TypeScript code demonstrating authenticating to and calling a MassDOT API

massdot.ts

// Usage: 
// 1. Request API access here: https://www.mass.gov/service-details/highway-data-for-developers
// 2. When your account details arrive create 3 environment vars
//    MASSDOT_USERNAME
//    MASSDOT_PASSWORD
//    MASSDOT_SECRET_KEY
// 3. ts-node massdot.ts


import dotenv from "dotenv";
import fetch, { RequestInit } from 'node-fetch';
import crypto from 'crypto';

// This file demostrates how to call the MassDot API using the credentials in the .env file.
// Swagger doc is available here: https://data-api.massgotime.com/index.html

// To call the MassDOT APIs you must first request a token from /auth-token then
// follow a six (!!) step process as described in the /auth-token docs and illustrated below.

dotenv.config({ path: ".env" });

function log(s) {
// Uncomment for debug output
//  console.log(s);
}

log(`Username: ${process.env.MASSDOT_USERNAME}`);
log(`Password: ${process.env.MASSDOT_PASSWORD}`);
log(`Secret:   ${process.env.MASSDOT_SECRET_KEY}`);

const basic = `${process.env.MASSDOT_USERNAME}:${process.env.MASSDOT_PASSWORD}`;
log(`Basic string: ${basic}`);
const authBasic = `Basic ${Buffer.from(basic).toString("base64")}`;
log(`Base64: ${authBasic}`);

log(authBasic);

const fetchOptions: RequestInit = {
  method: "GET",
  timeout: 5000,
  headers: {
    Authorization: authBasic,
    Accept: "application/json",
  }
}

fetch("https://data-api.massgotime.com/auth-token", fetchOptions)
  .then((res) => res.ok ? res.json() : Promise.reject(res))
  .then((data) => {
    // Step 1: Concatenate the user's secret key with the token provided herein, separated by a colon. ('SecretKey:token')
    let step1 = `${process.env.MASSDOT_SECRET_KEY}:${data.token}`;
    log(`Step 1: ${step1}`);
    // Step 2: Create a SHA256 hash of the concatenated string. (i.e. SHA256(secretKey:token))
    let step2 = crypto.createHash('sha256').update(step1);
    log(`Step 2: create SHA256 hash of ${step1}`);
    // Step 3: Convert the generated hash to a hexadecimal string representation
    let step3 = step2.digest('hex');
    log(`Step 3: ${step3}`);
    // Step 4: Concatenate the user's username with the hexadecimal hash, separated by a colon. ('username:hexadecimalHash')
    let step4 = `${process.env.MASSDOT_USERNAME}:${step3}`;
    log(`Step 4: ${step4}`);
    // Step 5: Create the base-64 string representation of the concatenation. (Base64('username:hexadecimalHash'))
    let step5 = Buffer.from(step4).toString("base64");
    log(`Bearer ${step5}`);
    // Step 6: The result is the signature required for Bearer type authorization. (Authorization Bearer 'generated signature')  
    fetchOptions.headers["Authorization"] = `Bearer ${step5}`;
    fetch("https://data-api.massgotime.com/v1/inventory/signs", fetchOptions)
      .then((res) => res.ok ? res.json() : Promise.reject(res))
      .then((data) => {
        console.log(JSON.stringify(data, null, 2));
      }).catch((err) => {
        log(`Error: ${err}`);
      });
  }).catch((err) => {
    console.error(err);
  });