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from __future__ import annotations
import io
import typing
from base64 import b64encode
from enum import Enum
from ..exceptions import UnrewindableBodyError
from .util import to_bytes
if typing.TYPE_CHECKING:
from typing import Final
# Pass as a value within ``headers`` to skip
# emitting some HTTP headers that are added automatically.
# The only headers that are supported are ``Accept-Encoding``,
# ``Host``, and ``User-Agent``.
SKIP_HEADER = "@@@SKIP_HEADER@@@"
SKIPPABLE_HEADERS = frozenset(["accept-encoding", "host", "user-agent"])
ACCEPT_ENCODING = "gzip,deflate"
try:
try:
import brotlicffi as _unused_module_brotli # type: ignore[import-not-found] # noqa: F401
except ImportError:
import brotli as _unused_module_brotli # type: ignore[import-not-found] # noqa: F401
except ImportError:
pass
else:
ACCEPT_ENCODING += ",br"
try:
import zstandard as _unused_module_zstd # noqa: F401
except ImportError:
pass
else:
ACCEPT_ENCODING += ",zstd"
class _TYPE_FAILEDTELL(Enum):
token = 0
_FAILEDTELL: Final[_TYPE_FAILEDTELL] = _TYPE_FAILEDTELL.token
_TYPE_BODY_POSITION = typing.Union[int, _TYPE_FAILEDTELL]
# When sending a request with these methods we aren't expecting
# a body so don't need to set an explicit 'Content-Length: 0'
# The reason we do this in the negative instead of tracking methods
# which 'should' have a body is because unknown methods should be
# treated as if they were 'POST' which *does* expect a body.
_METHODS_NOT_EXPECTING_BODY = {"GET", "HEAD", "DELETE", "TRACE", "OPTIONS", "CONNECT"}
def make_headers(
keep_alive: bool | None = None,
accept_encoding: bool | list[str] | str | None = None,
user_agent: str | None = None,
basic_auth: str | None = None,
proxy_basic_auth: str | None = None,
disable_cache: bool | None = None,
) -> dict[str, str]:
"""
Shortcuts for generating request headers.
:param keep_alive:
If ``True``, adds 'connection: keep-alive' header.
:param accept_encoding:
Can be a boolean, list, or string.
``True`` translates to 'gzip,deflate'. If the dependencies for
Brotli (either the ``brotli`` or ``brotlicffi`` package) and/or Zstandard
(the ``zstandard`` package) algorithms are installed, then their encodings are
included in the string ('br' and 'zstd', respectively).
List will get joined by comma.
String will be used as provided.
:param user_agent:
String representing the user-agent you want, such as
"python-urllib3/0.6"
:param basic_auth:
Colon-separated username:password string for 'authorization: basic ...'
auth header.
:param proxy_basic_auth:
Colon-separated username:password string for 'proxy-authorization: basic ...'
auth header.
:param disable_cache:
If ``True``, adds 'cache-control: no-cache' header.
Example:
.. code-block:: python
import urllib3
print(urllib3.util.make_headers(keep_alive=True, user_agent="Batman/1.0"))
# {'connection': 'keep-alive', 'user-agent': 'Batman/1.0'}
print(urllib3.util.make_headers(accept_encoding=True))
# {'accept-encoding': 'gzip,deflate'}
"""
headers: dict[str, str] = {}
if accept_encoding:
if isinstance(accept_encoding, str):
pass
elif isinstance(accept_encoding, list):
accept_encoding = ",".join(accept_encoding)
else:
accept_encoding = ACCEPT_ENCODING
headers["accept-encoding"] = accept_encoding
if user_agent:
headers["user-agent"] = user_agent
if keep_alive:
headers["connection"] = "keep-alive"
if basic_auth:
headers["authorization"] = (
f"Basic {b64encode(basic_auth.encode('latin-1')).decode()}"
)
if proxy_basic_auth:
headers["proxy-authorization"] = (
f"Basic {b64encode(proxy_basic_auth.encode('latin-1')).decode()}"
)
if disable_cache:
headers["cache-control"] = "no-cache"
return headers
def set_file_position(
body: typing.Any, pos: _TYPE_BODY_POSITION | None
) -> _TYPE_BODY_POSITION | None:
"""
If a position is provided, move file to that point.
Otherwise, we'll attempt to record a position for future use.
"""
if pos is not None:
rewind_body(body, pos)
elif getattr(body, "tell", None) is not None:
try:
pos = body.tell()
except OSError:
# This differentiates from None, allowing us to catch
# a failed `tell()` later when trying to rewind the body.
pos = _FAILEDTELL
return pos
def rewind_body(body: typing.IO[typing.AnyStr], body_pos: _TYPE_BODY_POSITION) -> None:
"""
Attempt to rewind body to a certain position.
Primarily used for request redirects and retries.
:param body:
File-like object that supports seek.
:param int pos:
Position to seek to in file.
"""
body_seek = getattr(body, "seek", None)
if body_seek is not None and isinstance(body_pos, int):
try:
body_seek(body_pos)
except OSError as e:
raise UnrewindableBodyError(
"An error occurred when rewinding request body for redirect/retry."
) from e
elif body_pos is _FAILEDTELL:
raise UnrewindableBodyError(
"Unable to record file position for rewinding "
"request body during a redirect/retry."
)
else:
raise ValueError(
f"body_pos must be of type integer, instead it was {type(body_pos)}."
)
class ChunksAndContentLength(typing.NamedTuple):
chunks: typing.Iterable[bytes] | None
content_length: int | None
def body_to_chunks(
body: typing.Any | None, method: str, blocksize: int
) -> ChunksAndContentLength:
"""Takes the HTTP request method, body, and blocksize and
transforms them into an iterable of chunks to pass to
socket.sendall() and an optional 'Content-Length' header.
A 'Content-Length' of 'None' indicates the length of the body
can't be determined so should use 'Transfer-Encoding: chunked'
for framing instead.
"""
chunks: typing.Iterable[bytes] | None
content_length: int | None
# No body, we need to make a recommendation on 'Content-Length'
# based on whether that request method is expected to have
# a body or not.
if body is None:
chunks = None
if method.upper() not in _METHODS_NOT_EXPECTING_BODY:
content_length = 0
else:
content_length = None
# Bytes or strings become bytes
elif isinstance(body, (str, bytes)):
chunks = (to_bytes(body),)
content_length = len(chunks[0])
# File-like object, TODO: use seek() and tell() for length?
elif hasattr(body, "read"):
def chunk_readable() -> typing.Iterable[bytes]:
nonlocal body, blocksize
encode = isinstance(body, io.TextIOBase)
while True:
datablock = body.read(blocksize)
if not datablock:
break
if encode:
datablock = datablock.encode("utf-8")
yield datablock
chunks = chunk_readable()
content_length = None
# Otherwise we need to start checking via duck-typing.
else:
try:
# Check if the body implements the buffer API.
mv = memoryview(body)
except TypeError:
try:
# Check if the body is an iterable
chunks = iter(body)
content_length = None
except TypeError:
raise TypeError(
f"'body' must be a bytes-like object, file-like "
f"object, or iterable. Instead was {body!r}"
) from None
else:
# Since it implements the buffer API can be passed directly to socket.sendall()
chunks = (body,)
content_length = mv.nbytes
return ChunksAndContentLength(chunks=chunks, content_length=content_length)
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