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KAZUHO / MIME-Base64-URLSafe-0.01 / lib / MIME / Base64 / URLSafe.pm 

            

              
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package MIME::Base64::URLSafe;
use strict;
use vars qw(@ISA @EXPORT $VERSION);
use MIME::Base64;
require Exporter;
@ISA = qw(Exporter);
@EXPORT = qw(urlsafe_b64encode urlsafe_b64decode);
$VERSION = '0.01';
sub encode ($) {
    my $data = encode_base64($_[0], '');
    $data =~ tr|+/=|\-_|d;
    $data;
}
sub decode ($) {
    my $data = $_[0];
    # +/ should not be handled, so convert them to invalid chars
    # also, remove spaces (\t..\r and SP) so as to calc padding len
    $data =~ tr|\-_\t-\x0d |+/|d;
    my $mod4 = length($data) % 4;
    if ($mod4) {
        $data .= substr('====', $mod4);
    }
    decode_base64($data);
}
*urlsafe_b64encode = \&encode;
*urlsafe_b64decode = \&decode;
1;
__END__
=head1 NAME
MIME::Base64::URLSafe - Perl version of Python's URL-safe base64 codec
=head1 SYNOPSIS
  use MIME::Base64::URLSafe;
   
  $encoded = urlsafe_b64encode('Alladdin: open sesame');
  $decoded = urlsafe_b64decode($encoded);
=head1 DESCRIPTION
This module is a perl version of python's URL-safe base64 encoder / decoder.
When embedding binary data in URL, it is preferable to use base64 encoding.  However, two characters ('+' and '/') used in the standard base64 encoding have special meanings in URLs, often leading to re-encoding with URL-encoding, or worse, interoperability problems.
To overcome the problem, the module provides a variation of base64 codec compatible with python's urlsafe_b64encode / urlsafe_b64decode.
Modification rules from base64:
    use '-' and '_' instead of '+' and '/'
    no line feeds
    no trailing equals (=)
The following functions are provided:
    urlsafe_b64encode($str)
    urlsafe_b64decode($str)
If you prefer not to import these routines to your namespace, you can call them as:
    use MIME::Base64::URLSafe ();
    $encoded = MIME::Base64::URLSafe::encode($decoded);
    $decoded = MIME::Base64::URLSafe::decode($encoded);
=head1 SEE ALSO
L<MIME::Base64>
Fore more discussion on using base64 encoding in URL applications, see: http://en.wikipedia.org/wiki/Base64#URL_Applications
=head1 AUTHOR
Kazuho Oku E<lt>kazuho ___at___ labs.cybozu.co.jpE<gt>
Copyright (C) 2006 Cybozu Labs, Inc.
This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself, either Perl version 5.8.7 or,
at your option, any later version of Perl 5 you may have available.
=cut