Django之request进入中间件《二》

 1     def _get_response(self, request):
 2         """
 3         Resolve and call the view, then apply view, exception, and
 4         template_response middleware. This method is everything that happens
 5         inside the request/response middleware.
 6         """
 7         response = None
 8 
 9         if hasattr(request, ‘urlconf‘):
10             urlconf = request.urlconf
11             set_urlconf(urlconf)
12             resolver = get_resolver(urlconf)
13         else:
14             resolver = get_resolver()
15         resolver_match = resolver.resolve(request.path_info)
16         callback, callback_args, callback_kwargs = resolver_match
17         request.resolver_match = resolver_match
18 
19         for middleware_method in self._view_middleware:
20 
21             """
22             <bound method
23              CsrfViewMiddleware.process_view of 
24              <django.middleware.csrf.CsrfViewMiddleware object at 0x034B1388>>
25             """
26             response = middleware_method(request, callback, callback_args, callback_kwargs)
27             if response:
28                 break
30         if response is None:
31             wrapped_callback = self.make_view_atomic(callback)
32             try:
33 
34                 response = wrapped_callback(request, *callback_args, **callback_kwargs)
35             except Exception as e:
36                 response = self.process_exception_by_middleware(e, request)
37 
38         # Complain if the view returned None (a common error).
40         if response is None:
41             if isinstance(callback, types.FunctionType):    # FBV
42                 view_name = callback.__name__
43             else:                                           # CBV
44                 view_name = callback.__class__.__name__ + ‘.__call__‘
45 
46             raise ValueError(
47                 "The view %s.%s didn‘t return an HttpResponse object. It "
48                 "returned None instead." % (callback.__module__, view_name)
49             )
50 
51         # If the response supports deferred rendering, apply template
52         # response middleware and then render the response
53         elif hasattr(response, ‘render‘) and callable(response.render):
54             for middleware_method in self._template_response_middleware:
55                 response = middleware_method(request, response)
56                 # Complain if the template response middleware returned None (a common error).
57                 if response is None:
58                     raise ValueError(
59                         "%s.process_template_response didn‘t return an "
60                         "HttpResponse object. It returned None instead."
61                         % (middleware_method.__self__.__class__.__name__)
62                     )
63 
64             try:
65                 response = response.render()
66             except Exception as e:
67                 response = self.process_exception_by_middleware(e, request)
68         return response