use 5.008001; use strict; use warnings; package Parse::CPAN::Meta; # ABSTRACT: Parse META.yml and META.json CPAN metadata files our $VERSION = '2.150010'; use Exporter; use Carp 'croak'; our @ISA = qw/Exporter/; our @EXPORT_OK = qw/Load LoadFile/; sub load_file { my ($class, $filename) = @_; my $meta = _slurp($filename); if ($filename =~ /\.ya?ml$/) { return $class->load_yaml_string($meta); } elsif ($filename =~ /\.json$/) { return $class->load_json_string($meta); } else { $class->load_string($meta); # try to detect yaml/json } } sub load_string { my ($class, $string) = @_; if ( $string =~ /^---/ ) { # looks like YAML return $class->load_yaml_string($string); } elsif ( $string =~ /^\s*\{/ ) { # looks like JSON return $class->load_json_string($string); } else { # maybe doc-marker-free YAML return $class->load_yaml_string($string); } } sub load_yaml_string { my ($class, $string) = @_; my $backend = $class->yaml_backend(); my $data = eval { no strict 'refs'; &{"$backend\::Load"}($string) }; croak $@ if $@; return $data || {}; # in case document was valid but empty } sub load_json_string { my ($class, $string) = @_; require Encode; # load_json_string takes characters, decode_json expects bytes my $encoded = Encode::encode('UTF-8', $string, Encode::PERLQQ()); my $data = eval { $class->json_decoder()->can('decode_json')->($encoded) }; croak $@ if $@; return $data || {}; } sub yaml_backend { if ($ENV{PERL_CORE} or not defined $ENV{PERL_YAML_BACKEND} ) { _can_load( 'CPAN::Meta::YAML', 0.011 ) or croak "CPAN::Meta::YAML 0.011 is not available\n"; return "CPAN::Meta::YAML"; } else { my $backend = $ENV{PERL_YAML_BACKEND}; _can_load( $backend ) or croak "Could not load PERL_YAML_BACKEND '$backend'\n"; $backend->can("Load") or croak "PERL_YAML_BACKEND '$backend' does not implement Load()\n"; return $backend; } } sub json_decoder { if ($ENV{PERL_CORE}) { _can_load( 'JSON::PP' => 2.27300 ) or croak "JSON::PP 2.27300 is not available\n"; return 'JSON::PP'; } if (my $decoder = $ENV{CPAN_META_JSON_DECODER}) { _can_load( $decoder ) or croak "Could not load CPAN_META_JSON_DECODER '$decoder'\n"; $decoder->can('decode_json') or croak "No decode_json sub provided by CPAN_META_JSON_DECODER '$decoder'\n"; return $decoder; } return $_[0]->json_backend; } sub json_backend { if ($ENV{PERL_CORE}) { _can_load( 'JSON::PP' => 2.27300 ) or croak "JSON::PP 2.27300 is not available\n"; return 'JSON::PP'; } if (my $backend = $ENV{CPAN_META_JSON_BACKEND}) { _can_load( $backend ) or croak "Could not load CPAN_META_JSON_BACKEND '$backend'\n"; $backend->can('new') or croak "No constructor provided by CPAN_META_JSON_BACKEND '$backend'\n"; return $backend; } if (! $ENV{PERL_JSON_BACKEND} or $ENV{PERL_JSON_BACKEND} eq 'JSON::PP') { _can_load( 'JSON::PP' => 2.27300 ) or croak "JSON::PP 2.27300 is not available\n"; return 'JSON::PP'; } else { _can_load( 'JSON' => 2.5 ) or croak "JSON 2.5 is required for " . "\$ENV{PERL_JSON_BACKEND} = '$ENV{PERL_JSON_BACKEND}'\n"; return "JSON"; } } sub _slurp { require Encode; open my $fh, "<:raw", "$_[0]" ## no critic or die "can't open $_[0] for reading: $!"; my $content = do { local $/; <$fh> }; $content = Encode::decode('UTF-8', $content, Encode::PERLQQ()); return $content; } sub _can_load { my ($module, $version) = @_; (my $file = $module) =~ s{::}{/}g; $file .= ".pm"; return 1 if $INC{$file}; return 0 if exists $INC{$file}; # prior load failed eval { require $file; 1 } or return 0; if ( defined $version ) { eval { $module->VERSION($version); 1 } or return 0; } return 1; } # Kept for backwards compatibility only # Create an object from a file sub LoadFile ($) { ## no critic return Load(_slurp(shift)); } # Parse a document from a string. sub Load ($) { ## no critic require CPAN::Meta::YAML; my $object = eval { CPAN::Meta::YAML::Load(shift) }; croak $@ if $@; return $object; } 1; __END__ =pod =encoding UTF-8 =head1 NAME Parse::CPAN::Meta - Parse META.yml and META.json CPAN metadata files =head1 VERSION version 2.150010 =head1 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}; =head1 DESCRIPTION B is a parser for F and F files, using L and/or L. B provides three methods: C, C, and C. These will read and deserialize CPAN metafiles, and are described below in detail. B 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. =begin Pod::Coverage =end Pod::Coverage =head1 METHODS =head2 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. =head2 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 C. =head2 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 C. =head2 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. =head2 yaml_backend my $backend = Parse::CPAN::Meta->yaml_backend; Returns the module name of the YAML serializer. See L for details. =head2 json_backend my $backend = Parse::CPAN::Meta->json_backend; Returns the module name of the JSON serializer. If C is set, this will be whatever that's set to. If not, this will either be L or L. If C is set, this will return L as further delegation is handled by the L module. See L for details. =head2 json_decoder my $decoder = Parse::CPAN::Meta->json_decoder; Returns the module name of the JSON decoder. Unlike L, this is not necessarily a full L-style module, but only something that will provide a C subroutine. If C is set, this will be whatever that's set to. If not, this will be whatever has been selected as L. See L for more notes. =head1 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 C. =head2 Load my @yaml = Parse::CPAN::Meta::Load( $string ); Parses a string containing a valid YAML stream into a list of Perl data structures. =head2 LoadFile my @yaml = Parse::CPAN::Meta::LoadFile( 'META.yml' ); Reads the YAML stream from a file instead of a string. =head1 ENVIRONMENT =head2 CPAN_META_JSON_DECODER By default, L will be used for deserializing JSON data. If the C environment variable exists, this is expected to be the name of a loadable module that provides a C 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 L, L, L, L, L, and L. =head2 CPAN_META_JSON_BACKEND By default, L will be used for deserializing JSON data. If the C environment variable exists, this is expected to be the name of a loadable module that provides the L API, since downstream code expects to be able to call C on this class. As such, while L, L, L and L will work for this, to use L or L for decoding requires setting L. =head2 PERL_JSON_BACKEND If the C environment variable does not exist, and if C environment variable exists, is true and is not "JSON::PP", then the L module (version 2.5 or greater) will be loaded and used to interpret C. If L 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 L to guess, or L - if you want to use a newer JSON module, see L. =head2 PERL_YAML_BACKEND By default, L will be used for deserializing YAML data. If the C 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 C function or an exception will be thrown. =head1 AUTHORS =over 4 =item * David Golden =item * Ricardo Signes =item * Adam Kennedy =back =head1 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. =cut