Implement websocket message coalescing (#77238)

Co-authored-by: Paulus Schoutsen <paulus@home-assistant.io>

homeassistant/components/websocket_api/commands.py

@@ -74,6 +74,7 @@ def async_register_commands(
     async_reg(hass, handle_validate_config)
     async_reg(hass, handle_subscribe_entities)
     async_reg(hass, handle_supported_brands)
+    async_reg(hass, handle_supported_features)
 
 
 def pong_message(iden: int) -> dict[str, Any]:
@@ -723,3 +724,18 @@ async def handle_supported_brands(
             raise int_or_exc
         data[int_or_exc.domain] = int_or_exc.manifest["supported_brands"]
     connection.send_result(msg["id"], data)
+
+
+@callback
+@decorators.websocket_command(
+    {
+        vol.Required("type"): "supported_features",
+        vol.Required("features"): {str: int},
+    }
+)
+def handle_supported_features(
+    hass: HomeAssistant, connection: ActiveConnection, msg: dict[str, Any]
+) -> None:
+    """Handle setting supported features."""
+    connection.supported_features = msg["features"]
+    connection.send_result(msg["id"])

homeassistant/components/websocket_api/connection.py

@@ -42,6 +42,7 @@ class ActiveConnection:
         self.refresh_token_id = refresh_token.id
         self.subscriptions: dict[Hashable, Callable[[], Any]] = {}
         self.last_id = 0
+        self.supported_features: dict[str, float] = {}
         current_connection.set(self)
 
     def context(self, msg: dict[str, Any]) -> Context:

homeassistant/components/websocket_api/const.py

@@ -55,3 +55,5 @@ COMPRESSED_STATE_ATTRIBUTES = "a"
 COMPRESSED_STATE_CONTEXT = "c"
 COMPRESSED_STATE_LAST_CHANGED = "lc"
 COMPRESSED_STATE_LAST_UPDATED = "lu"
+
+FEATURE_COALESCE_MESSAGES = "coalesce_messages"

homeassistant/components/websocket_api/http.py

@@ -6,7 +6,7 @@ from collections.abc import Callable
 from contextlib import suppress
 import datetime as dt
 import logging
-from typing import Any, Final
+from typing import TYPE_CHECKING, Any, Final
 
 from aiohttp import WSMsgType, web
 import async_timeout
@@ -16,11 +16,13 @@ from homeassistant.const import EVENT_HOMEASSISTANT_STOP
 from homeassistant.core import Event, HomeAssistant, callback
 from homeassistant.helpers.dispatcher import async_dispatcher_send
 from homeassistant.helpers.event import async_call_later
+from homeassistant.helpers.json import json_loads
 
 from .auth import AuthPhase, auth_required_message
 from .const import (
     CANCELLATION_ERRORS,
     DATA_CONNECTIONS,
+    FEATURE_COALESCE_MESSAGES,
     MAX_PENDING_MSG,
     PENDING_MSG_PEAK,
     PENDING_MSG_PEAK_TIME,
@@ -31,6 +33,10 @@ from .const import (
 from .error import Disconnect
 from .messages import message_to_json
 
+if TYPE_CHECKING:
+    from .connection import ActiveConnection
+
+
 _WS_LOGGER: Final = logging.getLogger(f"{__name__}.connection")
 
 
@@ -67,26 +73,47 @@ class WebSocketHandler:
         self._writer_task: asyncio.Task | None = None
         self._logger = WebSocketAdapter(_WS_LOGGER, {"connid": id(self)})
         self._peak_checker_unsub: Callable[[], None] | None = None
+        self.connection: ActiveConnection | None = None
 
     async def _writer(self) -> None:
         """Write outgoing messages."""
         # Exceptions if Socket disconnected or cancelled by connection handler
-        with suppress(RuntimeError, ConnectionResetError, *CANCELLATION_ERRORS):
+        to_write = self._to_write
-            while not self.wsock.closed:
+        logger = self._logger
-                if (process := await self._to_write.get()) is None:
+        wsock = self.wsock
-                    break
+        try:
+            with suppress(RuntimeError, ConnectionResetError, *CANCELLATION_ERRORS):
+                while not self.wsock.closed:
+                    if (process := await to_write.get()) is None:
+                        return
+                    message = process if isinstance(process, str) else process()
 
-                if not isinstance(process, str):
+                    if (
-                    message: str = process()
+                        to_write.empty()
-                else:
+                        or not self.connection
-                    message = process
+                        or FEATURE_COALESCE_MESSAGES
-                self._logger.debug("Sending %s", message)
+                        not in self.connection.supported_features
-                await self.wsock.send_str(message)
+                    ):
+                        logger.debug("Sending %s", message)
+                        await wsock.send_str(message)
+                        continue
 
-        # Clean up the peaker checker when we shut down the writer
+                    messages: list[str] = [message]
-        if self._peak_checker_unsub is not None:
+                    while not to_write.empty():
-            self._peak_checker_unsub()
+                        if (process := to_write.get_nowait()) is None:
-            self._peak_checker_unsub = None
+                            return
+                        messages.append(
+                            process if isinstance(process, str) else process()
+                        )
+
+                    coalesced_messages = "[" + ",".join(messages) + "]"
+                    self._logger.debug("Sending %s", coalesced_messages)
+                    await self.wsock.send_str(coalesced_messages)
+        finally:
+            # Clean up the peaker checker when we shut down the writer
+            if self._peak_checker_unsub is not None:
+                self._peak_checker_unsub()
+                self._peak_checker_unsub = None
 
     @callback
     def _send_message(self, message: str | dict[str, Any] | Callable[[], str]) -> None:
@@ -194,13 +221,13 @@ class WebSocketHandler:
                 raise Disconnect
 
             try:
-                msg_data = msg.json()
+                msg_data = msg.json(loads=json_loads)
             except ValueError as err:
                 disconnect_warn = "Received invalid JSON."
                 raise Disconnect from err
 
             self._logger.debug("Received %s", msg_data)
-            connection = await auth.async_handle(msg_data)
+            self.connection = connection = await auth.async_handle(msg_data)
             self.hass.data[DATA_CONNECTIONS] = (
                 self.hass.data.get(DATA_CONNECTIONS, 0) + 1
             )
@@ -218,13 +245,18 @@ class WebSocketHandler:
                     break
 
                 try:
-                    msg_data = msg.json()
+                    msg_data = msg.json(loads=json_loads)
                 except ValueError:
                     disconnect_warn = "Received invalid JSON."
                     break
 
                 self._logger.debug("Received %s", msg_data)
-                connection.async_handle(msg_data)
+                if not isinstance(msg_data, list):
+                    connection.async_handle(msg_data)
+                    continue
+
+                for split_msg in msg_data:
+                    connection.async_handle(split_msg)
 
         except asyncio.CancelledError:
             self._logger.info("Connection closed by client")
@@ -257,6 +289,8 @@ class WebSocketHandler:
 
                 if connection is not None:
                     self.hass.data[DATA_CONNECTIONS] -= 1
+                    self.connection = None
+
                 async_dispatcher_send(self.hass, SIGNAL_WEBSOCKET_DISCONNECTED)
 
         return wsock

tests/components/websocket_api/test_commands.py

@@ -13,12 +13,13 @@ from homeassistant.components.websocket_api.auth import (
     TYPE_AUTH_OK,
     TYPE_AUTH_REQUIRED,
 )
-from homeassistant.components.websocket_api.const import URL
+from homeassistant.components.websocket_api.const import FEATURE_COALESCE_MESSAGES, URL
 from homeassistant.const import SIGNAL_BOOTSTRAP_INTEGRATONS
 from homeassistant.core import Context, HomeAssistant, State, callback
 from homeassistant.exceptions import HomeAssistantError
 from homeassistant.helpers import entity
 from homeassistant.helpers.dispatcher import async_dispatcher_send
+from homeassistant.helpers.json import json_loads
 from homeassistant.loader import async_get_integration
 from homeassistant.setup import DATA_SETUP_TIME, async_setup_component
 
@@ -1788,3 +1789,186 @@ async def test_supported_brands(hass, websocket_client):
             "hello": "World",
         },
     }
+
+
+async def test_message_coalescing(hass, websocket_client, hass_admin_user):
+    """Test enabling message coalescing."""
+    await websocket_client.send_json(
+        {
+            "id": 1,
+            "type": "supported_features",
+            "features": {FEATURE_COALESCE_MESSAGES: 1},
+        }
+    )
+    hass.states.async_set("light.permitted", "on", {"color": "red"})
+
+    data = await websocket_client.receive_str()
+    msg = json_loads(data)
+    assert msg["id"] == 1
+    assert msg["type"] == const.TYPE_RESULT
+    assert msg["success"]
+
+    await websocket_client.send_json({"id": 7, "type": "subscribe_entities"})
+
+    data = await websocket_client.receive_str()
+    msgs = json_loads(data)
+    msg = msgs.pop(0)
+    assert msg["id"] == 7
+    assert msg["type"] == const.TYPE_RESULT
+    assert msg["success"]
+
+    msg = msgs.pop(0)
+    assert msg["id"] == 7
+    assert msg["type"] == "event"
+    assert msg["event"] == {
+        "a": {
+            "light.permitted": {"a": {"color": "red"}, "c": ANY, "lc": ANY, "s": "on"}
+        }
+    }
+
+    hass.states.async_set("light.permitted", "on", {"color": "yellow"})
+    hass.states.async_set("light.permitted", "on", {"color": "green"})
+    hass.states.async_set("light.permitted", "on", {"color": "blue"})
+
+    data = await websocket_client.receive_str()
+    msgs = json_loads(data)
+
+    msg = msgs.pop(0)
+    assert msg["id"] == 7
+    assert msg["type"] == "event"
+    assert msg["event"] == {
+        "c": {"light.permitted": {"+": {"a": {"color": "yellow"}, "c": ANY, "lu": ANY}}}
+    }
+
+    msg = msgs.pop(0)
+    assert msg["id"] == 7
+    assert msg["type"] == "event"
+    assert msg["event"] == {
+        "c": {"light.permitted": {"+": {"a": {"color": "green"}, "c": ANY, "lu": ANY}}}
+    }
+
+    msg = msgs.pop(0)
+    assert msg["id"] == 7
+    assert msg["type"] == "event"
+    assert msg["event"] == {
+        "c": {"light.permitted": {"+": {"a": {"color": "blue"}, "c": ANY, "lu": ANY}}}
+    }
+
+    hass.states.async_set("light.permitted", "on", {"color": "yellow"})
+    hass.states.async_set("light.permitted", "on", {"color": "green"})
+    hass.states.async_set("light.permitted", "on", {"color": "blue"})
+    await websocket_client.close()
+    await hass.async_block_till_done()
+
+
+async def test_message_coalescing_not_supported_by_websocket_client(
+    hass, websocket_client, hass_admin_user
+):
+    """Test enabling message coalescing not supported by websocket client."""
+    await websocket_client.send_json({"id": 7, "type": "subscribe_entities"})
+
+    data = await websocket_client.receive_str()
+    msg = json_loads(data)
+    assert msg["id"] == 7
+    assert msg["type"] == const.TYPE_RESULT
+    assert msg["success"]
+
+    hass.states.async_set("light.permitted", "on", {"color": "red"})
+    hass.states.async_set("light.permitted", "on", {"color": "blue"})
+
+    data = await websocket_client.receive_str()
+    msg = json_loads(data)
+    assert msg["id"] == 7
+    assert msg["type"] == "event"
+    assert msg["event"] == {"a": {}}
+
+    data = await websocket_client.receive_str()
+    msg = json_loads(data)
+    assert msg["id"] == 7
+    assert msg["type"] == "event"
+    assert msg["event"] == {
+        "a": {
+            "light.permitted": {"a": {"color": "red"}, "c": ANY, "lc": ANY, "s": "on"}
+        }
+    }
+
+    data = await websocket_client.receive_str()
+    msg = json_loads(data)
+    assert msg["id"] == 7
+    assert msg["type"] == "event"
+    assert msg["event"] == {
+        "c": {"light.permitted": {"+": {"a": {"color": "blue"}, "c": ANY, "lu": ANY}}}
+    }
+    await websocket_client.close()
+    await hass.async_block_till_done()
+
+
+async def test_client_message_coalescing(hass, websocket_client, hass_admin_user):
+    """Test client message coalescing."""
+    await websocket_client.send_json(
+        [
+            {
+                "id": 1,
+                "type": "supported_features",
+                "features": {FEATURE_COALESCE_MESSAGES: 1},
+            },
+            {"id": 7, "type": "subscribe_entities"},
+        ]
+    )
+    hass.states.async_set("light.permitted", "on", {"color": "red"})
+
+    data = await websocket_client.receive_str()
+    msgs = json_loads(data)
+
+    msg = msgs.pop(0)
+    assert msg["id"] == 1
+    assert msg["type"] == const.TYPE_RESULT
+    assert msg["success"]
+
+    msg = msgs.pop(0)
+    assert msg["id"] == 7
+    assert msg["type"] == const.TYPE_RESULT
+    assert msg["success"]
+
+    msg = msgs.pop(0)
+    assert msg["id"] == 7
+    assert msg["type"] == "event"
+    assert msg["event"] == {
+        "a": {
+            "light.permitted": {"a": {"color": "red"}, "c": ANY, "lc": ANY, "s": "on"}
+        }
+    }
+
+    hass.states.async_set("light.permitted", "on", {"color": "yellow"})
+    hass.states.async_set("light.permitted", "on", {"color": "green"})
+    hass.states.async_set("light.permitted", "on", {"color": "blue"})
+
+    data = await websocket_client.receive_str()
+    msgs = json_loads(data)
+
+    msg = msgs.pop(0)
+    assert msg["id"] == 7
+    assert msg["type"] == "event"
+    assert msg["event"] == {
+        "c": {"light.permitted": {"+": {"a": {"color": "yellow"}, "c": ANY, "lu": ANY}}}
+    }
+
+    msg = msgs.pop(0)
+    assert msg["id"] == 7
+    assert msg["type"] == "event"
+    assert msg["event"] == {
+        "c": {"light.permitted": {"+": {"a": {"color": "green"}, "c": ANY, "lu": ANY}}}
+    }
+
+    msg = msgs.pop(0)
+    assert msg["id"] == 7
+    assert msg["type"] == "event"
+    assert msg["event"] == {
+        "c": {"light.permitted": {"+": {"a": {"color": "blue"}, "c": ANY, "lu": ANY}}}
+    }
+
+    hass.states.async_set("light.permitted", "on", {"color": "yellow"})
+    hass.states.async_set("light.permitted", "on", {"color": "green"})
+    hass.states.async_set("light.permitted", "on", {"color": "blue"})
+    await websocket_client.close()
+    await hass.async_block_till_done()

tests/conftest.py

@@ -2,15 +2,25 @@
 from __future__ import annotations
 
 import asyncio
-from collections.abc import AsyncGenerator
+from collections.abc import AsyncGenerator, Callable, Generator
 from contextlib import asynccontextmanager
 import functools
+from json import JSONDecoder, loads
 import logging
 import ssl
 import threading
+from typing import Any
 from unittest.mock import AsyncMock, MagicMock, Mock, patch
 
-from aiohttp.test_utils import make_mocked_request
+from aiohttp import client
+from aiohttp.pytest_plugin import AiohttpClient
+from aiohttp.test_utils import (
+    BaseTestServer,
+    TestClient,
+    TestServer,
+    make_mocked_request,
+)
+from aiohttp.web import Application
 import freezegun
 import multidict
 import pytest
@@ -57,6 +67,7 @@ from tests.components.recorder.common import (  # noqa: E402, isort:skip
     async_recorder_block_till_done,
 )
 
+
 _LOGGER = logging.getLogger(__name__)
 
 logging.basicConfig(level=logging.DEBUG)
@@ -203,6 +214,97 @@ def load_registries():
     return True
 
 
+class CoalescingResponse(client.ClientWebSocketResponse):
+    """ClientWebSocketResponse client that mimics the websocket js code."""
+
+    def __init__(self, *args: Any, **kwargs: Any) -> None:
+        """Init the ClientWebSocketResponse."""
+        super().__init__(*args, **kwargs)
+        self._recv_buffer: list[Any] = []
+
+    async def receive_json(
+        self,
+        *,
+        loads: JSONDecoder = loads,
+        timeout: float | None = None,
+    ) -> Any:
+        """receive_json or from buffer."""
+        if self._recv_buffer:
+            return self._recv_buffer.pop(0)
+        data = await self.receive_str(timeout=timeout)
+        decoded = loads(data)
+        if isinstance(decoded, list):
+            self._recv_buffer = decoded
+            return self._recv_buffer.pop(0)
+        return decoded
+
+
+class CoalescingClient(TestClient):
+    """Client that mimics the websocket js code."""
+
+    def __init__(self, *args: Any, **kwargs: Any) -> None:
+        """Init TestClient."""
+        super().__init__(*args, ws_response_class=CoalescingResponse, **kwargs)
+
+
+@pytest.fixture
+def aiohttp_client_cls():
+    """Override the test class for aiohttp."""
+    return CoalescingClient
+
+
+@pytest.fixture
+def aiohttp_client(
+    loop: asyncio.AbstractEventLoop,
+) -> Generator[AiohttpClient, None, None]:
+    """Override the default aiohttp_client since 3.x does not support aiohttp_client_cls.
+
+    Remove this when upgrading to 4.x as aiohttp_client_cls
+    will do the same thing
+
+    aiohttp_client(app, **kwargs)
+    aiohttp_client(server, **kwargs)
+    aiohttp_client(raw_server, **kwargs)
+    """
+    clients = []
+
+    async def go(
+        __param: Application | BaseTestServer,
+        *args: Any,
+        server_kwargs: dict[str, Any] | None = None,
+        **kwargs: Any,
+    ) -> TestClient:
+
+        if isinstance(__param, Callable) and not isinstance(  # type: ignore[arg-type]
+            __param, (Application, BaseTestServer)
+        ):
+            __param = __param(loop, *args, **kwargs)
+            kwargs = {}
+        else:
+            assert not args, "args should be empty"
+
+        if isinstance(__param, Application):
+            server_kwargs = server_kwargs or {}
+            server = TestServer(__param, loop=loop, **server_kwargs)
+            client = CoalescingClient(server, loop=loop, **kwargs)
+        elif isinstance(__param, BaseTestServer):
+            client = TestClient(__param, loop=loop, **kwargs)
+        else:
+            raise ValueError("Unknown argument type: %r" % type(__param))
+
+        await client.start_server()
+        clients.append(client)
+        return client
+
+    yield go
+
+    async def finalize() -> None:
+        while clients:
+            await clients.pop().close()
+
+    loop.run_until_complete(finalize())
+
+
 @pytest.fixture
 def hass(loop, load_registries, hass_storage, request):
     """Fixture to provide a test instance of Home Assistant."""