Parse::CPAN::Meta(3pm) Perl Programmers Reference Guide
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 v5.38.2 2023-11-28 Parse::CPAN::Meta(3pm)
perl 5.38.2 - Generated Tue Dec 10 12:58:18 CST 2024