scrapy/scrapy/http/headers.py

140 lines
4.3 KiB
Python

from __future__ import annotations
from collections.abc import Mapping
from typing import (
TYPE_CHECKING,
Any,
AnyStr,
Dict,
Iterable,
List,
Optional,
Tuple,
Union,
cast,
)
from w3lib.http import headers_dict_to_raw
from scrapy.utils.datatypes import CaseInsensitiveDict, CaselessDict
from scrapy.utils.python import to_unicode
if TYPE_CHECKING:
# typing.Self requires Python 3.11
from typing_extensions import Self
_RawValueT = Union[bytes, str, int]
# isn't fully compatible typing-wise with either dict or CaselessDict,
# but it needs refactoring anyway, see also https://github.com/scrapy/scrapy/pull/5146
class Headers(CaselessDict):
"""Case insensitive http headers dictionary"""
def __init__(
self,
seq: Union[Mapping[AnyStr, Any], Iterable[Tuple[AnyStr, Any]], None] = None,
encoding: str = "utf-8",
):
self.encoding: str = encoding
super().__init__(seq)
def update( # type: ignore[override]
self, seq: Union[Mapping[AnyStr, Any], Iterable[Tuple[AnyStr, Any]]]
) -> None:
seq = seq.items() if isinstance(seq, Mapping) else seq
iseq: Dict[bytes, List[bytes]] = {}
for k, v in seq:
iseq.setdefault(self.normkey(k), []).extend(self.normvalue(v))
super().update(iseq)
def normkey(self, key: AnyStr) -> bytes: # type: ignore[override]
"""Normalize key to bytes"""
return self._tobytes(key.title())
def normvalue(self, value: Union[_RawValueT, Iterable[_RawValueT]]) -> List[bytes]:
"""Normalize values to bytes"""
_value: Iterable[_RawValueT]
if value is None:
_value = []
elif isinstance(value, (str, bytes)):
_value = [value]
elif hasattr(value, "__iter__"):
_value = value
else:
_value = [value]
return [self._tobytes(x) for x in _value]
def _tobytes(self, x: _RawValueT) -> bytes:
if isinstance(x, bytes):
return x
if isinstance(x, str):
return x.encode(self.encoding)
if isinstance(x, int):
return str(x).encode(self.encoding)
raise TypeError(f"Unsupported value type: {type(x)}")
def __getitem__(self, key: AnyStr) -> Optional[bytes]:
try:
return cast(List[bytes], super().__getitem__(key))[-1]
except IndexError:
return None
def get(self, key: AnyStr, def_val: Any = None) -> Optional[bytes]:
try:
return cast(List[bytes], super().get(key, def_val))[-1]
except IndexError:
return None
def getlist(self, key: AnyStr, def_val: Any = None) -> List[bytes]:
try:
return cast(List[bytes], super().__getitem__(key))
except KeyError:
if def_val is not None:
return self.normvalue(def_val)
return []
def setlist(self, key: AnyStr, list_: Iterable[_RawValueT]) -> None:
self[key] = list_
def setlistdefault(
self, key: AnyStr, default_list: Iterable[_RawValueT] = ()
) -> Any:
return self.setdefault(key, default_list)
def appendlist(self, key: AnyStr, value: Iterable[_RawValueT]) -> None:
lst = self.getlist(key)
lst.extend(self.normvalue(value))
self[key] = lst
def items(self) -> Iterable[Tuple[bytes, List[bytes]]]: # type: ignore[override]
return ((k, self.getlist(k)) for k in self.keys())
def values(self) -> List[Optional[bytes]]: # type: ignore[override]
return [
self[k] for k in self.keys() # pylint: disable=consider-using-dict-items
]
def to_string(self) -> bytes:
# cast() can be removed if the headers_dict_to_raw() hint is improved
return cast(bytes, headers_dict_to_raw(self))
def to_unicode_dict(self) -> CaseInsensitiveDict:
"""Return headers as a CaseInsensitiveDict with str keys
and str values. Multiple values are joined with ','.
"""
return CaseInsensitiveDict(
(
to_unicode(key, encoding=self.encoding),
to_unicode(b",".join(value), encoding=self.encoding),
)
for key, value in self.items()
)
def __copy__(self) -> Self:
return self.__class__(self)
copy = __copy__