From b43a7ff1fe5ea8d4f8099f6011e422ee58510d13 Mon Sep 17 00:00:00 2001
From: Paulus Schoutsen <balloob@gmail.com>
Date: Fri, 28 Feb 2025 22:01:39 +0000
Subject: [PATCH] Stream the TTS result from webview (#139543)

---
 homeassistant/components/tts/__init__.py | 36 ++++++++++++++++++------
 1 file changed, 27 insertions(+), 9 deletions(-)

diff --git a/homeassistant/components/tts/__init__.py b/homeassistant/components/tts/__init__.py
index 5b2da44eae2..32c4ba20670 100644
--- a/homeassistant/components/tts/__init__.py
+++ b/homeassistant/components/tts/__init__.py
@@ -3,6 +3,7 @@
 from __future__ import annotations
 
 import asyncio
+from collections.abc import AsyncGenerator
 from dataclasses import dataclass
 from datetime import datetime
 import hashlib
@@ -379,7 +380,7 @@ class ResultStream:
     """Class that will stream the result when available."""
 
     # Streaming/conversion properties
-    url: str
+    token: str
     extension: str
     content_type: str
 
@@ -391,6 +392,11 @@ class ResultStream:
 
     _manager: SpeechManager
 
+    @cached_property
+    def url(self) -> str:
+        """Get the URL to stream the result."""
+        return f"/api/tts_proxy/{self.token}"
+
     @cached_property
     def _result_cache_key(self) -> asyncio.Future[str]:
         """Get the future that returns the cache key."""
@@ -401,11 +407,11 @@ class ResultStream:
         """Set cache key for message to be streamed."""
         self._result_cache_key.set_result(cache_key)
 
-    async def async_get_result(self) -> bytes:
+    async def async_stream_result(self) -> AsyncGenerator[bytes]:
         """Get the stream of this result."""
         cache_key = await self._result_cache_key
         _extension, data = await self._manager.async_get_tts_audio(cache_key)
-        return data
+        yield data
 
 
 def _hash_options(options: dict) -> str:
@@ -603,7 +609,7 @@ class SpeechManager:
         token = f"{secrets.token_urlsafe(16)}.{extension}"
         content, _ = mimetypes.guess_type(token)
         result_stream = ResultStream(
-            url=f"/api/tts_proxy/{token}",
+            token=token,
             extension=extension,
             content_type=content or "audio/mpeg",
             use_file_cache=use_file_cache,
@@ -1027,20 +1033,32 @@ class TextToSpeechView(HomeAssistantView):
         """Initialize a tts view."""
         self.manager = manager
 
-    async def get(self, request: web.Request, token: str) -> web.Response:
+    async def get(self, request: web.Request, token: str) -> web.StreamResponse:
         """Start a get request."""
         stream = self.manager.token_to_stream.get(token)
 
         if stream is None:
             return web.Response(status=HTTPStatus.NOT_FOUND)
 
+        response: web.StreamResponse | None = None
         try:
-            data = await stream.async_get_result()
-        except HomeAssistantError as err:
-            _LOGGER.error("Error on get tts: %s", err)
+            async for data in stream.async_stream_result():
+                if response is None:
+                    response = web.StreamResponse()
+                    response.content_type = stream.content_type
+                    await response.prepare(request)
+
+                await response.write(data)
+        # pylint: disable=broad-except
+        except Exception as err:  # noqa: BLE001
+            _LOGGER.error("Error streaming tts: %s", err)
+
+        # Empty result or exception happened
+        if response is None:
             return web.Response(status=HTTPStatus.INTERNAL_SERVER_ERROR)
 
-        return web.Response(body=data, content_type=stream.content_type)
+        await response.write_eof()
+        return response
 
 
 @websocket_api.websocket_command(