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Parse::CPAN::Meta(3pm) Perl Programmers Reference Guide Parse::CPAN::Meta(3pm)




NAME

       Parse::CPAN::Meta - Parse META.yml and META.json CPAN metadata files


VERSION

       version 2.150010


SYNOPSIS

           #############################################
           # In your file

           ---
           name: My-Distribution
           version: 1.23
           resources:
             homepage: "http://example.com/dist/My-Distribution"


           #############################################
           # In your program

           use Parse::CPAN::Meta;

           my $distmeta = Parse::CPAN::Meta->load_file('META.yml');

           # Reading properties
           my $name     = $distmeta->{name};
           my $version  = $distmeta->{version};
           my $homepage = $distmeta->{resources}{homepage};


DESCRIPTION

       Parse::CPAN::Meta is a parser for META.json and META.yml files, using
       JSON::PP and/or CPAN::Meta::YAML.

       Parse::CPAN::Meta provides three methods: "load_file",
       "load_json_string", and "load_yaml_string".  These will read and
       deserialize CPAN metafiles, and are described below in detail.

       Parse::CPAN::Meta provides a legacy API of only two functions, based on
       the YAML functions of the same name. Wherever possible, identical
       calling semantics are used.  These may only be used with YAML sources.

       All error reporting is done with exceptions (die'ing).

       Note that META files are expected to be in UTF-8 encoding, only.  When
       converted string data, it must first be decoded from UTF-8.


METHODS

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

         my $metadata_structure = Parse::CPAN::Meta->load_file('META.yml');

       This method will read the named file and deserialize it to a data
       structure, determining whether it should be JSON or YAML based on the
       filename.  The file will be read using the ":utf8" IO layer.

   load_yaml_string
         my $metadata_structure = Parse::CPAN::Meta->load_yaml_string($yaml_string);

       This method deserializes the given string of YAML and returns the first
       document in it.  (CPAN metadata files should always have only one
       document.)  If the source was UTF-8 encoded, the string must be decoded
       before calling "load_yaml_string".

   load_json_string
         my $metadata_structure = Parse::CPAN::Meta->load_json_string($json_string);

       This method deserializes the given string of JSON and the result.  If
       the source was UTF-8 encoded, the string must be decoded before calling
       "load_json_string".

   load_string
         my $metadata_structure = Parse::CPAN::Meta->load_string($some_string);

       If you don't know whether a string contains YAML or JSON data, this
       method will use some heuristics and guess.  If it can't tell, it
       assumes YAML.

   yaml_backend
         my $backend = Parse::CPAN::Meta->yaml_backend;

       Returns the module name of the YAML serializer. See "ENVIRONMENT" for
       details.

   json_backend
         my $backend = Parse::CPAN::Meta->json_backend;

       Returns the module name of the JSON serializer.  If
       "CPAN_META_JSON_BACKEND" is set, this will be whatever that's set to.
       If not, this will either be JSON::PP or JSON.  If "PERL_JSON_BACKEND"
       is set, this will return JSON as further delegation is handled by the
       JSON module.  See "ENVIRONMENT" for details.

   json_decoder
         my $decoder = Parse::CPAN::Meta->json_decoder;

       Returns the module name of the JSON decoder.  Unlike "json_backend",
       this is not necessarily a full JSON-style module, but only something
       that will provide a "decode_json" subroutine.  If
       "CPAN_META_JSON_DECODER" is set, this will be whatever that's set to.
       If not, this will be whatever has been selected as "json_backend".  See
       "ENVIRONMENT" for more notes.


FUNCTIONS

       For maintenance clarity, no functions are exported by default.  These
       functions are available for backwards compatibility only and are best
       avoided in favor of "load_file".

   Load
         my @yaml = Parse::CPAN::Meta::Load( $string );

       Parses a string containing a valid YAML stream into a list of Perl data
       structures.

   LoadFile
         my @yaml = Parse::CPAN::Meta::LoadFile( 'META.yml' );

       Reads the YAML stream from a file instead of a string.


ENVIRONMENT

   CPAN_META_JSON_DECODER
       By default, JSON::PP will be used for deserializing JSON data.  If the
       "CPAN_META_JSON_DECODER" environment variable exists, this is expected
       to be the name of a loadable module that provides a "decode_json"
       subroutine, which will then be used for deserialization.  Relying only
       on the existence of said subroutine allows for maximum compatibility,
       since this API is provided by all of JSON::PP, JSON::XS,
       Cpanel::JSON::XS, JSON::MaybeXS, JSON::Tiny, and Mojo::JSON.

   CPAN_META_JSON_BACKEND
       By default, JSON::PP will be used for deserializing JSON data.  If the
       "CPAN_META_JSON_BACKEND" environment variable exists, this is expected
       to be the name of a loadable module that provides the JSON API, since
       downstream code expects to be able to call "new" on this class.  As
       such, while JSON::PP, JSON::XS, Cpanel::JSON::XS and JSON::MaybeXS will
       work for this, to use Mojo::JSON or JSON::Tiny for decoding requires
       setting "CPAN_META_JSON_DECODER".

   PERL_JSON_BACKEND
       If the "CPAN_META_JSON_BACKEND" environment variable does not exist,
       and if "PERL_JSON_BACKEND" environment variable exists, is true and is
       not "JSON::PP", then the JSON module (version 2.5 or greater) will be
       loaded and used to interpret "PERL_JSON_BACKEND".  If JSON is not
       installed or is too old, an exception will be thrown.  Note that at the
       time of writing, the only useful values are 1, which will tell JSON to
       guess, or JSON::XS - if you want to use a newer JSON module, see
       "CPAN_META_JSON_BACKEND".

   PERL_YAML_BACKEND
       By default, CPAN::Meta::YAML will be used for deserializing YAML data.
       If the "PERL_YAML_BACKEND" environment variable is defined, then it is
       interpreted as a module to use for deserialization.  The given module
       must be installed, must load correctly and must implement the "Load()"
       function or an exception will be thrown.


AUTHORS

       o   David Golden <dagolden@cpan.org>

       o   Ricardo Signes <rjbs@cpan.org>

       o   Adam Kennedy <adamk@cpan.org>


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 v5.26.1                      2017-07-18            Parse::CPAN::Meta(3pm)

perl 5.26.1 - Generated Mon Nov 6 16:11:41 CST 2017
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