1Bencode(3)            User Contributed Perl Documentation           Bencode(3)
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NAME

6       Bencode - BitTorrent serialisation format
7

SYNOPSIS

9        use Bencode qw( bencode bdecode );
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11        my $bencoded = bencode { 'age' => 25, 'eyes' => 'blue' };
12        print $bencoded, "\n";
13        my $decoded = bdecode $bencoded;
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DESCRIPTION

16       This module implements the BitTorrent bencode serialisation format, as
17       described in <http://www.bittorrent.org/beps/bep_0003.html#bencoding>.
18

INTERFACE

20   "bencode( $datastructure [, $undef_mode ] )"
21       Takes data to be encoded as a single argument which may be a scalar, or
22       may be a reference to either a scalar, an array or a hash. Arrays and
23       hashes may in turn contain values of these same types. Plain scalars
24       that look like canonically represented integers will be serialised as
25       such. To bypass the heuristic and force serialisation as a string, use
26       a reference to a scalar.
27
28       The second argument is optional (in which case it defaults to "str")
29       and specifies how to treat "undef" values. You can pick one of three
30       options:
31
32       "str" to encode "undef"s as empty strings;
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34       "num" to encode "undef"s as zeroes;
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36       "die" to croak upon encountering an "undef" value.
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38       Croaks on unhandled data types.
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40   "bdecode( $string [, $do_lenient_decode [, $max_depth ] ] )"
41       Takes a string and returns the corresponding deserialised data
42       structure.
43
44       If you pass a true value for the second option, it will disregard the
45       sort order of dict keys. This violation of the bencode format is
46       somewhat common.
47
48       If you pass an integer for the third option, it will croak when
49       attempting to parse dictionaries nested deeper than this level, to
50       prevent DoS attacks using maliciously crafted input.
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52       Croaks on malformed data.
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DIAGNOSTICS

55       "trailing garbage at %s"
56           Your data does not end after the first bencode-serialised item.
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58           You may also get this error if a malformed item follows.
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60       "garbage at %s"
61           Your data is malformed.
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63       "unexpected end of data at %s"
64           Your data is truncated.
65
66       "unexpected end of string data starting at %s"
67           Your data includes a string declared to be longer than the
68           available data.
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70       "malformed string length at %s"
71           Your data contained a string with negative length or a length with
72           leading zeroes.
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74       "malformed integer data at %s"
75           Your data contained something that was supposed to be an integer
76           but didn't make sense.
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78       "dict key not in sort order at %s"
79           Your data violates the bencode format constaint that dict keys must
80           appear in lexical sort order.
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82       "duplicate dict key at %s"
83           Your data violates the bencode format constaint that all dict keys
84           must be unique.
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86       "dict key is not a string at %s"
87           Your data violates the bencode format constaint that all dict keys
88           be strings.
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90       "dict key is missing value at %s"
91           Your data contains a dictionary with an odd number of elements.
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93       "nesting depth exceeded at %s"
94           Your data contains dicts or lists that are nested deeper than the
95           $max_depth passed to "bdecode()".
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97       "unhandled data type"
98           You are trying to serialise a data structure that consists of data
99           types other than
100
101           •   scalars
102
103           •   references to arrays
104
105           •   references to hashes
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107           •   references to scalars
108
109           The format does not support this.
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BUGS AND LIMITATIONS

112       Strings and numbers are practically indistinguishable in Perl, so
113       "bencode()" has to resort to a heuristic to decide how to serialise a
114       scalar. This cannot be fixed.
115

AUTHOR

117       Aristotle Pagaltzis <pagaltzis@gmx.de>
118

120       This software is copyright (c) 2017 by Aristotle Pagaltzis.
121
122       This is free software; you can redistribute it and/or modify it under
123       the same terms as the Perl 5 programming language system itself.
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127perl v5.36.0                      2022-08-16                        Bencode(3)
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