from __future__ import annotations
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import re
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import typing as t
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import warnings
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from datetime import datetime
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from .._internal import _dt_as_utc
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from ..http import generate_etag
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from ..http import parse_date
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from ..http import parse_etags
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from ..http import parse_if_range_header
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from ..http import unquote_etag
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_etag_re = re.compile(r'([Ww]/)?(?:"(.*?)"|(.*?))(?:\s*,\s*|$)')
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def is_resource_modified(
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http_range: str | None = None,
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http_if_range: str | None = None,
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http_if_modified_since: str | None = None,
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http_if_none_match: str | None = None,
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http_if_match: str | None = None,
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etag: str | None = None,
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data: bytes | None = None,
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last_modified: datetime | str | None = None,
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ignore_if_range: bool = True,
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) -> bool:
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"""Convenience method for conditional requests.
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:param http_range: Range HTTP header
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:param http_if_range: If-Range HTTP header
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:param http_if_modified_since: If-Modified-Since HTTP header
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:param http_if_none_match: If-None-Match HTTP header
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:param http_if_match: If-Match HTTP header
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:param etag: the etag for the response for comparison.
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:param data: or alternatively the data of the response to automatically
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generate an etag using :func:`generate_etag`.
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:param last_modified: an optional date of the last modification.
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:param ignore_if_range: If `False`, `If-Range` header will be taken into
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account.
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:return: `True` if the resource was modified, otherwise `False`.
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.. versionadded:: 2.2
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"""
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if etag is None and data is not None:
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etag = generate_etag(data)
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elif data is not None:
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raise TypeError("both data and etag given")
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unmodified = False
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if isinstance(last_modified, str):
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last_modified = parse_date(last_modified)
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# HTTP doesn't use microsecond, remove it to avoid false positive
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# comparisons. Mark naive datetimes as UTC.
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if last_modified is not None:
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last_modified = _dt_as_utc(last_modified.replace(microsecond=0))
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if_range = None
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if not ignore_if_range and http_range is not None:
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# https://tools.ietf.org/html/rfc7233#section-3.2
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# A server MUST ignore an If-Range header field received in a request
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# that does not contain a Range header field.
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if_range = parse_if_range_header(http_if_range)
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if if_range is not None and if_range.date is not None:
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modified_since: datetime | None = if_range.date
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else:
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modified_since = parse_date(http_if_modified_since)
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if modified_since and last_modified and last_modified <= modified_since:
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unmodified = True
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if etag:
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etag, _ = unquote_etag(etag)
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etag = t.cast(str, etag)
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if if_range is not None and if_range.etag is not None:
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unmodified = parse_etags(if_range.etag).contains(etag)
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else:
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if_none_match = parse_etags(http_if_none_match)
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if if_none_match:
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# https://tools.ietf.org/html/rfc7232#section-3.2
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# "A recipient MUST use the weak comparison function when comparing
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# entity-tags for If-None-Match"
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unmodified = if_none_match.contains_weak(etag)
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# https://tools.ietf.org/html/rfc7232#section-3.1
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# "Origin server MUST use the strong comparison function when
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# comparing entity-tags for If-Match"
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if_match = parse_etags(http_if_match)
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if if_match:
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unmodified = not if_match.is_strong(etag)
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return not unmodified
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_cookie_re = re.compile(
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r"""
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([^=;]*)
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(?:\s*=\s*
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(
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"(?:[^\\"]|\\.)*"
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.*?
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)
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)?
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\s*;\s*
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""",
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flags=re.ASCII | re.VERBOSE,
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)
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_cookie_unslash_re = re.compile(rb"\\([0-3][0-7]{2}|.)")
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def _cookie_unslash_replace(m: t.Match[bytes]) -> bytes:
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v = m.group(1)
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if len(v) == 1:
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return v
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return int(v, 8).to_bytes(1, "big")
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def parse_cookie(
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cookie: str | None = None,
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charset: str | None = None,
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errors: str | None = None,
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cls: type[ds.MultiDict] | None = None,
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) -> ds.MultiDict[str, str]:
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"""Parse a cookie from a string.
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The same key can be provided multiple times, the values are stored
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in-order. The default :class:`MultiDict` will have the first value
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first, and all values can be retrieved with
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:meth:`MultiDict.getlist`.
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:param cookie: The cookie header as a string.
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:param cls: A dict-like class to store the parsed cookies in.
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Defaults to :class:`MultiDict`.
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.. versionchanged:: 2.3
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Passing bytes, and the ``charset`` and ``errors`` parameters, are deprecated and
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will be removed in Werkzeug 3.0.
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.. versionadded:: 2.2
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"""
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if cls is None:
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cls = ds.MultiDict
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if isinstance(cookie, bytes):
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warnings.warn(
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"The 'cookie' parameter must be a string. Passing bytes is deprecated and"
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" will not be supported in Werkzeug 3.0.",
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DeprecationWarning,
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stacklevel=2,
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)
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cookie = cookie.decode()
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if charset is not None:
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warnings.warn(
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"The 'charset' parameter is deprecated and will be removed in Werkzeug 3.0",
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DeprecationWarning,
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stacklevel=2,
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)
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else:
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charset = "utf-8"
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if errors is not None:
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warnings.warn(
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"The 'errors' parameter is deprecated and will be removed in Werkzeug 3.0",
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DeprecationWarning,
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stacklevel=2,
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)
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else:
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errors = "replace"
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if not cookie:
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return cls()
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cookie = f"{cookie};"
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out = []
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for ck, cv in _cookie_re.findall(cookie):
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ck = ck.strip()
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cv = cv.strip()
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if not ck:
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continue
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if len(cv) >= 2 and cv[0] == cv[-1] == '"':
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# Work with bytes here, since a UTF-8 character could be multiple bytes.
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cv = _cookie_unslash_re.sub(
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_cookie_unslash_replace, cv[1:-1].encode()
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).decode(charset, errors)
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out.append((ck, cv))
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return cls(out)
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# circular dependencies
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from .. import datastructures as ds
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