+
−from django.utils.http import http_date
+
−
+
−class ConditionalGetMiddleware(object):
+
−    """
+
−    Handles conditional GET operations. If the response has a ETag or
+
−    Last-Modified header, and the request has If-None-Match or
+
−    If-Modified-Since, the response is replaced by an HttpNotModified.
+
−
+
−    Also sets the Date and Content-Length response-headers.
+
−    """
+
−    def process_response(self, request, response):
+
−        response['Date'] = http_date()
+
−        if not response.has_header('Content-Length'):
+
−            response['Content-Length'] = str(len(response.content))
+
−
+
−        if response.has_header('ETag'):
+
−            if_none_match = request.META.get('HTTP_IF_NONE_MATCH', None)
+
−            if if_none_match == response['ETag']:
+
−                # Setting the status is enough here. The response handling path
+
−                # automatically removes content for this status code (in
+
−                # http.conditional_content_removal()).
+
−                response.status = 304
+
−
+
−        if response.has_header('Last-Modified'):
+
−            if_modified_since = request.META.get('HTTP_IF_MODIFIED_SINCE', None)
+
−            if if_modified_since == response['Last-Modified']:
+
−                # Setting the status code is enough here (same reasons as
+
−                # above).
+
−                response.status = 304
+
−
+
−        return response
+
−
+
−class SetRemoteAddrFromForwardedFor(object):
+
−    """
+
−    Middleware that sets REMOTE_ADDR based on HTTP_X_FORWARDED_FOR, if the
+
−    latter is set. This is useful if you're sitting behind a reverse proxy that
+
−    causes each request's REMOTE_ADDR to be set to 127.0.0.1.
+
−
+
−    Note that this does NOT validate HTTP_X_FORWARDED_FOR. If you're not behind
+
−    a reverse proxy that sets HTTP_X_FORWARDED_FOR automatically, do not use
+
−    this middleware. Anybody can spoof the value of HTTP_X_FORWARDED_FOR, and
+
−    because this sets REMOTE_ADDR based on HTTP_X_FORWARDED_FOR, that means
+
−    anybody can "fake" their IP address. Only use this when you can absolutely
+
−    trust the value of HTTP_X_FORWARDED_FOR.
+
−    """
+
−    def process_request(self, request):
+
−        try:
+
−            real_ip = request.META['HTTP_X_FORWARDED_FOR']
+
−        except KeyError:
+
−            return None
+
−        else:
+
−            # HTTP_X_FORWARDED_FOR can be a comma-separated list of IPs. The
+
−            # client's IP will be the first one.
+
−            real_ip = real_ip.split(",")[0].strip()
+
−            request.META['REMOTE_ADDR'] = real_ip