libjson-tiny-perl/lib/JSON/Tiny.pod
2018-03-27 21:25:33 +02:00

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=pod
=encoding utf8
=head1 NAME
JSON::Tiny - Minimalistic JSON. No dependencies.
=head1 SYNOPSIS
use JSON::Tiny qw(decode_json encode_json);
my $bytes = encode_json {foo => [1, 2], bar => 'hello!', baz => \1};
my $hash = decode_json $bytes;
=head1 DESCRIPTION
L<JSON::Tiny> is a minimalistic standalone adaptation of L<Mojo::JSON>, from
the L<Mojolicious> framework. It is a single-source-file module with under 300
lines of code and core-only dependencies.
Features include transparent Unicode support, speed, small memory footprint,
and a minimal code base ideal for bundling or inlining. Along with
L<Mojo::JSON>, it is among the fastest pure-Perl implementations of
L<RFC 7159|http://tools.ietf.org/html/rfc7159>.
L<JSON::Tiny> supports normal Perl data types like scalar, array reference,
hash reference, and will try to call the L<TO_JSON> method on blessed
references, or stringify them if it doesn't exist.
Differentiating between strings and numbers in Perl is hard; depending on how
it has been used, a scalar can be both at the same time. The string value has a
higher precedence unless both representations are equivalent.
[1, -2, 3] -> [1, -2, 3]
{"foo": "bar"} -> {foo => 'bar'}
Literal names will be translated to and from L<JSON::Tiny> constants or a
similar native Perl value.
true -> JSON::Tiny->true
false -> JSON::Tiny->false
null -> undef
Scalar references will be used to generate Booleans, based on if their values
are true or false.
\1 => true
\0 => false
The two Unicode whitespace characters C<u2028> and C<u2029> will always be
escaped to make JSONP easier, and the character C</> to prevent XSS attacks.
=head1 FUNCTIONS
L<JSON::Tiny> implements the following functions, which can be imported
individually.
=head2 decode_json
my $value = decode_json $bytes;
Decode JSON to Perl value and die if decoding fails.
=head2 encode_json
my $bytes = encode_json {foo => 'bar'};
Encode Perl value to JSON.
=head2 false
my $false = false;
False value, used because Perl has no equivalent.
=head2 from_json
my $value = from_json $chars;
Decode JSON text that is not C<UTF-8> encoded to Perl value and die if
decoding fails.
=head2 j
my $bytes = j [1, 2, 3];
my $bytes = j {foo => 'bar'};
my $value = j $bytes;
Encode Perl data structure (which may only be an array reference or hash
reference) or decode JSON. An C<undef> return value indicates a bare C<null>.
Dies if decoding fails.
=head2 to_json
my $chars = to_json {i => '♥ Perl'};
Encode Perl value to JSON text without C<UTF-8> encoding it.
=head2 true
my $true = true;
True value, used because Perl has no native equivalent.
=head3 More on Booleans
A reference to a scalar (even if blessed) is encoded as a Boolean value unless
it has a TO_JSON method.
my $json = $j->encode( { b => \1, a => \0 } ); # {"b":true,"a":false}
Boolean false and true values returned when JSON is decoded are
JSON::Tiny::_Bool objects with overloaded stringification.
B<Advanced option>: Users requiring a plain old literal C<0> or C<1>, may set
C<$JSON::Tiny::FALSE = 0;> and C<$JSON::Tiny::TRUE = 1;>. Any value, including
blessed references will work. This must be set prior to calling a JSON decoding
function. Use C<local> to limit scope.
=head1 Tiny
JSON::Tiny compared with JSON::PP from the L<JSON> distribution:
=over 4
=item * L<JSON::PP> is configurable, but more complex. L<JSON::Tiny> offers
sane defaults, and no configuration.
=item * Download and install with C<cpanm>: L<JSON::PP>, 5.2 seconds.
L<JSON::Tiny>, 1.9 seconds.
=item * Minimal Dependencies: Both L<JSON::PP> and L<JSON::Tiny> only use core
dependencies. JSON::Tiny requires Perl 5.8.4, while L<JSON::PP> requires 5.6.
=item * Simple Design: L<JSON> has 2254 lines of code, six modules and five
files. Distribution: 85KB.
L<JSON::Tiny> has under 300 lines of code; an embeddable single-file module.
Distribution: 18KB.
=item * L<JSON::PP> has 42 functions and methods. L<JSON::Tiny> has seven.
=item * Performance:
Rate JSON_PP JSON_Tiny
JSON_PP 304/s -- -52%
JSON_Tiny 636/s 109% --
L<JSON> uses L<JSON::XS> if it's available, in which case L<JSON> wins.
See C<examples/json_bench.pl> for benchmark code.
JSON::Tiny's lightweight design reduces its startup time compared to the
L<JSON> module. This may benefit frequently run applications like CGI.
=item * Light Memory Needs: Memory usage was tested with
L<http://valgrind.org/valgrind> and L<Devel::MemoryTrace::Light> by running
C<examples/json_pp.pl> and C<examples/json_tiny.pl>.
valgrind Devel::MemoryTrace::Light
JSON::PP 5.1MB 3.7MB
JSON::Tiny 4.5MB 2.6MB
=back
=head1 CONFIGURATION AND ENVIRONMENT
No configuration.
=head1 DEPENDENCIES
Perl 5.8.4 or newer. B<Perl 5.10+ is recommended due to bugs in Perl 5.8's
regular expression engine.>
=head1 INCOMPATIBILITIES
Incompatible with L<Exporter> versions older than 5.59 (ie, predating Perl
5.8.4).
=head1 AUTHOR
David Oswald, C<< <davido at cpan.org> >>
Code and tests adapted from L<Mojo::JSON>.
=head1 SUPPORT
Direct support requests to the author. Direct bug reports to CPAN's Request
Tracker (RT).
You can find documentation for this module with the perldoc command.
perldoc JSON::Tiny
You may look for additional information at:
=over 4
=item * Github: Development is hosted on Github at:
L<http://www.github.com/daoswald/JSON-Tiny>
=item * RT: CPAN's request tracker (bug reports)
L<http://rt.cpan.org/NoAuth/Bugs.html?Dist=JSON-Tiny>
=item * AnnoCPAN: Annotated CPAN documentation
L<http://annocpan.org/dist/JSON-Tiny>
=item * CPAN Ratings
L<http://cpanratings.perl.org/d/JSON-Tiny>
=item * Search CPAN
L<http://search.cpan.org/dist/JSON-Tiny/>
=back
=head1 ACKNOWLEDGEMENTS
L<Mojolicious> team for its lightweight JSON implementation. This module was
adapted from L<Mojo::JSON> because it is robust, minimal, and well tested.
Mojo::JSON's tests were also adapted to a dependency-free design.
Christian Hansen, whos L<GitHub Gist|https://gist.github.com/chansen/810296>
formed the basis for L<Mojo::JSON>, and subsequently JSON::Tiny.
Randal Schwartz showed his pure-regexp JSON parser
(L<PerlMonks|http://perlmonks.org/?node_id=995856>) to Los Angeles Perl Mongers
(09/2012). He wasn't involved in JSON::Tiny, but exploring alternatives to his
solution led to this project.
=head1 LICENSE AND COPYRIGHT
Copyright 2012-2014 David Oswald.
This program is free software, you can redistribute it and/or modify it under
the terms of the Artistic License version 2.0.
See L<http://www.perlfoundation.org/artistic_license_2_0> for more information.
=head1 SEE ALSO
L<Mojo::JSON>, L<JSON>, L<RFC7159|http://tools.ietf.org/html/rfc7159>.
=cut