convert torrent to magnet link

torrent2magnet.py

import sys
import bencode
import hashlib
import base64
import urllib


def make_magnet_from_file(file) :
    with open(file,'r') as f:
    	torrent = f.read()
    metadata = bencode.bdecode(torrent)
    hashcontents = bencode.bencode(metadata['info'])
    digest = hashlib.sha1(hashcontents).digest()
    b32hash = base64.b32encode(digest)
    params = {'xt': 'urn:btih:%s' % b32hash,
    	      'dn': metadata['info']['name'],
	      'tr': metadata['announce']}
    paramstr = urllib.urlencode(params)
    magneturi = 'magnet:?%s' % paramstr
    return magneturi

if __name__ == "__main__":
    magnet = make_magnet_from_file(sys.argv[1])
    print(magnet)