No longer using tuple for WATSON_MIDDLEWARE_FLAG

src/watson/middleware.py

@@ -2,6 +2,8 @@
 
 from __future__ import unicode_literals
 
+from django.core.exceptions import ImproperlyConfigured
+
 from watson.registration import search_context_manager
 
 
@@ -9,26 +11,28 @@ WATSON_MIDDLEWARE_FLAG = "watson.search_context_middleware_active"
 
 
 class SearchContextMiddleware(object):
-    
+
     """Wraps the entire request in a search context."""
-    
+
     def process_request(self, request):
         """Starts a new search context."""
-        request.META[(WATSON_MIDDLEWARE_FLAG, self)] = True
+        if request.META.get(WATSON_MIDDLEWARE_FLAG, False):
+            raise ImproperlyConfigured("SearchContextMiddleware can only be included in MIDDLEWARE_CLASSES once.")
+        request.META[WATSON_MIDDLEWARE_FLAG] = True
         search_context_manager.start()
-    
+
     def _close_search_context(self, request):
         """Closes the search context."""
-        if request.META.get((WATSON_MIDDLEWARE_FLAG, self), False):
-            del request.META[(WATSON_MIDDLEWARE_FLAG, self)]
+        if request.META.get(WATSON_MIDDLEWARE_FLAG, False):
+            del request.META[WATSON_MIDDLEWARE_FLAG]
             search_context_manager.end()
-    
+
     def process_response(self, request, response):
         """Closes the search context."""
         self._close_search_context(request)
         return response
-        
+
     def process_exception(self, request, exception):
         """Closes the search context."""
-        search_context_manager.invalidate()    
+        search_context_manager.invalidate()
         self._close_search_context(request)