[GTK] Fix unable to prefetch magnet in thinclient

A UnicodeDecodeError is raised in transfer module when attempting to
prefetch a magnet.

This is result of passing a Python dict containing text bytes and raw
bytes that cannot be decoded as utf-8 in rencode when recieving the
message. This could be handled in rencode by returning raw bytes if
decoding fails (perhaps with a strict mode?) however better to follow
convention of encoding raw bytes in base64 in API calls.

Fixed by retaining bencoding and encoding with base64 when sending
result.

Resolves: #334

deluge/core/core.py

@@ -432,12 +432,14 @@ def prefetch_magnet_metadata(self, magnet, timeout=30):
 
         Used by UIs to get magnet files for selection before adding to session.
 
+        The metadata is bencoded and for transfer base64 encoded.
+
         Args:
             magnet (str): The magnet URI.
             timeout (int): Number of seconds to wait before canceling request.
 
         Returns:
-            Deferred: A tuple of (torrent_id (str), metadata (dict)) for the magnet.
+            Deferred: A tuple of (torrent_id (str), metadata (str)) for the magnet.
 
         """
 

deluge/core/torrentmanager.py

@@ -13,6 +13,7 @@
 import os
 import pickle
 import time
+from base64 import b64encode
 from collections import namedtuple
 from tempfile import gettempdir
 
@@ -396,12 +397,12 @@ def on_prefetch_metadata(self, torrent_info, torrent_id, defer_timeout):
         else:
             self.session.remove_torrent(torrent_handle, 1)
 
-        metadata = None
+        metadata = b''
         if isinstance(torrent_info, lt.torrent_info):
             log.debug('prefetch metadata received')
-            metadata = lt.bdecode(torrent_info.metadata())
+            metadata = torrent_info.metadata()
 
-        return torrent_id, metadata
+        return torrent_id, b64encode(metadata)
 
     def _build_torrent_options(self, options):
         """Load default options and update if needed."""

deluge/tests/test_core.py

@@ -317,7 +317,7 @@ def test_pause_torrents_all(self):
     def test_prefetch_metadata_existing(self):
         """Check another call with same magnet returns existing deferred."""
         magnet = 'magnet:?xt=urn:btih:ab570cdd5a17ea1b61e970bb72047de141bce173'
-        expected = ('ab570cdd5a17ea1b61e970bb72047de141bce173', None)
+        expected = ('ab570cdd5a17ea1b61e970bb72047de141bce173', b'')
 
         def on_result(result):
             self.assertEqual(result, expected)

deluge/tests/test_torrentmanager.py

@@ -15,6 +15,7 @@
 from twisted.trial import unittest
 
 from deluge import component
+from deluge.bencode import bencode
 from deluge.common import windows_check
 from deluge.core.core import Core
 from deluge.core.rpcserver import RPCServer
@@ -82,42 +83,46 @@ def test_prefetch_metadata(self):
 
         expected = (
             'ab570cdd5a17ea1b61e970bb72047de141bce173',
-            {
-                b'piece length': 32768,
-                b'sha1': (
-                    b'2\xce\xb6\xa8"\xd7\xf0\xd4\xbf\xdc^K\xba\x1bh'
-                    b'\x9d\xc5\xb7\xac\xdd'
-                ),
-                b'name': b'azcvsupdater_2.6.2.jar',
-                b'private': 0,
-                b'pieces': (
-                    b"\xdb\x04B\x05\xc3'\xdab\xb8su97\xa9u"
-                    b'\xca<w\\\x1ef\xd4\x9b\x16\xa9}\xc0\x9f:\xfd'
-                    b'\x97qv\x83\xa2"\xef\x9d7\x0by!\rl\xe5v\xb7'
-                    b'\x18{\xf7/"P\xe9\x8d\x01D\x9e8\xbd\x16\xe3'
-                    b'\xfb-\x9d\xaa\xbcM\x11\xba\x92\xfc\x13F\xf0'
-                    b'\x1c\x86x+\xc8\xd0S\xa9\x90`\xa1\xe4\x82\xe8'
-                    b'\xfc\x08\xf7\xe3\xe5\xf6\x85\x1c%\xe7%\n\xed'
-                    b'\xc0\x1f\xa1;\x9a\xea\xcf\x90\x0c/F>\xdf\xdagA'
-                    b'\xc42|\xda\x82\xf5\xa6b\xa1\xb8#\x80wI\xd8f'
-                    b'\xf8\xbd\xacW\xab\xc3s\xe0\xbbw\xf2K\xbe\xee'
-                    b'\xa8rG\xe1W\xe8\xb7\xc2i\xf3\xd8\xaf\x9d\xdc'
-                    b'\xd0#\xf4\xc1\x12u\xcd\x0bE?:\xe8\x9c\x1cu'
-                    b'\xabb(oj\r^\xd5\xd5A\x83\x88\x9a\xa1J\x1c?'
-                    b'\xa1\xd6\x8c\x83\x9e&'
-                ),
-                b'length': 307949,
-                b'name.utf-8': b'azcvsupdater_2.6.2.jar',
-                b'ed2k': b'>p\xefl\xfa]\x95K\x1b^\xc2\\;;e\xb7',
-            },
+            b64encode(
+                bencode(
+                    {
+                        b'piece length': 32768,
+                        b'sha1': (
+                            b'2\xce\xb6\xa8"\xd7\xf0\xd4\xbf\xdc^K\xba\x1bh'
+                            b'\x9d\xc5\xb7\xac\xdd'
+                        ),
+                        b'name': b'azcvsupdater_2.6.2.jar',
+                        b'private': 0,
+                        b'pieces': (
+                            b"\xdb\x04B\x05\xc3'\xdab\xb8su97\xa9u"
+                            b'\xca<w\\\x1ef\xd4\x9b\x16\xa9}\xc0\x9f:\xfd'
+                            b'\x97qv\x83\xa2"\xef\x9d7\x0by!\rl\xe5v\xb7'
+                            b'\x18{\xf7/"P\xe9\x8d\x01D\x9e8\xbd\x16\xe3'
+                            b'\xfb-\x9d\xaa\xbcM\x11\xba\x92\xfc\x13F\xf0'
+                            b'\x1c\x86x+\xc8\xd0S\xa9\x90`\xa1\xe4\x82\xe8'
+                            b'\xfc\x08\xf7\xe3\xe5\xf6\x85\x1c%\xe7%\n\xed'
+                            b'\xc0\x1f\xa1;\x9a\xea\xcf\x90\x0c/F>\xdf\xdagA'
+                            b'\xc42|\xda\x82\xf5\xa6b\xa1\xb8#\x80wI\xd8f'
+                            b'\xf8\xbd\xacW\xab\xc3s\xe0\xbbw\xf2K\xbe\xee'
+                            b'\xa8rG\xe1W\xe8\xb7\xc2i\xf3\xd8\xaf\x9d\xdc'
+                            b'\xd0#\xf4\xc1\x12u\xcd\x0bE?:\xe8\x9c\x1cu'
+                            b'\xabb(oj\r^\xd5\xd5A\x83\x88\x9a\xa1J\x1c?'
+                            b'\xa1\xd6\x8c\x83\x9e&'
+                        ),
+                        b'length': 307949,
+                        b'name.utf-8': b'azcvsupdater_2.6.2.jar',
+                        b'ed2k': b'>p\xefl\xfa]\x95K\x1b^\xc2\\;;e\xb7',
+                    }
+                )
+            ),
         )
         self.assertEqual(expected, self.successResultOf(d))
 
     def test_prefetch_metadata_timeout(self):
         magnet = 'magnet:?xt=urn:btih:ab570cdd5a17ea1b61e970bb72047de141bce173'
         d = self.tm.prefetch_metadata(magnet, 30)
         self.clock.advance(30)
-        expected = ('ab570cdd5a17ea1b61e970bb72047de141bce173', None)
+        expected = ('ab570cdd5a17ea1b61e970bb72047de141bce173', b'')
         return d.addCallback(self.assertEqual, expected)
 
     @pytest.mark.todo

deluge/ui/gtk3/addtorrentdialog.py

@@ -8,14 +8,15 @@
 
 import logging
 import os
-from base64 import b64encode
+from base64 import b64decode, b64encode
 from xml.sax.saxutils import escape as xml_escape
 from xml.sax.saxutils import unescape as xml_unescape
 
 from gi.repository import Gtk
 from gi.repository.GObject import TYPE_INT64, TYPE_UINT64
 
 import deluge.component as component
+from deluge.bencode import bdecode
 from deluge.common import (
     create_magnet_uri,
     decode_bytes,
@@ -268,6 +269,7 @@ def _on_uri_metadata(self, result, uri, trackers):
             return
 
         if metadata:
+            metadata = bdecode(b64decode(metadata))
             info = TorrentInfo.from_metadata(metadata, [[t] for t in trackers])
             self.files[info_hash] = info.files
             self.infos[info_hash] = info.filedata