Fixes an issue with magnets without fallback trackers + loads directly into standard client defined for torrent files(xdg-open).

magnet2torrent.py

#!/usr/bin/env python
'''
Created on Apr 19, 2012
@author: dan, Faless

    GNU GENERAL PUBLIC LICENSE - Version 3

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.

    http://www.gnu.org/licenses/gpl-3.0.txt

'''

import shutil
import tempfile
import os.path as pt
import sys
import subprocess
import os
import libtorrent as lt
from time import sleep
from argparse import ArgumentParser


def magnet2torrent(magnet, output_name=None):
    if output_name and \
            not pt.isdir(output_name) and \
            not pt.isdir(pt.dirname(pt.abspath(output_name))):
        print("Invalid output folder: " + pt.dirname(pt.abspath(output_name)))
        print("")
        sys.exit(0)

    tempdir = tempfile.mkdtemp()
    ses = lt.session()
    params = {
        'save_path': tempdir,
        'storage_mode': lt.storage_mode_t(2),
        'paused': False,
        'auto_managed': True,
        'duplicate_is_error': True
    }
    ses.add_dht_router("router.bittorrent.com", 6881) 
    ses.add_dht_router("router.utorrent.com", 6881) 
    ses.add_dht_router("dht.transmissionbt.com", 6881) 
    ses.add_dht_router("dht.aelitis.com", 6881) 
    ses.add_dht_router("router.bitcomet.com", 6881) 
    ses.start_dht()
    sleep(2)
    handle = lt.add_magnet_uri(ses, magnet, params)

    print("Downloading Metadata (this may take a while)")
    while (not handle.has_metadata()):
        try:
            sleep(1)
        except KeyboardInterrupt:
            print("Aborting...")
            ses.pause()
            print("Cleanup dir " + tempdir)
            shutil.rmtree(tempdir)
            sys.exit(0)
    ses.pause()
    print("Done")

    torinfo = handle.get_torrent_info()
    torfile = lt.create_torrent(torinfo)

    output = pt.abspath(torinfo.name() + ".torrent")

    if output_name:
        if pt.isdir(output_name):
            output = pt.abspath(pt.join(
                output_name, torinfo.name() + ".torrent"))
        elif pt.isdir(pt.dirname(pt.abspath(output_name))):
            output = pt.abspath(output_name)

    print("Saving torrent file here : " + output + " ...")
    torcontent = lt.bencode(torfile.generate())
    f = open(output, "wb")
    f.write(lt.bencode(torfile.generate()))
    f.close()
    print("Saved! Cleaning up dir: " + tempdir)
    ses.remove_torrent(handle)
    shutil.rmtree(tempdir)
    subprocess.call(('sh','xdg-open',output))
    os.remove(output)

    return output

def main():
    parser = ArgumentParser(description="A command line tool that converts magnet links in to .torrent files")
    parser.add_argument('-m','--magnet', help='The magnet url')
    parser.add_argument('-o','--output', help='The output torrent file name')

    #
    # This second parser is created to force the user to provide
    # the 'output' arg if they provide the 'magnet' arg.
    #
    # The current version of argparse does not have support
    # for conditionally required arguments. That is the reason
    # for creating the second parser
    #
    # Side note: one should look into forking argparse and adding this
    # feature.
    #
    conditionally_required_arg_parser = ArgumentParser(description="A command line tool that converts magnet links in to .torrent files")
    conditionally_required_arg_parser.add_argument('-m','--magnet', help='The magnet url')
    conditionally_required_arg_parser.add_argument('-o','--output', help='The output torrent file name', required=True)

    magnet = None
    output_name = None

    #
    # Attempting to retrieve args using the new method
    #
    args = vars(parser.parse_known_args()[0])
    if args['magnet'] is not None:
        magnet = args['magnet']
        argsHack = vars(conditionally_required_arg_parser.parse_known_args()[0])
        output_name = argsHack['output']
    if args['output'] is not None and output_name is None:
        output_name = args['output']
        if magnet is None:
            #
            # This is a special case.
            # This is when the user provides only the "output" args.
            # We're forcing him to provide the 'magnet' args in the new method
            #
            print ('usage: {0} [-h] [-m MAGNET] -o OUTPUT'.format(sys.argv[0]))
            print ('{0}: error: argument -m/--magnet is required'.format(sys.argv[0]))
            sys.exit()
    #
    # Defaulting to the old of doing things
    # 
    if output_name is None and magnet is None:
        if len(sys.argv) >= 2:
            magnet = sys.argv[1]
        if len(sys.argv) >= 3:
            output_name = sys.argv[2]

    magnet2torrent(magnet, output_name)


if __name__ == "__main__":
    main()