More efficient cover checking

src/calibre/ebooks/metadata/fetch.py

@@ -3,14 +3,14 @@ __license__ = 'GPL 3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import traceback, sys, textwrap, re, urllib2
+import traceback, sys, textwrap, re
 from threading import Thread
 
-from calibre import prints, browser
+from calibre import prints
 from calibre.utils.config import OptionParser
 from calibre.utils.logging import default_log
 from calibre.customize import Plugin
-from calibre.ebooks.metadata.library_thing import OPENLIBRARY
+from calibre.ebooks.metadata.library_thing import check_for_cover
 
 metadata_config = None
 
@@ -271,16 +271,10 @@ def filter_metadata_results(item):
             return False
     return True
 
-class HeadRequest(urllib2.Request):
-    def get_method(self):
-        return "HEAD"
-
 def do_cover_check(item):
-    opener = browser()
     item.has_cover = False
     try:
-        opener.open(HeadRequest(OPENLIBRARY%item.isbn), timeout=5)
-        item.has_cover = True
+        item.has_cover = check_for_cover(item.isbn)
     except:
         pass # Cover not found
 

src/calibre/ebooks/metadata/library_thing.py

@@ -14,6 +14,16 @@ from calibre.ebooks.BeautifulSoup import BeautifulSoup
 
 OPENLIBRARY = 'http://covers.openlibrary.org/b/isbn/%s-L.jpg?default=false'
 
+def check_for_cover(isbn):
+    br = browser()
+    br.set_handle_redirect(False)
+    try:
+        br.open_novisit(OPENLIBRARY%isbn)
+    except Exception, e:
+        if callable(getattr(e, 'getcode', None)) and e.getcode() == 302:
+            return True
+    return False
+
 class LibraryThingError(Exception):
     pass