tests versuch 2

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# SPDX-FileCopyrightText: 2015 Eric Larson
#
# SPDX-License-Identifier: Apache-2.0
"""CacheControl import Interface.
Make it easy to import from cachecontrol without long namespaces.
"""
__author__ = "Eric Larson"
__email__ = "eric@ionrock.org"
__version__ = "0.12.11"
from .wrapper import CacheControl
from .adapter import CacheControlAdapter
from .controller import CacheController
import logging
logging.getLogger(__name__).addHandler(logging.NullHandler())

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# SPDX-FileCopyrightText: 2015 Eric Larson
#
# SPDX-License-Identifier: Apache-2.0
import logging
from pip._vendor import requests
from pip._vendor.cachecontrol.adapter import CacheControlAdapter
from pip._vendor.cachecontrol.cache import DictCache
from pip._vendor.cachecontrol.controller import logger
from argparse import ArgumentParser
def setup_logging():
logger.setLevel(logging.DEBUG)
handler = logging.StreamHandler()
logger.addHandler(handler)
def get_session():
adapter = CacheControlAdapter(
DictCache(), cache_etags=True, serializer=None, heuristic=None
)
sess = requests.Session()
sess.mount("http://", adapter)
sess.mount("https://", adapter)
sess.cache_controller = adapter.controller
return sess
def get_args():
parser = ArgumentParser()
parser.add_argument("url", help="The URL to try and cache")
return parser.parse_args()
def main(args=None):
args = get_args()
sess = get_session()
# Make a request to get a response
resp = sess.get(args.url)
# Turn on logging
setup_logging()
# try setting the cache
sess.cache_controller.cache_response(resp.request, resp.raw)
# Now try to get it
if sess.cache_controller.cached_request(resp.request):
print("Cached!")
else:
print("Not cached :(")
if __name__ == "__main__":
main()

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# 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()

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# SPDX-FileCopyrightText: 2015 Eric Larson
#
# SPDX-License-Identifier: Apache-2.0
"""
The cache object API for implementing caches. The default is a thread
safe in-memory dictionary.
"""
from threading import Lock
class BaseCache(object):
def get(self, key):
raise NotImplementedError()
def set(self, key, value, expires=None):
raise NotImplementedError()
def delete(self, key):
raise NotImplementedError()
def close(self):
pass
class DictCache(BaseCache):
def __init__(self, init_dict=None):
self.lock = Lock()
self.data = init_dict or {}
def get(self, key):
return self.data.get(key, None)
def set(self, key, value, expires=None):
with self.lock:
self.data.update({key: value})
def delete(self, key):
with self.lock:
if key in self.data:
self.data.pop(key)
class SeparateBodyBaseCache(BaseCache):
"""
In this variant, the body is not stored mixed in with the metadata, but is
passed in (as a bytes-like object) in a separate call to ``set_body()``.
That is, the expected interaction pattern is::
cache.set(key, serialized_metadata)
cache.set_body(key)
Similarly, the body should be loaded separately via ``get_body()``.
"""
def set_body(self, key, body):
raise NotImplementedError()
def get_body(self, key):
"""
Return the body as file-like object.
"""
raise NotImplementedError()

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# SPDX-FileCopyrightText: 2015 Eric Larson
#
# SPDX-License-Identifier: Apache-2.0
from .file_cache import FileCache, SeparateBodyFileCache
from .redis_cache import RedisCache
__all__ = ["FileCache", "SeparateBodyFileCache", "RedisCache"]

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# SPDX-FileCopyrightText: 2015 Eric Larson
#
# SPDX-License-Identifier: Apache-2.0
import hashlib
import os
from textwrap import dedent
from ..cache import BaseCache, SeparateBodyBaseCache
from ..controller import CacheController
try:
FileNotFoundError
except NameError:
# py2.X
FileNotFoundError = (IOError, OSError)
def _secure_open_write(filename, fmode):
# We only want to write to this file, so open it in write only mode
flags = os.O_WRONLY
# os.O_CREAT | os.O_EXCL will fail if the file already exists, so we only
# will open *new* files.
# We specify this because we want to ensure that the mode we pass is the
# mode of the file.
flags |= os.O_CREAT | os.O_EXCL
# Do not follow symlinks to prevent someone from making a symlink that
# we follow and insecurely open a cache file.
if hasattr(os, "O_NOFOLLOW"):
flags |= os.O_NOFOLLOW
# On Windows we'll mark this file as binary
if hasattr(os, "O_BINARY"):
flags |= os.O_BINARY
# Before we open our file, we want to delete any existing file that is
# there
try:
os.remove(filename)
except (IOError, OSError):
# The file must not exist already, so we can just skip ahead to opening
pass
# Open our file, the use of os.O_CREAT | os.O_EXCL will ensure that if a
# race condition happens between the os.remove and this line, that an
# error will be raised. Because we utilize a lockfile this should only
# happen if someone is attempting to attack us.
fd = os.open(filename, flags, fmode)
try:
return os.fdopen(fd, "wb")
except:
# An error occurred wrapping our FD in a file object
os.close(fd)
raise
class _FileCacheMixin:
"""Shared implementation for both FileCache variants."""
def __init__(
self,
directory,
forever=False,
filemode=0o0600,
dirmode=0o0700,
use_dir_lock=None,
lock_class=None,
):
if use_dir_lock is not None and lock_class is not None:
raise ValueError("Cannot use use_dir_lock and lock_class together")
try:
from lockfile import LockFile
from lockfile.mkdirlockfile import MkdirLockFile
except ImportError:
notice = dedent(
"""
NOTE: In order to use the FileCache you must have
lockfile installed. You can install it via pip:
pip install lockfile
"""
)
raise ImportError(notice)
else:
if use_dir_lock:
lock_class = MkdirLockFile
elif lock_class is None:
lock_class = LockFile
self.directory = directory
self.forever = forever
self.filemode = filemode
self.dirmode = dirmode
self.lock_class = lock_class
@staticmethod
def encode(x):
return hashlib.sha224(x.encode()).hexdigest()
def _fn(self, name):
# NOTE: This method should not change as some may depend on it.
# See: https://github.com/ionrock/cachecontrol/issues/63
hashed = self.encode(name)
parts = list(hashed[:5]) + [hashed]
return os.path.join(self.directory, *parts)
def get(self, key):
name = self._fn(key)
try:
with open(name, "rb") as fh:
return fh.read()
except FileNotFoundError:
return None
def set(self, key, value, expires=None):
name = self._fn(key)
self._write(name, value)
def _write(self, path, data: bytes):
"""
Safely write the data to the given path.
"""
# Make sure the directory exists
try:
os.makedirs(os.path.dirname(path), self.dirmode)
except (IOError, OSError):
pass
with self.lock_class(path) as lock:
# Write our actual file
with _secure_open_write(lock.path, self.filemode) as fh:
fh.write(data)
def _delete(self, key, suffix):
name = self._fn(key) + suffix
if not self.forever:
try:
os.remove(name)
except FileNotFoundError:
pass
class FileCache(_FileCacheMixin, BaseCache):
"""
Traditional FileCache: body is stored in memory, so not suitable for large
downloads.
"""
def delete(self, key):
self._delete(key, "")
class SeparateBodyFileCache(_FileCacheMixin, SeparateBodyBaseCache):
"""
Memory-efficient FileCache: body is stored in a separate file, reducing
peak memory usage.
"""
def get_body(self, key):
name = self._fn(key) + ".body"
try:
return open(name, "rb")
except FileNotFoundError:
return None
def set_body(self, key, body):
name = self._fn(key) + ".body"
self._write(name, body)
def delete(self, key):
self._delete(key, "")
self._delete(key, ".body")
def url_to_file_path(url, filecache):
"""Return the file cache path based on the URL.
This does not ensure the file exists!
"""
key = CacheController.cache_url(url)
return filecache._fn(key)

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# SPDX-FileCopyrightText: 2015 Eric Larson
#
# SPDX-License-Identifier: Apache-2.0
from __future__ import division
from datetime import datetime
from pip._vendor.cachecontrol.cache import BaseCache
class RedisCache(BaseCache):
def __init__(self, conn):
self.conn = conn
def get(self, key):
return self.conn.get(key)
def set(self, key, value, expires=None):
if not expires:
self.conn.set(key, value)
elif isinstance(expires, datetime):
expires = expires - datetime.utcnow()
self.conn.setex(key, int(expires.total_seconds()), value)
else:
self.conn.setex(key, expires, value)
def delete(self, key):
self.conn.delete(key)
def clear(self):
"""Helper for clearing all the keys in a database. Use with
caution!"""
for key in self.conn.keys():
self.conn.delete(key)
def close(self):
"""Redis uses connection pooling, no need to close the connection."""
pass

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# SPDX-FileCopyrightText: 2015 Eric Larson
#
# SPDX-License-Identifier: Apache-2.0
try:
from urllib.parse import urljoin
except ImportError:
from urlparse import urljoin
try:
import cPickle as pickle
except ImportError:
import pickle
# Handle the case where the requests module has been patched to not have
# urllib3 bundled as part of its source.
try:
from pip._vendor.requests.packages.urllib3.response import HTTPResponse
except ImportError:
from pip._vendor.urllib3.response import HTTPResponse
try:
from pip._vendor.requests.packages.urllib3.util import is_fp_closed
except ImportError:
from pip._vendor.urllib3.util import is_fp_closed
# Replicate some six behaviour
try:
text_type = unicode
except NameError:
text_type = str

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# SPDX-FileCopyrightText: 2015 Eric Larson
#
# SPDX-License-Identifier: Apache-2.0
"""
The httplib2 algorithms ported for use with requests.
"""
import logging
import re
import calendar
import time
from email.utils import parsedate_tz
from pip._vendor.requests.structures import CaseInsensitiveDict
from .cache import DictCache, SeparateBodyBaseCache
from .serialize import Serializer
logger = logging.getLogger(__name__)
URI = re.compile(r"^(([^:/?#]+):)?(//([^/?#]*))?([^?#]*)(\?([^#]*))?(#(.*))?")
PERMANENT_REDIRECT_STATUSES = (301, 308)
def parse_uri(uri):
"""Parses a URI using the regex given in Appendix B of RFC 3986.
(scheme, authority, path, query, fragment) = parse_uri(uri)
"""
groups = URI.match(uri).groups()
return (groups[1], groups[3], groups[4], groups[6], groups[8])
class CacheController(object):
"""An interface to see if request should cached or not."""
def __init__(
self, cache=None, cache_etags=True, serializer=None, status_codes=None
):
self.cache = DictCache() if cache is None else cache
self.cache_etags = cache_etags
self.serializer = serializer or Serializer()
self.cacheable_status_codes = status_codes or (200, 203, 300, 301, 308)
@classmethod
def _urlnorm(cls, uri):
"""Normalize the URL to create a safe key for the cache"""
(scheme, authority, path, query, fragment) = parse_uri(uri)
if not scheme or not authority:
raise Exception("Only absolute URIs are allowed. uri = %s" % uri)
scheme = scheme.lower()
authority = authority.lower()
if not path:
path = "/"
# Could do syntax based normalization of the URI before
# computing the digest. See Section 6.2.2 of Std 66.
request_uri = query and "?".join([path, query]) or path
defrag_uri = scheme + "://" + authority + request_uri
return defrag_uri
@classmethod
def cache_url(cls, uri):
return cls._urlnorm(uri)
def parse_cache_control(self, headers):
known_directives = {
# https://tools.ietf.org/html/rfc7234#section-5.2
"max-age": (int, True),
"max-stale": (int, False),
"min-fresh": (int, True),
"no-cache": (None, False),
"no-store": (None, False),
"no-transform": (None, False),
"only-if-cached": (None, False),
"must-revalidate": (None, False),
"public": (None, False),
"private": (None, False),
"proxy-revalidate": (None, False),
"s-maxage": (int, True),
}
cc_headers = headers.get("cache-control", headers.get("Cache-Control", ""))
retval = {}
for cc_directive in cc_headers.split(","):
if not cc_directive.strip():
continue
parts = cc_directive.split("=", 1)
directive = parts[0].strip()
try:
typ, required = known_directives[directive]
except KeyError:
logger.debug("Ignoring unknown cache-control directive: %s", directive)
continue
if not typ or not required:
retval[directive] = None
if typ:
try:
retval[directive] = typ(parts[1].strip())
except IndexError:
if required:
logger.debug(
"Missing value for cache-control " "directive: %s",
directive,
)
except ValueError:
logger.debug(
"Invalid value for cache-control directive " "%s, must be %s",
directive,
typ.__name__,
)
return retval
def cached_request(self, request):
"""
Return a cached response if it exists in the cache, otherwise
return False.
"""
cache_url = self.cache_url(request.url)
logger.debug('Looking up "%s" in the cache', cache_url)
cc = self.parse_cache_control(request.headers)
# Bail out if the request insists on fresh data
if "no-cache" in cc:
logger.debug('Request header has "no-cache", cache bypassed')
return False
if "max-age" in cc and cc["max-age"] == 0:
logger.debug('Request header has "max_age" as 0, cache bypassed')
return False
# Request allows serving from the cache, let's see if we find something
cache_data = self.cache.get(cache_url)
if cache_data is None:
logger.debug("No cache entry available")
return False
if isinstance(self.cache, SeparateBodyBaseCache):
body_file = self.cache.get_body(cache_url)
else:
body_file = None
# Check whether it can be deserialized
resp = self.serializer.loads(request, cache_data, body_file)
if not resp:
logger.warning("Cache entry deserialization failed, entry ignored")
return False
# If we have a cached permanent redirect, return it immediately. We
# don't need to test our response for other headers b/c it is
# intrinsically "cacheable" as it is Permanent.
#
# See:
# https://tools.ietf.org/html/rfc7231#section-6.4.2
#
# Client can try to refresh the value by repeating the request
# with cache busting headers as usual (ie no-cache).
if int(resp.status) in PERMANENT_REDIRECT_STATUSES:
msg = (
"Returning cached permanent redirect response "
"(ignoring date and etag information)"
)
logger.debug(msg)
return resp
headers = CaseInsensitiveDict(resp.headers)
if not headers or "date" not in headers:
if "etag" not in headers:
# Without date or etag, the cached response can never be used
# and should be deleted.
logger.debug("Purging cached response: no date or etag")
self.cache.delete(cache_url)
logger.debug("Ignoring cached response: no date")
return False
now = time.time()
date = calendar.timegm(parsedate_tz(headers["date"]))
current_age = max(0, now - date)
logger.debug("Current age based on date: %i", current_age)
# TODO: There is an assumption that the result will be a
# urllib3 response object. This may not be best since we
# could probably avoid instantiating or constructing the
# response until we know we need it.
resp_cc = self.parse_cache_control(headers)
# determine freshness
freshness_lifetime = 0
# Check the max-age pragma in the cache control header
if "max-age" in resp_cc:
freshness_lifetime = resp_cc["max-age"]
logger.debug("Freshness lifetime from max-age: %i", freshness_lifetime)
# If there isn't a max-age, check for an expires header
elif "expires" in headers:
expires = parsedate_tz(headers["expires"])
if expires is not None:
expire_time = calendar.timegm(expires) - date
freshness_lifetime = max(0, expire_time)
logger.debug("Freshness lifetime from expires: %i", freshness_lifetime)
# Determine if we are setting freshness limit in the
# request. Note, this overrides what was in the response.
if "max-age" in cc:
freshness_lifetime = cc["max-age"]
logger.debug(
"Freshness lifetime from request max-age: %i", freshness_lifetime
)
if "min-fresh" in cc:
min_fresh = cc["min-fresh"]
# adjust our current age by our min fresh
current_age += min_fresh
logger.debug("Adjusted current age from min-fresh: %i", current_age)
# Return entry if it is fresh enough
if freshness_lifetime > current_age:
logger.debug('The response is "fresh", returning cached response')
logger.debug("%i > %i", freshness_lifetime, current_age)
return resp
# we're not fresh. If we don't have an Etag, clear it out
if "etag" not in headers:
logger.debug('The cached response is "stale" with no etag, purging')
self.cache.delete(cache_url)
# return the original handler
return False
def conditional_headers(self, request):
cache_url = self.cache_url(request.url)
resp = self.serializer.loads(request, self.cache.get(cache_url))
new_headers = {}
if resp:
headers = CaseInsensitiveDict(resp.headers)
if "etag" in headers:
new_headers["If-None-Match"] = headers["ETag"]
if "last-modified" in headers:
new_headers["If-Modified-Since"] = headers["Last-Modified"]
return new_headers
def _cache_set(self, cache_url, request, response, body=None, expires_time=None):
"""
Store the data in the cache.
"""
if isinstance(self.cache, SeparateBodyBaseCache):
# We pass in the body separately; just put a placeholder empty
# string in the metadata.
self.cache.set(
cache_url,
self.serializer.dumps(request, response, b""),
expires=expires_time,
)
self.cache.set_body(cache_url, body)
else:
self.cache.set(
cache_url,
self.serializer.dumps(request, response, body),
expires=expires_time,
)
def cache_response(self, request, response, body=None, status_codes=None):
"""
Algorithm for caching requests.
This assumes a requests Response object.
"""
# From httplib2: Don't cache 206's since we aren't going to
# handle byte range requests
cacheable_status_codes = status_codes or self.cacheable_status_codes
if response.status not in cacheable_status_codes:
logger.debug(
"Status code %s not in %s", response.status, cacheable_status_codes
)
return
response_headers = CaseInsensitiveDict(response.headers)
if "date" in response_headers:
date = calendar.timegm(parsedate_tz(response_headers["date"]))
else:
date = 0
# If we've been given a body, our response has a Content-Length, that
# Content-Length is valid then we can check to see if the body we've
# been given matches the expected size, and if it doesn't we'll just
# skip trying to cache it.
if (
body is not None
and "content-length" in response_headers
and response_headers["content-length"].isdigit()
and int(response_headers["content-length"]) != len(body)
):
return
cc_req = self.parse_cache_control(request.headers)
cc = self.parse_cache_control(response_headers)
cache_url = self.cache_url(request.url)
logger.debug('Updating cache with response from "%s"', cache_url)
# Delete it from the cache if we happen to have it stored there
no_store = False
if "no-store" in cc:
no_store = True
logger.debug('Response header has "no-store"')
if "no-store" in cc_req:
no_store = True
logger.debug('Request header has "no-store"')
if no_store and self.cache.get(cache_url):
logger.debug('Purging existing cache entry to honor "no-store"')
self.cache.delete(cache_url)
if no_store:
return
# https://tools.ietf.org/html/rfc7234#section-4.1:
# A Vary header field-value of "*" always fails to match.
# Storing such a response leads to a deserialization warning
# during cache lookup and is not allowed to ever be served,
# so storing it can be avoided.
if "*" in response_headers.get("vary", ""):
logger.debug('Response header has "Vary: *"')
return
# If we've been given an etag, then keep the response
if self.cache_etags and "etag" in response_headers:
expires_time = 0
if response_headers.get("expires"):
expires = parsedate_tz(response_headers["expires"])
if expires is not None:
expires_time = calendar.timegm(expires) - date
expires_time = max(expires_time, 14 * 86400)
logger.debug("etag object cached for {0} seconds".format(expires_time))
logger.debug("Caching due to etag")
self._cache_set(cache_url, request, response, body, expires_time)
# Add to the cache any permanent redirects. We do this before looking
# that the Date headers.
elif int(response.status) in PERMANENT_REDIRECT_STATUSES:
logger.debug("Caching permanent redirect")
self._cache_set(cache_url, request, response, b"")
# Add to the cache if the response headers demand it. If there
# is no date header then we can't do anything about expiring
# the cache.
elif "date" in response_headers:
date = calendar.timegm(parsedate_tz(response_headers["date"]))
# cache when there is a max-age > 0
if "max-age" in cc and cc["max-age"] > 0:
logger.debug("Caching b/c date exists and max-age > 0")
expires_time = cc["max-age"]
self._cache_set(
cache_url,
request,
response,
body,
expires_time,
)
# If the request can expire, it means we should cache it
# in the meantime.
elif "expires" in response_headers:
if response_headers["expires"]:
expires = parsedate_tz(response_headers["expires"])
if expires is not None:
expires_time = calendar.timegm(expires) - date
else:
expires_time = None
logger.debug(
"Caching b/c of expires header. expires in {0} seconds".format(
expires_time
)
)
self._cache_set(
cache_url,
request,
response,
body,
expires_time,
)
def update_cached_response(self, request, response):
"""On a 304 we will get a new set of headers that we want to
update our cached value with, assuming we have one.
This should only ever be called when we've sent an ETag and
gotten a 304 as the response.
"""
cache_url = self.cache_url(request.url)
cached_response = self.serializer.loads(request, self.cache.get(cache_url))
if not cached_response:
# we didn't have a cached response
return response
# Lets update our headers with the headers from the new request:
# http://tools.ietf.org/html/draft-ietf-httpbis-p4-conditional-26#section-4.1
#
# The server isn't supposed to send headers that would make
# the cached body invalid. But... just in case, we'll be sure
# to strip out ones we know that might be problmatic due to
# typical assumptions.
excluded_headers = ["content-length"]
cached_response.headers.update(
dict(
(k, v)
for k, v in response.headers.items()
if k.lower() not in excluded_headers
)
)
# we want a 200 b/c we have content via the cache
cached_response.status = 200
# update our cache
self._cache_set(cache_url, request, cached_response)
return cached_response

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# SPDX-FileCopyrightText: 2015 Eric Larson
#
# SPDX-License-Identifier: Apache-2.0
from tempfile import NamedTemporaryFile
import mmap
class CallbackFileWrapper(object):
"""
Small wrapper around a fp object which will tee everything read into a
buffer, and when that file is closed it will execute a callback with the
contents of that buffer.
All attributes are proxied to the underlying file object.
This class uses members with a double underscore (__) leading prefix so as
not to accidentally shadow an attribute.
The data is stored in a temporary file until it is all available. As long
as the temporary files directory is disk-based (sometimes it's a
memory-backed-``tmpfs`` on Linux), data will be unloaded to disk if memory
pressure is high. For small files the disk usually won't be used at all,
it'll all be in the filesystem memory cache, so there should be no
performance impact.
"""
def __init__(self, fp, callback):
self.__buf = NamedTemporaryFile("rb+", delete=True)
self.__fp = fp
self.__callback = callback
def __getattr__(self, name):
# The vaguaries of garbage collection means that self.__fp is
# not always set. By using __getattribute__ and the private
# name[0] allows looking up the attribute value and raising an
# AttributeError when it doesn't exist. This stop thigns from
# infinitely recursing calls to getattr in the case where
# self.__fp hasn't been set.
#
# [0] https://docs.python.org/2/reference/expressions.html#atom-identifiers
fp = self.__getattribute__("_CallbackFileWrapper__fp")
return getattr(fp, name)
def __is_fp_closed(self):
try:
return self.__fp.fp is None
except AttributeError:
pass
try:
return self.__fp.closed
except AttributeError:
pass
# We just don't cache it then.
# TODO: Add some logging here...
return False
def _close(self):
if self.__callback:
if self.__buf.tell() == 0:
# Empty file:
result = b""
else:
# Return the data without actually loading it into memory,
# relying on Python's buffer API and mmap(). mmap() just gives
# a view directly into the filesystem's memory cache, so it
# doesn't result in duplicate memory use.
self.__buf.seek(0, 0)
result = memoryview(
mmap.mmap(self.__buf.fileno(), 0, access=mmap.ACCESS_READ)
)
self.__callback(result)
# We assign this to None here, because otherwise we can get into
# really tricky problems where the CPython interpreter dead locks
# because the callback is holding a reference to something which
# has a __del__ method. Setting this to None breaks the cycle
# and allows the garbage collector to do it's thing normally.
self.__callback = None
# Closing the temporary file releases memory and frees disk space.
# Important when caching big files.
self.__buf.close()
def read(self, amt=None):
data = self.__fp.read(amt)
if data:
# We may be dealing with b'', a sign that things are over:
# it's passed e.g. after we've already closed self.__buf.
self.__buf.write(data)
if self.__is_fp_closed():
self._close()
return data
def _safe_read(self, amt):
data = self.__fp._safe_read(amt)
if amt == 2 and data == b"\r\n":
# urllib executes this read to toss the CRLF at the end
# of the chunk.
return data
self.__buf.write(data)
if self.__is_fp_closed():
self._close()
return data

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# SPDX-FileCopyrightText: 2015 Eric Larson
#
# SPDX-License-Identifier: Apache-2.0
import calendar
import time
from email.utils import formatdate, parsedate, parsedate_tz
from datetime import datetime, timedelta
TIME_FMT = "%a, %d %b %Y %H:%M:%S GMT"
def expire_after(delta, date=None):
date = date or datetime.utcnow()
return date + delta
def datetime_to_header(dt):
return formatdate(calendar.timegm(dt.timetuple()))
class BaseHeuristic(object):
def warning(self, response):
"""
Return a valid 1xx warning header value describing the cache
adjustments.
The response is provided too allow warnings like 113
http://tools.ietf.org/html/rfc7234#section-5.5.4 where we need
to explicitly say response is over 24 hours old.
"""
return '110 - "Response is Stale"'
def update_headers(self, response):
"""Update the response headers with any new headers.
NOTE: This SHOULD always include some Warning header to
signify that the response was cached by the client, not
by way of the provided headers.
"""
return {}
def apply(self, response):
updated_headers = self.update_headers(response)
if updated_headers:
response.headers.update(updated_headers)
warning_header_value = self.warning(response)
if warning_header_value is not None:
response.headers.update({"Warning": warning_header_value})
return response
class OneDayCache(BaseHeuristic):
"""
Cache the response by providing an expires 1 day in the
future.
"""
def update_headers(self, response):
headers = {}
if "expires" not in response.headers:
date = parsedate(response.headers["date"])
expires = expire_after(timedelta(days=1), date=datetime(*date[:6]))
headers["expires"] = datetime_to_header(expires)
headers["cache-control"] = "public"
return headers
class ExpiresAfter(BaseHeuristic):
"""
Cache **all** requests for a defined time period.
"""
def __init__(self, **kw):
self.delta = timedelta(**kw)
def update_headers(self, response):
expires = expire_after(self.delta)
return {"expires": datetime_to_header(expires), "cache-control": "public"}
def warning(self, response):
tmpl = "110 - Automatically cached for %s. Response might be stale"
return tmpl % self.delta
class LastModified(BaseHeuristic):
"""
If there is no Expires header already, fall back on Last-Modified
using the heuristic from
http://tools.ietf.org/html/rfc7234#section-4.2.2
to calculate a reasonable value.
Firefox also does something like this per
https://developer.mozilla.org/en-US/docs/Web/HTTP/Caching_FAQ
http://lxr.mozilla.org/mozilla-release/source/netwerk/protocol/http/nsHttpResponseHead.cpp#397
Unlike mozilla we limit this to 24-hr.
"""
cacheable_by_default_statuses = {
200, 203, 204, 206, 300, 301, 404, 405, 410, 414, 501
}
def update_headers(self, resp):
headers = resp.headers
if "expires" in headers:
return {}
if "cache-control" in headers and headers["cache-control"] != "public":
return {}
if resp.status not in self.cacheable_by_default_statuses:
return {}
if "date" not in headers or "last-modified" not in headers:
return {}
date = calendar.timegm(parsedate_tz(headers["date"]))
last_modified = parsedate(headers["last-modified"])
if date is None or last_modified is None:
return {}
now = time.time()
current_age = max(0, now - date)
delta = date - calendar.timegm(last_modified)
freshness_lifetime = max(0, min(delta / 10, 24 * 3600))
if freshness_lifetime <= current_age:
return {}
expires = date + freshness_lifetime
return {"expires": time.strftime(TIME_FMT, time.gmtime(expires))}
def warning(self, resp):
return None

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# SPDX-FileCopyrightText: 2015 Eric Larson
#
# SPDX-License-Identifier: Apache-2.0
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")
_default_body_read = object()
class Serializer(object):
def dumps(self, request, response, body=None):
response_headers = CaseInsensitiveDict(response.headers)
if body is None:
# When a body isn't passed in, we'll read the response. We
# also update the response with a new file handler to be
# sure it acts as though it was never read.
body = response.read(decode_content=False)
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, # Empty bytestring if body is stored separately
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, body_file=None):
# 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, body_file)
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, body_file=None):
"""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:
if body_file is None:
body = io.BytesIO(body_raw)
else:
body = body_file
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, body_file=None):
# 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, body_file=None):
try:
cached = pickle.loads(data)
except ValueError:
return
return self.prepare_response(request, cached, body_file)
def _loads_v2(self, request, data, body_file=None):
assert body_file is None
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, body_file)
def _loads_v3(self, request, data, body_file):
# 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, body_file=None):
try:
cached = msgpack.loads(data, raw=False)
except ValueError:
return
return self.prepare_response(request, cached, body_file)

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# SPDX-FileCopyrightText: 2015 Eric Larson
#
# SPDX-License-Identifier: Apache-2.0
from .adapter import CacheControlAdapter
from .cache import DictCache
def CacheControl(
sess,
cache=None,
cache_etags=True,
serializer=None,
heuristic=None,
controller_class=None,
adapter_class=None,
cacheable_methods=None,
):
cache = DictCache() if cache is None else cache
adapter_class = adapter_class or CacheControlAdapter
adapter = adapter_class(
cache,
cache_etags=cache_etags,
serializer=serializer,
heuristic=heuristic,
controller_class=controller_class,
cacheable_methods=cacheable_methods,
)
sess.mount("http://", adapter)
sess.mount("https://", adapter)
return sess