Don't fail on downloading all remaining covers if there is an error downloading a single cover in the list

resources/recipes/welt.recipe

@@ -15,7 +15,7 @@ class weltDe(BasicNewsRecipe):
     __author__ = 'Oliver Niesner'
     use_embedded_content   = False
     timefmt = ' [%d %b %Y]'
-    max_articles_per_feed = 25 # reduced to this value to prevent to many articles (suggested by Gregory Riker
+    max_articles_per_feed = 15 # reduced to this value to prevent too many articles (suggested by Gregory Riker
     no_stylesheets = True
     remove_stylesheets = True
     remove_javascript = True

src/calibre/gui2/main.py

@@ -1046,7 +1046,8 @@ class Main(MainWindow, Ui_MainWindow, DeviceGUI):
             _('Downloading %s for %d book(s)')%(x, len(ids)))
         self._book_metadata_download_check = QTimer(self)
         self.connect(self._book_metadata_download_check,
-                SIGNAL('timeout()'), self.book_metadata_download_check)
+                SIGNAL('timeout()'), self.book_metadata_download_check,
+                Qt.QueuedConnection)
         self._book_metadata_download_check.start(100)
 
     def book_metadata_download_check(self):

src/calibre/gui2/metadata.py

@@ -6,6 +6,7 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
+import traceback
 from threading import Thread
 from Queue import Queue, Empty
 
@@ -27,9 +28,12 @@ class Worker(Thread):
             isbn = self.jobs.get()
             if not isbn:
                 break
-            cdata, _ = cover_from_isbn(isbn)
-            if cdata:
-                self.results.put((isbn, cdata))
+            try:
+                cdata, _ = cover_from_isbn(isbn)
+                if cdata:
+                    self.results.put((isbn, cdata))
+            except:
+                traceback.print_exc()
 
     def __enter__(self):
         self.start()