JezK
Edit File: adapter.py
# SPDX-FileCopyrightText: 2015 Eric Larson # # SPDX-License-Identifier: Apache-2.0 import types import functools import zlib from pip._vendor.requests.adapters import HTTPAdapter from .controller import CacheController, PERMANENT_REDIRECT_STATUSES from .cache import DictCache from .filewrapper import CallbackFileWrapper class CacheControlAdapter(HTTPAdapter): invalidating_methods = {"PUT", "PATCH", "DELETE"} def __init__( self, cache=None, cache_etags=True, controller_class=None, serializer=None, heuristic=None, cacheable_methods=None, *args, **kw ): super(CacheControlAdapter, self).__init__(*args, **kw) self.cache = DictCache() if cache is None else cache self.heuristic = heuristic self.cacheable_methods = cacheable_methods or ("GET",) controller_factory = controller_class or CacheController self.controller = controller_factory( self.cache, cache_etags=cache_etags, serializer=serializer ) def send(self, request, cacheable_methods=None, **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. """ cacheable = cacheable_methods or self.cacheable_methods if request.method in cacheable: try: cached_response = self.controller.cached_request(request) except zlib.error: cached_response = None 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, cacheable_methods=None ): """ Build a response by making a request or using the cache. This will end up calling send and returning a potentially cached response """ cacheable = cacheable_methods or self.cacheable_methods if not from_cache and request.method in cacheable: # Check for any heuristics that might update headers # before trying to cache. if self.heuristic: response = self.heuristic.apply(response) # 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 int(response.status) in PERMANENT_REDIRECT_STATUSES: self.controller.cache_response(request, response) else: # 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 ), ) if response.chunked: super_update_chunk_length = response._update_chunk_length def _update_chunk_length(self): super_update_chunk_length() if self.chunk_left == 0: self._fp._close() response._update_chunk_length = types.MethodType( _update_chunk_length, 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()