[TrackerIcon] Fixed parse error on UTF-8 sites with non-english chars

When parsing the site's page in search for the FAVICON, the page gets opens.
The default file encoding in dependent on the running OS, and might not
be `UTF-8` on Windows.
Therefor, some trackers might not get their icon downloaded at all because of
an error:
`UnicodeDecodeError: 'charmap' codec can't decode byte 0x90 in position 2158: character maps to <undefined>`.
This fix adds a detection of file encoding using the optional `chardet` dependency, and also a test.

Closes: deluge-torrent/deluge#333
Closes: https://dev.deluge-torrent.org/ticket/3479

1 files changed, 12 insertions, 1 deletions

diff --git a/deluge/ui/tracker_icons.py b/deluge/ui/tracker_icons.py
index a771a0ecf..813f82df4 100644
--- a/deluge/ui/tracker_icons.py
+++ b/deluge/ui/tracker_icons.py
@@ -22,6 +22,11 @@ from deluge.decorators import proxy
 from deluge.httpdownloader import download_file
 
 try:
+    import chardet
+except ImportError:
+    chardet = None
+
+try:
     from PIL import Image
 except ImportError:
     Image = None
@@ -289,7 +294,13 @@ class TrackerIcons(Component):
         :returns: a Deferred which callbacks a list of available favicons (url, type)
         :rtype: Deferred
         """
-        with open(page) as _file:
+        encoding = 'UTF-8'
+        if chardet:
+            with open(page, 'rb') as _file:
+                result = chardet.detect(_file.read())
+                encoding = result['encoding']
+
+        with open(page, encoding=encoding) as _file:
             parser = FaviconParser()
             for line in _file:
                 parser.feed(line)