thumbnails: Handle non-ASCII filenames

The WSGI specification requires that URL-paths be encoded as ISO-8859-1
(Latin-1). For filenames that only use ASCII characters, this works
correctly. When a filename includes characters encoded in other
character sets, however, the thumbnail controller will return always
HTTP 404 if the local filesystem does not also use the Latin-1 character
set.

To work around this discrepancy and ensure that requested file names are
looked up on the local filesystem correctly, the string must be
re-encoded in the proper character set.

src/dcow/thumbnails.py

@@ -3,6 +3,10 @@ from milla import controllers
 import milla
 import os
 import webob.static
+import sys
+
+
+fs_encoding = sys.getfilesystemencoding()
 
 
 class ThumbnailController(milla.controllers.HTTPVerbController):
@@ -11,6 +15,7 @@ class ThumbnailController(milla.controllers.HTTPVerbController):
     THUMB_SIZE = (262, 148)
 
     def GET(self, request, image):
+        image = image.encode('latin-1').decode(fs_encoding)
         thumb_dir = request.config['gallery.thumbnail_dir']
         image_dir = request.config['gallery.screenshot_dir']
         screenshot = os.path.join(image_dir, image)