Add simplified pstn examples (#1822)

* Add simplified pstn examples
* Add daily_twilio_sip_dial_out example

examples/phone-chatbot/daily-twilio-sip-dial-in/server.py

@@ -0,0 +1,116 @@
+"""Webhook server to handle Twilio calls and start the voice bot."""
+
+import os
+import shlex
+import subprocess
+from contextlib import asynccontextmanager
+
+import aiohttp
+import uvicorn
+from dotenv import load_dotenv
+from fastapi import FastAPI, HTTPException, Request
+from fastapi.responses import PlainTextResponse
+from twilio.twiml.voice_response import VoiceResponse
+from utils.daily_helpers import create_sip_room
+
+# Load environment variables
+load_dotenv()
+
+
+# Initialize FastAPI app with aiohttp session
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    # Create aiohttp session to be used for Daily API calls
+    app.state.session = aiohttp.ClientSession()
+    yield
+    # Close session when shutting down
+    await app.state.session.close()
+
+
+app = FastAPI(lifespan=lifespan)
+
+
+@app.post("/start", response_class=PlainTextResponse)
+async def handle_call(request: Request):
+    """Handle incoming Twilio call webhook."""
+    print("Received call webhook from Twilio")
+
+    try:
+        # Get form data from Twilio webhook
+        form_data = await request.form()
+        data = dict(form_data)
+
+        # Extract call ID (required to forward the call later)
+        call_sid = data.get("CallSid")
+        if not call_sid:
+            raise HTTPException(status_code=400, detail="Missing CallSid in request")
+
+        # Extract the caller's phone number
+        caller_phone = str(data.get("From", "unknown-caller"))
+        print(f"Processing call with ID: {call_sid} from {caller_phone}")
+
+        # Create a Daily room with SIP capabilities
+        try:
+            room_details = await create_sip_room(request.app.state.session, caller_phone)
+        except Exception as e:
+            print(f"Error creating Daily room: {e}")
+            raise HTTPException(status_code=500, detail=f"Failed to create Daily room: {str(e)}")
+
+        # Extract necessary details
+        room_url = room_details["room_url"]
+        token = room_details["token"]
+        sip_endpoint = room_details["sip_endpoint"]
+
+        # Make sure we have a SIP endpoint
+        if not sip_endpoint:
+            raise HTTPException(status_code=500, detail="No SIP endpoint provided by Daily")
+
+        # Start the bot process
+        bot_cmd = f"python bot.py -u {room_url} -t {token} -i {call_sid} -s {sip_endpoint}"
+        try:
+            # Use shlex to properly split the command for subprocess
+            cmd_parts = shlex.split(bot_cmd)
+
+            # CHANGE: Keep stdout/stderr for debugging
+            # Start the bot in the background but capture output
+            subprocess.Popen(
+                cmd_parts,
+                # Don't redirect output so we can see logs
+                # stdout=subprocess.DEVNULL,
+                # stderr=subprocess.DEVNULL
+            )
+            print(f"Started bot process with command: {bot_cmd}")
+        except Exception as e:
+            print(f"Error starting bot: {e}")
+            raise HTTPException(status_code=500, detail=f"Failed to start bot: {str(e)}")
+
+        # Generate TwiML response to put the caller on hold with music
+        # You can replace the URL with your own music file
+        # or use Twilio's built-in music on hold
+        # https://www.twilio.com/docs/voice/twiml/play#music-on-hold
+        resp = VoiceResponse()
+        resp.play(
+            url="https://therapeutic-crayon-2467.twil.io/assets/US_ringback_tone.mp3",
+            loop=10,
+        )
+
+        return str(resp)
+
+    except HTTPException:
+        raise
+    except Exception as e:
+        print(f"Unexpected error: {str(e)}")
+        raise HTTPException(status_code=500, detail=f"Server error: {str(e)}")
+
+
+@app.get("/health")
+async def health_check():
+    """Simple health check endpoint."""
+    return {"status": "healthy"}
+
+
+if __name__ == "__main__":
+    # Run the server
+    port = int(os.getenv("PORT", "7860"))
+    print(f"Starting server on port {port}")
+    uvicorn.run("server:app", host="0.0.0.0", port=port, reload=True)