Current File : //usr/share/doc/perl-CPAN-Meta-2.120921/README
NAME
CPAN::Meta - the distribution metadata for a CPAN dist
VERSION
version 2.120921
SYNOPSIS
my $meta = CPAN::Meta->load_file('META.json');
printf "testing requirements for %s version %s\n",
$meta->name,
$meta->version;
my $prereqs = $meta->requirements_for('configure');
for my $module ($prereqs->required_modules) {
my $version = get_local_version($module);
die "missing required module $module" unless defined $version;
die "version for $module not in range"
unless $prereqs->accepts_module($module, $version);
}
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()".
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.
$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.
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
has 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_struct( {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.
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
<http://rt.cpan.org/Public/Dist/Display.html?Name=CPAN-Meta>. 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.
<http://github.com/dagolden/cpan-meta>
git clone git://github.com/dagolden/cpan-meta.git
AUTHORS
* David Golden <dagolden@cpan.org>
* Ricardo Signes <rjbs@cpan.org>
COPYRIGHT AND LICENSE
This software is copyright (c) 2010 by David Golden and Ricardo Signes.
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.
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