Build a Virtual Whiteboard for Back to School: Save Incoming SMS, MMS, and Voice Calls to Airtable with JavaScript

Friends gathered around laptop reviewing virtual whiteboard

Time to read: 5 minutes

August 25, 2022
Written by
Ashley Boucher
Twilion
Reviewed by
Hayden Powers
Twilion
Matthew Setter
Twilion

It’s back to school time and for college students in a remote environment, what better way to recreate the dorm experience than with a virtual whiteboard. Your friends can send a text or MMS to your Twilio phone number and it will appear on your web app.

In learning how to build a virtual whiteboard, you’ll master two concepts: saving incoming SMS and MMS messages to an Airtable database, and displaying these messages on a web app. That second part – displaying the messages on a web app – will be covered in a second post.

Prerequisites

To get started with this tutorial, you’ll need the following:

Create your Airtable base

Login to your Airtable dashboard and click on the grey square with the plus button to create a new base in your workspace. Once you click on it, a small submenu will appear. Select the Start from Scratch option. When prompted, name your base “Virtual Whiteboard”.

In the top left of your new base, you’ll see a tab for the current table named Table 1. Double click the tab and change the name of the tab to “Posts”.

There are four columns, known in Airtable as fields, that have been automatically added to your table.

Screenshot of new airtable with autogenerated fields

Delete the three rightmost fields, Notes, Attachments, and Status, by clicking the small arrow next to each of their names and selecting Delete Field at the very bottom of the sub-menu.

Double click the name of the remaining field, Name, to edit its name and type. Change its type to an auto-generated ID by selecting Autonumber from the dropdown. Then change the name of the Name field to id.

Add the following fields by clicking the + button to the right of the final column:

Field nameField Type
`created`Created time
`body`Long text
`from`Single line text
`attachmentUrl`Single line text
`type`Single line text

At this point, your Airtable base should look like this:

Screenshot of airtable base with appropriate fields

Build the app’s backend with Twilio Functions

The backend of your app will run on Twilio Functions. Twilio Functions is a serverless environment that lets you deploy backend services without the overhead of setting up a server. With Twilio Functions, you can develop locally and deploy to production through the Twilio CLI.

The first step is to create a Functions Service. If you haven’t already, install the Twilio CLI using the following command:

npm install twilio-cli -g

Next, install the Twilio Serverless Toolkit plugin for the Twilio CLI:

twilio plugins:install @twilio-labs/plugin-serverless

Run the following command to login to the Twilio CLI:

twilio login

You’ll be prompted to enter your credentials, which can be found in the Twilio Console.

Now that you have the plugin installed and you’re logged in, you can initialize a new Functions service:

twilio serverless:init virtual-whiteboard-server

This command will create a new directory on your computer called virtual-whiteboard-server. Still inside your terminal, navigate into this folder by running the following command:

cd virtual-whiteboard-server

Because you’re using Airtable to store incoming messages to your Twilio number, you’ll need to install the Airtable npm package:

npm install airtable

Add your Twilio and Airtable credentials to your environment

In your file navigator, find your new virtual-whiteboard-server folder and open the .env file that was automatically created for you when you created the Functions Service. This file should be pre-populated with your Twilio Account SID. It may also be pre-populated with your Auth Token or have a blank variable where you can add it. Verify that both these values are present and correct. They can be found in the Twilio Console.

Get an Airtable API Key

To get an Airtable API key, visit the Account section of Airtable and scroll down to the API section. Click the button that says Generate API key.

screenshot of airtable account page with generate api key button

This will create a new key that will be masked unless you click on it.

screenshot of masked api key in airtable account page

Click into the field with your masked key to toggle the visibility.

In your .env file, add your new Airtable API key by pasting in the following line and replacing the placeholder XXX value with your actual API key.

AIRTABLE_API_KEY=XXX

Save and close your .env file.

Create your functions

Open the sub-folder virtual-whiteboard-server/functions and delete the folder's contents, but not the folder itself.

To create the three function files you’ll need for this app, run the following command from your terminal or create them in your text editor:

touch functions/messaging.js functions/voice.js functions/record.js

Open the new messaging.js file in your favorite text editor. Paste in the following code:


var Airtable = require('airtable');

exports.handler = async function(context, event, callback) {
  var base = new Airtable({apiKey: context.AIRTABLE_API_KEY}).base('XXX');
  const client = context.getTwilioClient();

  //formats phone number
  const from = await client.lookups.phoneNumbers(event.From).fetch();
  const fromFormatted = from.nationalFormat;

  //creates object from message data
  const newPost = {
    "body": event.Body,
    "from": fromFormatted,
    "type": event.MediaContentType0 || 'text'
  }

  if (parseInt(event.NumMedia) > 0) {
    newPost.attachmentUrl = event.MediaUrl0;
  }

  //tries to insert object into Airtable database
  try {
    const record = await base('Posts').create(newPost);
    console.log(record.getId());
  } catch (err) {
    console.log(err);
  }

  //replies to sender with a thank you message for confirmation
  const twiml = new Twilio.twiml.MessagingResponse();
  twiml.message("Thanks for writing on my whiteboard!");
  return callback(null, twiml);
};

On line four in the code above, be sure to replace the XXX with your actual Base ID. The Base ID can be found in the API documentation for your base.

This function will be run every time a message comes in to your Twilio phone number. The function intercepts the message, processes and organizes some of the data attached to the message, and then uploads the organized data to Airtable using the Airtable API.

Save and close this file.

Open the voice.js file and paste in the following code:

exports.handler = async function(context, event, callback) {
  const twiml = new Twilio.twiml.VoiceResponse();
  twiml.say('Thanks for leaving a voice message on my virtual whiteboard!');
  twiml.record({
    action: '/record'
  });

  return callback(null, twiml);
};

The function runs whenever there is an incoming voice call to your Twilio phone number. When the call connects, the caller will hear “Thanks for leaving a voice message on my virtual whiteboard!” Afterward there will be a beep and the code will initialize a recording sequence that allows the caller to leave a voice message.

When the recording has finished processing, this function will run whatever file is referenced in the action value on line five. In this case, that’s record.js, which you’ll complete now.

Open record.js and paste in the following code:

var Airtable = require('airtable');

exports.handler = async function(context, event, callback) {
  var base = new Airtable({apiKey: context.AIRTABLE_API_KEY}).base('XXX');
  const client = context.getTwilioClient();
  const from = await client.lookups.phoneNumbers(event.Caller).fetch();
  const fromFormatted = from.nationalFormat;

  const newPost = {
    "type": 'voice',
    "from": fromFormatted,
    "attachmentUrl": event.RecordingUrl
  }

  try {
    const record = await base('Posts').create(newPost);
    console.log(record.getId());
  } catch (err) {
    console.log(err);
  }

  return callback(null);
};

On line four in the code above, be sure to replace the XXX with your actual Base ID.

This code is very similar to the code in messaging.js, except the post data uploaded to Airtable will be of type voice and it will include the recording URL provided by Twilio, and not a text message body.

Save and close any open files.

Deploy your functions

From your terminal, first make sure you’re in the top-level directory of your project (virtual-whiteboard-server), and then run the following command to deploy your Function Service:

twilio serverless:deploy

It will take a few moments for the deployment to complete, but once it does, you’ll be presented with details about it including the URL to each of your functions (and any assets, if you had any).

Take note of the URLs for your messaging.js and voice.js functions. These URLs should look something like this:

https://virtual-whiteboard-server-XXX-dev.twil.io/messaging
https://virtual-whiteboard-server-XXX-dev.twil.io/voice

You’ll need these URLs in just a moment to configure your webhooks.

If you already had the Twilio Serverless Plugin installed and ran into an error about the Twilio Runtime when you tried to deploy, here is a good troubleshooting guide.

Configure your webhooks

In your web browser, navigate to the Phone Numbers section of the Twilio Console and then click on your phone number.

Voice webhook

Scroll down to the Voice & Fax section and select the following settings:

  • For “Accept Incoming” select Voice Calls.
  • For “Configure with” select Webhook, TwiML Bin, Function, Studio Flow, Proxy Service.
  • For “A call comes in” select Function in the left dropdown.
  • For “Service” select virtual-whiteboard-server, or the name of the service you created earlier.
  • For “Environment” select dev-environment.
  • For “Function Path” select /voice.

Screenshot of voice webhook configuration section

Messaging webhook

Scroll down a little farther on the page to the Messaging section, and select the following settings:

  • For “Configure with” select Webhook, TwiML Bin, Function, Studio Flow, or Proxy Service.
  • For “A message comes in” select Function in the left dropdown.
  • For “Service” select virtual-whiteboard-server, or the name of the service you created earlier.
  • For “Environment” select dev-environment.
  • For “Function Path” select /messaging.

screenshot of messaging configuration for twilio phone number

Don’t forget to click the Save button at the bottom of the page to record these changes!

Test it out

On your mobile device, text or call your Twilio phone number. If you’re calling, leave a voice message. In your web browser, head over to your Airtable base to see if your text or voice message was properly inserted.

I hope you enjoyed learning about saving incoming messages and voice calls to your virtual whiteboard to Airtable. In the next part of this article, learn how to access these posts in a Svelte app.

Ashley is a JavaScript Editor for the Twilio blog. To work with her and bring your technical stories to Twilio, find her at @ahl389 on Twitter. If you can’t find her there, she’s probably on a patio somewhere having a cup of coffee (or glass of wine, depending on the time).

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