Access sender phone number twilio Node.js webhook - node.js

Question

To respond if a user replies to a Twilio message, Twilio makes a post request to a server you can specify. How exactly can I access the sender phone number from the post request params? I want to be able to send them a Twilio message at a later date.
Example Code
const http = require('http');
const express = require('express');
const MessagingResponse = require('twilio').twiml.MessagingResponse;
const app = express();
app.post('/sms', (req, res) => {
const twiml = new MessagingResponse();
twiml.message('The Robots are coming! Head for the hills!');
// is it
// req.params.From
// ?
// that's giving me undefined
res.writeHead(200, {'Content-Type': 'text/xml'});
res.end(twiml.toString());
});
http.createServer(app).listen(8080, () => {
console.log('Express server listening on port 8080');
});
The docs say this information is given in the "post request params" but like I indicated in the example code, req.params.From is returning undefined for me.

Answer 1

Twilio developer evangelist here.
The from phone number, and other parameters, are sent as form encoded parameters (application/x-www-form-urlencoded) in the body of the post request. All the request parameters are listed in the documentation.
To read them, you will need to parse the body of the request using Express's urlencoded middleware (you can set this up for your application by calling app.use(express.urlencoded());) and you will then be able to read the parameters from req.body.From.
const http = require('http');
const express = require('express');
const MessagingResponse = require('twilio').twiml.MessagingResponse;
const app = express();
app.use(express.urlencoded());
app.post('/sms', (req, res) => {
const twiml = new MessagingResponse();
twiml.message('The Robots are coming! Head for the hills!');
console.log(req.body.From);
res.writeHead(200, {'Content-Type': 'text/xml'});
res.end(twiml.toString());
});
http.createServer(app).listen(8080, () => {
console.log('Express server listening on port 8080');
});