484 lines
17 KiB
Python
484 lines
17 KiB
Python
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from __future__ import annotations
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import typing
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from collections import OrderedDict
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from enum import Enum, auto
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from threading import RLock
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if typing.TYPE_CHECKING:
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# We can only import Protocol if TYPE_CHECKING because it's a development
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# dependency, and is not available at runtime.
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from typing import Protocol
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from typing_extensions import Self
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class HasGettableStringKeys(Protocol):
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def keys(self) -> typing.Iterator[str]:
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...
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def __getitem__(self, key: str) -> str:
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...
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__all__ = ["RecentlyUsedContainer", "HTTPHeaderDict"]
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# Key type
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_KT = typing.TypeVar("_KT")
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# Value type
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_VT = typing.TypeVar("_VT")
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# Default type
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_DT = typing.TypeVar("_DT")
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ValidHTTPHeaderSource = typing.Union[
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"HTTPHeaderDict",
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typing.Mapping[str, str],
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typing.Iterable[typing.Tuple[str, str]],
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"HasGettableStringKeys",
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]
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class _Sentinel(Enum):
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not_passed = auto()
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def ensure_can_construct_http_header_dict(
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potential: object,
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) -> ValidHTTPHeaderSource | None:
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if isinstance(potential, HTTPHeaderDict):
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return potential
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elif isinstance(potential, typing.Mapping):
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# Full runtime checking of the contents of a Mapping is expensive, so for the
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# purposes of typechecking, we assume that any Mapping is the right shape.
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return typing.cast(typing.Mapping[str, str], potential)
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elif isinstance(potential, typing.Iterable):
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# Similarly to Mapping, full runtime checking of the contents of an Iterable is
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# expensive, so for the purposes of typechecking, we assume that any Iterable
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# is the right shape.
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return typing.cast(typing.Iterable[typing.Tuple[str, str]], potential)
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elif hasattr(potential, "keys") and hasattr(potential, "__getitem__"):
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return typing.cast("HasGettableStringKeys", potential)
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else:
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return None
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class RecentlyUsedContainer(typing.Generic[_KT, _VT], typing.MutableMapping[_KT, _VT]):
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"""
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Provides a thread-safe dict-like container which maintains up to
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``maxsize`` keys while throwing away the least-recently-used keys beyond
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``maxsize``.
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:param maxsize:
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Maximum number of recent elements to retain.
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:param dispose_func:
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Every time an item is evicted from the container,
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``dispose_func(value)`` is called. Callback which will get called
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"""
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_container: typing.OrderedDict[_KT, _VT]
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_maxsize: int
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dispose_func: typing.Callable[[_VT], None] | None
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lock: RLock
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def __init__(
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self,
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maxsize: int = 10,
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dispose_func: typing.Callable[[_VT], None] | None = None,
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) -> None:
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super().__init__()
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self._maxsize = maxsize
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self.dispose_func = dispose_func
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self._container = OrderedDict()
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self.lock = RLock()
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def __getitem__(self, key: _KT) -> _VT:
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# Re-insert the item, moving it to the end of the eviction line.
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with self.lock:
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item = self._container.pop(key)
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self._container[key] = item
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return item
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def __setitem__(self, key: _KT, value: _VT) -> None:
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evicted_item = None
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with self.lock:
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# Possibly evict the existing value of 'key'
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try:
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# If the key exists, we'll overwrite it, which won't change the
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# size of the pool. Because accessing a key should move it to
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# the end of the eviction line, we pop it out first.
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evicted_item = key, self._container.pop(key)
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self._container[key] = value
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except KeyError:
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# When the key does not exist, we insert the value first so that
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# evicting works in all cases, including when self._maxsize is 0
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self._container[key] = value
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if len(self._container) > self._maxsize:
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# If we didn't evict an existing value, and we've hit our maximum
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# size, then we have to evict the least recently used item from
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# the beginning of the container.
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evicted_item = self._container.popitem(last=False)
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# After releasing the lock on the pool, dispose of any evicted value.
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if evicted_item is not None and self.dispose_func:
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_, evicted_value = evicted_item
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self.dispose_func(evicted_value)
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def __delitem__(self, key: _KT) -> None:
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with self.lock:
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value = self._container.pop(key)
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if self.dispose_func:
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self.dispose_func(value)
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def __len__(self) -> int:
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with self.lock:
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return len(self._container)
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def __iter__(self) -> typing.NoReturn:
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raise NotImplementedError(
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"Iteration over this class is unlikely to be threadsafe."
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)
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def clear(self) -> None:
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with self.lock:
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# Copy pointers to all values, then wipe the mapping
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values = list(self._container.values())
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self._container.clear()
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if self.dispose_func:
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for value in values:
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self.dispose_func(value)
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def keys(self) -> set[_KT]: # type: ignore[override]
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with self.lock:
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return set(self._container.keys())
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class HTTPHeaderDictItemView(typing.Set[typing.Tuple[str, str]]):
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"""
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HTTPHeaderDict is unusual for a Mapping[str, str] in that it has two modes of
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address.
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If we directly try to get an item with a particular name, we will get a string
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back that is the concatenated version of all the values:
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>>> d['X-Header-Name']
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'Value1, Value2, Value3'
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However, if we iterate over an HTTPHeaderDict's items, we will optionally combine
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these values based on whether combine=True was called when building up the dictionary
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>>> d = HTTPHeaderDict({"A": "1", "B": "foo"})
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>>> d.add("A", "2", combine=True)
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>>> d.add("B", "bar")
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>>> list(d.items())
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[
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('A', '1, 2'),
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('B', 'foo'),
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('B', 'bar'),
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]
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This class conforms to the interface required by the MutableMapping ABC while
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also giving us the nonstandard iteration behavior we want; items with duplicate
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keys, ordered by time of first insertion.
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"""
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_headers: HTTPHeaderDict
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def __init__(self, headers: HTTPHeaderDict) -> None:
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self._headers = headers
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def __len__(self) -> int:
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return len(list(self._headers.iteritems()))
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def __iter__(self) -> typing.Iterator[tuple[str, str]]:
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return self._headers.iteritems()
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def __contains__(self, item: object) -> bool:
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if isinstance(item, tuple) and len(item) == 2:
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passed_key, passed_val = item
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if isinstance(passed_key, str) and isinstance(passed_val, str):
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return self._headers._has_value_for_header(passed_key, passed_val)
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return False
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class HTTPHeaderDict(typing.MutableMapping[str, str]):
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"""
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:param headers:
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An iterable of field-value pairs. Must not contain multiple field names
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when compared case-insensitively.
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:param kwargs:
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Additional field-value pairs to pass in to ``dict.update``.
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A ``dict`` like container for storing HTTP Headers.
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Field names are stored and compared case-insensitively in compliance with
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RFC 7230. Iteration provides the first case-sensitive key seen for each
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case-insensitive pair.
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Using ``__setitem__`` syntax overwrites fields that compare equal
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case-insensitively in order to maintain ``dict``'s api. For fields that
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compare equal, instead create a new ``HTTPHeaderDict`` and use ``.add``
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in a loop.
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If multiple fields that are equal case-insensitively are passed to the
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constructor or ``.update``, the behavior is undefined and some will be
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lost.
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>>> headers = HTTPHeaderDict()
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>>> headers.add('Set-Cookie', 'foo=bar')
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>>> headers.add('set-cookie', 'baz=quxx')
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>>> headers['content-length'] = '7'
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>>> headers['SET-cookie']
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'foo=bar, baz=quxx'
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>>> headers['Content-Length']
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'7'
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"""
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_container: typing.MutableMapping[str, list[str]]
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def __init__(self, headers: ValidHTTPHeaderSource | None = None, **kwargs: str):
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super().__init__()
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self._container = {} # 'dict' is insert-ordered
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if headers is not None:
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if isinstance(headers, HTTPHeaderDict):
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self._copy_from(headers)
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else:
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self.extend(headers)
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if kwargs:
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self.extend(kwargs)
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def __setitem__(self, key: str, val: str) -> None:
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# avoid a bytes/str comparison by decoding before httplib
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if isinstance(key, bytes):
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key = key.decode("latin-1")
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self._container[key.lower()] = [key, val]
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def __getitem__(self, key: str) -> str:
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val = self._container[key.lower()]
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return ", ".join(val[1:])
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def __delitem__(self, key: str) -> None:
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del self._container[key.lower()]
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def __contains__(self, key: object) -> bool:
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if isinstance(key, str):
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return key.lower() in self._container
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return False
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def setdefault(self, key: str, default: str = "") -> str:
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return super().setdefault(key, default)
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def __eq__(self, other: object) -> bool:
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maybe_constructable = ensure_can_construct_http_header_dict(other)
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if maybe_constructable is None:
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return False
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else:
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other_as_http_header_dict = type(self)(maybe_constructable)
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return {k.lower(): v for k, v in self.itermerged()} == {
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k.lower(): v for k, v in other_as_http_header_dict.itermerged()
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}
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def __ne__(self, other: object) -> bool:
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return not self.__eq__(other)
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def __len__(self) -> int:
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return len(self._container)
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def __iter__(self) -> typing.Iterator[str]:
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# Only provide the originally cased names
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for vals in self._container.values():
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yield vals[0]
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def discard(self, key: str) -> None:
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try:
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del self[key]
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except KeyError:
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pass
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def add(self, key: str, val: str, *, combine: bool = False) -> None:
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"""Adds a (name, value) pair, doesn't overwrite the value if it already
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exists.
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If this is called with combine=True, instead of adding a new header value
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as a distinct item during iteration, this will instead append the value to
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any existing header value with a comma. If no existing header value exists
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for the key, then the value will simply be added, ignoring the combine parameter.
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>>> headers = HTTPHeaderDict(foo='bar')
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>>> headers.add('Foo', 'baz')
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>>> headers['foo']
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'bar, baz'
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>>> list(headers.items())
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[('foo', 'bar'), ('foo', 'baz')]
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>>> headers.add('foo', 'quz', combine=True)
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>>> list(headers.items())
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[('foo', 'bar, baz, quz')]
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"""
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# avoid a bytes/str comparison by decoding before httplib
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if isinstance(key, bytes):
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key = key.decode("latin-1")
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key_lower = key.lower()
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new_vals = [key, val]
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# Keep the common case aka no item present as fast as possible
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vals = self._container.setdefault(key_lower, new_vals)
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if new_vals is not vals:
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# if there are values here, then there is at least the initial
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# key/value pair
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assert len(vals) >= 2
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if combine:
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vals[-1] = vals[-1] + ", " + val
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else:
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vals.append(val)
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def extend(self, *args: ValidHTTPHeaderSource, **kwargs: str) -> None:
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"""Generic import function for any type of header-like object.
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Adapted version of MutableMapping.update in order to insert items
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with self.add instead of self.__setitem__
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"""
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if len(args) > 1:
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raise TypeError(
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f"extend() takes at most 1 positional arguments ({len(args)} given)"
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)
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other = args[0] if len(args) >= 1 else ()
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if isinstance(other, HTTPHeaderDict):
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for key, val in other.iteritems():
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self.add(key, val)
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elif isinstance(other, typing.Mapping):
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for key, val in other.items():
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self.add(key, val)
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elif isinstance(other, typing.Iterable):
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other = typing.cast(typing.Iterable[typing.Tuple[str, str]], other)
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for key, value in other:
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self.add(key, value)
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elif hasattr(other, "keys") and hasattr(other, "__getitem__"):
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# THIS IS NOT A TYPESAFE BRANCH
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# In this branch, the object has a `keys` attr but is not a Mapping or any of
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# the other types indicated in the method signature. We do some stuff with
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# it as though it partially implements the Mapping interface, but we're not
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# doing that stuff safely AT ALL.
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for key in other.keys():
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self.add(key, other[key])
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for key, value in kwargs.items():
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self.add(key, value)
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@typing.overload
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def getlist(self, key: str) -> list[str]:
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...
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@typing.overload
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def getlist(self, key: str, default: _DT) -> list[str] | _DT:
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...
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def getlist(
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self, key: str, default: _Sentinel | _DT = _Sentinel.not_passed
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) -> list[str] | _DT:
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"""Returns a list of all the values for the named field. Returns an
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empty list if the key doesn't exist."""
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try:
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vals = self._container[key.lower()]
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except KeyError:
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if default is _Sentinel.not_passed:
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# _DT is unbound; empty list is instance of List[str]
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return []
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# _DT is bound; default is instance of _DT
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return default
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else:
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# _DT may or may not be bound; vals[1:] is instance of List[str], which
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# meets our external interface requirement of `Union[List[str], _DT]`.
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return vals[1:]
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def _prepare_for_method_change(self) -> Self:
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"""
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Remove content-specific header fields before changing the request
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method to GET or HEAD according to RFC 9110, Section 15.4.
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"""
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content_specific_headers = [
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"Content-Encoding",
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"Content-Language",
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"Content-Location",
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"Content-Type",
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"Content-Length",
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"Digest",
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"Last-Modified",
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]
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for header in content_specific_headers:
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self.discard(header)
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return self
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# Backwards compatibility for httplib
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getheaders = getlist
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getallmatchingheaders = getlist
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iget = getlist
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# Backwards compatibility for http.cookiejar
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get_all = getlist
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def __repr__(self) -> str:
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return f"{type(self).__name__}({dict(self.itermerged())})"
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def _copy_from(self, other: HTTPHeaderDict) -> None:
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for key in other:
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val = other.getlist(key)
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self._container[key.lower()] = [key, *val]
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def copy(self) -> HTTPHeaderDict:
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clone = type(self)()
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clone._copy_from(self)
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return clone
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def iteritems(self) -> typing.Iterator[tuple[str, str]]:
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"""Iterate over all header lines, including duplicate ones."""
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for key in self:
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|
vals = self._container[key.lower()]
|
||
|
for val in vals[1:]:
|
||
|
yield vals[0], val
|
||
|
|
||
|
def itermerged(self) -> typing.Iterator[tuple[str, str]]:
|
||
|
"""Iterate over all headers, merging duplicate ones together."""
|
||
|
for key in self:
|
||
|
val = self._container[key.lower()]
|
||
|
yield val[0], ", ".join(val[1:])
|
||
|
|
||
|
def items(self) -> HTTPHeaderDictItemView: # type: ignore[override]
|
||
|
return HTTPHeaderDictItemView(self)
|
||
|
|
||
|
def _has_value_for_header(self, header_name: str, potential_value: str) -> bool:
|
||
|
if header_name in self:
|
||
|
return potential_value in self._container[header_name.lower()][1:]
|
||
|
return False
|
||
|
|
||
|
def __ior__(self, other: object) -> HTTPHeaderDict:
|
||
|
# Supports extending a header dict in-place using operator |=
|
||
|
# combining items with add instead of __setitem__
|
||
|
maybe_constructable = ensure_can_construct_http_header_dict(other)
|
||
|
if maybe_constructable is None:
|
||
|
return NotImplemented
|
||
|
self.extend(maybe_constructable)
|
||
|
return self
|
||
|
|
||
|
def __or__(self, other: object) -> HTTPHeaderDict:
|
||
|
# Supports merging header dicts using operator |
|
||
|
# combining items with add instead of __setitem__
|
||
|
maybe_constructable = ensure_can_construct_http_header_dict(other)
|
||
|
if maybe_constructable is None:
|
||
|
return NotImplemented
|
||
|
result = self.copy()
|
||
|
result.extend(maybe_constructable)
|
||
|
return result
|
||
|
|
||
|
def __ror__(self, other: object) -> HTTPHeaderDict:
|
||
|
# Supports merging header dicts using operator | when other is on left side
|
||
|
# combining items with add instead of __setitem__
|
||
|
maybe_constructable = ensure_can_construct_http_header_dict(other)
|
||
|
if maybe_constructable is None:
|
||
|
return NotImplemented
|
||
|
result = type(self)(maybe_constructable)
|
||
|
result.extend(self)
|
||
|
return result
|