PyBencoder - your bencoded strings module

What is a Bencoded String?

Bencode (pronounced like B encode) is the encoding used by the peer-to-peer file sharing system BitTorrent for storing and transmitting loosely structured data.

For more info on bencoding check out

It provides:
  • decoding of the different bencoded elements
  • encoding of the allowed types (byte strings, integers, lists, and dictionaries).


Requires Python 2.6 or later.



Import the module

from bencoder import PyBencoder


Encoding is very easy to do. Just pass as an argument your data to encode method. It will automagically call the right encoder for you.

ben = PyBencoder()

ben.encode(123) # encode an integer 'i123e' ben.encode('123') # encode a string '3:123' ben.encode([1, 2, 3]) # encode a list 'li1ei2ei3ee' ben.encode([1, 2, [ 4, 5]]) # encode a slightly more complex list 'li1ei2eli4ei5eee' ben.encode({ 'one': 1, 'two': 2, 'three': 3 }) # encode a dictionary 'd5:threei3e3:twoi2e3:onei1ee'


Decoding is also easy to deal with. Just pass the bencoded string to decode method. Two mentions: - the first char of your bencoded string must be actually bencoded data, no garbage is allowed - at the end of the bencoded string it might be garbage data; after the extraction, you can also retrieve it

ben = PyBencoder()

ben.decode('i123e') # decode an integer 123 ben.decode('i123esomeothergarbagedata') # decode an integer with garbage data at the end ben.get_left() # gets what's left -> 'someothergarbagedata'

ben.decode('3:123somegarbage') # decode a 3 chars string

ben.decode('li1ei2eli4ei5eee') # decode a list [1, 2, [4, 5]]