app/django/middleware/http.py
author Sverre Rabbelier <srabbelier@gmail.com>
Thu, 16 Oct 2008 23:23:16 +0000
changeset 363 d35ffa6ca643
parent 323 ff1a9aa48cfd
permissions -rw-r--r--
Add a framework for generic views This commit does not enable the new code, as such there should be no change in functionality. In order to use the new code the maps.py file should be updated to point at the new views/models/sponsor.py module. Patch by: Sverre Rabbelier Reviewed by: to-be-reviewed

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):
    """
    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