simple-oauth2

import { AuthorizationCode } from 'simple-oauth2'; import express from 'express'; import 'dotenv/config'; // For process.env const app = express(); const port = process.env.PORT || 3000; // Basic configuration for the OAuth2 client const config = { client: { id: process.env.OAUTH_CLIENT_ID ?? 'YOUR_CLIENT_ID', secret: process.env.OAUTH_CLIENT_SECRET ?? 'YOUR_CLIENT_SECRET' }, auth: { tokenHost: process.env.OAUTH_TOKEN_HOST ?? 'https://oauth.example.com', authorizePath: process.env.OAUTH_AUTHORIZE_PATH ?? '/oauth/authorize', tokenPath: process.env.OAUTH_TOKEN_PATH ?? '/oauth/token' } }; const client = new AuthorizationCode(config); const redirect_uri = process.env.OAUTH_REDIRECT_URI ?? `http://localhost:${port}/callback`; const scope = process.env.OAUTH_SCOPE ?? 'read write'; // Step 1: Redirect to the authorization server app.get('/auth', (req, res) => { const authorizationUri = client.authorizeURL({ redirect_uri, scope, state: 'random_state_string' // Should be a securely generated random string }); console.log(`Redirecting to: ${authorizationUri}`); res.redirect(authorizationUri); }); // Step 2: Handle the callback from the authorization server app.get('/callback', async (req, res) => { const { code, state } = req.query; // You should validate the 'state' parameter here to prevent CSRF attacks if (state !== 'random_state_string') { return res.status(403).send('Invalid state parameter'); } const tokenParams = { code: code as string, redirect_uri, scope }; try { const accessToken = await client.getToken(tokenParams); console.log('Successfully retrieved access token:'); console.log(accessToken.token); // Example: Refresh token if expired (or near expiration) if (accessToken.expired()) { console.log('Access token is expired, attempting to refresh...'); const refreshedToken = await accessToken.refresh(); console.log('Refreshed token:', refreshedToken.token); } res.send(`Access Token: ${accessToken.token.access_token}<br/>Refresh Token: ${accessToken.token.refresh_token || 'N/A'}`); } catch (error: any) { console.error('Access Token Error', error.message); res.status(500).send(`Authentication failed: ${error.message}`); } }); app.get('/', (req, res) => { res.send('<a href="/auth">Login with OAuth2</a>'); }); app.listen(port, () => { console.log(`Server running at http://localhost:${port}`); console.log('Visit /auth to initiate the OAuth2 flow.'); });