app.py 文件源码

def _find_error_handler(self, e):
        """Finds a registered error handler for the request’s blueprint.
        Otherwise falls back to the app, returns None if not a suitable
        handler is found.
        """
        exc_class, code = self._get_exc_class_and_code(type(e))

        def find_handler(handler_map):
            if not handler_map:
                return
            for cls in exc_class.__mro__:
                handler = handler_map.get(cls)
                if handler is not None:
                    # cache for next time exc_class is raised
                    handler_map[exc_class] = handler
                    return handler

        # try blueprint handlers
        handler = find_handler(self.error_handler_spec
                               .get(request.blueprint, {})
                               .get(code))
        if handler is not None:
            return handler

        # fall back to app handlers
        return find_handler(self.error_handler_spec[None].get(code))