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helpers.py
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helpers.py
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"""Various helper functions"""
import asyncio
import base64
import binascii
import cgi
import datetime
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 math import ceil
from pathlib import Path
from types import TracebackType
from typing import ( # noqa
Any,
Awaitable,
Callable,
Dict,
Generator,
Iterable,
Iterator,
List,
Mapping,
Optional,
Pattern,
Set,
Tuple,
Type,
TypeVar,
Union,
cast,
)
from urllib.parse import quote
from urllib.request import getproxies
import async_timeout
import attr
from multidict import MultiDict, MultiDictProxy
from typing_extensions import final
from yarl import URL
from . import hdrs
from .log import client_logger
from .typedefs import PathLike # noqa
__all__ = ('BasicAuth', 'ChainMapProxy')
PY_36 = sys.version_info >= (3, 6)
PY_37 = sys.version_info >= (3, 7)
PY_38 = sys.version_info >= (3, 8)
if not PY_37:
import idna_ssl
idna_ssl.patch_match_hostname()
try:
from typing import ContextManager
except ImportError:
from typing_extensions import ContextManager
def all_tasks(
loop: Optional[asyncio.AbstractEventLoop] = None
) -> Set['asyncio.Task[Any]']:
tasks = list(asyncio.Task.all_tasks(loop))
return {t for t in tasks if not t.done()}
if PY_37:
all_tasks = getattr(asyncio, 'all_tasks') # noqa
_T = TypeVar('_T')
sentinel = object() # type: Any
NO_EXTENSIONS = bool(os.environ.get('AIOHTTP_NO_EXTENSIONS')) # type: bool
# N.B. sys.flags.dev_mode is available on Python 3.7+, use getattr
# for compatibility with older versions
DEBUG = (getattr(sys.flags, 'dev_mode', False) or
(not sys.flags.ignore_environment and
bool(os.environ.get('PYTHONASYNCIODEBUG')))) # type: bool
CHAR = set(chr(i) for i in range(0, 128))
CTL = set(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
if PY_38:
iscoroutinefunction = asyncio.iscoroutinefunction
else:
def iscoroutinefunction(func: Callable[..., Any]) -> bool:
while isinstance(func, functools.partial):
func = func.func
return asyncio.iscoroutinefunction(func)
json_re = re.compile(r'^application/(?:[\w.+-]+?\+)?json')
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)
@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)
@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")
if url.user is None:
return None
return cls(url.user, url.password or '', encoding=encoding)
def encode(self) -> str:
"""Encode credentials."""
creds = ('%s:%s' % (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]]:
auth = BasicAuth.from_url(url)
if auth is None:
return url, None
else:
return url.with_user(None), auth
def netrc_from_env() -> Optional[netrc.netrc]:
"""Attempt to load the netrc file 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 platform.system() == '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:
# we couldn't read the file (doesn't exist, permissions, etc.)
if netrc_env or netrc_path.is_file():
# 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(frozen=True, slots=True)
class ProxyInfo:
proxy = attr.ib(type=URL)
proxy_auth = attr.ib(type=Optional[BasicAuth])
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', 'ws', 'wss'):
client_logger.warning(
"%s proxies %s are not supported, ignoring",
proxy.scheme.upper(), proxy)
continue
if netrc_obj and auth is None:
auth_from_netrc = None
if proxy.host is not None:
auth_from_netrc = netrc_obj.authenticators(proxy.host)
if auth_from_netrc is not None:
# auth_from_netrc is a (`user`, `account`, `password`) tuple,
# `user` and `account` both can be username,
# if `user` is None, use `account`
*logins, password = auth_from_netrc
login = logins[0] if logins[0] else logins[-1]
auth = BasicAuth(cast(str, login), cast(str, password))
ret[proto] = ProxyInfo(proxy, auth)
return ret
def current_task(
loop: Optional[asyncio.AbstractEventLoop]=None
) -> 'asyncio.Task[Any]':
if PY_37:
return asyncio.current_task(loop=loop) # type: ignore
else:
return asyncio.Task.current_task(loop=loop)
if sys.version_info >= (3, 7):
create_task = asyncio.create_task
else:
def create_task(coro: Awaitable[_T]) -> 'asyncio.Task[_T]':
loop = asyncio.get_event_loop()
return loop.create_task(coro)
def get_running_loop() -> asyncio.AbstractEventLoop:
loop = asyncio.get_event_loop()
if not loop.is_running():
raise RuntimeError(
"The object should be created within an async function"
)
return loop
def isasyncgenfunction(obj: Any) -> bool:
func = getattr(inspect, 'isasyncgenfunction', None)
if func is not None:
return func(obj)
else:
return False
@attr.s(frozen=True, slots=True)
class MimeType:
type = attr.ib(type=str)
subtype = attr.ib(type=str)
suffix = attr.ib(type=str)
parameters = attr.ib(type=MultiDictProxy) # type: 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() # type: MultiDict[str]
for item in parts[1:]:
if not item:
continue
key, value = cast(Tuple[str, str],
item.split('=', 1) if '=' in item else (item, ''))
params.add(key.lower().strip(), value.strip(' "'))
fulltype = parts[0].strip().lower()
if fulltype == '*':
fulltype = '*/*'
mtype, stype = (cast(Tuple[str, str], fulltype.split('/', 1))
if '/' in fulltype else (fulltype, ''))
stype, suffix = (cast(Tuple[str, str], stype.split('+', 1))
if '+' in stype else (stype, ''))
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
def content_disposition_header(disptype: str,
quote_fields: bool=True,
**params: str) -> str:
"""Sets ``Content-Disposition`` header.
disptype is a disposition type: inline, attachment, form-data.
Should be valid extension token (see RFC 2183)
params is a dict with disposition params.
"""
if not disptype or not (TOKEN > set(disptype)):
raise ValueError('bad content disposition type {!r}'
''.format(disptype))
value = disptype
if params:
lparams = []
for key, val in params.items():
if not key or not (TOKEN > set(key)):
raise ValueError('bad content disposition parameter'
' {!r}={!r}'.format(key, val))
qval = quote(val, '') if quote_fields else val
lparams.append((key, '"%s"' % qval))
if key == 'filename':
lparams.append(('filename*', "utf-8''" + qval))
sparams = '; '.join('='.join(pair) for pair in lparams)
value = '; '.join((value, sparams))
return value
def is_expected_content_type(response_content_type: str,
expected_content_type: str) -> bool:
if expected_content_type == 'application/json':
return json_re.match(response_content_type) is not None
return expected_content_type in response_content_type
class reify:
"""Use as a class method decorator. It operates almost exactly like
the Python `@property` decorator, but it puts the result of the
method it decorates into the instance dict after the first call,
effectively replacing the function it decorates with an instance
variable. It is, in Python parlance, a data descriptor.
"""
def __init__(self, wrapped: Callable[..., Any]) -> None:
self.wrapped = wrapped
self.__doc__ = wrapped.__doc__
self.name = wrapped.__name__
def __get__(self, inst: Any, owner: Any) -> Any:
try:
try:
return inst._cache[self.name]
except KeyError:
val = self.wrapped(inst)
inst._cache[self.name] = val
return val
except AttributeError:
if inst is None:
return self
raise
def __set__(self, inst: Any, value: Any) -> None:
raise AttributeError("reified property is read-only")
reify_py = reify
try:
from ._helpers import reify as reify_c
if not NO_EXTENSIONS:
reify = reify_c # type: ignore
except ImportError:
pass
_ipv4_pattern = (r'^(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}'
r'(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$')
_ipv6_pattern = (
r'^(?:(?:(?:[A-F0-9]{1,4}:){6}|(?=(?:[A-F0-9]{0,4}:){0,6}'
r'(?:[0-9]{1,3}\.){3}[0-9]{1,3}$)(([0-9A-F]{1,4}:){0,5}|:)'
r'((:[0-9A-F]{1,4}){1,5}:|:)|::(?:[A-F0-9]{1,4}:){5})'
r'(?:(?:25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])\.){3}'
r'(?:25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])|(?:[A-F0-9]{1,4}:){7}'
r'[A-F0-9]{1,4}|(?=(?:[A-F0-9]{0,4}:){0,7}[A-F0-9]{0,4}$)'
r'(([0-9A-F]{1,4}:){1,7}|:)((:[0-9A-F]{1,4}){1,7}|:)|(?:[A-F0-9]{1,4}:){7}'
r':|:(:[A-F0-9]{1,4}){7})$')
_ipv4_regex = re.compile(_ipv4_pattern)
_ipv6_regex = re.compile(_ipv6_pattern, flags=re.IGNORECASE)
_ipv4_regexb = re.compile(_ipv4_pattern.encode('ascii'))
_ipv6_regexb = re.compile(_ipv6_pattern.encode('ascii'), flags=re.IGNORECASE)
def _is_ip_address(
regex: Pattern[str], regexb: Pattern[bytes],
host: Optional[Union[str, bytes]]) -> bool:
if host is None:
return False
if isinstance(host, str):
return bool(regex.match(host))
elif isinstance(host, (bytes, bytearray, memoryview)):
return bool(regexb.match(host))
else:
raise TypeError("{} [{}] is not a str or bytes"
.format(host, type(host)))
is_ipv4_address = functools.partial(_is_ip_address, _ipv4_regex, _ipv4_regexb)
is_ipv6_address = functools.partial(_is_ip_address, _ipv6_regex, _ipv6_regexb)
def is_ip_address(
host: Optional[Union[str, bytes, bytearray, memoryview]]) -> bool:
return is_ipv4_address(host) or is_ipv6_address(host)
def next_whole_second() -> datetime.datetime:
"""Return current time rounded up to the next whole second."""
return (
datetime.datetime.now(
datetime.timezone.utc).replace(microsecond=0) +
datetime.timedelta(seconds=0)
)
_cached_current_datetime = None # type: Optional[int]
_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): # type: ignore
ref, name = info
ob = ref()
if ob is not None:
with suppress(Exception):
getattr(ob, name)()
def weakref_handle(ob, name, timeout, loop, ceil_timeout=True): # type: ignore
if timeout is not None and timeout > 0:
when = loop.time() + timeout
if ceil_timeout:
when = ceil(when)
return loop.call_at(when, _weakref_handle, (weakref.ref(ob), name))
def call_later(cb, timeout, loop): # type: ignore
if timeout is not None and timeout > 0:
when = ceil(loop.time() + timeout)
return loop.call_at(when, cb)
class TimeoutHandle:
""" Timeout handle """
def __init__(self,
loop: asyncio.AbstractEventLoop,
timeout: Optional[float]) -> None:
self._timeout = timeout
self._loop = loop
self._callbacks = [] # type: List[Tuple[Callable[..., None], Tuple[Any, ...], Dict[str, Any]]] # noqa
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.Handle]:
if self._timeout is not None and self._timeout > 0:
at = ceil(self._loop.time() + self._timeout)
return self._loop.call_at(at, 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']):
pass
class TimerNoop(BaseTimerContext):
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 """
def __init__(self, loop: asyncio.AbstractEventLoop) -> None:
self._loop = loop
self._tasks = [] # type: List[asyncio.Task[Any]]
self._cancelled = False
def __enter__(self) -> BaseTimerContext:
task = current_task(loop=self._loop)
if task is None:
raise RuntimeError('Timeout context manager should be used '
'inside a task')
if self._cancelled:
task.cancel()
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]:
if self._tasks:
self._tasks.pop()
if exc_type is asyncio.CancelledError and self._cancelled:
raise asyncio.TimeoutError from None
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]) -> async_timeout.Timeout:
if delay is not None:
loop = get_running_loop()
now = loop.time()
return async_timeout.timeout_at(ceil(now + delay))
else:
return async_timeout.timeout(None)
class HeadersMixin:
__slots__ = ('_content_type', '_content_dict', '_stored_content_type')
def __init__(self) -> None:
self._content_type = None # type: Optional[str]
self._content_dict = None # type: Optional[Dict[str, str]]
self._stored_content_type = sentinel
def _parse_content_type(self, raw: 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:
self._content_type, self._content_dict = cgi.parse_header(raw)
@property
def content_type(self) -> str:
"""The value of content part for Content-Type HTTP header."""
raw = self._headers.get(hdrs.CONTENT_TYPE) # type: ignore
if self._stored_content_type != raw:
self._parse_content_type(raw)
return self._content_type # type: ignore
@property
def charset(self) -> Optional[str]:
"""The value of charset part for Content-Type HTTP header."""
raw = self._headers.get(hdrs.CONTENT_TYPE) # type: ignore
if self._stored_content_type != raw:
self._parse_content_type(raw)
return self._content_dict.get('charset') # type: ignore
@property
def content_length(self) -> Optional[int]:
"""The value of Content-Length HTTP header."""
content_length = self._headers.get(hdrs.CONTENT_LENGTH) # type: ignore
if content_length is not None:
return int(content_length)
else:
return None
def set_result(fut: 'asyncio.Future[_T]', result: _T) -> None:
if not fut.done():
fut.set_result(result)
def set_exception(fut: 'asyncio.Future[_T]', exc: BaseException) -> None:
if not fut.done():
fut.set_exception(exc)
@final
class ChainMapProxy(Mapping[str, Any]):
__slots__ = ('_maps',)
def __init__(self, maps: Iterable[Mapping[str, Any]]) -> None:
self._maps = tuple(maps)
def __init_subclass__(cls) -> None:
raise TypeError("Inheritance class {} from ChainMapProxy "
"is forbidden".format(cls.__name__))
def __getitem__(self, key: str) -> Any:
for mapping in self._maps:
try:
return mapping[key]
except KeyError:
pass
raise KeyError(key)
def get(self, key: str, default: Any=None) -> Any:
return self[key] if key in self else default
def __len__(self) -> int:
# reuses stored hash values if possible
return len(set().union(*self._maps)) # type: ignore
def __iter__(self) -> Iterator[str]:
d = {} # type: Dict[str, 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 'ChainMapProxy({})'.format(content)