def learn_cache_key(request, response, cache_timeout=None, key_prefix=None, cache=None):
"""
Learns what headers to take into account for some request path from the
response object. It stores those headers in a global path registry so that
later access to that path will know what headers to take into account
without building the response object itself. The headers are named in the
Vary header of the response, but we want to prevent response generation.
The list of headers to use for cache key generation is stored in the same
cache as the pages themselves. If the cache ages some data out of the
cache, this just means that we have to build the response once to get at
the Vary header and so at the list of headers to use for the cache key.
"""
if key_prefix is None:
key_prefix = settings.CACHE_MIDDLEWARE_KEY_PREFIX
if cache_timeout is None:
cache_timeout = settings.CACHE_MIDDLEWARE_SECONDS
cache_key = _generate_cache_header_key(key_prefix, request)
if cache is None:
cache = get_cache(settings.CACHE_MIDDLEWARE_ALIAS)
if response.has_header("Vary"):
headerlist = ["HTTP_" + header.upper().replace("-", "_") for header in cc_delim_re.split(response["Vary"])]
cache.set(cache_key, headerlist, cache_timeout)
return _generate_cache_key(request, request.method, headerlist, key_prefix)
else:
# if there is no Vary header, we still need a cache key
# for the request.get_full_path()
cache.set(cache_key, [], cache_timeout)
return _generate_cache_key(request, request.method, [], key_prefix)
def get_cache_key(request, key_prefix=None, method="GET", cache=None):
"""
Returns a cache key based on the request path and query. It can be used
in the request phase because it pulls the list of headers to take into
account from the global path registry and uses those to build a cache key
to check against.
If there is no headerlist stored, the page needs to be rebuilt, so this
function returns None.
"""
if key_prefix is None:
key_prefix = settings.CACHE_MIDDLEWARE_KEY_PREFIX
cache_key = _generate_cache_header_key(key_prefix, request)
if cache is None:
cache = get_cache(settings.CACHE_MIDDLEWARE_ALIAS)
headerlist = cache.get(cache_key, None)
if headerlist is not None:
return _generate_cache_key(request, method, headerlist, key_prefix)
else:
return None
def get_cache_key(request, key_prefix=None, method='GET', cache=None):
"""
Returns a cache key based on the request path and query. It can be used
in the request phase because it pulls the list of headers to take into
account from the global path registry and uses those to build a cache key
to check against.
If there is no headerlist stored, the page needs to be rebuilt, so this
function returns None.
"""
if key_prefix is None:
key_prefix = settings.CACHE_MIDDLEWARE_KEY_PREFIX
cache_key = _generate_cache_header_key(key_prefix, request)
if cache is None:
cache = get_cache(settings.CACHE_MIDDLEWARE_ALIAS)
headerlist = cache.get(cache_key, None)
if headerlist is not None:
return _generate_cache_key(request, method, headerlist, key_prefix)
else:
return None
def learn_cache_key(request,
response,
cache_timeout=None,
key_prefix=None,
cache=None):
"""
Learns what headers to take into account for some request path from the
response object. It stores those headers in a global path registry so that
later access to that path will know what headers to take into account
without building the response object itself. The headers are named in the
Vary header of the response, but we want to prevent response generation.
The list of headers to use for cache key generation is stored in the same
cache as the pages themselves. If the cache ages some data out of the
cache, this just means that we have to build the response once to get at
the Vary header and so at the list of headers to use for the cache key.
"""
if key_prefix is None:
key_prefix = settings.CACHE_MIDDLEWARE_KEY_PREFIX
if cache_timeout is None:
cache_timeout = settings.CACHE_MIDDLEWARE_SECONDS
cache_key = _generate_cache_header_key(key_prefix, request)
if cache is None:
cache = get_cache(settings.CACHE_MIDDLEWARE_ALIAS)
if response.has_header('Vary'):
headerlist = [
'HTTP_' + header.upper().replace('-', '_')
for header in cc_delim_re.split(response['Vary'])
]
cache.set(cache_key, headerlist, cache_timeout)
return _generate_cache_key(request, request.method, headerlist,
key_prefix)
else:
# if there is no Vary header, we still need a cache key
# for the request.get_full_path()
cache.set(cache_key, [], cache_timeout)
return _generate_cache_key(request, request.method, [], key_prefix)
