How To Use Recording Add-ons in Node.js

Time to read: 2 minutes

January 10, 2017
Written by
Andrew T. Baker
Twilion
Reviewed by
Paul Kamp
Twilion
Kevin Whinnery
Twilion
Rob Spectre
Twilion
Ricky Robinett
Twilion
David Prothero
Twilion
Stephen Wai
Twilion
Kat King
Twilion
Hector Ortega
Contributor
Opinions expressed by Twilio contributors are their own
Jose Oliveros
Contributor
Opinions expressed by Twilio contributors are their own

recording-add-ons-node

In this guide we’ll cover how to combine Twilio Add-ons with Programmable Voice to use data from Twilio's partners in your Express web application. Let's get started!

What’s an Add-On?

Twilio Add-ons are pre-integrated third party services that you can use with your Twilio application. Add-ons enhance the responses your application receives from Twilio by including additional data from Twilio’s partners.

In this guide we’ll cover how to combine Twilio Add-ons with Programmable Voice to use data from Twilio's partners in your Express web application. The sample code in this guide will use the Twilio Node SDK and the Express web framework. Let's get started.

{
  "status":"successful",
  "message":null,
  "code":null,
  "results":{
    "ibm_watson_speechtotext":{
      "request_sid":"XRc82d4197bbc51d5982588ae367365a51",
      "status":"successful",
      "message":null,
      "code":null,
      "payload":[
        {
        "content_type":"application/json",
        "url":"https://api.twilio.com/2010-04-01/Accounts/AC597d02bf69de79f8f411f289ac211a0d/Recordings/REab85c1c2860471abf040b545c4e5aa40/AddOnResults/XRc82d4197bbc51d5982588ae367365a51/Payloads/XH364bd4514b1377fd8844cd9793416131/Data"
        }
      ],
      "links":{
        "add_on_result":"https://api.twilio.com/2010-04-01/Accounts/AC597d02bf69de79f8f411f289ac211a0d/Recordings/REab85c1c2860471abf040b545c4e5aa40/AddOnResults/XRc82d4197bbc51d5982588ae367365a51",
        "payloads":"https://api.twilio.com/2010-04-01/Accounts/AC597d02bf69de79f8f411f289ac211a0d/Recordings/REab85c1c2860471abf040b545c4e5aa40/AddOnResults/XRc82d4197bbc51d5982588ae367365a51/Payloads",
        "recording":"https://api.twilio.com/2010-04-01/Accounts/AC597d02bf69de79f8f411f289ac211a0d/Recordings/REab85c1c2860471abf040b545c4e5aa40"
      }
    }
  }
}

Here’s an example that uses the IBM Watson Speech to Text Add-on. The generated transcription will be pushed to the application through a callback from Twilio.

The IBM Watson Speech add-on can convert Twilio audio recordings into text using machine intelligence to combine information about grammar and language structure.

{
  "user_token": "XRf951c9b0bce23930750991099e553b0a",
  "results":[
    {
      "results":[
        {
          "keywords_result":{},
          "alternatives":[
            {
            "timestamps":[
              ["I", 0.04, 0.28],
              ["love", 0.28, 0.71],
              ["coding", 0.74, 1.25]
            ],
            "confidence":0.782,
            "transcript":"I love coding "
            }
          ],
          "final":true
        }
      ],
      "result_index":0
    }
  ],
  "id":"b0e7a660-bcb6-11e6-8b1b-192a5f5dc12f",
  "event":"recognitions.completed_with_results"
}

Enabling Add-ons in the Twilio Console

The first stop in using an add-on is your Twilio Console. Log in and navigate to the Add-ons page within the Marketplace section.

Add-ons catalog

Then choose on the add-on you want to enable and click the “Install” button. After accepting the Terms of Service, it will be installed on your account. In this example, we’ll use the IBM Watson Speech to Text Add-on.

IBM Watson Speech to Text install Add-on


Once installed, select the checkbox for the recording method you are using (see the different recording methods here). In our example to follow, we would only need the "Record Verb Recordings".  

Set the "Callback URL" and "Callback Request Method" as appropriate for your public server URL (instructions below).

Pro Tip: you can quickly inspect what Twilio will send to your callback URL using tools like PostBin before you actually set up your server.

IBM Watson Speech to Text Configure tab

Legal implications of call recording

If you choose to record voice or video calls, you need to comply with certain laws and regulations, including those regarding obtaining consent to record (such as California’s Invasion of Privacy Act and similar laws in other jurisdictions). Additional information on the legal implications of call recording can be found in the "Legal Considerations with Recording Voice and Video Communications" Help Center article.

Notice: Twilio recommends that you consult with your legal counsel to make sure that you are complying with all applicable laws in connection with communications you record or store using Twilio.

Now we’re ready to use the extra data from our add-on in our application.

Using Add-on data in your application

Twilio will include data from all of your add-ons in an “AddOns” field on HTTP requests it makes to your application. The following example demonstrates how to access add-on data within your Express application.

const express = require('express');
const bodyParser = require('body-parser')
const axios = require('axios')
const VoiceResponse = require('twilio').twiml.VoiceResponse;

const app = express();
app.use(bodyParser.urlencoded({extended: false}))

app.post('/voice', (req, res) => {
  const twiml = new VoiceResponse()

  twiml.say('Hi! I want to know what do you think about coding.')
  twiml.record({maxLength: '10', action: '/recording'})
  twiml.hangup()

  res.send(twiml.toString())
});

app.post('/recording', (req, res) => {
  const twiml = new VoiceResponse()
  const recordingUrl = req.body.RecordingUrl

  twiml.say('Thanks for howling... take a listen to what you howled.')
  twiml.play(recordingUrl)
  twiml.say('Goodbye.')

  res.send(twiml.toString())
})

app.post('/callback', (req, res) => {
  const addOns = JSON.parse(req.body.AddOns)

  if (!('ibm_watson_speechtotext' in addOns.results)) {
    return 'Add Watson Speech to Text add-on in your Twilio console'
  }

  const payloadUrl = addOns.results.ibm_watson_speechtotext.payload[0].url
  // To set up environmental variables, see http://twil.io/secure
  const accountSID = process.env.TWILIO_ACCOUNT_SID
  const authToken = process.env.TWILIO_AUTH_TOKEN;

  axios.get(payloadUrl, {auth: {username: accountSID, password: authToken}})
    .then(response => {
      const results = response.data.results[0].results
      const transcripts = results.map(item => item.alternatives[0].transcript)
      return transcripts
    })
     .then(transcripts => res.send(transcripts.join(' ')))
})

app.listen();

This application gets the transcription for the recorded call from IBM Watson Speech to Text Add-on we configured in the Twilio console. You can find a detailed specification of the data structure for an individual add-on within that add-on's page in the catalog.

And that’s it! Try giving your application a call to see your add-on in action. If you've never received a Twilio phone call with JavaScript before, check out our guide on that topic.

Where to next?

We focused on the IBM Watson Speech to Text Add-on in this guide, but you can just as easily use any of the add-ons available in the catalog in your Twilio Console.

Check out the full Add-Ons API Reference documentation if you want to learn more about how add-ons work, or even how to publish your own.

Related Posts

Related Resources

A newspaper article

Twilio Docs

From APIs to SDKs to sample apps

API reference documentation, SDKs, helper libraries, quickstarts, and tutorials for your language and platform.
An Open book

Resource Center

The latest ebooks, industry reports, and webinars

Learn from customer engagement experts to improve your own communication.
User group reactions

Ahoy

Twilio's developer community hub

Best practices, code samples, and inspiration to build communications and digital engagement experiences.