Parse::CPAN::Meta - Parse META.yml and META.json CPAN metadata files
version 2.150010
- #############################################
- # 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};
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.
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.
- 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
.
- 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
.
- 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.
- my $backend = Parse::CPAN::Meta->yaml_backend;
Returns the module name of the YAML serializer. See ENVIRONMENT for details.
- 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.
- 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.
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
.
- my @yaml = Parse::CPAN::Meta::Load( $string );
Parses a string containing a valid YAML stream into a list of Perl data structures.
- my @yaml = Parse::CPAN::Meta::LoadFile( 'META.yml' );
Reads the YAML stream from a file instead of a string.
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.
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.
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.
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.
David Golden <[email protected]>
Ricardo Signes <[email protected]>
Adam Kennedy <[email protected]>
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.