import functools from pip._vendor.requests.adapters import HTTPAdapter from .controller import CacheController from .cache import DictCache from .filewrapper import CallbackFileWrapper class CacheControlAdapter(HTTPAdapter): invalidating_methods = set(['PUT', 'DELETE']) def __init__(self, cache=None, cache_etags=True, controller_class=None, serializer=None, heuristic=None, *args, **kw): super(CacheControlAdapter, self).__init__(*args, **kw) self.cache = cache or DictCache() self.heuristic = heuristic controller_factory = controller_class or CacheController self.controller = controller_factory( self.cache, cache_etags=cache_etags, serializer=serializer, ) def send(self, request, **kw): """ Send a request. Use the request information to see if it exists in the cache and cache the response if we need to and can. """ if request.method == 'GET': cached_response = self.controller.cached_request(request) if cached_response: return self.build_response(request, cached_response, from_cache=True) # check for etags and add headers if appropriate request.headers.update( self.controller.conditional_headers(request) ) resp = super(CacheControlAdapter, self).send(request, **kw) return resp def build_response(self, request, response, from_cache=False): """ Build a response by making a request or using the cache. This will end up calling send and returning a potentially cached response """ if not from_cache and request.method == 'GET': # apply any expiration heuristics if response.status == 304: # We must have sent an ETag request. This could mean # that we've been expired already or that we simply # have an etag. In either case, we want to try and # update the cache if that is the case. cached_response = self.controller.update_cached_response( request, response ) if cached_response is not response: from_cache = True # We are done with the server response, read a # possible response body (compliant servers will # not return one, but we cannot be 100% sure) and # release the connection back to the pool. response.read(decode_content=False) response.release_conn() response = cached_response # We always cache the 301 responses elif response.status == 301: self.controller.cache_response(request, response) else: # Check for any heuristics that might update headers # before trying to cache. if self.heuristic: response = self.heuristic.apply(response) # Wrap the response file with a wrapper that will cache the # response when the stream has been consumed. response._fp = CallbackFileWrapper( response._fp, functools.partial( self.controller.cache_response, request, response, ) ) resp = super(CacheControlAdapter, self).build_response( request, response ) # See if we should invalidate the cache. if request.method in self.invalidating_methods and resp.ok: cache_url = self.controller.cache_url(request.url) self.cache.delete(cache_url) # Give the request a from_cache attr to let people use it resp.from_cache = from_cache return resp def close(self): self.cache.close() super(CacheControlAdapter, self).close()