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134 lines
4.8 KiB
Python
134 lines
4.8 KiB
Python
2 years ago
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import types
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import functools
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import zlib
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from pip._vendor.requests.adapters import HTTPAdapter
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from .controller import CacheController
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from .cache import DictCache
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from .filewrapper import CallbackFileWrapper
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class CacheControlAdapter(HTTPAdapter):
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invalidating_methods = {"PUT", "DELETE"}
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def __init__(
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self,
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cache=None,
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cache_etags=True,
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controller_class=None,
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serializer=None,
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heuristic=None,
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cacheable_methods=None,
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*args,
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**kw
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):
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super(CacheControlAdapter, self).__init__(*args, **kw)
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self.cache = DictCache() if cache is None else cache
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self.heuristic = heuristic
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self.cacheable_methods = cacheable_methods or ("GET",)
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controller_factory = controller_class or CacheController
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self.controller = controller_factory(
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self.cache, cache_etags=cache_etags, serializer=serializer
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)
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def send(self, request, cacheable_methods=None, **kw):
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"""
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Send a request. Use the request information to see if it
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exists in the cache and cache the response if we need to and can.
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"""
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cacheable = cacheable_methods or self.cacheable_methods
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if request.method in cacheable:
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try:
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cached_response = self.controller.cached_request(request)
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except zlib.error:
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cached_response = None
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if cached_response:
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return self.build_response(request, cached_response, from_cache=True)
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# check for etags and add headers if appropriate
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request.headers.update(self.controller.conditional_headers(request))
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resp = super(CacheControlAdapter, self).send(request, **kw)
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return resp
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def build_response(
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self, request, response, from_cache=False, cacheable_methods=None
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):
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"""
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Build a response by making a request or using the cache.
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This will end up calling send and returning a potentially
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cached response
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"""
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cacheable = cacheable_methods or self.cacheable_methods
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if not from_cache and request.method in cacheable:
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# Check for any heuristics that might update headers
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# before trying to cache.
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if self.heuristic:
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response = self.heuristic.apply(response)
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# apply any expiration heuristics
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if response.status == 304:
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# We must have sent an ETag request. This could mean
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# that we've been expired already or that we simply
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# have an etag. In either case, we want to try and
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# update the cache if that is the case.
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cached_response = self.controller.update_cached_response(
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request, response
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)
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if cached_response is not response:
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from_cache = True
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# We are done with the server response, read a
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# possible response body (compliant servers will
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# not return one, but we cannot be 100% sure) and
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# release the connection back to the pool.
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response.read(decode_content=False)
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response.release_conn()
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response = cached_response
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# We always cache the 301 responses
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elif response.status == 301:
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self.controller.cache_response(request, response)
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else:
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# Wrap the response file with a wrapper that will cache the
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# response when the stream has been consumed.
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response._fp = CallbackFileWrapper(
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response._fp,
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functools.partial(
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self.controller.cache_response, request, response
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),
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)
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if response.chunked:
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super_update_chunk_length = response._update_chunk_length
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def _update_chunk_length(self):
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super_update_chunk_length()
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if self.chunk_left == 0:
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self._fp._close()
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response._update_chunk_length = types.MethodType(
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_update_chunk_length, response
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)
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resp = super(CacheControlAdapter, self).build_response(request, response)
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# See if we should invalidate the cache.
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if request.method in self.invalidating_methods and resp.ok:
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cache_url = self.controller.cache_url(request.url)
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self.cache.delete(cache_url)
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# Give the request a from_cache attr to let people use it
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resp.from_cache = from_cache
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return resp
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def close(self):
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self.cache.close()
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super(CacheControlAdapter, self).close()
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