"""Various helper functions"""
import asyncio
import base64
import binascii
import contextlib
import datetime
import enum
import functools
import inspect
import netrc
import os
import platform
import re
import sys
import time
import weakref
from collections import namedtuple
from contextlib import suppress
from email.parser import HeaderParser
from email.utils import parsedate
from math import ceil
from pathlib import Path
from types import TracebackType
from typing import (
Any,
Callable,
ContextManager,
Dict,
Generator,
Generic,
Iterable,
Iterator,
List,
Mapping,
Optional,
Protocol,
Tuple,
Type,
TypeVar,
Union,
get_args,
overload,
)
from urllib.parse import quote
from urllib.request import getproxies, proxy_bypass
import attr
from multidict import MultiDict, MultiDictProxy, MultiMapping
from propcache.api import under_cached_property as reify
from yarl import URL
from . import hdrs
from .log import client_logger
if sys.version_info >= (3, 11):
import asyncio as async_timeout
else:
import async_timeout
__all__ = ("BasicAuth", "ChainMapProxy", "ETag", "reify")
IS_MACOS = platform.system() == "Darwin"
IS_WINDOWS = platform.system() == "Windows"
PY_310 = sys.version_info >= (3, 10)
PY_311 = sys.version_info >= (3, 11)
_T = TypeVar("_T")
_S = TypeVar("_S")
_SENTINEL = enum.Enum("_SENTINEL", "sentinel")
sentinel = _SENTINEL.sentinel
NO_EXTENSIONS = bool(os.environ.get("AIOHTTP_NO_EXTENSIONS"))
# https://datatracker.ietf.org/doc/html/rfc9112#section-6.3-2.1
EMPTY_BODY_STATUS_CODES = frozenset((204, 304, *range(100, 200)))
# https://datatracker.ietf.org/doc/html/rfc9112#section-6.3-2.1
# https://datatracker.ietf.org/doc/html/rfc9112#section-6.3-2.2
EMPTY_BODY_METHODS = hdrs.METH_HEAD_ALL
DEBUG = sys.flags.dev_mode or (
not sys.flags.ignore_environment and bool(os.environ.get("PYTHONASYNCIODEBUG"))
)
CHAR = {chr(i) for i in range(0, 128)}
CTL = {chr(i) for i in range(0, 32)} | {
chr(127),
}
SEPARATORS = {
"(",
")",
"<",
">",
"@",
",",
";",
":",
"\\",
'"',
"/",
"[",
"]",
"?",
"=",
"{",
"}",
" ",
chr(9),
}
TOKEN = CHAR ^ CTL ^ SEPARATORS
class noop:
def __await__(self) -> Generator[None, None, None]:
yield
[docs]
class BasicAuth(namedtuple("BasicAuth", ["login", "password", "encoding"])):
"""Http basic authentication helper."""
def __new__(
cls, login: str, password: str = "", encoding: str = "latin1"
) -> "BasicAuth":
if login is None:
raise ValueError("None is not allowed as login value")
if password is None:
raise ValueError("None is not allowed as password value")
if ":" in login:
raise ValueError('A ":" is not allowed in login (RFC 1945#section-11.1)')
return super().__new__(cls, login, password, encoding)
[docs]
@classmethod
def decode(cls, auth_header: str, encoding: str = "latin1") -> "BasicAuth":
"""Create a BasicAuth object from an Authorization HTTP header."""
try:
auth_type, encoded_credentials = auth_header.split(" ", 1)
except ValueError:
raise ValueError("Could not parse authorization header.")
if auth_type.lower() != "basic":
raise ValueError("Unknown authorization method %s" % auth_type)
try:
decoded = base64.b64decode(
encoded_credentials.encode("ascii"), validate=True
).decode(encoding)
except binascii.Error:
raise ValueError("Invalid base64 encoding.")
try:
# RFC 2617 HTTP Authentication
# https://www.ietf.org/rfc/rfc2617.txt
# the colon must be present, but the username and password may be
# otherwise blank.
username, password = decoded.split(":", 1)
except ValueError:
raise ValueError("Invalid credentials.")
return cls(username, password, encoding=encoding)
[docs]
@classmethod
def from_url(cls, url: URL, *, encoding: str = "latin1") -> Optional["BasicAuth"]:
"""Create BasicAuth from url."""
if not isinstance(url, URL):
raise TypeError("url should be yarl.URL instance")
# Check raw_user and raw_password first as yarl is likely
# to already have these values parsed from the netloc in the cache.
if url.raw_user is None and url.raw_password is None:
return None
return cls(url.user or "", url.password or "", encoding=encoding)
[docs]
def encode(self) -> str:
"""Encode credentials."""
creds = (f"{self.login}:{self.password}").encode(self.encoding)
return "Basic %s" % base64.b64encode(creds).decode(self.encoding)
def strip_auth_from_url(url: URL) -> Tuple[URL, Optional[BasicAuth]]:
"""Remove user and password from URL if present and return BasicAuth object."""
# Check raw_user and raw_password first as yarl is likely
# to already have these values parsed from the netloc in the cache.
if url.raw_user is None and url.raw_password is None:
return url, None
return url.with_user(None), BasicAuth(url.user or "", url.password or "")
def netrc_from_env() -> Optional[netrc.netrc]:
"""Load netrc from file.
Attempt to load it from the path specified by the env-var
NETRC or in the default location in the user's home directory.
Returns None if it couldn't be found or fails to parse.
"""
netrc_env = os.environ.get("NETRC")
if netrc_env is not None:
netrc_path = Path(netrc_env)
else:
try:
home_dir = Path.home()
except RuntimeError as e: # pragma: no cover
# if pathlib can't resolve home, it may raise a RuntimeError
client_logger.debug(
"Could not resolve home directory when "
"trying to look for .netrc file: %s",
e,
)
return None
netrc_path = home_dir / ("_netrc" if IS_WINDOWS else ".netrc")
try:
return netrc.netrc(str(netrc_path))
except netrc.NetrcParseError as e:
client_logger.warning("Could not parse .netrc file: %s", e)
except OSError as e:
netrc_exists = False
with contextlib.suppress(OSError):
netrc_exists = netrc_path.is_file()
# we couldn't read the file (doesn't exist, permissions, etc.)
if netrc_env or netrc_exists:
# only warn if the environment wanted us to load it,
# or it appears like the default file does actually exist
client_logger.warning("Could not read .netrc file: %s", e)
return None
@attr.s(auto_attribs=True, frozen=True, slots=True)
class ProxyInfo:
proxy: URL
proxy_auth: Optional[BasicAuth]
def basicauth_from_netrc(netrc_obj: Optional[netrc.netrc], host: str) -> BasicAuth:
"""
Return :py:class:`~aiohttp.BasicAuth` credentials for ``host`` from ``netrc_obj``.
:raises LookupError: if ``netrc_obj`` is :py:data:`None` or if no
entry is found for the ``host``.
"""
if netrc_obj is None:
raise LookupError("No .netrc file found")
auth_from_netrc = netrc_obj.authenticators(host)
if auth_from_netrc is None:
raise LookupError(f"No entry for {host!s} found in the `.netrc` file.")
login, account, password = auth_from_netrc
# TODO(PY311): username = login or account
# Up to python 3.10, account could be None if not specified,
# and login will be empty string if not specified. From 3.11,
# login and account will be empty string if not specified.
username = login if (login or account is None) else account
# TODO(PY311): Remove this, as password will be empty string
# if not specified
if password is None:
password = ""
return BasicAuth(username, password)
def proxies_from_env() -> Dict[str, ProxyInfo]:
proxy_urls = {
k: URL(v)
for k, v in getproxies().items()
if k in ("http", "https", "ws", "wss")
}
netrc_obj = netrc_from_env()
stripped = {k: strip_auth_from_url(v) for k, v in proxy_urls.items()}
ret = {}
for proto, val in stripped.items():
proxy, auth = val
if proxy.scheme in ("https", "wss"):
client_logger.warning(
"%s proxies %s are not supported, ignoring", proxy.scheme.upper(), proxy
)
continue
if netrc_obj and auth is None:
if proxy.host is not None:
try:
auth = basicauth_from_netrc(netrc_obj, proxy.host)
except LookupError:
auth = None
ret[proto] = ProxyInfo(proxy, auth)
return ret
def get_env_proxy_for_url(url: URL) -> Tuple[URL, Optional[BasicAuth]]:
"""Get a permitted proxy for the given URL from the env."""
if url.host is not None and proxy_bypass(url.host):
raise LookupError(f"Proxying is disallowed for `{url.host!r}`")
proxies_in_env = proxies_from_env()
try:
proxy_info = proxies_in_env[url.scheme]
except KeyError:
raise LookupError(f"No proxies found for `{url!s}` in the env")
else:
return proxy_info.proxy, proxy_info.proxy_auth
@attr.s(auto_attribs=True, frozen=True, slots=True)
class MimeType:
type: str
subtype: str
suffix: str
parameters: "MultiDictProxy[str]"
@functools.lru_cache(maxsize=56)
def parse_mimetype(mimetype: str) -> MimeType:
"""Parses a MIME type into its components.
mimetype is a MIME type string.
Returns a MimeType object.
Example:
>>> parse_mimetype('text/html; charset=utf-8')
MimeType(type='text', subtype='html', suffix='',
parameters={'charset': 'utf-8'})
"""
if not mimetype:
return MimeType(
type="", subtype="", suffix="", parameters=MultiDictProxy(MultiDict())
)
parts = mimetype.split(";")
params: MultiDict[str] = MultiDict()
for item in parts[1:]:
if not item:
continue
key, _, value = item.partition("=")
params.add(key.lower().strip(), value.strip(' "'))
fulltype = parts[0].strip().lower()
if fulltype == "*":
fulltype = "*/*"
mtype, _, stype = fulltype.partition("/")
stype, _, suffix = stype.partition("+")
return MimeType(
type=mtype, subtype=stype, suffix=suffix, parameters=MultiDictProxy(params)
)
def guess_filename(obj: Any, default: Optional[str] = None) -> Optional[str]:
name = getattr(obj, "name", None)
if name and isinstance(name, str) and name[0] != "<" and name[-1] != ">":
return Path(name).name
return default
not_qtext_re = re.compile(r"[^\041\043-\133\135-\176]")
QCONTENT = {chr(i) for i in range(0x20, 0x7F)} | {"\t"}
def quoted_string(content: str) -> str:
"""Return 7-bit content as quoted-string.
Format content into a quoted-string as defined in RFC5322 for
Internet Message Format. Notice that this is not the 8-bit HTTP
format, but the 7-bit email format. Content must be in usascii or
a ValueError is raised.
"""
if not (QCONTENT > set(content)):
raise ValueError(f"bad content for quoted-string {content!r}")
return not_qtext_re.sub(lambda x: "\\" + x.group(0), content)
def content_disposition_header(
disptype: str, quote_fields: bool = True, _charset: str = "utf-8", **params: str
) -> str:
"""Sets ``Content-Disposition`` header for MIME.
This is the MIME payload Content-Disposition header from RFC 2183
and RFC 7579 section 4.2, not the HTTP Content-Disposition from
RFC 6266.
disptype is a disposition type: inline, attachment, form-data.
Should be valid extension token (see RFC 2183)
quote_fields performs value quoting to 7-bit MIME headers
according to RFC 7578. Set to quote_fields to False if recipient
can take 8-bit file names and field values.
_charset specifies the charset to use when quote_fields is True.
params is a dict with disposition params.
"""
if not disptype or not (TOKEN > set(disptype)):
raise ValueError(f"bad content disposition type {disptype!r}")
value = disptype
if params:
lparams = []
for key, val in params.items():
if not key or not (TOKEN > set(key)):
raise ValueError(f"bad content disposition parameter {key!r}={val!r}")
if quote_fields:
if key.lower() == "filename":
qval = quote(val, "", encoding=_charset)
lparams.append((key, '"%s"' % qval))
else:
try:
qval = quoted_string(val)
except ValueError:
qval = "".join(
(_charset, "''", quote(val, "", encoding=_charset))
)
lparams.append((key + "*", qval))
else:
lparams.append((key, '"%s"' % qval))
else:
qval = val.replace("\\", "\\\\").replace('"', '\\"')
lparams.append((key, '"%s"' % qval))
sparams = "; ".join("=".join(pair) for pair in lparams)
value = "; ".join((value, sparams))
return value
def is_ip_address(host: Optional[str]) -> bool:
"""Check if host looks like an IP Address.
This check is only meant as a heuristic to ensure that
a host is not a domain name.
"""
if not host:
return False
# For a host to be an ipv4 address, it must be all numeric.
# The host must contain a colon to be an IPv6 address.
return ":" in host or host.replace(".", "").isdigit()
_cached_current_datetime: Optional[int] = None
_cached_formatted_datetime = ""
def rfc822_formatted_time() -> str:
global _cached_current_datetime
global _cached_formatted_datetime
now = int(time.time())
if now != _cached_current_datetime:
# Weekday and month names for HTTP date/time formatting;
# always English!
# Tuples are constants stored in codeobject!
_weekdayname = ("Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun")
_monthname = (
"", # Dummy so we can use 1-based month numbers
"Jan",
"Feb",
"Mar",
"Apr",
"May",
"Jun",
"Jul",
"Aug",
"Sep",
"Oct",
"Nov",
"Dec",
)
year, month, day, hh, mm, ss, wd, *tail = time.gmtime(now)
_cached_formatted_datetime = "%s, %02d %3s %4d %02d:%02d:%02d GMT" % (
_weekdayname[wd],
day,
_monthname[month],
year,
hh,
mm,
ss,
)
_cached_current_datetime = now
return _cached_formatted_datetime
def _weakref_handle(info: "Tuple[weakref.ref[object], str]") -> None:
ref, name = info
ob = ref()
if ob is not None:
with suppress(Exception):
getattr(ob, name)()
def weakref_handle(
ob: object,
name: str,
timeout: float,
loop: asyncio.AbstractEventLoop,
timeout_ceil_threshold: float = 5,
) -> Optional[asyncio.TimerHandle]:
if timeout is not None and timeout > 0:
when = loop.time() + timeout
if timeout >= timeout_ceil_threshold:
when = ceil(when)
return loop.call_at(when, _weakref_handle, (weakref.ref(ob), name))
return None
def call_later(
cb: Callable[[], Any],
timeout: float,
loop: asyncio.AbstractEventLoop,
timeout_ceil_threshold: float = 5,
) -> Optional[asyncio.TimerHandle]:
if timeout is None or timeout <= 0:
return None
now = loop.time()
when = calculate_timeout_when(now, timeout, timeout_ceil_threshold)
return loop.call_at(when, cb)
def calculate_timeout_when(
loop_time: float,
timeout: float,
timeout_ceiling_threshold: float,
) -> float:
"""Calculate when to execute a timeout."""
when = loop_time + timeout
if timeout > timeout_ceiling_threshold:
return ceil(when)
return when
class TimeoutHandle:
"""Timeout handle"""
__slots__ = ("_timeout", "_loop", "_ceil_threshold", "_callbacks")
def __init__(
self,
loop: asyncio.AbstractEventLoop,
timeout: Optional[float],
ceil_threshold: float = 5,
) -> None:
self._timeout = timeout
self._loop = loop
self._ceil_threshold = ceil_threshold
self._callbacks: List[
Tuple[Callable[..., None], Tuple[Any, ...], Dict[str, Any]]
] = []
def register(
self, callback: Callable[..., None], *args: Any, **kwargs: Any
) -> None:
self._callbacks.append((callback, args, kwargs))
def close(self) -> None:
self._callbacks.clear()
def start(self) -> Optional[asyncio.TimerHandle]:
timeout = self._timeout
if timeout is not None and timeout > 0:
when = self._loop.time() + timeout
if timeout >= self._ceil_threshold:
when = ceil(when)
return self._loop.call_at(when, self.__call__)
else:
return None
def timer(self) -> "BaseTimerContext":
if self._timeout is not None and self._timeout > 0:
timer = TimerContext(self._loop)
self.register(timer.timeout)
return timer
else:
return TimerNoop()
def __call__(self) -> None:
for cb, args, kwargs in self._callbacks:
with suppress(Exception):
cb(*args, **kwargs)
self._callbacks.clear()
class BaseTimerContext(ContextManager["BaseTimerContext"]):
__slots__ = ()
def assert_timeout(self) -> None:
"""Raise TimeoutError if timeout has been exceeded."""
class TimerNoop(BaseTimerContext):
__slots__ = ()
def __enter__(self) -> BaseTimerContext:
return self
def __exit__(
self,
exc_type: Optional[Type[BaseException]],
exc_val: Optional[BaseException],
exc_tb: Optional[TracebackType],
) -> None:
return
class TimerContext(BaseTimerContext):
"""Low resolution timeout context manager"""
__slots__ = ("_loop", "_tasks", "_cancelled", "_cancelling")
def __init__(self, loop: asyncio.AbstractEventLoop) -> None:
self._loop = loop
self._tasks: List[asyncio.Task[Any]] = []
self._cancelled = False
self._cancelling = 0
def assert_timeout(self) -> None:
"""Raise TimeoutError if timer has already been cancelled."""
if self._cancelled:
raise asyncio.TimeoutError from None
def __enter__(self) -> BaseTimerContext:
task = asyncio.current_task(loop=self._loop)
if task is None:
raise RuntimeError("Timeout context manager should be used inside a task")
if sys.version_info >= (3, 11):
# Remember if the task was already cancelling
# so when we __exit__ we can decide if we should
# raise asyncio.TimeoutError or let the cancellation propagate
self._cancelling = task.cancelling()
if self._cancelled:
raise asyncio.TimeoutError from None
self._tasks.append(task)
return self
def __exit__(
self,
exc_type: Optional[Type[BaseException]],
exc_val: Optional[BaseException],
exc_tb: Optional[TracebackType],
) -> Optional[bool]:
enter_task: Optional[asyncio.Task[Any]] = None
if self._tasks:
enter_task = self._tasks.pop()
if exc_type is asyncio.CancelledError and self._cancelled:
assert enter_task is not None
# The timeout was hit, and the task was cancelled
# so we need to uncancel the last task that entered the context manager
# since the cancellation should not leak out of the context manager
if sys.version_info >= (3, 11):
# If the task was already cancelling don't raise
# asyncio.TimeoutError and instead return None
# to allow the cancellation to propagate
if enter_task.uncancel() > self._cancelling:
return None
raise asyncio.TimeoutError from exc_val
return None
def timeout(self) -> None:
if not self._cancelled:
for task in set(self._tasks):
task.cancel()
self._cancelled = True
def ceil_timeout(
delay: Optional[float], ceil_threshold: float = 5
) -> async_timeout.Timeout:
if delay is None or delay <= 0:
return async_timeout.timeout(None)
loop = asyncio.get_running_loop()
now = loop.time()
when = now + delay
if delay > ceil_threshold:
when = ceil(when)
return async_timeout.timeout_at(when)
class HeadersMixin:
"""Mixin for handling headers."""
ATTRS = frozenset(["_content_type", "_content_dict", "_stored_content_type"])
_headers: MultiMapping[str]
_content_type: Optional[str] = None
_content_dict: Optional[Dict[str, str]] = None
_stored_content_type: Union[str, None, _SENTINEL] = sentinel
def _parse_content_type(self, raw: Optional[str]) -> None:
self._stored_content_type = raw
if raw is None:
# default value according to RFC 2616
self._content_type = "application/octet-stream"
self._content_dict = {}
else:
msg = HeaderParser().parsestr("Content-Type: " + raw)
self._content_type = msg.get_content_type()
params = msg.get_params(())
self._content_dict = dict(params[1:]) # First element is content type again
@property
def content_type(self) -> str:
"""The value of content part for Content-Type HTTP header."""
raw = self._headers.get(hdrs.CONTENT_TYPE)
if self._stored_content_type != raw:
self._parse_content_type(raw)
assert self._content_type is not None
return self._content_type
@property
def charset(self) -> Optional[str]:
"""The value of charset part for Content-Type HTTP header."""
raw = self._headers.get(hdrs.CONTENT_TYPE)
if self._stored_content_type != raw:
self._parse_content_type(raw)
assert self._content_dict is not None
return self._content_dict.get("charset")
@property
def content_length(self) -> Optional[int]:
"""The value of Content-Length HTTP header."""
content_length = self._headers.get(hdrs.CONTENT_LENGTH)
return None if content_length is None else int(content_length)
def set_result(fut: "asyncio.Future[_T]", result: _T) -> None:
if not fut.done():
fut.set_result(result)
_EXC_SENTINEL = BaseException()
class ErrorableProtocol(Protocol):
def set_exception(
self,
exc: BaseException,
exc_cause: BaseException = ...,
) -> None: ... # pragma: no cover
def set_exception(
fut: "asyncio.Future[_T] | ErrorableProtocol",
exc: BaseException,
exc_cause: BaseException = _EXC_SENTINEL,
) -> None:
"""Set future exception.
If the future is marked as complete, this function is a no-op.
:param exc_cause: An exception that is a direct cause of ``exc``.
Only set if provided.
"""
if asyncio.isfuture(fut) and fut.done():
return
exc_is_sentinel = exc_cause is _EXC_SENTINEL
exc_causes_itself = exc is exc_cause
if not exc_is_sentinel and not exc_causes_itself:
exc.__cause__ = exc_cause
fut.set_exception(exc)
[docs]
@functools.total_ordering
class AppKey(Generic[_T]):
"""Keys for static typing support in Application."""
__slots__ = ("_name", "_t", "__orig_class__")
# This may be set by Python when instantiating with a generic type. We need to
# support this, in order to support types that are not concrete classes,
# like Iterable, which can't be passed as the second parameter to __init__.
__orig_class__: Type[object]
def __init__(self, name: str, t: Optional[Type[_T]] = None):
# Prefix with module name to help deduplicate key names.
frame = inspect.currentframe()
while frame:
if frame.f_code.co_name == "<module>":
module: str = frame.f_globals["__name__"]
break
frame = frame.f_back
self._name = module + "." + name
self._t = t
def __lt__(self, other: object) -> bool:
if isinstance(other, AppKey):
return self._name < other._name
return True # Order AppKey above other types.
def __repr__(self) -> str:
t = self._t
if t is None:
with suppress(AttributeError):
# Set to type arg.
t = get_args(self.__orig_class__)[0]
if t is None:
t_repr = "<<Unknown>>"
elif isinstance(t, type):
if t.__module__ == "builtins":
t_repr = t.__qualname__
else:
t_repr = f"{t.__module__}.{t.__qualname__}"
else:
t_repr = repr(t)
return f"<AppKey({self._name}, type={t_repr})>"
[docs]
class ChainMapProxy(Mapping[Union[str, AppKey[Any]], Any]):
__slots__ = ("_maps",)
def __init__(self, maps: Iterable[Mapping[Union[str, AppKey[Any]], Any]]) -> None:
self._maps = tuple(maps)
def __init_subclass__(cls) -> None:
raise TypeError(
"Inheritance class {} from ChainMapProxy "
"is forbidden".format(cls.__name__)
)
@overload # type: ignore[override]
def __getitem__(self, key: AppKey[_T]) -> _T: ...
@overload
def __getitem__(self, key: str) -> Any: ...
def __getitem__(self, key: Union[str, AppKey[_T]]) -> Any:
for mapping in self._maps:
try:
return mapping[key]
except KeyError:
pass
raise KeyError(key)
@overload # type: ignore[override]
def get(self, key: AppKey[_T], default: _S) -> Union[_T, _S]: ...
@overload
def get(self, key: AppKey[_T], default: None = ...) -> Optional[_T]: ...
@overload
def get(self, key: str, default: Any = ...) -> Any: ...
def get(self, key: Union[str, AppKey[_T]], default: Any = None) -> Any:
try:
return self[key]
except KeyError:
return default
def __len__(self) -> int:
# reuses stored hash values if possible
return len(set().union(*self._maps))
def __iter__(self) -> Iterator[Union[str, AppKey[Any]]]:
d: Dict[Union[str, AppKey[Any]], Any] = {}
for mapping in reversed(self._maps):
# reuses stored hash values if possible
d.update(mapping)
return iter(d)
def __contains__(self, key: object) -> bool:
return any(key in m for m in self._maps)
def __bool__(self) -> bool:
return any(self._maps)
def __repr__(self) -> str:
content = ", ".join(map(repr, self._maps))
return f"ChainMapProxy({content})"
# https://tools.ietf.org/html/rfc7232#section-2.3
_ETAGC = r"[!\x23-\x7E\x80-\xff]+"
_ETAGC_RE = re.compile(_ETAGC)
_QUOTED_ETAG = rf'(W/)?"({_ETAGC})"'
QUOTED_ETAG_RE = re.compile(_QUOTED_ETAG)
LIST_QUOTED_ETAG_RE = re.compile(rf"({_QUOTED_ETAG})(?:\s*,\s*|$)|(.)")
ETAG_ANY = "*"
[docs]
@attr.s(auto_attribs=True, frozen=True, slots=True)
class ETag:
value: str
is_weak: bool = False
def validate_etag_value(value: str) -> None:
if value != ETAG_ANY and not _ETAGC_RE.fullmatch(value):
raise ValueError(
f"Value {value!r} is not a valid etag. Maybe it contains '\"'?"
)
def parse_http_date(date_str: Optional[str]) -> Optional[datetime.datetime]:
"""Process a date string, return a datetime object"""
if date_str is not None:
timetuple = parsedate(date_str)
if timetuple is not None:
with suppress(ValueError):
return datetime.datetime(*timetuple[:6], tzinfo=datetime.timezone.utc)
return None
@functools.lru_cache
def must_be_empty_body(method: str, code: int) -> bool:
"""Check if a request must return an empty body."""
return (
code in EMPTY_BODY_STATUS_CODES
or method in EMPTY_BODY_METHODS
or (200 <= code < 300 and method in hdrs.METH_CONNECT_ALL)
)
def should_remove_content_length(method: str, code: int) -> bool:
"""Check if a Content-Length header should be removed.
This should always be a subset of must_be_empty_body
"""
# https://www.rfc-editor.org/rfc/rfc9110.html#section-8.6-8
# https://www.rfc-editor.org/rfc/rfc9110.html#section-15.4.5-4
return code in EMPTY_BODY_STATUS_CODES or (
200 <= code < 300 and method in hdrs.METH_CONNECT_ALL
)
