Fix double file extension issue

Author: E.S. Rosenberg a.k.a. Keeper of the Keys

src/gpodder/coverart.py

@@ -60,6 +60,9 @@ def get_cover(self, podcast, download=False, episode = None):
         password = podcast.auth_password
 
         # Return already existing files
+        if os.path.exists(filename):
+            return filename
+
         for extension in self.EXTENSIONS:
             if os.path.exists(filename + extension):
                 return filename + extension
@@ -85,10 +88,27 @@ def get_cover(self, podcast, download=False, episode = None):
             try:
                 extension = None
 
-                for filetype, check in list(self.SUPPORTED_EXTENSIONS.items()):
-                    if check(data):
-                        extension = filetype
-                        break
+                fname, ext = os.path.splitext(filename)
+
+                # Check if an extension is part of the filename and that it matches the filetype
+                if ext != None and ext != '' :
+                    ext_unchanged = ext
+                    # Assume last part of filename parts is extension
+                    ext = ext.lower()
+                    # Deal with alternative extensions for supported format,
+                    # should more cases need to be added a mapping dictionary can be created.
+                    if ext == '.jpeg':
+                        ext = '.jpg'
+                    if ext in self.SUPPORTED_EXTENSIONS:
+                        if self.SUPPORTED_EXTENSIONS[ext](data):
+                            filename = fname
+                            extension = ext_unchanged
+                # Filename did not include an extension or the extension did not match the filetype
+                if extension is None:
+                    for filetype, check in list(self.SUPPORTED_EXTENSIONS.items()):
+                        if check(data):
+                            extension = filetype
+                            break
 
                 if extension is None:
                     msg = 'Unknown file type: %s (%r)' % (cover_url, data[:6])