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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>

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.