minimal ws echo server

2026-01-28 11:51:46 +08:00
parent 14013608a9
commit 4cb267a288
2 changed files with 297 additions and 0 deletions
--- a/main.py
+++ b/main.py
@@ -0,0 +1,137 @@
+"""
+Step 1: Minimal WebSocket Echo Server
+
+This is the simplest possible WebSocket audio server.
+It accepts connections and echoes back events.
+
+What you'll learn:
+- How to create a FastAPI WebSocket endpoint
+- How to handle mixed text/binary frames
+- Basic event sending
+
+Test with:
+    python main.py
+    python test_client.py
+"""
+
+import asyncio
+import json
+import uuid
+from fastapi import FastAPI, WebSocket
+from loguru import logger
+
+# Configure logging
+logger.remove()
+logger.add(lambda msg: print(msg, end=""), level="INFO", format="<green>{time:HH:mm:ss}</green> | {level} | {message}")
+
+# Create FastAPI app
+app = FastAPI(title="Voice Gateway - Step 1")
+
+
+@app.get("/health")
+async def health_check():
+    """Health check endpoint."""
+    return {"status": "healthy", "step": "1_minimal_echo"}
+
+
+@app.websocket("/ws")
+async def websocket_endpoint(websocket: WebSocket):
+    """
+    WebSocket endpoint for audio streaming.
+
+    This is a minimal echo server that:
+    1. Accepts WebSocket connections
+    2. Sends a welcome event
+    3. Receives text commands and binary audio
+    4. Echoes speaking events back
+    """
+    await websocket.accept()
+
+    # Generate unique session ID
+    session_id = str(uuid.uuid4())
+    logger.info(f"[{session_id}] Client connected")
+
+    try:
+        # Send welcome event (answer)
+        await websocket.send_json({
+            "event": "answer",
+            "trackId": session_id,
+            "timestamp": _get_timestamp_ms()
+        })
+        logger.info(f"[{session_id}] Sent answer event")
+
+        # Message receive loop
+        while True:
+            message = await websocket.receive()
+
+            # Handle binary audio data
+            if "bytes" in message:
+                audio_bytes = message["bytes"]
+                logger.info(f"[{session_id}] Received audio: {len(audio_bytes)} bytes")
+
+                # Send speaking event (echo back)
+                await websocket.send_json({
+                    "event": "speaking",
+                    "trackId": session_id,
+                    "timestamp": _get_timestamp_ms(),
+                    "startTime": _get_timestamp_ms()
+                })
+
+            # Handle text commands
+            elif "text" in message:
+                text_data = message["text"]
+                logger.info(f"[{session_id}] Received text: {text_data[:100]}...")
+
+                try:
+                    data = json.loads(text_data)
+                    command = data.get("command", "unknown")
+                    logger.info(f"[{session_id}] Command: {command}")
+
+                    # Handle basic commands
+                    if command == "invite":
+                        await websocket.send_json({
+                            "event": "answer",
+                            "trackId": session_id,
+                            "timestamp": _get_timestamp_ms()
+                        })
+                        logger.info(f"[{session_id}] Responded to invite")
+
+                    elif command == "hangup":
+                        logger.info(f"[{session_id}] Hangup requested")
+                        break
+
+                    elif command == "ping":
+                        await websocket.send_json({
+                            "event": "pong",
+                            "timestamp": _get_timestamp_ms()
+                        })
+
+                except json.JSONDecodeError as e:
+                    logger.error(f"[{session_id}] Invalid JSON: {e}")
+
+    except Exception as e:
+        logger.error(f"[{session_id}] Error: {e}")
+
+    finally:
+        logger.info(f"[{session_id}] Connection closed")
+
+
+def _get_timestamp_ms() -> int:
+    """Get current timestamp in milliseconds."""
+    import time
+    return int(time.time() * 1000)
+
+
+if __name__ == "__main__":
+    import uvicorn
+
+    logger.info("🚀 Starting Step 1: Minimal WebSocket Echo Server")
+    logger.info("📡 Server: ws://localhost:8000/ws")
+    logger.info("🩺 Health: http://localhost:8000/health")
+
+    uvicorn.run(
+        app,
+        host="0.0.0.0",
+        port=8000,
+        log_level="info"
+    )