Provided by: perl-doc_5.34.0-3ubuntu1.4_all 
NAME
CPAN::Meta - the distribution metadata for a CPAN dist
VERSION
version 2.150010
SYNOPSIS
use v5.10;
use strict;
use warnings;
use CPAN::Meta;
use Module::Load;
my $meta = CPAN::Meta->load_file('META.json');
printf "testing requirements for %s version %s\n",
$meta->name,
$meta->version;
my $prereqs = $meta->effective_prereqs;
for my $phase ( qw/configure runtime build test/ ) {
say "Requirements for $phase:";
my $reqs = $prereqs->requirements_for($phase, "requires");
for my $module ( sort $reqs->required_modules ) {
my $status;
if ( eval { load $module unless $module eq 'perl'; 1 } ) {
my $version = $module eq 'perl' ? $] : $module->VERSION;
$status = $reqs->accepts_module($module, $version)
? "$version ok" : "$version not ok";
} else {
$status = "missing"
};
say " $module ($status)";
}
}
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()".
load_string
my $meta = CPAN::Meta->load_string($string, \%options);
If you don't know if a string contains YAML or JSON, this method will use Parse::CPAN::Meta to guess. 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. Note that neither the version
format nor "release_status" are considered.
$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. Note that neither
the version format nor "release_status" are considered.
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 hash 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_string( {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.
The serialized structure will include a "x_serialization_backend" entry giving the package and version
used to serialize. Any existing key in the given $meta object will be clobbered.
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.
SEE ALSO
• CPAN::Meta::Converter
• CPAN::Meta::Validator
SUPPORT
Bugs / Feature Requests
Please report any bugs or feature requests through the issue tracker at
<https://github.com/Perl-Toolchain-Gang/CPAN-Meta/issues>. 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.
<https://github.com/Perl-Toolchain-Gang/CPAN-Meta>
git clone https://github.com/Perl-Toolchain-Gang/CPAN-Meta.git
AUTHORS
• David Golden <dagolden@cpan.org>
• Ricardo Signes <rjbs@cpan.org>
• Adam Kennedy <adamk@cpan.org>
CONTRIBUTORS
• Ansgar Burchardt <ansgar@cpan.org>
• Avar Arnfjord Bjarmason <avar@cpan.org>
• Benjamin Noggle <agwind@users.noreply.github.com>
• Christopher J. Madsen <cjm@cpan.org>
• Chuck Adams <cja987@gmail.com>
• Cory G Watson <gphat@cpan.org>
• Damyan Ivanov <dam@cpan.org>
• David Golden <xdg@xdg.me>
• Eric Wilhelm <ewilhelm@cpan.org>
• Graham Knop <haarg@haarg.org>
• Gregor Hermann <gregoa@debian.org>
• Karen Etheridge <ether@cpan.org>
• Kenichi Ishigaki <ishigaki@cpan.org>
• Kent Fredric <kentfredric@gmail.com>
• Ken Williams <kwilliams@cpan.org>
• Lars Dieckow <daxim@cpan.org>
• Leon Timmermans <leont@cpan.org>
• majensen <maj@fortinbras.us>
• Mark Fowler <markf@cpan.org>
• Matt S Trout <mst@shadowcat.co.uk>
• Michael G. Schwern <mschwern@cpan.org>
• Mohammad S Anwar <mohammad.anwar@yahoo.com>
• mohawk2 <mohawk2@users.noreply.github.com>
• moznion <moznion@gmail.com>
• Niko Tyni <ntyni@debian.org>
• Olaf Alders <olaf@wundersolutions.com>
• Olivier Mengué <dolmen@cpan.org>
• Randy Sims <randys@thepierianspring.org>
• Tomohiro Hosaka <bokutin@bokut.in>
COPYRIGHT AND LICENSE
This software is copyright (c) 2010 by David Golden, Ricardo Signes, Adam Kennedy and Contributors.
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 v5.34.0 2025-04-08 CPAN::Meta(3perl)