Workaround for windows limitation when reading from network sockets. Should fix issues with large files in calibre libraries on network shares. Fixes #3248 (exception on saving book details)

src/calibre/library/database2.py

@@ -721,7 +721,13 @@ class LibraryDatabase2(LibraryDatabase, SchemaUpgrade, CustomColumns):
         path = self.format_abspath(index, format, index_is_id=index_is_id)
         if path is not None:
             f = open(path, mode)
-            ret = f if as_file else f.read()
+            try:
+                ret = f if as_file else f.read()
+            except IOError:
+                f.seek(0)
+                out = cStringIO.StringIO()
+                shutil.copyfileobj(f, out)
+                ret = out.getvalue()
             if not as_file:
                 f.close()
             return ret

src/calibre/library/server/content.py

@@ -123,8 +123,6 @@ class ContentServer(object):
 
         return self.static('index.html')
 
-
-
     # Actually get content from the database {{{
     def get_cover(self, id, thumbnail=False):
         cover = self.db.cover(id, index_is_id=True, as_file=False)