As you know, I've been playing around with RingCentral lately. While working on another idea (for another post of course), I ran into some difficulty getting their webhook support working. While everything is documented, it didn't quite make sense to me and I had to get it working myself before I actually believed it worked. So with that in mind, here's how I got webhooks with RingCentral working.

Stuff to Know First

First off, take a look at the docs for Webhooks on their platform. In some platforms, you simply specify a URL to hit for a webhook and you're good to go. RingCentral requires you to register a webhook via an API call.

In order to use webhooks, your application has to enable that permission (this is under your app, Settings, OAuth Settings):

Next, note that your webhook must be up and running before you register it. That's not necessarily a bad thing, but it was kind of surprising. In most cases a platform just assumes your URL will work and leaves it it up to you.

When registering your webhook, RingCentral is going to pass a header, validation-token, and if it exists, your webhook has to echo it back in a header and end the request.

To register a webhook, you tell RingCentral what events you care about. Getting that list was a bit difficult. If I read the docs right, the event is basically the same as the API related to that event. My code was working with voicemails, so I used this value: /restapi/v1.0/account/~/extension/~/voicemail.

Now for the last bit, and this is the part I really don't like. When you register a webhook, it isn't permanent. No, it expires after a time. If you want, you can actually specify that you want the service to hit your webhook when it expires. And I guess you... just re-enable it again? Honestly I don't quite get this part. Maybe it's a security setting, but honestly it feels like a lot of burden on the developer. It's already difficult to setup the webhook compared to other services which just let you type in a URL, and this feels like pouring salt in the wound a bit. Now, there may be a very good reason for this setup.

Ok, good news! So I was about to post to a forum thread where I asked why this was necessary (https://forums.developers.ringcentral.com/questions/9774/purpose-of-webhook-expiration.html), and it turns out the API to register a webhook supports an expiresIn value that can be set to as high as 20 years. As Phong Vu explains, instead of trying to listen for a callback saying the webhook expired, if you know the exact time it will expire, you could just schedule the re-register yourself.

So this is good! I still think RingCentral should support a "never expire" option, but I can deal with twenty years.

The Code

What follows is "Get it Working" code. You should not consider this production ready unless your production system is run by these fine people:

My code consists of two parts. First, I wrote a simple Node server with Express to handle my webhook. RingCentral has a Node example as well but I wanted to use Express because, well, I always use Express when I do server stuff. That being said, I realized today I had not used Express in ages. Serverless has made me a bit lazy. So again, do not consider this code to best practice. Here's my webhook which handles the validation and then just logs the incoming request.

//import dependencies
const express = require('express');
const bodyParser = require('body-parser');
const cors = require('cors');
const helmet = require('helmet');
const morgan = require('morgan');

// define the Express app
const app = express();

// enhance your app security with Helmet
app.use(helmet());

// use bodyParser to parse application/json content-type
app.use(bodyParser.json());

// enable all CORS requests
app.use(cors());

// log HTTP requests
app.use(morgan('combined'));

// start the server
app.listen(8081, () => {
	console.log('listening on port 8081');
});

app.post('/webhook', (req,res) => {
	let vt = req.headers['validation-token'];
	if(vt) { 
		res.set('Validation-Token', vt);
		res.end();
	}
	console.log(JSON.stringify(req.body,null,'\t'));  
	res.send('ok');
});

The part you care about is at the end. You can see the validation support and then after that I simply dump the incoming data to the terminal. It's a pretty big object, but it's nicely documented here: https://developers.ringcentral.com/api-reference/Voicemail-Message-Event That's for Voicemails, but in the navigation you can see they define all the different event types.

I ran this and then used ngrok to create an externally facing proxy to my laptop. I've blogged about ngrok before and if you haven't checked it out, definitely do so. It's incredibly helpful for cases like this.

Now for the script I used to create the webhook. Here's the script I used:

const SDK = require('@ringcentral/sdk').SDK

RECIPIENT = '3374128987'

RINGCENTRAL_CLIENTID = 'secret'
RINGCENTRAL_CLIENTSECRET = 'secret'
RINGCENTRAL_SERVER = 'https://platform.devtest.ringcentral.com'

RINGCENTRAL_USERNAME = 'so secret'
RINGCENTRAL_PASSWORD = 'super secret'
RINGCENTRAL_EXTENSION = '101'

var rcsdk = new SDK({
    server: RINGCENTRAL_SERVER,
    clientId: RINGCENTRAL_CLIENTID,
    clientSecret: RINGCENTRAL_CLIENTSECRET
});
var platform = rcsdk.platform();

(async function() {

	await platform.login({
		username: RINGCENTRAL_USERNAME,
		password: RINGCENTRAL_PASSWORD,
		extension: RINGCENTRAL_EXTENSION
	});

	let response = await rcsdk.send({
		method:'POST',
		url:'/restapi/v1.0/subscription', 
		body:{
			eventFilters:[
				'/restapi/v1.0/account/~/extension/~/voicemail'
			],
			deliveryMode: {
				'transportType':'WebHook',
				'address':'http://c45955bf.ngrok.io/webhook'
			}
		}

	});

	console.log(await response.json());	
	
})();

The important bits are the call to the subscription endpoint. You can see me specifying my filter for voicemail and the URL I got via ngrok. As I said above, I now know I can specify expiresIn in my call (here's the full API doc for creating subscriptions) so I'd modify the above to specify the max value, 630720000.

Ok, after all of that... it worked. I called the number RingCentral has assigned my user, left a voice mail, and saw my webhook get called in about five to ten seconds! I hope this helps. As I said, I found this to be very difficult to get working, but honestly it probably only took me an hour or so and now that I've got it working, I think I could do it again easily enough. Let me know if any of this doesn't make sense!

Header photo by Chunlea Ju on Unsplash