Node and Twilio integration - node.js

Question

I have written a programmable SMS feature using Twilio in nodejs. I have a message that has options to select and when user sends back any response I want to send an automated response using twilio.
I have completed all except after processing the response from user my automated response is not being delivered to user.
I keep getting above thing from my twilio dashboard.
Here is my response handler code..
app.post('/ui/sms',function(req, res) {
//req.headers['Content-type'] = 'text/xml';
//req.headers['Accept'] = 'text/xml';
try {
console.log('Processing Response', req.headers);
const MessagingResponse = require('twilio').twiml.MessagingResponse;
const twiml = new MessagingResponse();
const fromTwilio = isFromTwilio(req);
console.log('isFromTwilio: ', fromTwilio);
if (fromTwilio) {
let msg = req.body.Body||'';
if (msg.indexOf('1')>-1) {
twiml.message('Thanks for confirming your appointment.');
} else if (msg.indexOf('2')>-1) {
twiml.message('Please call 408-xxx-xxxx to reschedule.');
} else if (msg.indexOf('3')>-1) {
twiml.message('We will call you to follow up.');
} else {
twiml.message(
'Unknown option, please call 408-xxx-xxxx to talk with us.'
);
}
res.writeHead(200, { 'Content-Type': 'text/xml' });
res.end(twiml.toString());
}
else {
// we don't expect these
res.status(500).json({ error: 'Cannot process your request.' });
}
/*processSMSResponse(req, function(response) {
res.json(response);
});*/
} catch(e) {
res.json(e);
}
});
function isFromTwilio(req) {
console.log('REQ HEADER:::::::::\n', req);
// Get twilio-node from twilio.com/docs/libraries/node
const client = require('twilio');
// Your Auth Token from twilio.com/console
const authToken = 'xxxxxxxxxxxxxxxxx';
// The Twilio request URL
//const url = 'https://mycompany.com/myapp.php?foo=1&bar=2';
const url = 'https://xxxx.com/ui/sms';
var reqUrl = 'https://xxxx.com/ui/sms'
// The post variables in Twilio's request
//const params = {
//CallSid: 'CA1234567890ABCDE',
//Caller: '[phone]',
//Digits: '1234',
//From: '[phone]',
//To: '[phone]',
//};
const params = req.body;
console.log('post params: ', params);
// The X-Twilio-Signature header attached to the request
try{
Object.keys(params).sort().forEach(function(key) {
reqUrl = reqUrl + key + params[key];
});
var twilioSignature = crypto.createHmac('sha1', authToken).update(Buffer.from(reqUrl, 'utf-8')).digest('base64');
//const twilioSignature = req.header('HTTP_X_TWILIO_SIGNATURE');
console.log('twilioSignature: ', twilioSignature);
} catch(e){
console.log(e);
}
return client.validateRequest(
authToken,
twilioSignature,
url,
params
);
}
I have explicitly tried setting headers but no use. I'm clue less on what twilio expects from me or how to modify headers.
{
"status": "Error",
"error": "<?xml version=\"1.0\" encoding=\"UTF-8\"?><Response><Message>Please call 408-xxx-xxxx to reschedule.</Message></Response>"
}
I see this as body in Twilio console and it has the response that I need but could not send as a message..

Answer 1

Twilio Developer Evangelist here.
From looking at your code and trying it myself I can't see anything generally wrong with it. There are two potential failing points here though:
1) I can't see your isFromTwilio function. If that one fails it might cause an error and then return JSON instead of XML on your error handler. I don't know why it would reply with the TwiML in that JSON though.
2) The other behavior I could reproduce (except that the TwiML is not being sent in the response body) is when I don't include body-parser in the middleware chain. This will cause req.body to be undefined and therefore req.body.Body will throw an error that is then being caught and JSON is being returned.
Do you have body-parser included and properly included as a middleware? You can either do it this way:
const { urlencoded } = require('body-parser');
app.use(urlencoded({ extended: false });
or if you only want to use it for this one endpoint you can add urlencoded({ extended: false }) as an argument before your request handler:
app.post('/ui/sms', urlencoded({ extended: false }), function(req, res) {
I hope this helps.
Cheers,
Dominik