callControl.js

const express = require('express');
const telnyx = require('telnyx')(process.env.TELNYX_API_KEY);
const router = module.exports = express.Router();
const db = require('./db');

const outboundCallController = async (req, res) => {
  res.sendStatus(200); // Play nice and respond to webhook
  const event = req.body.data;
  const callIds = {
    call_control_id: event.payload.call_control_id,
    call_session_id: event.payload.call_session_id,
    call_leg_id: event.payload.call_leg_id
  }
  console.log(`Received Call-Control event: ${event.event_type} DLR with call_session_id: ${callIds.call_session_id}`);
}

const handleInboundAnswer = async (call, event, req) => {
  console.log(`call_session_id: ${call.call_session_id}; event_type: ${event.event_type}`);
  try {
    const webhook_url = (new URL('/call-control/outbound', `${req.protocol}://${req.hostname}`)).href;
    const destinationPhoneNumber = db.getDestinationPhoneNumber(event.payload.to);
    await call.transfer({
      to: destinationPhoneNumber,
      webhook_url
    })
  } catch (e) {
    console.log(`Error transferring on call_session_id: ${call.call_session_id}`);
    console.log(e);
  }
}

const handleInboundHangup = (call, event) => {
  console.log(`call_session_id: ${call.call_session_id}; event_type: ${event.event_type}`);
  db.saveCall(event);
}

const inboundCallController = async (req, res) => {
  res.sendStatus(200); // Play nice and respond to webhook
  const event = req.body.data;
  const callIds = {
    call_control_id: event.payload.call_control_id,
    call_session_id: event.payload.call_session_id,
    call_leg_id: event.payload.call_leg_id
  }
  const call = new telnyx.Call(callIds);
  switch (event.event_type) {
    case 'call.initiated':
      await call.answer();
      break;
    case 'call.answered':
      await handleInboundAnswer(call, event, req);
      break;
    case 'call.hangup':
      handleInboundHangup(call, event);
      break;
    default:
      console.log(`Received Call-Control event: ${event.event_type} DLR with call_session_id: ${call.call_session_id}`);
  }
}

router.route('/outbound')
.post(outboundCallController);

router.route('/inbound')
.post(inboundCallController);