You cannot select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.

141 lines
5.0 KiB
Python

2 years ago
import re
import typing as t
from datetime import datetime
from .._internal import _cookie_parse_impl
from .._internal import _dt_as_utc
from .._internal import _to_str
from ..http import generate_etag
from ..http import parse_date
from ..http import parse_etags
from ..http import parse_if_range_header
from ..http import unquote_etag
_etag_re = re.compile(r'([Ww]/)?(?:"(.*?)"|(.*?))(?:\s*,\s*|$)')
def is_resource_modified(
http_range: t.Optional[str] = None,
http_if_range: t.Optional[str] = None,
http_if_modified_since: t.Optional[str] = None,
http_if_none_match: t.Optional[str] = None,
http_if_match: t.Optional[str] = None,
etag: t.Optional[str] = None,
data: t.Optional[bytes] = None,
last_modified: t.Optional[t.Union[datetime, str]] = None,
ignore_if_range: bool = True,
) -> bool:
"""Convenience method for conditional requests.
:param http_range: Range HTTP header
:param http_if_range: If-Range HTTP header
:param http_if_modified_since: If-Modified-Since HTTP header
:param http_if_none_match: If-None-Match HTTP header
:param http_if_match: If-Match HTTP header
:param etag: the etag for the response for comparison.
:param data: or alternatively the data of the response to automatically
generate an etag using :func:`generate_etag`.
:param last_modified: an optional date of the last modification.
:param ignore_if_range: If `False`, `If-Range` header will be taken into
account.
:return: `True` if the resource was modified, otherwise `False`.
.. versionadded:: 2.2
"""
if etag is None and data is not None:
etag = generate_etag(data)
elif data is not None:
raise TypeError("both data and etag given")
unmodified = False
if isinstance(last_modified, str):
last_modified = parse_date(last_modified)
# HTTP doesn't use microsecond, remove it to avoid false positive
# comparisons. Mark naive datetimes as UTC.
if last_modified is not None:
last_modified = _dt_as_utc(last_modified.replace(microsecond=0))
if_range = None
if not ignore_if_range and http_range is not None:
# https://tools.ietf.org/html/rfc7233#section-3.2
# A server MUST ignore an If-Range header field received in a request
# that does not contain a Range header field.
if_range = parse_if_range_header(http_if_range)
if if_range is not None and if_range.date is not None:
modified_since: t.Optional[datetime] = if_range.date
else:
modified_since = parse_date(http_if_modified_since)
if modified_since and last_modified and last_modified <= modified_since:
unmodified = True
if etag:
etag, _ = unquote_etag(etag)
etag = t.cast(str, etag)
if if_range is not None and if_range.etag is not None:
unmodified = parse_etags(if_range.etag).contains(etag)
else:
if_none_match = parse_etags(http_if_none_match)
if if_none_match:
# https://tools.ietf.org/html/rfc7232#section-3.2
# "A recipient MUST use the weak comparison function when comparing
# entity-tags for If-None-Match"
unmodified = if_none_match.contains_weak(etag)
# https://tools.ietf.org/html/rfc7232#section-3.1
# "Origin server MUST use the strong comparison function when
# comparing entity-tags for If-Match"
if_match = parse_etags(http_if_match)
if if_match:
unmodified = not if_match.is_strong(etag)
return not unmodified
def parse_cookie(
cookie: t.Union[bytes, str, None] = "",
charset: str = "utf-8",
errors: str = "replace",
cls: t.Optional[t.Type["ds.MultiDict"]] = None,
) -> "ds.MultiDict[str, str]":
"""Parse a cookie from a string.
The same key can be provided multiple times, the values are stored
in-order. The default :class:`MultiDict` will have the first value
first, and all values can be retrieved with
:meth:`MultiDict.getlist`.
:param cookie: The cookie header as a string.
:param charset: The charset for the cookie values.
:param errors: The error behavior for the charset decoding.
:param cls: A dict-like class to store the parsed cookies in.
Defaults to :class:`MultiDict`.
.. versionadded:: 2.2
"""
# PEP 3333 sends headers through the environ as latin1 decoded
# strings. Encode strings back to bytes for parsing.
if isinstance(cookie, str):
cookie = cookie.encode("latin1", "replace")
if cls is None:
cls = ds.MultiDict
def _parse_pairs() -> t.Iterator[t.Tuple[str, str]]:
for key, val in _cookie_parse_impl(cookie): # type: ignore
key_str = _to_str(key, charset, errors, allow_none_charset=True)
if not key_str:
continue
val_str = _to_str(val, charset, errors, allow_none_charset=True)
yield key_str, val_str
return cls(_parse_pairs())
# circular dependencies
from .. import datastructures as ds