Advanced Twilio Setup Guide for Textable.io - Allow you to use Twilio Functions and Twilio Studio

twilioToTextableAndSlack.js

// https://www.textable.co/docs/twilio-setup-guide/
// Textable setup guide doesn't allow you to use Twilio functions or Studio easily. 
// Instead, you can create a twilio function with this code, then use that function
// in Twilio Studio 
// Add axios 0.20.0 as a dependency under Functions Global Config, Dependencies
const axios = require('axios');
// Add qs 6.9.4 as a dependency under Functions Global Config, Dependencies
const qs = require('qs');
const crypto = require('crypto');
// Add awesome-phonenumber 2.55 as a dependency under Functions Global Config, Dependencies
const PhoneNumber = require( 'awesome-phonenumber' );

exports.handler = async function(context, event, callback) {  
    await postToTextable(context, event);
    await postToSlack(event);
    return callback(null);
};

async function postToTextable(context, event) {
  const textableUrl = 'https://inbound.textable.app/receive?provider=twilio';
  const twilioRequestSignature = getExpectedTwilioSignature(context.AUTH_TOKEN, textableUrl, event);
  await axios({
    method: 'post',
    url: textableUrl,
    data: qs.stringify(event),
    headers: {
      'X-Twilio-Signature': twilioRequestSignature,
      'User-Agent': 'TwilioProxy/1.1',
      'Content-Type': 'application/x-www-form-urlencoded',
    },
  })
}

async function postToSlack(event) {
  const message = event.Body;
  const mediaCount = event.NumMedia;
  const fromCity = event.FromCity;
  const fromNumber = event.From;
  const phoneNumber = new PhoneNumber(fromNumber);
  const fromState = event.FromState;
  console.log(JSON.stringify(event));
  
  const blocks = [];
  
  if (message) {
    blocks.push(SlackBlockKit.section.plain_text(message));
  }
  
  blocks.push(SlackBlockKit.context.plain_text(`From: ${phoneNumber.getNumber('national')} - ${fromCity}, ${fromState} - ${mediaCount} media/attachments`));
  blocks.push(SlackBlockKit.divider())
  
  await axios({
    method: 'post',
    url: YOUR_SLACK_WEBHOOK_URL,
    data: {
      "blocks": blocks
    }
  })
}

const SlackBlockKit = {
  divider: () => {
    return  {
      "type": "divider"
    }
  },
  context: {
    plain_text: (text) => {
      return {
        "type": "context",
        "elements": [
          {
            "type": "plain_text",
            "text": text,
            "emoji": true
          }
        ]
      }
    },
  },
  section: {
    plain_text: (text) => {
      return {
        "type": "section",
        "text": {
          "type": "plain_text",
          "text": text,
          "emoji": true
        }
      }
    },
  },
  image: {
    title: (url, title) => {
      return {
        "type": "image",
        "title": {
          "type": "plain_text",
          "text": title,
          "emoji": true
        },
        "image_url": url,
        "alt_text": title
      }
    },
  },
};

/**
 Unfortunately, the twilio node library doesn't expose this method. So I copy/pasted it
 Textable will reject any requests that don't have a proper signature.
 Copy pasted from here: https://github.com/twilio/twilio-node/blob/main/lib/webhooks/webhooks.js#L61-L74
 Here are a couple articles about how the signature is used in wehooks:
 - https://www.twilio.com/docs/usage/security
 - https://www.twilio.com/docs/usage/webhooks/webhooks-security
 Utility function to get the expected signature for a given request
 @param {string} authToken - The auth token, as seen in the Twilio portal
 @param {string} url - The full URL (with query string) you configured to handle this request
 @param {object} params - the parameters sent with this request
 @returns {string} - signature
 */
function getExpectedTwilioSignature(authToken, url, params) {
  if (url.indexOf('bodySHA256') !== -1 && params === null) {
    params = {};
  }

  var data = Object.keys(params)
    .sort()
    .reduce((acc, key) => acc + key + params[key], url);

  return crypto
    .createHmac('sha1', authToken)
    .update(Buffer.from(data, 'utf-8'))
    .digest('base64');
}