Manual OAuth 2.0

env.example

@@ -18,4 +18,9 @@ OAUTH_CLIENT_ID=<foo>
 OAUTH_SECRET=<foo>
 OAUTH_TOKEN_URI=https://id.fabric.swire.io/oauth/token
 OAUTH_AUTH_URI=https://id.fabric.swire.io/login/oauth/authorize
-OAUTH_REDIRECT_URI=https://<foo>.ngrok-free.app/callback
+OAUTH_REDIRECT_URI=https://<foo>.ngrok-free.app/callback
+
+SESSION_SECRET=
+
+SUBSCRIBER_REFERENCE=
+SUBSCRIBER_PASSWORD=

index.js

@@ -1,13 +1,16 @@
 require('dotenv').config();
 const express = require('express');
+const session = require('express-session');
 const app = express();
 const axios = require('axios');
-const ClientOAuth2 = require('client-oauth2')
+const base64url = require('base64url');
+const crypto = require('crypto');
 
 app.set('view engine', 'ejs');
 app.use(express.urlencoded({ extended: true }));
 app.use(express.json());
 app.use(express.static('public'));
+app.use(session({ secret: process.env.SESSION_SECRET, resave: false, saveUninitialized: true }));
 
 const FIREBASE_CONFIG = JSON.stringify({
   apiKey: process.env.FIREBASE_API_KEY,
@@ -28,16 +31,6 @@ const token_request = {
 
 const host = process.env.RELAY_HOST
 
-const oauthConfig = {
-  clientId: process.env.OAUTH_CLIENT_ID,
-  clientSecret: process.env.OAUTH_SECRET,
-  accessTokenUri: process.env.OAUTH_TOKEN_URI,
-  authorizationUri: process.env.OAUTH_AUTH_URI,
-  redirectUri: process.env.OAUTH_REDIRECT_URI
-}
-
-const oauthClient = new ClientOAuth2(oauthConfig)
-
 async function apiRequest(endpoint, payload = {}, method = 'POST') {
   var url = `https://${process.env.SIGNALWIRE_SPACE}${endpoint}`
 
@@ -71,21 +64,56 @@ app.get('/minimal', async (req, res) => {
 });
 
 app.get('/oauth', (req, res) => {
-  const authorizationUri = oauthClient.code.getUri()
+  console.log("oauth: begin initiation");
+  // console.log("Request Headers: ", req.headers);
+
+  const authEndpoint = process.env.OAUTH_AUTH_URI;
+  const verifier = base64url(crypto.pseudoRandomBytes(32));
+  req.session.verifier = verifier;
+  const challenge = base64url(crypto.createHash('sha256').update(verifier).digest());
+
+  const queryParams = new URLSearchParams({
+    response_type: 'code',
+    client_id: process.env.OAUTH_CLIENT_ID,
+    redirect_uri: process.env.OAUTH_REDIRECT_URI,
+    code_challenge: challenge,
+    code_challenge_method: 'S256'
+  })
 
-  res.redirect(authorizationUri)
+  const authorizationUri = `${authEndpoint}?${queryParams}`
+
+  res.redirect(authorizationUri);
 });
 
 app.get('/callback', async (req, res) => {
-  const credentials = await oauthClient.code.getToken(req.originalUrl);
-
-  res.render('index', {
-    host,
-    token: credentials.accessToken,
-    destination: process.env.DEFAULT_DESTINATION,
-    firebaseConfig: FIREBASE_CONFIG,
+  console.log("oauth: process callback");
+  // console.log("Request Headers: ", req.headers);
+
+  const params = new URLSearchParams();
+  params.append('client_id', process.env.OAUTH_CLIENT_ID);
+  params.append('grant_type', 'authorization_code');
+  params.append('code', req.query.code);
+  params.append('redirect_uri', process.env.OAUTH_REDIRECT_URI);
+  params.append('code_verifier', req.session.verifier);
+
+  const response = await fetch(process.env.OAUTH_TOKEN_URI, {
+    method: 'POST',
+    headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
+    body: params
   });
-})
+
+  if (response.ok) {
+    const data = await response.json();
+    res.render('index', {
+      host,
+      token: data.access_token,
+      destination: process.env.DEFAULT_DESTINATION,
+      firebaseConfig: FIREBASE_CONFIG,
+    });
+  } else {
+    throw new Error(`HTTP error! status: ${response.status}`);
+  }
+});
 
 app.get('/service-worker.js', async (req, res) => {
   res.set({
@@ -99,4 +127,4 @@ app.get('/service-worker.js', async (req, res) => {
 
 app.listen(process.env.PORT || 3000, () => {
   console.log("Server running on port 3000");
-});
+});