141 lines
5.0 KiB
Python
141 lines
5.0 KiB
Python
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import re
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import typing as t
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from datetime import datetime
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from .._internal import _cookie_parse_impl
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from .._internal import _dt_as_utc
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from .._internal import _to_str
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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: t.Optional[str] = None,
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http_if_range: t.Optional[str] = None,
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http_if_modified_since: t.Optional[str] = None,
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http_if_none_match: t.Optional[str] = None,
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http_if_match: t.Optional[str] = None,
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etag: t.Optional[str] = None,
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data: t.Optional[bytes] = None,
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last_modified: t.Optional[t.Union[datetime, str]] = 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: t.Optional[datetime] = 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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def parse_cookie(
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cookie: t.Union[bytes, str, None] = "",
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charset: str = "utf-8",
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errors: str = "replace",
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cls: t.Optional[t.Type["ds.MultiDict"]] = 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 charset: The charset for the cookie values.
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:param errors: The error behavior for the charset decoding.
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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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.. versionadded:: 2.2
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"""
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# PEP 3333 sends headers through the environ as latin1 decoded
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# strings. Encode strings back to bytes for parsing.
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if isinstance(cookie, str):
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cookie = cookie.encode("latin1", "replace")
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if cls is None:
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cls = ds.MultiDict
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def _parse_pairs() -> t.Iterator[t.Tuple[str, str]]:
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for key, val in _cookie_parse_impl(cookie): # type: ignore
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key_str = _to_str(key, charset, errors, allow_none_charset=True)
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if not key_str:
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continue
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val_str = _to_str(val, charset, errors, allow_none_charset=True)
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yield key_str, val_str
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return cls(_parse_pairs())
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# circular dependencies
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from .. import datastructures as ds
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