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Editing: serialize.py
import base64 import io import json import zlib from pip._vendor import msgpack from pip._vendor.requests.structures import CaseInsensitiveDict from .compat import HTTPResponse, pickle, text_type 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) # NOTE: This is all a bit weird, but it's really important that on # Python 2.x these objects are unicode and not str, even when # they contain only ascii. The problem here is that msgpack # understands the difference between unicode and bytes and we # have it set to differentiate between them, however Python 2 # doesn't know the difference. Forcing these to unicode will be # enough to have msgpack know the difference. data = { u"response": { u"body": body, u"headers": dict( (text_type(k), text_type(v)) for k, v in response.headers.items() ), u"status": response.status, u"version": response.version, u"reason": text_type(response.reason), u"strict": response.strict, u"decode_content": response.decode_content, } } # Construct our vary headers data[u"vary"] = {} if u"vary" in response_headers: varied_headers = response_headers[u"vary"].split(",") for header in varied_headers: header = text_type(header).strip() header_value = request.headers.get(header, None) if header_value is not None: header_value = text_type(header_value) data[u"vary"][header] = header_value return b",".join([b"cc=4", msgpack.dumps(data, use_bin_type=True)]) 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{}".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. # This case is also handled in the controller code when creating # a cache entry, but is left here for backwards compatibility. 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, zlib.error): 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) def _loads_v3(self, request, data): # Due to Python 2 encoding issues, it's impossible to know for sure # exactly how to load v3 entries, thus we'll treat these as a miss so # that they get rewritten out as v4 entries. return def _loads_v4(self, request, data): try: cached = msgpack.loads(data, raw=False) except ValueError: return return self.prepare_response(request, cached)
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