resp.from_cache = True
return resp
- # we're not fresh.
- self.cache.delete(cache_url)
+ # we're not fresh. If we don't have an Etag, clear it out
+ if 'etag' not in resp.headers:
+ self.cache.delete(cache_url)
+
+ if 'etag' in resp.headers:
+ headers['If-None-Match'] = resp.headers['ETag']
+
+ if 'last-modified' in resp.headers:
+ headers['If-Modified-Since'] = resp.headers['Last-Modified']
+
# return the original handler
return False
+ def add_headers(self, url):
+ resp = self.cache.get(url)
+ if resp and 'etag' in resp.headers:
+ return {'If-None-Match': resp.headers['etag']}
+ return {}
+
def cache_response(self, request, resp):
"""
Algorithm for caching requests.
if no_store and self.cache.get(cache_url):
self.cache.delete(cache_url)
+ # If we've been given an etag, then keep the response
+ if self.cache_etags and 'etag' in resp.headers:
+ self.cache.set(cache_url, resp)
+
# Add to the cache if the response headers demand it. If there
# is no date header then we can't do anything about expiring
# the cache.
- if 'date' in resp.headers:
+ elif 'date' in resp.headers:
# cache when there is a max-age > 0
if cc_resp and cc_resp.get('max-age'):
if int(cc_resp['max-age']) > 0:
elif 'expires' in resp.headers:
if resp.headers['expires']:
self.cache.set(cache_url, resp)
+
+ def update_cached_response(self, request, response):
+ """On a 304 we will get a new set of headers that we want to
+ update our cached value with, assuming we have one.
+
+ This should only ever be called when we've sent an ETag and
+ gotten a 304 as the response.
+ """
+ cache_url = self.cache_url(request.url)
+
+ resp = self.cache.get(cache_url)
+
+ if not resp:
+ # we didn't have a cached response
+ return response
+
+ # did so lets update our headers
+ resp.headers.update(response.headers)
+
+ # we want a 200 b/c we have content via the cache
+ request.status_code = 200
+
+ # update the request as it has the if-none-match header + any
+ # other headers that the server might have updated (ie Date,
+ # Cache-Control, Expires, etc.)
+ resp.request = request
+
+ # update our cache
+ self.cache.set(cache_url, resp)
+
+ # Let everyone know this was from the cache.
+ resp.from_cache = True
+
+ return resp