Clean up __before__ and __after__ handling and make it Python 3-compatible

--HG--
branch : py3k

src/milla/app.py

@@ -90,40 +90,12 @@ class Application(object):
         start_response_wrapper = StartResponseWrapper(start_response)
         request.start_response = start_response_wrapper
         try:
-            # If the callable has an __before__ attribute, call it
-            if hasattr(func, '__before__'):
-                func.__before__(request)
-            # If the callable is an instance method and its class has
-            # a __before__ method, call that
-            elif hasattr(func, 'im_self') and \
-                hasattr(func.im_self, '__before__'):
-                func.im_self.__before__(request)
-            # The callable might be a partial, so check the inner func
-            elif hasattr(func, 'func'):
-                if hasattr(func.func, '__before__'):
-                    func.func.__before__(request)
-                elif hasattr(func.func, 'im_self') and \
-                    hasattr(func.func.im_self, '__before__'):
-                    func.func.im_self.__before__(request)
+            self._call_before(func)(request)
             response = func(request)
         except WSGIHTTPException as e:
             return e(environ, start_response)
         finally:
-            # If the callable has an __after__ method, call it
-            if hasattr(func, '__after__'):
-                func.__after__(request)
-            # If the callable is an instance method and its class has
-            # an __after__ method, call that
-            elif hasattr(func, 'im_self') and \
-                hasattr(func.im_self, '__after__'):
-                func.im_self.__after__(request)
-            # The callable might be a partial, so check the inner func
-            elif hasattr(func, 'func'):
-                if hasattr(func.func, '__after__'):
-                    func.func.__after__(request)
-                elif hasattr(func.func, 'im_self') and \
-                    hasattr(func.func.im_self, '__after__'):
-                    func.func.im_self.__after__(request)
+            self._call_after(func)(request)
 
         # The callable might have returned just a string, which is OK,
         # but we need to wrap it in a Response object
@@ -141,6 +113,31 @@ class Application(object):
             start_response(response.status, response.headerlist)
         if not environ['REQUEST_METHOD'] == 'HEAD':
             return response.app_iter
+    
+    def _call_after(self, func):
+        try:
+            return self._find_attr(func, '__after__')
+        except AttributeError:
+            return lambda r: None
+
+    def _call_before(self, func):
+        try:
+            return self._find_attr(func, '__before__')
+        except AttributeError:
+            return lambda r: None
+    
+    def _find_attr(self, obj, attr):
+        try:
+            # Object has the specified attribute itself
+            return getattr(obj, attr)
+        except AttributeError:
+            # Object is a bound method; look for the attribute on the instance
+            if hasattr(obj, '__self__'):
+                return self._find_attr(obj.__self__, attr)
+            # Object is a partial; look for the attribute on the inner function
+            elif hasattr(obj, 'func'):
+                return self._find_attr(obj.func, attr)
+            raise
 
 class StartResponseWrapper():