Fixed #20126 -- XViewMiddleware moved to django.contrib.admindocs.middleware

django/contrib/admindocs/middleware.py

@@ -0,0 +1,23 @@
+from django.conf import settings
+from django import http
+
+class XViewMiddleware(object):
+    """
+    Adds an X-View header to internal HEAD requests -- used by the documentation system.
+    """
+    def process_view(self, request, view_func, view_args, view_kwargs):
+        """
+        If the request method is HEAD and either the IP is internal or the
+        user is a logged-in staff member, quickly return with an x-header
+        indicating the view function.  This is used by the documentation module
+        to lookup the view function for an arbitrary page.
+        """
+        assert hasattr(request, 'user'), (
+            "The XView middleware requires authentication middleware to be "
+            "installed. Edit your MIDDLEWARE_CLASSES setting to insert "
+            "'django.contrib.auth.middleware.AuthenticationMiddleware'.")
+        if request.method == 'HEAD' and (request.META.get('REMOTE_ADDR') in settings.INTERNAL_IPS or
+                                         (request.user.is_active and request.user.is_staff)):
+            response = http.HttpResponse()
+            response['X-View'] = "%s.%s" % (view_func.__module__, view_func.__name__)
+            return response