/usr/lib/python3/dist-packages/cachecontrol/serialize.py is in python3-cachecontrol 0.11.7-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 | import base64
import io
import json
import zlib
from requests.structures import CaseInsensitiveDict
from .compat import HTTPResponse, pickle, text_type
def _b64_encode_bytes(b):
return base64.b64encode(b).decode("ascii")
def _b64_encode_str(s):
return _b64_encode_bytes(s.encode("utf8"))
def _b64_encode(s):
if isinstance(s, text_type):
return _b64_encode_str(s)
return _b64_encode_bytes(s)
def _b64_decode_bytes(b):
return base64.b64decode(b.encode("ascii"))
def _b64_decode_str(s):
return _b64_decode_bytes(s).decode("utf8")
class Serializer(object):
def dumps(self, request, response, body=None):
response_headers = CaseInsensitiveDict(response.headers)
if body is None:
body = response.read(decode_content=False)
# NOTE: 99% sure this is dead code. I'm only leaving it
# here b/c I don't have a test yet to prove
# it. Basically, before using
# `cachecontrol.filewrapper.CallbackFileWrapper`,
# this made an effort to reset the file handle. The
# `CallbackFileWrapper` short circuits this code by
# setting the body as the content is consumed, the
# result being a `body` argument is *always* passed
# into cache_response, and in turn,
# `Serializer.dump`.
response._fp = io.BytesIO(body)
data = {
"response": {
"body": _b64_encode_bytes(body),
"headers": dict(
(_b64_encode(k), _b64_encode(v))
for k, v in response.headers.items()
),
"status": response.status,
"version": response.version,
"reason": _b64_encode_str(response.reason),
"strict": response.strict,
"decode_content": response.decode_content,
},
}
# Construct our vary headers
data["vary"] = {}
if "vary" in response_headers:
varied_headers = response_headers['vary'].split(',')
for header in varied_headers:
header = header.strip()
data["vary"][header] = request.headers.get(header, None)
# Encode our Vary headers to ensure they can be serialized as JSON
data["vary"] = dict(
(_b64_encode(k), _b64_encode(v) if v is not None else v)
for k, v in data["vary"].items()
)
return b",".join([
b"cc=2",
zlib.compress(
json.dumps(
data, separators=(",", ":"), sort_keys=True,
).encode("utf8"),
),
])
def loads(self, request, data):
# Short circuit if we've been given an empty set of data
if not data:
return
# Determine what version of the serializer the data was serialized
# with
try:
ver, data = data.split(b",", 1)
except ValueError:
ver = b"cc=0"
# Make sure that our "ver" is actually a version and isn't a false
# positive from a , being in the data stream.
if ver[:3] != b"cc=":
data = ver + data
ver = b"cc=0"
# Get the version number out of the cc=N
ver = ver.split(b"=", 1)[-1].decode("ascii")
# Dispatch to the actual load method for the given version
try:
return getattr(self, "_loads_v{0}".format(ver))(request, data)
except AttributeError:
# This is a version we don't have a loads function for, so we'll
# just treat it as a miss and return None
return
def prepare_response(self, request, cached):
"""Verify our vary headers match and construct a real urllib3
HTTPResponse object.
"""
# Special case the '*' Vary value as it means we cannot actually
# determine if the cached response is suitable for this request.
if "*" in cached.get("vary", {}):
return
# Ensure that the Vary headers for the cached response match our
# request
for header, value in cached.get("vary", {}).items():
if request.headers.get(header, None) != value:
return
body_raw = cached["response"].pop("body")
headers = CaseInsensitiveDict(data=cached['response']['headers'])
if headers.get('transfer-encoding', '') == 'chunked':
headers.pop('transfer-encoding')
cached['response']['headers'] = headers
try:
body = io.BytesIO(body_raw)
except TypeError:
# This can happen if cachecontrol serialized to v1 format (pickle)
# using Python 2. A Python 2 str(byte string) will be unpickled as
# a Python 3 str (unicode string), which will cause the above to
# fail with:
#
# TypeError: 'str' does not support the buffer interface
body = io.BytesIO(body_raw.encode('utf8'))
return HTTPResponse(
body=body,
preload_content=False,
**cached["response"]
)
def _loads_v0(self, request, data):
# The original legacy cache data. This doesn't contain enough
# information to construct everything we need, so we'll treat this as
# a miss.
return
def _loads_v1(self, request, data):
try:
cached = pickle.loads(data)
except ValueError:
return
return self.prepare_response(request, cached)
def _loads_v2(self, request, data):
try:
cached = json.loads(zlib.decompress(data).decode("utf8"))
except ValueError:
return
# We need to decode the items that we've base64 encoded
cached["response"]["body"] = _b64_decode_bytes(
cached["response"]["body"]
)
cached["response"]["headers"] = dict(
(_b64_decode_str(k), _b64_decode_str(v))
for k, v in cached["response"]["headers"].items()
)
cached["response"]["reason"] = _b64_decode_str(
cached["response"]["reason"],
)
cached["vary"] = dict(
(_b64_decode_str(k), _b64_decode_str(v) if v is not None else v)
for k, v in cached["vary"].items()
)
return self.prepare_response(request, cached)
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