.
       In other respects it is identical to "load_file()".

   save
         $meta->save($distmeta_file, \%options);

       Serializes the object as JSON and writes it to the given file.  The only valid option is "version",
       which defaults to '2'. On Perl 5.8.1 or later, the file is saved with UTF-8 encoding.

       For "version" 2 (or higher), the filename should end in '.json'.  JSON::PP is the default JSON
       backend. Using another JSON backend requires JSON 2.5 or later and you must set the
       $ENV{PERL_JSON_BACKEND} to a supported alternate backend like JSON::XS.

       For "version" less than 2, the filename should end in '.yml'.  CPAN::Meta::Converter is used to
       generate an older metadata structure, which is serialized to YAML.  CPAN::Meta::YAML is the default
       YAML backend.  You may set the $ENV{PERL_YAML_BACKEND} to a supported alternative backend, though
       this is not recommended due to subtle incompatibilities between YAML parsers on CPAN.

   meta_spec_version
       This method returns the version part of the "meta_spec" entry in the distmeta structure.  It is
       equivalent to:

         $meta->meta_spec->{version};

   effective_prereqs
         my $prereqs = $meta->effective_prereqs;

         my $prereqs = $meta->effective_prereqs( \@feature_identifiers );

       This method returns a CPAN::Meta::Prereqs object describing all the prereqs for the distribution.  If
       an arrayref of feature identifiers is given, the prereqs for the identified features are merged
       together with the distribution's core prereqs before the CPAN::Meta::Prereqs object is returned.

   should_index_file
         ... if $meta->should_index_file( $filename );

       This method returns true if the given file should be indexed.  It decides this by checking the "file"
       and "directory" keys in the "no_index" property of the distmeta structure.

       $filename should be given in unix format.

   should_index_package
         ... if $meta->should_index_package( $package );

       This method returns true if the given package should be indexed.  It decides this by checking the
       "package" and "namespace" keys in the "no_index" property of the distmeta structure.

   features
         my @feature_objects = $meta->features;

       This method returns a list of CPAN::Meta::Feature objects, one for each optional feature described by
       the distribution's metadata.

   feature
         my $feature_object = $meta->feature( $identifier );

       This method returns a CPAN::Meta::Feature object for the optional feature with the given identifier.
       If no feature with that identifier exists, an exception will be raised.

   as_struct
         my $copy = $meta->as_struct( \%options );

       This method returns a deep copy of the object's metadata as an unblessed has reference.  It takes an
       optional hashref of options.  If the hashref contains a "version" argument, the copied metadata will
       be converted to the version of the specification and returned.  For example:

         my $old_spec = $meta->as_struct( {version => "1.4"} );

   as_string
         my $string = $meta->as_string( \%options );

       This method returns a serialized copy of the object's metadata as a character string.  (The strings
       are not UTF-8 encoded.)  It takes an optional hashref of options.  If the hashref contains a
       "version" argument, the copied metadata will be converted to the version of the specification and
       returned.  For example:

         my $string = $meta->as_struct( {version => "1.4"} );

       For "version" greater than or equal to 2, the string will be serialized as JSON.  For "version" less
       than 2, the string will be serialized as YAML.  In both cases, the same rules are followed as in the
       "save()" method for choosing a serialization backend.

STRING DATA
       The following methods return a single value, which is the value for the corresponding entry in the
       distmeta structure.  Values should be either undef or strings.

       •   abstract

       •   description

       •   dynamic_config

       •   generated_by

       •   name

       •   release_status

       •   version

LIST DATA
       These methods return lists of string values, which might be represented in the distmeta structure as
       arrayrefs or scalars:

       •   authors

       •   keywords

       •   licenses

       The "authors" and "licenses" methods may also be called as "author" and "license", respectively, to
       match the field name in the distmeta structure.

MAP DATA
       These readers return hashrefs of arbitrary unblessed data structures, each described more fully in
       the specification:

       •   meta_spec

       •   resources

       •   provides

       •   no_index

       •   prereqs

       •   optional_features

CUSTOM DATA
       A list of custom keys are available from the "custom_keys" method and particular keys may be
       retrieved with the "custom" method.

         say $meta->custom($_) for $meta->custom_keys;

       If a custom key refers to a data structure, a deep clone is returned.

BUGS
       Please report any bugs or feature using the CPAN Request Tracker.  Bugs can be submitted through the
       web interface at http://rt.cpan.org/Dist/Display.html?Queue=CPAN-Meta
       <http://rt.cpan.org/Dist/Display.html?Queue=CPAN-Meta>

       When submitting a bug or request, please include a test-file or a patch to an existing test-file that
       illustrates the bug or desired feature.

SEE ALSO
       •   CPAN::Meta::Converter

       •   CPAN::Meta::Validator

SUPPORT
   Bugs / Feature Requests
       Please report any bugs or feature requests through the issue tracker at
       http://rt.cpan.org/Public/Dist/Display.html?Name=CPAN-Meta
       <http://rt.cpan.org/Public/Dist/Display.html?Name=CPAN-Meta>.  You will be notified automatically of
       any progress on your issue.

   Source Code
       This is open source software.  The code repository is available for public review and contribution
       under the terms of the license.

       http://github.com/dagolden/cpan-meta <http://github.com/dagolden/cpan-meta>

         git clone git://github.com/dagolden/cpan-meta.git

AUTHORS
       •   David Golden <dagolden@cpan.org>

       •   Ricardo Signes <rjbs@cpan.org>

COPYRIGHT AND LICENSE
       This software is copyright (c) 2010 by David Golden and Ricardo Signes.

       This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5
       programming language system itself.



perl v5.16.2                                     2012-04-01                                    CPAN::Meta(3)