Display the appropriate type of error message depending on the type of the incoming request

lib/util/middleware.py

@@ -13,3 +13,30 @@ class ExceptionLoggingMiddleware(object):
         def process_exception(self, request, exception):
             log.exception(exception)
             return HttpResponseServerError("Server Error - Please try again later.")
+
+# From http://djangosnippets.org/snippets/1042/
+def parse_accept_header(accept):
+    """Parse the Accept header *accept*, returning a list with pairs of
+    (media_type, q_value), ordered by q values.
+    """
+    result = []
+    for media_range in accept.split(","):
+        parts = media_range.split(";")
+        media_type = parts.pop(0)
+        media_params = []
+        q = 1.0
+        for part in parts:
+            (key, value) = part.lstrip().split("=", 1)
+            if key == "q":
+                q = float(value)
+            else:
+                media_params.append((key, value))
+        result.append((media_type, tuple(media_params), q))
+    result.sort(lambda x, y: -cmp(x[2], y[2]))
+    return result
+
+class AcceptMiddleware(object):
+    def process_request(self, request):
+        accept = parse_accept_header(request.META.get("HTTP_ACCEPT", ""))
+        request.accept = accept
+        request.accepted_types = map(lambda (t, p, q): t, accept)