Convert a .torrent seed file into a magnet:? magnetic link for easier batch import into some offline downloading service

torrent2magnet.py

#!/usr/bin/python
# vim: set fileencoding=utf-8:

# Code shamelessly copied from:
# http://stackoverflow.com/questions/12479570/given-a-torrent-file-how-do-i-generate-a-magnet-link-in-python

# How to install the `bencode' module for Python on Windows:
# Run a command line window as Administrator:
# % python -m pip install bencode

import sys
import bencode
import hashlib
import base64
import urllib

if len(sys.argv) != 2:
	print "Must provide one argument"
	sys.exit(1)

torrent = open(sys.argv[1], 'rb').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'] }
#			'xl': metadata['info']['length'] }

paramstr = urllib.urlencode(params)
magneturi = 'magnet:?%s' % paramstr
print magneturi

Successfully tested using:
Python 2.7.11
Windows 10 Version 1607 (OS Build 14393.693)