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# begin copy of stock Django UpdateCacheMiddleware
# this is to address feeds caching issue which makes it horribly
# unperformant
from django.conf import settings
from django.core.cache import cache
from django.utils.cache import get_cache_key, learn_cache_key, patch_response_headers, get_max_age
class UpdateCacheMiddleware(object):
"""
Response-phase cache middleware that updates the cache if the response is
cacheable.
Must be used as part of the two-part update/fetch cache middleware.
UpdateCacheMiddleware must be the first piece of middleware in
MIDDLEWARE_CLASSES so that it'll get called last during the response phase.
"""
def __init__(self):
self.cache_timeout = settings.CACHE_MIDDLEWARE_SECONDS
self.key_prefix = settings.CACHE_MIDDLEWARE_KEY_PREFIX
self.cache_anonymous_only = getattr(settings, 'CACHE_MIDDLEWARE_ANONYMOUS_ONLY', False)
def process_response(self, request, response):
"""Sets the cache, if needed."""
if not hasattr(request, '_cache_update_cache') or not request._cache_update_cache:
# We don't need to update the cache, just return.
return response
if request.method != 'GET':
# This is a stronger requirement than above. It is needed
# because of interactions between this middleware and the
# HTTPMiddleware, which throws the body of a HEAD-request
# away before this middleware gets a chance to cache it.
return response
if not response.status_code == 200:
return response
# Try to get the timeout from the "max-age" section of the "Cache-
# Control" header before reverting to using the default cache_timeout
# length.
timeout = get_max_age(response)
if timeout == None:
timeout = self.cache_timeout
elif timeout == 0:
# max-age was set to 0, don't bother caching.
return response
patch_response_headers(response, timeout)
if timeout:
response.content = response.content
cache_key = learn_cache_key(request, response, timeout, self.key_prefix)
cache.set(cache_key, response, timeout)
return response
# vim: set ts=4 sw=4 et:
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