Initial commit: Gold Trading Simulator with AI-powered analysis

backend/app/api/stream_sse.py

@@ -0,0 +1,87 @@
+from __future__ import annotations
+
+import asyncio
+import contextlib
+import json
+from typing import List, Callable, Awaitable
+
+from fastapi import APIRouter, HTTPException
+from fastapi.responses import StreamingResponse
+
+from app.streaming.binance_hub import hub as binance_hub
+from app.streaming.alpha_hub import alpha_hub
+
+router = APIRouter(prefix="/stream", tags=["Stream"]) 
+
+
+@router.get("/sse")
+async def stream_sse(symbols: str = "BTCUSDT,XAUUSD", timeframe: str = "1m"):
+    """
+    Server-Sent Events (SSE) multiplexer for multiple symbols over a single connection.
+    - Supports 1m timeframe (server streams 1m updates; clients can resample locally).
+    - symbols: comma-separated list (e.g., BTCUSDT,ETHUSDT,XAUUSD)
+    """
+    if not symbols:
+        raise HTTPException(status_code=400, detail="symbols must not be empty")
+    if timeframe != "1m":
+        raise HTTPException(status_code=400, detail="Only timeframe=1m is supported")
+
+    syms: List[str] = [s.strip().upper().replace("/", "") for s in symbols.split(",") if s.strip()]
+    if not syms:
+        raise HTTPException(status_code=400, detail="No valid symbols provided")
+
+    out_queue: asyncio.Queue = asyncio.Queue(maxsize=1000)
+    tasks: List[asyncio.Task] = []
+    unsubscribers: List[Callable[[], Awaitable[None]]] = []
+
+    async def add_subscription(sym: str):
+        if sym.startswith("XAU"):
+            q, unsubscribe = await alpha_hub.subscribe(sym, timeframe="1m")
+        else:
+            q, unsubscribe = await binance_hub.subscribe(sym, timeframe="1m")
+        unsubscribers.append(unsubscribe)
+
+        async def worker():
+            try:
+                while True:
+                    evt = await q.get()
+                    if evt is None:
+                        break
+                    try:
+                        await out_queue.put(evt)
+                    except Exception:
+                        await asyncio.sleep(0)
+            except asyncio.CancelledError:
+                pass
+        tasks.append(asyncio.create_task(worker()))
+
+    for s in syms:
+        await add_subscription(s)
+
+    async def event_generator():
+        try:
+            while True:
+                try:
+                    evt = await asyncio.wait_for(out_queue.get(), timeout=15.0)
+                    data = json.dumps(evt, separators=(",", ":"))
+                    yield f"event: kline\n".encode("utf-8")
+                    yield f"data: {data}\n\n".encode("utf-8")
+                except asyncio.TimeoutError:
+                    # Keep-alive comment
+                    yield b": ping\n\n"
+        finally:
+            for t in tasks:
+                t.cancel()
+            for t in tasks:
+                with contextlib.suppress(Exception):
+                    await t
+            for u in unsubscribers:
+                with contextlib.suppress(Exception):
+                    await u()
+
+    headers = {
+        "Cache-Control": "no-cache",
+        "Connection": "keep-alive",
+        "X-Accel-Buffering": "no",
+    }
+    return StreamingResponse(event_generator(), media_type="text/event-stream", headers=headers)