Files
ha-core/homeassistant/helpers/aiohttp_client.py
2026-02-13 19:31:35 +01:00

507 lines
15 KiB
Python

"""Helper for aiohttp webclient stuff."""
from __future__ import annotations
import asyncio
from collections.abc import Awaitable, Callable, Sequence
from contextlib import suppress
from functools import lru_cache
from ipaddress import ip_address
import socket
from ssl import SSLContext
import sys
from types import MappingProxyType
from typing import TYPE_CHECKING, Any, Self
import aiohttp
from aiohttp import ClientMiddlewareType, hdrs, web
from aiohttp.hdrs import CONTENT_TYPE, USER_AGENT
from aiohttp.web_exceptions import HTTPBadGateway, HTTPGatewayTimeout
from aiohttp_asyncmdnsresolver.api import AsyncDualMDNSResolver
from yarl import URL
from homeassistant import config_entries
from homeassistant.components import zeroconf
from homeassistant.const import APPLICATION_NAME, EVENT_HOMEASSISTANT_CLOSE, __version__
from homeassistant.core import Event, HomeAssistant, callback
from homeassistant.loader import bind_hass
from homeassistant.util import ssl as ssl_util
from homeassistant.util.hass_dict import HassKey
from homeassistant.util.json import json_loads
from homeassistant.util.network import is_loopback
from .frame import warn_use
from .json import json_dumps
from .singleton import singleton
if TYPE_CHECKING:
from aiohttp.typedefs import JSONDecoder
DATA_CONNECTOR: HassKey[dict[tuple[bool, int, str], aiohttp.BaseConnector]] = HassKey(
"aiohttp_connector"
)
DATA_CLIENTSESSION: HassKey[dict[tuple[bool, int, str], aiohttp.ClientSession]] = (
HassKey("aiohttp_clientsession")
)
DATA_RESOLVER: HassKey[HassAsyncDNSResolver] = HassKey("aiohttp_resolver")
SERVER_SOFTWARE = (
f"{APPLICATION_NAME}/{__version__} "
f"aiohttp/{aiohttp.__version__} Python/{sys.version_info[0]}.{sys.version_info[1]}"
)
WARN_CLOSE_MSG = "closes the Home Assistant aiohttp session"
_LOCALHOST = "localhost"
_TRAILING_LOCAL_HOST = f".{_LOCALHOST}"
class SSRFRedirectError(aiohttp.ClientError):
"""SSRF redirect protection.
Raised when a redirect targets a blocked address (loopback or unspecified).
"""
async def _ssrf_redirect_middleware(
request: aiohttp.ClientRequest,
handler: aiohttp.ClientHandlerType,
) -> aiohttp.ClientResponse:
"""Block redirects from non-loopback origins to loopback targets."""
resp = await handler(request)
# Return early if not a redirect or already loopback to allow loopback origins
connector = request.session.connector
if not (300 <= resp.status < 400) or await _async_is_blocked_host(
request.url.host, connector
):
return resp
location = resp.headers.get(hdrs.LOCATION, "")
if not location:
return resp
redirect_url = URL(location)
if not redirect_url.is_absolute():
# Relative redirects stay on the same host - always safe
return resp
host = redirect_url.host
if await _async_is_blocked_host(host, connector):
resp.close()
raise SSRFRedirectError(
f"Redirect from {request.url.host} to a blocked address"
f" is not allowed: {host}"
)
return resp
@lru_cache
def _is_ssrf_address(address: str) -> bool:
"""Check if an IP address is a potential SSRF target.
Returns True for loopback and unspecified addresses.
"""
ip = ip_address(address)
return is_loopback(ip) or ip.is_unspecified
async def _async_is_blocked_host(
host: str | None, connector: aiohttp.BaseConnector | None
) -> bool:
"""Check if a host is blocked by hostname or by resolved IP.
First does a fast sync check on the hostname string, then resolves
the hostname via the connector and checks each resolved IP address.
"""
if not host:
return False
# Strip FQDN trailing dot (RFC 1035) since yarl preserves it,
# preventing an attacker from bypassing the check with "localhost."
stripped_host = host.strip().removesuffix(".")
if stripped_host == _LOCALHOST or stripped_host.endswith(_TRAILING_LOCAL_HOST):
return True
with suppress(ValueError):
return _is_ssrf_address(host)
if not isinstance(connector, HomeAssistantTCPConnector):
return False
try:
results = await connector.async_resolve_host(host)
except Exception: # noqa: BLE001
return False
return any(_is_ssrf_address(result["host"]) for result in results)
#
# The default connection limit of 100 meant that you could only have
# 100 concurrent connections.
#
# This was effectively a limit of 100 devices and than
# the supervisor API would fail as soon as it was hit.
#
# We now apply the 100 limit per host, so that we can have 100 connections
# to a single host, but can have more than 4096 connections in total to
# prevent a single host from using all available connections.
#
MAXIMUM_CONNECTIONS = 4096
MAXIMUM_CONNECTIONS_PER_HOST = 100
class HassAsyncDNSResolver(AsyncDualMDNSResolver):
"""Home Assistant AsyncDNSResolver.
This is a wrapper around the AsyncDualMDNSResolver to only
close the resolver when the Home Assistant instance is closed.
"""
async def real_close(self) -> None:
"""Close the resolver."""
await super().close()
async def close(self) -> None:
"""Close the resolver."""
class HassClientResponse(aiohttp.ClientResponse):
"""aiohttp.ClientResponse with a json method that uses json_loads by default."""
async def json(
self,
*args: Any,
loads: JSONDecoder = json_loads,
**kwargs: Any,
) -> Any:
"""Send a json request and parse the json response."""
return await super().json(*args, loads=loads, **kwargs)
class ChunkAsyncStreamIterator:
"""Async iterator for chunked streams.
Based on aiohttp.streams.ChunkTupleAsyncStreamIterator, but yields
bytes instead of tuple[bytes, bool].
"""
__slots__ = ("_stream",)
def __init__(self, stream: aiohttp.StreamReader) -> None:
"""Initialize."""
self._stream = stream
def __aiter__(self) -> Self:
"""Iterate."""
return self
async def __anext__(self) -> bytes:
"""Yield next chunk."""
rv = await self._stream.readchunk()
if rv == (b"", False):
raise StopAsyncIteration
return rv[0]
@callback
@bind_hass
def async_get_clientsession(
hass: HomeAssistant,
verify_ssl: bool = True,
family: socket.AddressFamily = socket.AF_UNSPEC,
ssl_cipher: ssl_util.SSLCipherList = ssl_util.SSLCipherList.PYTHON_DEFAULT,
) -> aiohttp.ClientSession:
"""Return default aiohttp ClientSession.
This method must be run in the event loop.
"""
session_key = _make_key(verify_ssl, family, ssl_cipher)
sessions = hass.data.setdefault(DATA_CLIENTSESSION, {})
if session_key not in sessions:
session = _async_create_clientsession(
hass,
verify_ssl,
auto_cleanup_method=_async_register_default_clientsession_shutdown,
family=family,
ssl_cipher=ssl_cipher,
)
sessions[session_key] = session
else:
session = sessions[session_key]
return session
@callback
@bind_hass
def async_create_clientsession(
hass: HomeAssistant,
verify_ssl: bool = True,
auto_cleanup: bool = True,
family: socket.AddressFamily = socket.AF_UNSPEC,
ssl_cipher: ssl_util.SSLCipherList = ssl_util.SSLCipherList.PYTHON_DEFAULT,
**kwargs: Any,
) -> aiohttp.ClientSession:
"""Create a new ClientSession with kwargs, i.e. for cookies.
If auto_cleanup is False, you need to call detach() after the session
returned is no longer used. Default is True, the session will be
automatically detached on homeassistant_stop or when being created
in config entry setup, the config entry is unloaded.
This method must be run in the event loop.
"""
auto_cleanup_method = None
if auto_cleanup:
auto_cleanup_method = _async_register_clientsession_shutdown
return _async_create_clientsession(
hass,
verify_ssl,
auto_cleanup_method=auto_cleanup_method,
family=family,
ssl_cipher=ssl_cipher,
**kwargs,
)
@callback
def _async_create_clientsession(
hass: HomeAssistant,
verify_ssl: bool = True,
auto_cleanup_method: Callable[[HomeAssistant, aiohttp.ClientSession], None]
| None = None,
family: socket.AddressFamily = socket.AF_UNSPEC,
ssl_cipher: ssl_util.SSLCipherList = ssl_util.SSLCipherList.PYTHON_DEFAULT,
**kwargs: Any,
) -> aiohttp.ClientSession:
"""Create a new ClientSession with kwargs, i.e. for cookies."""
middlewares: Sequence[ClientMiddlewareType] = (
_ssrf_redirect_middleware,
*kwargs.pop("middlewares", ()),
)
clientsession = aiohttp.ClientSession(
connector=_async_get_connector(hass, verify_ssl, family, ssl_cipher),
json_serialize=json_dumps,
response_class=HassClientResponse,
middlewares=middlewares,
**kwargs,
)
# Prevent packages accidentally overriding our default headers
# It's important that we identify as Home Assistant
# If a package requires a different user agent, override it by passing a headers
# dictionary to the request method.
clientsession._default_headers = MappingProxyType( # type: ignore[assignment] # noqa: SLF001
{USER_AGENT: SERVER_SOFTWARE},
)
clientsession.close = warn_use( # type: ignore[method-assign]
clientsession.close,
WARN_CLOSE_MSG,
)
if auto_cleanup_method:
auto_cleanup_method(hass, clientsession)
return clientsession
@bind_hass
async def async_aiohttp_proxy_web(
hass: HomeAssistant,
request: web.BaseRequest,
web_coro: Awaitable[aiohttp.ClientResponse],
buffer_size: int = 102400,
timeout: int = 10,
) -> web.StreamResponse | None:
"""Stream websession request to aiohttp web response."""
try:
async with asyncio.timeout(timeout):
req = await web_coro
except asyncio.CancelledError:
# The user cancelled the request
return None
except TimeoutError as err:
# Timeout trying to start the web request
raise HTTPGatewayTimeout from err
except aiohttp.ClientError as err:
# Something went wrong with the connection
raise HTTPBadGateway from err
try:
return await async_aiohttp_proxy_stream(
hass, request, req.content, req.headers.get(CONTENT_TYPE)
)
finally:
req.close()
@bind_hass
async def async_aiohttp_proxy_stream(
hass: HomeAssistant,
request: web.BaseRequest,
stream: aiohttp.StreamReader,
content_type: str | None,
buffer_size: int = 102400,
timeout: int = 10,
) -> web.StreamResponse:
"""Stream a stream to aiohttp web response."""
response = web.StreamResponse()
if content_type is not None:
response.content_type = content_type
await response.prepare(request)
# Suppressing something went wrong fetching data, closed connection
with suppress(TimeoutError, aiohttp.ClientError):
while hass.is_running:
async with asyncio.timeout(timeout):
data = await stream.read(buffer_size)
if not data:
break
await response.write(data)
return response
@callback
def _async_register_clientsession_shutdown(
hass: HomeAssistant, clientsession: aiohttp.ClientSession
) -> None:
"""Register ClientSession close on Home Assistant shutdown or config entry unload.
This method must be run in the event loop.
"""
@callback
def _async_close_websession(*_: Any) -> None:
"""Close websession."""
clientsession.detach()
unsub = hass.bus.async_listen_once(
EVENT_HOMEASSISTANT_CLOSE, _async_close_websession
)
if not (config_entry := config_entries.current_entry.get()):
return
config_entry.async_on_unload(unsub)
config_entry.async_on_unload(_async_close_websession)
@callback
def _async_register_default_clientsession_shutdown(
hass: HomeAssistant, clientsession: aiohttp.ClientSession
) -> None:
"""Register default ClientSession close on Home Assistant shutdown.
This method must be run in the event loop.
"""
@callback
def _async_close_websession(event: Event) -> None:
"""Close websession."""
clientsession.detach()
hass.bus.async_listen_once(EVENT_HOMEASSISTANT_CLOSE, _async_close_websession)
@callback
def _make_key(
verify_ssl: bool = True,
family: socket.AddressFamily = socket.AF_UNSPEC,
ssl_cipher: ssl_util.SSLCipherList = ssl_util.SSLCipherList.PYTHON_DEFAULT,
) -> tuple[bool, socket.AddressFamily, ssl_util.SSLCipherList]:
"""Make a key for connector or session pool."""
return (verify_ssl, family, ssl_cipher)
class HomeAssistantTCPConnector(aiohttp.TCPConnector):
"""Home Assistant TCP Connector.
Same as aiohttp.TCPConnector but with a longer cleanup_closed timeout.
By default the cleanup_closed timeout is 2 seconds. This is too short
for Home Assistant since we churn through a lot of connections. We set
it to 60 seconds to reduce the overhead of aborting TLS connections
that are likely already closed.
"""
# abort transport after 60 seconds (cleanup broken connections)
_cleanup_closed_period = 60.0
async def async_resolve_host(self, host: str) -> list[aiohttp.abc.ResolveResult]:
"""Resolve a host to a list of addresses."""
return await self._resolve_host(host, 0)
@callback
def _async_get_connector(
hass: HomeAssistant,
verify_ssl: bool = True,
family: socket.AddressFamily = socket.AF_UNSPEC,
ssl_cipher: ssl_util.SSLCipherList = ssl_util.SSLCipherList.PYTHON_DEFAULT,
) -> aiohttp.BaseConnector:
"""Return the connector pool for aiohttp.
This method must be run in the event loop.
"""
connector_key = _make_key(verify_ssl, family, ssl_cipher)
connectors = hass.data.setdefault(DATA_CONNECTOR, {})
if connector_key in connectors:
return connectors[connector_key]
if verify_ssl:
ssl_context: SSLContext = ssl_util.client_context(
ssl_cipher, ssl_util.SSL_ALPN_HTTP11
)
else:
ssl_context = ssl_util.client_context_no_verify(
ssl_cipher, ssl_util.SSL_ALPN_HTTP11
)
connector = HomeAssistantTCPConnector(
family=family,
ssl=ssl_context,
limit=MAXIMUM_CONNECTIONS,
limit_per_host=MAXIMUM_CONNECTIONS_PER_HOST,
resolver=_async_get_or_create_resolver(hass),
)
connectors[connector_key] = connector
async def _async_close_connector(event: Event) -> None:
"""Close connector pool."""
await connector.close()
hass.bus.async_listen_once(EVENT_HOMEASSISTANT_CLOSE, _async_close_connector)
return connector
@singleton(DATA_RESOLVER)
@callback
def _async_get_or_create_resolver(hass: HomeAssistant) -> HassAsyncDNSResolver:
"""Return the HassAsyncDNSResolver."""
resolver = _async_make_resolver(hass)
async def _async_close_resolver(event: Event) -> None:
await resolver.real_close()
hass.bus.async_listen_once(EVENT_HOMEASSISTANT_CLOSE, _async_close_resolver)
return resolver
@callback
def _async_make_resolver(hass: HomeAssistant) -> HassAsyncDNSResolver:
return HassAsyncDNSResolver(async_zeroconf=zeroconf.async_get_async_zeroconf(hass))