Node.js web application (Express)

This quickstart adds OneiD to a server web application with openid-client. Every file is complete and runs as it is.

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Before you start

• A OneiD address, for example https://YOUR_ONEID. The code below uses the demonstration instance https://auth.oltinid.com; replace it with your own.
• A client registered for this application (step 1). The code uses the client ID quickstart; replace it with yours.
• A user who can sign in to your OneiD. For the demonstration instance, ask for a demo account.

1. Register the application

Ask your OneiD administrator to register a client with these settings, or register it yourself in the admin console. See Register an application.

2. Install

npm install express express-session openid-client

3. Add the code

server.js

import express from 'express';
import session from 'express-session';
import * as client from 'openid-client';

const redirectUri = 'http://localhost:3000/callback';

// Reads the endpoints and signing keys from OneiD. `None` = a public client without a secret.
const oneid = await client.discovery(
  new URL('https://auth.oltinid.com'),
  'quickstart',
  undefined,
  client.None(),
);

const app = express();
app.use(session({ secret: 'change-me', resave: false, saveUninitialized: false }));

app.get('/', (req, res) => {
  const user = req.session.user;
  res.send(user ? `Hello, ${user.name}. <a href="/logout">Sign out</a>` : '<a href="/login">Sign in with OneiD</a>');
});

app.get('/login', async (req, res) => {
  const codeVerifier = client.randomPKCECodeVerifier();
  const state = client.randomState();
  req.session.oidc = { codeVerifier, state };

  res.redirect(
    client.buildAuthorizationUrl(oneid, {
      redirect_uri: redirectUri,
      scope: 'openid profile email',
      code_challenge: await client.calculatePKCECodeChallenge(codeVerifier),
      code_challenge_method: 'S256',
      state,
    }).href,
  );
});

app.get('/callback', async (req, res) => {
  const { codeVerifier, state } = req.session.oidc ?? {};
  const tokens = await client.authorizationCodeGrant(oneid, new URL(req.originalUrl, redirectUri), {
    pkceCodeVerifier: codeVerifier,
    expectedState: state,
  });

  req.session.user = tokens.claims(); // the checked ID token: sub, name, email
  req.session.idToken = tokens.id_token;
  res.redirect('/');
});

app.get('/logout', (req, res) => {
  const idToken = req.session.idToken;
  req.session.destroy(() => {
    res.redirect(
      client.buildEndSessionUrl(oneid, {
        id_token_hint: idToken,
        post_logout_redirect_uri: 'http://localhost:3000',
      }).href,
    );
  });
});

app.listen(3000, () => console.log('http://localhost:3000'));

4. Run it

Set “type”: “module” in package.json, then run: node server.js.

The example uses a public client so that it runs without a secret. For your own server application, use a confidential client and pass its secret to the library.

Checkpoint Open http://localhost:3000 and select Sign in with OneiD. After you sign in, the page shows Hello, followed by the user’s name, and a Sign out link.

Common issues

• OneiD shows an error page about the redirect address (invalid_request). The redirect URI the code sends is not registered on the client exactly as written. Register it, including scheme and port.
• invalid_grant from the token endpoint. The code was used before or expired. Start the sign-in again; do not reload the callback page.
• More errors and fixes: Errors and troubleshooting.

Learn more

• Authorization code flow with PKCE
• Sign-out
• Scopes, claims and roles
• Refresh tokens