Parse::CPAN::Meta(3pm)

1Parse::CPAN::Meta(3)  User Contributed Perl Documentation Parse::CPAN::Meta(3)
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NAME

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

9       version 2.150010
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SYNOPSIS

12           #############################################
13           # In your file
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15           ---
16           name: My-Distribution
17           version: 1.23
18           resources:
19             homepage: "http://example.com/dist/My-Distribution"
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21
22           #############################################
23           # In your program
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25           use Parse::CPAN::Meta;
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27           my $distmeta = Parse::CPAN::Meta->load_file('META.yml');
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29           # Reading properties
30           my $name     = $distmeta->{name};
31           my $version  = $distmeta->{version};
32           my $homepage = $distmeta->{resources}{homepage};
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DESCRIPTION

35       Parse::CPAN::Meta is a parser for META.json and META.yml files, using
36       JSON::PP and/or CPAN::Meta::YAML.
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38       Parse::CPAN::Meta provides three methods: "load_file",
39       "load_json_string", and "load_yaml_string".  These will read and
40       deserialize CPAN metafiles, and are described below in detail.
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42       Parse::CPAN::Meta provides a legacy API of only two functions, based on
43       the YAML functions of the same name. Wherever possible, identical
44       calling semantics are used.  These may only be used with YAML sources.
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46       All error reporting is done with exceptions (die'ing).
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48       Note that META files are expected to be in UTF-8 encoding, only.  When
49       converted string data, it must first be decoded from UTF-8.
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METHODS

52   load_file
53         my $metadata_structure = Parse::CPAN::Meta->load_file('META.json');
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55         my $metadata_structure = Parse::CPAN::Meta->load_file('META.yml');
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57       This method will read the named file and deserialize it to a data
58       structure, determining whether it should be JSON or YAML based on the
59       filename.  The file will be read using the ":utf8" IO layer.
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61   load_yaml_string
62         my $metadata_structure = Parse::CPAN::Meta->load_yaml_string($yaml_string);
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64       This method deserializes the given string of YAML and returns the first
65       document in it.  (CPAN metadata files should always have only one
66       document.)  If the source was UTF-8 encoded, the string must be decoded
67       before calling "load_yaml_string".
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69   load_json_string
70         my $metadata_structure = Parse::CPAN::Meta->load_json_string($json_string);
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72       This method deserializes the given string of JSON and the result.  If
73       the source was UTF-8 encoded, the string must be decoded before calling
74       "load_json_string".
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76   load_string
77         my $metadata_structure = Parse::CPAN::Meta->load_string($some_string);
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79       If you don't know whether a string contains YAML or JSON data, this
80       method will use some heuristics and guess.  If it can't tell, it
81       assumes YAML.
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83   yaml_backend
84         my $backend = Parse::CPAN::Meta->yaml_backend;
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86       Returns the module name of the YAML serializer. See "ENVIRONMENT" for
87       details.
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89   json_backend
90         my $backend = Parse::CPAN::Meta->json_backend;
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92       Returns the module name of the JSON serializer.  If
93       "CPAN_META_JSON_BACKEND" is set, this will be whatever that's set to.
94       If not, this will either be JSON::PP or JSON.  If "PERL_JSON_BACKEND"
95       is set, this will return JSON as further delegation is handled by the
96       JSON module.  See "ENVIRONMENT" for details.
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98   json_decoder
99         my $decoder = Parse::CPAN::Meta->json_decoder;
100
101       Returns the module name of the JSON decoder.  Unlike "json_backend",
102       this is not necessarily a full JSON-style module, but only something
103       that will provide a "decode_json" subroutine.  If
104       "CPAN_META_JSON_DECODER" is set, this will be whatever that's set to.
105       If not, this will be whatever has been selected as "json_backend".  See
106       "ENVIRONMENT" for more notes.
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FUNCTIONS

109       For maintenance clarity, no functions are exported by default.  These
110       functions are available for backwards compatibility only and are best
111       avoided in favor of "load_file".
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113   Load
114         my @yaml = Parse::CPAN::Meta::Load( $string );
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116       Parses a string containing a valid YAML stream into a list of Perl data
117       structures.
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119   LoadFile
120         my @yaml = Parse::CPAN::Meta::LoadFile( 'META.yml' );
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122       Reads the YAML stream from a file instead of a string.
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ENVIRONMENT

125   CPAN_META_JSON_DECODER
126       By default, JSON::PP will be used for deserializing JSON data.  If the
127       "CPAN_META_JSON_DECODER" environment variable exists, this is expected
128       to be the name of a loadable module that provides a "decode_json"
129       subroutine, which will then be used for deserialization.  Relying only
130       on the existence of said subroutine allows for maximum compatibility,
131       since this API is provided by all of JSON::PP, JSON::XS,
132       Cpanel::JSON::XS, JSON::MaybeXS, JSON::Tiny, and Mojo::JSON.
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134   CPAN_META_JSON_BACKEND
135       By default, JSON::PP will be used for deserializing JSON data.  If the
136       "CPAN_META_JSON_BACKEND" environment variable exists, this is expected
137       to be the name of a loadable module that provides the JSON API, since
138       downstream code expects to be able to call "new" on this class.  As
139       such, while JSON::PP, JSON::XS, Cpanel::JSON::XS and JSON::MaybeXS will
140       work for this, to use Mojo::JSON or JSON::Tiny for decoding requires
141       setting "CPAN_META_JSON_DECODER".
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143   PERL_JSON_BACKEND
144       If the "CPAN_META_JSON_BACKEND" environment variable does not exist,
145       and if "PERL_JSON_BACKEND" environment variable exists, is true and is
146       not "JSON::PP", then the JSON module (version 2.5 or greater) will be
147       loaded and used to interpret "PERL_JSON_BACKEND".  If JSON is not
148       installed or is too old, an exception will be thrown.  Note that at the
149       time of writing, the only useful values are 1, which will tell JSON to
150       guess, or JSON::XS - if you want to use a newer JSON module, see
151       "CPAN_META_JSON_BACKEND".
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153   PERL_YAML_BACKEND
154       By default, CPAN::Meta::YAML will be used for deserializing YAML data.
155       If the "PERL_YAML_BACKEND" environment variable is defined, then it is
156       interpreted as a module to use for deserialization.  The given module
157       must be installed, must load correctly and must implement the Load()
158       function or an exception will be thrown.
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AUTHORS

161       •   David Golden <dagolden@cpan.org>
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163       •   Ricardo Signes <rjbs@cpan.org>
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165       •   Adam Kennedy <adamk@cpan.org>
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COPYRIGHT AND LICENSE

168       This software is copyright (c) 2010 by David Golden, Ricardo Signes,
169       Adam Kennedy and Contributors.
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171       This is free software; you can redistribute it and/or modify it under
172       the same terms as the Perl 5 programming language system itself.
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176perl v5.38.0                      2023-07-20              Parse::CPAN::Meta(3)