tickets: 5797

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5797 2007-10-22 21:15:11 2018-05-21 15:10:32 2022-03-06 03:35:24.751783 Accepted new HTTP handling Bug Normal dev   decorator_from_middleware can cause middleware hooks to run out of correct order. cache_page, gzip_page, and conditional_page all use decorator_from_middleware. decorator_from_middleware wraps the view function to simulate middleware being run on a per-view basis. Here's the interesting bit: {{{ def _wrapped_view(request, *args, **kwargs): if hasattr(middleware, 'process_request'): result = middleware.process_request(request) if result is not None: return result if hasattr(middleware, 'process_view'): result = middleware.process_view(request, view_func, *args, **kwargs) if result is not None: return result try: response = view_func(request, *args, **kwargs) except Exception, e: if hasattr(middleware, 'process_exception'): result = middleware.process_exception(request, e) if result is not None: return result raise if hasattr(middleware, 'process_response'): result = middleware.process_response(request, response) if result is not None: return result return response }}} The problem is that middleware's order is important. Suppose two middleware decorators, A and B, are applied to the same view. The normal flow of middleware processing would be: A.process_request, B.process_request, A.process_view, B.process_view, view, B.process_response, A.process_response. The flow of the *decorated execution* is this: A.process_request, A.process_view, B.process_request, B.process_view, view, B.process_response, A.process_response. This is not yet a real-world issue as far as I know, but seems to be a lurking problem. I think the only reason it hasn't surfaced is that view decorators are fairly uncommon. I don't see a simple way to fix this.   jdunck cache middleware decorator gzip conditional http 0 1 1 0 0 0