Fixed registration of custom extensions

This fixes some minor problems with the pull request from jvanasco so
that it may be included into the next release:

- Only one extension registry is used internally and custom extensions
  do not have to be stored two times.
- Fix the bug that entry extensions were loaded for feeds.
- Do not fail if there is only a feed extension.
- Extensions for entries do not need a feed extension class.

Signed-off-by: Lars Kiesow <lkiesow@uos.de>

feedgen/entry.py

@@ -641,33 +641,22 @@ class FeedEntry(object):
 
 		# Load extension
 		extname = name[0].upper() + name[1:] + 'EntryExtension'
-
-		# Try to import extension from dedicated module for entry:
 		try:
 			supmod = __import__('feedgen.ext.%s_entry' % name)
 			extmod = getattr(supmod.ext, name + '_entry')
 		except ImportError:
-			# Try the FeedExtension module instead
+			# Use FeedExtension module instead
 			supmod = __import__('feedgen.ext.%s' % name)
 			extmod = getattr(supmod.ext, name)
-
 		ext = getattr(extmod, extname)
-		extinst = ext()
-		setattr(self, name, extinst)
-		self.__extensions[name] = {'inst':extinst,'atom':atom,'rss':rss}
+		self.register_extension(name, ext, atom, rss)
 
-	def register_extension(
-		self,
-		namespace,
-		extension_class_feed=None,
-		extension_class_entry=None,
-		atom=True,
-		rss=True
-	):
+
+	def register_extension(self, namespace, extension_class_entry=None,
+			atom=True, rss=True):
 		'''Register a specific extension by classes to a namespace.
 
 		:param namespace: namespace for the extension
-		:param extension_class_feed: Class of the feed extension to load.
 		:param extension_class_entry: Class of the entry extension to load.
 		:param atom: If the extension should be used for ATOM feeds.
 		:param rss: If the extension should be used for RSS feeds.
@@ -678,20 +667,16 @@ class FeedEntry(object):
 			self.__extensions = {}
 		if namespace in self.__extensions.keys():
 			raise ImportError('Extension already loaded')
+		if not extension_class_entry:
+			raise ImportError('No extension class')
 
 		extinst = extension_class_entry()
 		setattr(self, namespace, extinst)
 
 		# `load_extension` registry
-		self.__extensions[namespace] = {'inst': extinst,
+		self.__extensions[namespace] = {
+				'inst':extinst,
+				'extension_class_entry': extension_class_entry,
 				'atom':atom,
 				'rss':rss
 				}
-
-		# `register_extension` registry
-		self.__extensions_register[namespace] = {
-			'extension_class_feed': extension_class_feed,
-			'extension_class_entry': extension_class_entry,
-			'atom': atom,
-			'rss': rss,
-		}

feedgen/feed.py

@@ -82,7 +82,6 @@ class FeedGenerator(object):
 
 		# Extension list:
 		self.__extensions = {}
-		self.__extensions_register = {}
 
 
 	def _create_atom(self, extensions=True):
@@ -1024,14 +1023,9 @@ class FeedGenerator(object):
 		# Try to load extensions:
 		for extname,ext in items:
 			try:
-				if extname in self.__extensions_register:
-					ext_reg = self.__extensions_register[extname]
 				feedEntry.register_extension(extname,
-												 ext_reg['extension_class_feed'],
-												 ext_reg['extension_class_entry'],
-												 ext_reg['atom'], ext_reg['rss'] )
-				else:
-					feedEntry.load_extension( extname, ext['atom'], ext['rss'] )
+						ext['extension_class_entry'],
+						ext['atom'], ext['rss'] )
 			except ImportError:
 				pass
 
@@ -1073,14 +1067,9 @@ class FeedGenerator(object):
 			for e in entry:
 				for extname,ext in items:
 					try:
-						if extname in self.__extensions_register:
-							ext_reg = self.__extensions_register[extname]
 						e.register_extension(extname,
-												 ext_reg['extension_class_feed'],
-												 ext_reg['extension_class_entry'],
-												 ext_reg['atom'], ext_reg['rss'] )
-						else:
-							e.load_extension( extname, ext['atom'], ext['rss'] )
+								ext['extension_class_entry'],
+								ext['atom'], ext['rss'] )
 					except ImportError:
 						pass
 
@@ -1127,29 +1116,26 @@ class FeedGenerator(object):
 			raise ImportError('Extension already loaded')
 
 		# Load extension
-		extname = name[0].upper() + name[1:] + 'Extension'
-		supmod = __import__('feedgen.ext.%s' % name)
-		extmod = getattr(supmod.ext, name)
-		ext    = getattr(extmod, extname)
-		extinst = ext()
-		setattr(self, name, extinst)
-		self.__extensions[name] = {'inst':extinst,'atom':atom,'rss':rss}
-
-		# Try to load the extension for already existing entries:
-		for entry in self.__feed_entries:
+		extname = name[0].upper() + name[1:]
+		feedsupmod = __import__('feedgen.ext.%s' % name)
+		feedextmod = getattr(feedsupmod.ext, name)
 		try:
-				entry.load_extension( name, atom, rss )
+			entrysupmod = __import__('feedgen.ext.%s_entry' % name)
+			entryextmod = getattr(entrysupmod.ext, name + '_entry')
 		except ImportError:
-				pass
+			# Use FeedExtension module instead
+			entrysupmod = feedsupmod
+			entryextmod = feedextmod
+		feedext = getattr(feedextmod, extname + 'Extension')
+		try:
+			entryext = getattr(entryextmod, extname + 'EntryExtension')
+		except AttributeError:
+			entryext = None
+		self.register_extension(name, feedext, entryext, atom, rss)
 
-	def register_extension(
-		self,
-		namespace,
-		extension_class_feed = None,
-		extension_class_entry = None,
-		atom=True,
-		rss=True
-	):
+
+	def register_extension(self, namespace, extension_class_feed = None,
+			extension_class_entry = None, atom=True, rss=True):
 		'''Registers an extension by class.
 
 		:param namespace: namespace for the extension
@@ -1166,29 +1152,22 @@ class FeedGenerator(object):
 			raise ImportError('Extension already loaded')
 
 		# Load extension
-		extinst = extension_class_entry()
+		extinst = extension_class_feed()
 		setattr(self, namespace, extinst)
 
 		# `load_extension` registry
-		self.__extensions[namespace] = {'inst':extinst,
-										'atom':atom,
-										'rss':rss
-										}
-
-		# `register_extension` registry
-		self.__extensions_register[namespace] = {
+		self.__extensions[namespace] = {
+				'inst':extinst,
 				'extension_class_feed': extension_class_feed,
 				'extension_class_entry': extension_class_entry,
 				'atom':atom,
-			'rss': rss,
+				'rss':rss
 				}
 
 		# Try to load the extension for already existing entries:
 		for entry in self.__feed_entries:
 			try:
 				entry.register_extension(namespace,
-										 extension_class_entry,
-										 extension_class_feed,
-										 atom, rss)
+						extension_class_entry, atom, rss)
 			except ImportError:
-				raise
+				pass

feedgen/tests/test_feed.py

@@ -10,6 +10,7 @@ A basic feed does not contain entries so far.
 import unittest
 from lxml import etree
 from ..feed import FeedGenerator
+from ..ext.dc import DcExtension, DcEntryExtension
 
 class TestSequenceFunctions(unittest.TestCase):
 
@@ -234,11 +235,27 @@ class TestSequenceFunctions(unittest.TestCase):
 
 	def test_loadPodcastExtension(self):
 		fg = self.fg
+		fg.add_entry()
 		fg.load_extension('podcast', atom=True, rss=True)
+		fg.add_entry()
 
 	def test_loadDcExtension(self):
 		fg = self.fg
+		fg.add_entry()
 		fg.load_extension('dc', atom=True, rss=True)
+		fg.add_entry()
+
+	def test_extensionAlreadyLoaded(self):
+		fg = self.fg
+		fg.load_extension('dc', atom=True, rss=True)
+		with self.assertRaises(ImportError) as context:
+			fg.load_extension('dc')
+
+	def test_registerCustomExtension(self):
+		fg = self.fg
+		fg.add_entry()
+		fg.register_extension('dc', DcExtension, DcEntryExtension)
+		fg.add_entry()
 
 	def checkRssString(self, rssString):