python (3.11.7)
1 # SPDX-FileCopyrightText: 2015 Eric Larson
2 #
3 # SPDX-License-Identifier: Apache-2.0
4
5 import types
6 import functools
7 import zlib
8
9 from pip._vendor.requests.adapters import HTTPAdapter
10
11 from .controller import CacheController, PERMANENT_REDIRECT_STATUSES
12 from .cache import DictCache
13 from .filewrapper import CallbackFileWrapper
14
15
16 class ESC[4;38;5;81mCacheControlAdapter(ESC[4;38;5;149mHTTPAdapter):
17 invalidating_methods = {"PUT", "PATCH", "DELETE"}
18
19 def __init__(
20 self,
21 cache=None,
22 cache_etags=True,
23 controller_class=None,
24 serializer=None,
25 heuristic=None,
26 cacheable_methods=None,
27 *args,
28 **kw
29 ):
30 super(CacheControlAdapter, self).__init__(*args, **kw)
31 self.cache = DictCache() if cache is None else cache
32 self.heuristic = heuristic
33 self.cacheable_methods = cacheable_methods or ("GET",)
34
35 controller_factory = controller_class or CacheController
36 self.controller = controller_factory(
37 self.cache, cache_etags=cache_etags, serializer=serializer
38 )
39
40 def send(self, request, cacheable_methods=None, **kw):
41 """
42 Send a request. Use the request information to see if it
43 exists in the cache and cache the response if we need to and can.
44 """
45 cacheable = cacheable_methods or self.cacheable_methods
46 if request.method in cacheable:
47 try:
48 cached_response = self.controller.cached_request(request)
49 except zlib.error:
50 cached_response = None
51 if cached_response:
52 return self.build_response(request, cached_response, from_cache=True)
53
54 # check for etags and add headers if appropriate
55 request.headers.update(self.controller.conditional_headers(request))
56
57 resp = super(CacheControlAdapter, self).send(request, **kw)
58
59 return resp
60
61 def build_response(
62 self, request, response, from_cache=False, cacheable_methods=None
63 ):
64 """
65 Build a response by making a request or using the cache.
66
67 This will end up calling send and returning a potentially
68 cached response
69 """
70 cacheable = cacheable_methods or self.cacheable_methods
71 if not from_cache and request.method in cacheable:
72 # Check for any heuristics that might update headers
73 # before trying to cache.
74 if self.heuristic:
75 response = self.heuristic.apply(response)
76
77 # apply any expiration heuristics
78 if response.status == 304:
79 # We must have sent an ETag request. This could mean
80 # that we've been expired already or that we simply
81 # have an etag. In either case, we want to try and
82 # update the cache if that is the case.
83 cached_response = self.controller.update_cached_response(
84 request, response
85 )
86
87 if cached_response is not response:
88 from_cache = True
89
90 # We are done with the server response, read a
91 # possible response body (compliant servers will
92 # not return one, but we cannot be 100% sure) and
93 # release the connection back to the pool.
94 response.read(decode_content=False)
95 response.release_conn()
96
97 response = cached_response
98
99 # We always cache the 301 responses
100 elif int(response.status) in PERMANENT_REDIRECT_STATUSES:
101 self.controller.cache_response(request, response)
102 else:
103 # Wrap the response file with a wrapper that will cache the
104 # response when the stream has been consumed.
105 response._fp = CallbackFileWrapper(
106 response._fp,
107 functools.partial(
108 self.controller.cache_response, request, response
109 ),
110 )
111 if response.chunked:
112 super_update_chunk_length = response._update_chunk_length
113
114 def _update_chunk_length(self):
115 super_update_chunk_length()
116 if self.chunk_left == 0:
117 self._fp._close()
118
119 response._update_chunk_length = types.MethodType(
120 _update_chunk_length, response
121 )
122
123 resp = super(CacheControlAdapter, self).build_response(request, response)
124
125 # See if we should invalidate the cache.
126 if request.method in self.invalidating_methods and resp.ok:
127 cache_url = self.controller.cache_url(request.url)
128 self.cache.delete(cache_url)
129
130 # Give the request a from_cache attr to let people use it
131 resp.from_cache = from_cache
132
133 return resp
134
135 def close(self):
136 self.cache.close()
137 super(CacheControlAdapter, self).close()
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