Overview
ExotelFrameSerializer enables integration with Exotel’s WebSocket media streaming protocol, allowing your Pipecat application to handle phone calls via Exotel’s voice services.
Features
- Bidirectional audio conversion between Pipecat and Exotel
- DTMF (touch-tone) event handling
Installation
The ExotelFrameSerializer does not require any additional dependencies beyond the core Pipecat library.
Configuration
Constructor Parameters
call_sid
Optional[str]
default:"None"
The associated Exotel Call SID.
params
InputParams
default:"InputParams()"
Sample rate used by Exotel (typically 8kHz)
Optional override for pipeline input sample rate
Basic Usage
from pipecat.serializers.exotel import ExotelFrameSerializer
from pipecat.transports.network.fastapi_websocket import (
FastAPIWebsocketTransport,
FastAPIWebsocketParams
)
# Extract required values from Exotel WebSocket connection
stream_id = call_data["stream_id"]
call_sid = call_data["start"]["call_sid"]
# Create serializer
serializer = ExotelFrameSerializer(
stream_id=stream_id,
call_sid,
)
# Use with FastAPIWebsocketTransport
transport = FastAPIWebsocketTransport(
websocket=websocket,
params=FastAPIWebsocketParams(
audio_in_enabled=True,
audio_out_enabled=True,
vad_analyzer=SileroVADAnalyzer(),
serializer=serializer,
)
)
Server Code Example
Here’s a complete example of handling a Exotel WebSocket connection:
from fastapi import FastAPI, WebSocket
from pipecat.serializers.exotel import ExotelFrameSerializer
import json
import os
app = FastAPI()
@app.websocket("/ws")
async def websocket_endpoint(websocket: WebSocket):
await websocket.accept()
# Read initial messages from Exotel
start_data = websocket.iter_text()
await start_data.__anext__() # Skip first message
# Parse the second message to get call details
call_data = json.loads(await start_data.__anext__())
# Extract Exotel-specific IDs and encoding
stream_id = call_data["stream_id"]
call_sid = call_data["start"]["call_sid"]
# Create serializer with API key for auto hang-up
serializer = ExotelFrameSerializer(
stream_id=stream_id,
call_sid=call_sid,
)
# Continue with transport and pipeline setup...
