Add go2rtc proxy to fix CORS-blocked WebRTC/MSE streams

backend/routes/go2rtc_proxy.py

@@ -0,0 +1,65 @@
+import asyncio
+import logging
+
+import httpx
+import websockets
+from fastapi import APIRouter, Request, WebSocket, WebSocketDisconnect, Response
+
+from config import get_config
+
+logger = logging.getLogger(__name__)
+router = APIRouter(prefix="/api/go2rtc")
+
+
+@router.post("/webrtc")
+async def proxy_webrtc(request: Request, src: str):
+    """Proxy WebRTC SDP exchange to go2rtc."""
+    config = get_config()
+    target = f"{config.go2rtc.url}/api/webrtc?src={src}"
+    body = await request.body()
+
+    async with httpx.AsyncClient() as client:
+        resp = await client.post(
+            target,
+            content=body,
+            headers={"Content-Type": "application/sdp"},
+            timeout=10.0,
+        )
+
+    return Response(
+        content=resp.content,
+        status_code=resp.status_code,
+        media_type="application/sdp",
+    )
+
+
+@router.websocket("/ws")
+async def proxy_mse_ws(ws: WebSocket, src: str):
+    """Proxy MSE WebSocket to go2rtc."""
+    config = get_config()
+    go2rtc_ws_url = config.go2rtc.url.replace("http", "ws")
+    target = f"{go2rtc_ws_url}/api/ws?src={src}"
+
+    await ws.accept()
+
+    try:
+        async with websockets.connect(target) as upstream:
+
+            async def forward_to_client():
+                async for msg in upstream:
+                    if isinstance(msg, bytes):
+                        await ws.send_bytes(msg)
+                    else:
+                        await ws.send_text(msg)
+
+            async def forward_to_upstream():
+                while True:
+                    data = await ws.receive_text()
+                    await upstream.send(data)
+
+            await asyncio.gather(
+                forward_to_client(),
+                forward_to_upstream(),
+            )
+    except (WebSocketDisconnect, websockets.ConnectionClosed, Exception):
+        pass