# Express (https://docs.idra.zone/docs/quickstarts/express)

Add IdRa sign-in to an Express app with openid-client: register, configure, run, sign out.

A server-side app using the authorization code flow with PKCE, [`openid-client`](https://github.com/panva/openid-client) and `express-session`. Node.js 20.6 or later.

Sample repository (being opened soon): [IdRaHQ/idra-sample-express](https://github.com/IdRaHQ/idra-sample-express). It has this quickstart's code plus a protected page.

## Register the app

Use one app for local development and production. Open your organization's admin console at `https://<your-org>.idra.team/admin` (or `/admin` on your own IdRa). Go to **Applications → Create App Integration**, choose **OIDC - OpenID Connect**, and set:

- **Application type:** **Web Application**
- **App integration name:** any name
- **Sign-in redirect URIs:** `http://localhost:3000/callback`

Leave **Assign this app to me so I can test it** on, then select **Create**. Copy the client secret, shown **once**, and select **I've saved it**.

The app's **Sign On** tab opens:

1. Under **Connect your app**, copy the **Issuer** and **Client ID**. The `.env` snippet there has the same values, named `OIDC_*`; this quickstart names them `IDRA_*`.
2. Add `http://localhost:3000/` to **Sign-out redirect URIs** and select **Save**.

To let other people sign in, assign them or their groups on **Assignments**.

**Local redirects and production**

  `http` redirects work on `localhost`, `127.0.0.1` or `[::1]`, with a port, and match exactly. PKCE stays required while the app has one. For production, add your `https` URIs (such as `https://app.example.com/callback` and `https://app.example.com/`) to the same app, then remove the local ones.

## Configure

```sh title=".env"
IDRA_ISSUER=https://<your-org>.idra.team/api/auth
IDRA_CLIENT_ID=<Client ID>
IDRA_CLIENT_SECRET=<client secret>
APP_URL=http://localhost:3000
SESSION_SECRET=<output of: openssl rand -hex 32>
```

## Install

```sh
mkdir idra-express && cd idra-express
npm init -y && npm pkg set type=module
npm install express express-session openid-client
```

## Code

```js title="server.js"
import express from 'express';
import session from 'express-session';
import * as oidc from 'openid-client';

const { IDRA_ISSUER, IDRA_CLIENT_ID, IDRA_CLIENT_SECRET, APP_URL, SESSION_SECRET } = process.env;
const issuer = new URL(IDRA_ISSUER);
const redirectUri = `${APP_URL}/callback`;

// Discovery reads the endpoints. With a secret: client_secret_basic. Without one: a public client.
const config = await oidc.discovery(
  issuer,
  IDRA_CLIENT_ID,
  undefined,
  IDRA_CLIENT_SECRET ? oidc.ClientSecretBasic(IDRA_CLIENT_SECRET) : oidc.None(),
  // Only for an IdRa you run locally on http. Never needed for an https issuer.
  issuer.protocol === 'http:' ? { execute: [oidc.allowInsecureRequests] } : undefined,
);

const app = express();
app.set('trust proxy', 1);
app.use(
  session({
    name: 'app.sid',
    secret: SESSION_SECRET,
    resave: false,
    saveUninitialized: false,
    cookie: { httpOnly: true, sameSite: 'lax', secure: APP_URL.startsWith('https://') },
  }),
);

app.get('/', (req, res) => {
  const { user } = req.session;
  if (!user) return res.send('<h1>Signed out</h1><a href="/login">Sign in with IdRa</a>');
  res.send(`<h1>Signed in</h1><pre>${JSON.stringify(user, null, 2).replace(/</g, '&lt;')}</pre>
    <a href="/logout">Sign out</a>`);
});

app.get('/login', async (req, res) => {
  const verifier = oidc.randomPKCECodeVerifier();
  req.session.flow = { verifier, state: oidc.randomState(), nonce: oidc.randomNonce() };
  const url = oidc.buildAuthorizationUrl(config, {
    redirect_uri: redirectUri,
    scope: 'openid profile email groups',
    code_challenge: await oidc.calculatePKCECodeChallenge(verifier),
    code_challenge_method: 'S256',
    state: req.session.flow.state,
    nonce: req.session.flow.nonce,
  });
  res.redirect(url.href);
});

app.get('/callback', async (req, res) => {
  const { flow } = req.session;
  if (!flow) return res.redirect('/login');
  delete req.session.flow;
  try {
    const tokens = await oidc.authorizationCodeGrant(
      config,
      new URL(req.originalUrl, APP_URL),
      { pkceCodeVerifier: flow.verifier, expectedState: flow.state, expectedNonce: flow.nonce },
    );
    // The ID token has no email or name: they come from UserInfo.
    req.session.user = await oidc.fetchUserInfo(config, tokens.access_token, tokens.claims().sub);
    req.session.idToken = tokens.id_token;
    res.redirect('/');
  } catch (e) {
    console.error(e);
    res.status(400).send(`Sign-in failed: ${e.error ?? e.message}`);
  }
});

app.get('/logout', (req, res) => {
  const idTokenHint = req.session.idToken;
  req.session.destroy(() => {
    if (!idTokenHint) return res.redirect('/');
    const url = oidc.buildEndSessionUrl(config, {
      id_token_hint: idTokenHint,
      post_logout_redirect_uri: `${APP_URL}/`,
    });
    res.redirect(url.href);
  });
});

app.listen(process.env.PORT ?? 3000, () => console.log(`Listening on ${APP_URL}`));
```

**Before production**

  `express-session`'s default memory store is for development. Use a shared store. The `allowInsecureRequests` line only applies to an `http` issuer, such as an IdRa on your own machine.

## Run

```sh
node --env-file=.env server.js
```

## Verify sign-in and sign-out

1. Open `http://localhost:3000` and select **Sign in with IdRa**. You land on IdRa's sign-in page.
2. Sign in, with MFA if your policies ask for it. You come back to a **Signed in** page showing your claims.
3. Select **Sign out**. You return to **Signed out**. This also ends the IdRa session, so the next sign-in asks for your credentials again.

**Reports → System Log** in the admin console shows the sign-in.

## What the app receives

The ID token doesn't carry `email` or `name`. Read them from UserInfo, as this sample does.

| Claim | ID token | UserInfo | Scope |
| --- | --- | --- | --- |
| `sub` | Yes | Yes | `openid` |
| `preferred_username` (the email), `updated_at` | Yes | Yes | `profile` |
| `name`, `given_name`, `family_name` | No | Yes | `profile` |
| `email`, `email_verified` | No | Yes | `email` |
| `groups` (group names, always including `Everyone`) | Yes | Yes | `groups` |

Add `offline_access` to the scopes to receive a refresh token. Access tokens last an hour. See [OpenID Connect](https://docs.idra.zone/docs/admin/oidc) for the rest.

## Troubleshooting

| What you see | Cause | Fix |
| --- | --- | --- |
| `Use https on a public host, or for local development http on localhost, 127.0.0.1 or [::1] with a port (…)` | The redirect URI is `http` on another host or without a port, or `https` on a loopback host. | Use `http://localhost:3000/callback` locally and `https` on a public host in production. |
| **Sign-in error**: `invalid redirect uri` | The app sent a redirect URI that isn't registered. Matching is exact, including port and path. | Make it match **Sign-in redirect URIs** on the **Sign On** tab. |
| **Access to … denied**: `You are not assigned to this application.` | The person isn't assigned. | Assign them on **Assignments**. |
| **Access to … denied**: `This application is currently inactive.` | The app is deactivated. | Activate it on the app's page. |
| **Access denied**: `This application is not registered with your organization.` | Wrong client ID, or a client ID from another organization. | Copy the **Client ID** from **Sign On**. |
| **Access denied**: `Your organization's sign-on policy does not allow this access.`, URL has `code=invalid_scope` | The app asked for a scope that doesn't exist. | Use `openid`, `profile`, `email`, `groups`, `offline_access` or a scope defined under **Security → API**. |
| `pkce is required for this client` | The authorize request has no PKCE challenge. | Send `code_challenge` with `code_challenge_method=S256`. IdRa accepts only `S256`. |
| `invalid_client`: `invalid client_secret` | Wrong secret, or it was rotated. | Use **Generate new secret** on **Sign On**. |
| `invalid_client`: `client registered for client_secret_basic cannot use none` | A Web Application is running without its secret. | Set `IDRA_CLIENT_SECRET`. |
| `invalid_client`: `client registered for client_secret_basic cannot use client_secret_post` | The library sent the secret in the body. | Send it as HTTP Basic, or change **Client authentication** on **Sign On**. |
| `invalid_grant`: `redirect_uri mismatch` | The token request's redirect URI differs from the authorize request's. | Use the same value in both. |
| `invalid_grant`: `code verification failed` | The PKCE verifier doesn't match the challenge. | Keep the verifier from the authorize step, per sign-in. |
| `404` on discovery | The issuer is missing `/api/auth`. | Use the **Issuer** from **Sign On**: `https://<your-org>.idra.team/api/auth`. |
| Page says `Logged out. The requested post-logout redirect was not registered.` | The person was signed out, but the return URL isn't registered. | Add it to **Sign-out redirect URIs**. |
| **Confirm logout** page | No `id_token_hint`, or it's for a different session than the browser's. | Send the ID token as the hint. Without one, the page is the expected safeguard. |

**Reports → System Log** records refused access as `app.access` with the reason.