from django.core.exceptions import MiddlewareNotUsed
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_code = 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_code = 304
return response
class SetRemoteAddrFromForwardedFor(object):
"""
This middleware has been removed; see the Django 1.1 release notes for
details.
It previously set REMOTE_ADDR based on HTTP_X_FORWARDED_FOR. However, after
investiagtion, it turns out this is impossible to do in a general manner:
different proxies treat the X-Forwarded-For header differently. Thus, a
built-in middleware can lead to application-level security problems, and so
this was removed in Django 1.1
"""
def __init__(self):
import warnings
warnings.warn("SetRemoteAddrFromForwardedFor has been removed. "
"See the Django 1.1 release notes for details.",
category=DeprecationWarning)
raise MiddlewareNotUsed()
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