add exception_base

sanic/app.py

@@ -272,6 +272,25 @@ class Sanic:
 
         return response
 
+    # Decorator
+    def exception_base(self, *exceptions):
+        """Decorate a function to be registered as a handler for exceptions
+
+        :param exceptions: exceptions
+        :return: decorated function
+        """
+
+        def response(handler):
+            for exception in exceptions:
+                if isinstance(exception, (tuple, list)):
+                    for e in exception:
+                        self.error_handler.add_base(e, handler)
+                else:
+                    self.error_handler.add_base(exception, handler)
+            return handler
+
+        return response
+		
     # Decorator
     def middleware(self, middleware_or_request):
         """Decorate and register middleware to be called before a request.

sanic/handlers.py

@@ -23,6 +23,7 @@ class ErrorHandler:
 
     def __init__(self):
         self.handlers = []
+        self.handlers_base = []
         self.cached_handlers = {}
         self.debug = False
 
@@ -56,6 +57,9 @@ class ErrorHandler:
     def add(self, exception, handler):
         self.handlers.append((exception, handler))
 		
+    def add_base(self, exception, handler):
+        self.handlers_base.append((exception, handler))
+
     def lookup(self, exception):
         handler = self.cached_handlers.get(exception, self._missing)
         if handler is self._missing:
@@ -63,6 +67,15 @@ class ErrorHandler:
                 if isinstance(exception, exception_class):
                     self.cached_handlers[type(exception)] = handler
                     return handler
+
+            for exception_class, handler in self.handlers_base:
+                try:
+                    raise 
+                except exception_class:
+                    return handler
+                except Exception:
+                    pass
+			
             self.cached_handlers[type(exception)] = None
             handler = None
         return handler