=head1 NAME

URL::Encode - Encoding and decoding of C<application/x-www-form-urlencoded> encoding.

=head1 SYNOPSIS

    $octets = url_decode($octets);
    $string = url_decode_utf8($octets);
    
    $octets = url_encode($octets);
    $octets = url_encode_utf8($string);
    
    $params = url_params_flat($octets [, $utf8 = false]);
    $params = url_params_mixed($octets [, $utf8 = false]);
    $params = url_params_multi($octets [, $utf8 = false]);
              url_params_each($octets, $callback [, $utf8 = false]);

=head1 DESCRIPTION

This module provides functions to encode and decode strings into and from the 
C<application/x-www-form-urlencoded> encoding.

The C<application/x-www-form-urlencoded> format encodes a ordered data 
sets of pairs consisting of a name and a value, with pairs seperated by 
ampersand or semicolon and names and values seperated by the equal sign. 
Space characters are replaced with plus sign and any characters not in 
the unreserved character set is encoded using the percent-encoding scheme 
also used for resource identifiers. A percent-encoded octet is encoded as 
a character triplet, consisting of the percent character "%" followed by 
the two hexadecimal digits representing that octet's numeric value.

The unreserved character set includes the uppercase and lowercase letters, 
decimal digits, hyphen, period, underscore, and tilde.

    ABCDEFGHIJKLMNOPQRSTUVWXYZ
    abcdefghijklmnopqrstuvwxyz
    0123456789
    - . _ ~

=head1 FUNCTIONS

=head2 url_decode

    $octets = url_decode($octets);
    
Returns a decoded representation of the given URL-encoded C<$octets> as an 
octet string.

=head2 url_decode_utf8

    $string = url_decode_utf8($octets);

Returns a decoded representation of the given URL-encoded C<$octets> in
UTF-8 encoding as a character string.

=head2 url_encode

    $octets = url_encode($octets);

Returns a URL-encoded representation of the given C<$octets> as an octet 
string.

=head2 url_encode_utf8

    $octets = url_encode_utf8($string);

Returns a URL-encoded representation of C<$string> in UTF-8 encoding as an 
octet string.

=head2 url_params_flat

    $params = url_params_flat($octets);
    $params = url_params_flat($octets, $utf8);

Parses a URL-encoded data set of name/value pairs from the given octets. 
Returns an ARRAY reference containing the URL-decoded name/value pairs in order.

    $params = url_params_flat('foo=A&foo=B&bar=C');
    $params; # [ foo => 'A', foo => 'B', bar => 'C' ]

=head2 url_params_mixed

    $params = url_params_mixed($octets);
    $params = url_params_mixed($octets, $utf8);

Parses a URL-encoded data set of name/value pairs from the given octets. 
Returns a HASH reference containing the URL-decoded name/value pairs. Multiple 
occurrences of a parameter will result in an ARRAY reference holding all 
the values for that parameter in order.

    $params = url_params_mixed('foo=A&foo=B&bar=C');
    $params; # { foo => [ 'A', 'B' ], bar => 'C' }

=head2 url_params_multi

    $params = url_params_multi($octets);
    $params = url_params_multi($octets, $utf8);

Parses a URL-encoded data set of name/value pairs from the given octets. 
Returns a HASH reference containing the URL-decoded name/value pairs. Values 
are stored in an ARRAY reference.

    $params = url_params_multi('foo=A&foo=B&bar=C');
    $params; # { foo => [ 'A', 'B' ], bar => [ 'C' ] }

=head2 url_params_each

    url_params_each($octets, $callback);
    url_params_each($octets, $callback, $utf8);

Parses a URL-encoded data set of name/value pairs from the given octets. 
Invokes the given callback for each URL-decoded name/value pair.

    $callback = sub {
        my ($name, $value) = @_;
    };
    
    url_params_each($octets, $callback);

=head1 EXPORTS

None by default. All functions can be exported using the C<:all> tag or individually.

=head1 DIAGNOSTICS

=over 4

=item B<(F)> Usage: %s

Subroutine called with wrong number of arguments.

=item B<(F)> Wide character in octet string

=item B<(F)> Malformed UTF-8 in URL-decoded octets

=back

=head1 PERFORMANCE

The L<URL::Encode::XS> module provides faster C/XS implementations of 
the functions found in this module. This module will automatically use 
L<URL::Encode::XS> if it's installed.

    Benchmarking url_decode() PP vs XS:

            Rate    PP    XS
    PP  507520/s    --  -92%
    XS 6389812/s 1159%    --

    Benchmarking url_encode() PP vs XS:

            Rate    PP    XS
    PP  119866/s    --  -98%
    XS 7214089/s 5918%    --

    Benchmarking url_params_mixed() PP vs XS:

          Rate    PP    XS
    PP  4450/s    --  -95%
    XS 95015/s 2035%    --

    Benchmarking URL::Encode::XS vs CGI::Deurl::XS

                       Rate  CGI::Deurl::XS URL::Encode::XS
    CGI::Deurl::XS  51932/s              --            -48%
    URL::Encode::XS 99444/s             91%              --

=head1 SEE ALSO

=over 4

=item L<URL::Encode::XS>

XS implementation of C<URL::Encode>.

=item L<CGI::Deurl::XS>

=back

=head1 SUPPORT

=head2 BUGS

Please report any bugs by email to C<bug-url-encode at rt.cpan.org>, or 
through the web interface at L<http://rt.cpan.org/Public/Dist/Display.html?Name=URL-Encode>. 
You will be automatically notified of any progress on the request by the system.

=head2 SOURCE CODE

This is open source software. The code repository is available for public 
review and contribution under the terms of the license.

L<http://github.com/chansen/p5-url-encode>

    git clone http://github.com/chansen/p5-url-encode

=head1 AUTHOR

Christian Hansen C<chansen@cpan.org>

=head1 COPYRIGHT

Copyright 2011-2014 by Christian Hansen.

This library is free software; you can redistribute it and/or modify 
it under the same terms as Perl itself.

