handleSignIn()

The handleSignIn() function returns an Express route handler for the sign-in path.

Signature

handleSignIn(): express.RequestHandler

Import

const {handleSignIn} = require('@thunderid/express');

Prerequisites

• Mount thunderID() before this handler
• Register this handler on the route that matches your afterSignInUrl

Usage

index.js

const express = require('express');
const cookieParser = require('cookie-parser');
const {thunderID, handleSignIn} = require('@thunderid/express');

const app = express();

app.use(cookieParser());
app.use(
  thunderID({
    baseUrl: 'https://localhost:8090',
    clientId: '<your-client-id>',
    clientSecret: '<your-client-secret>',
    afterSignInUrl: 'http://localhost:3000/login',
  }),
);

app.get('/login', handleSignIn());

Runtime Behavior

handleSignIn() supports two stages on the same route:

1. If the request does not include a code query parameter, the handler starts the OAuth 2.0 redirect flow.
2. If the request includes a code query parameter, the handler exchanges the authorization code for tokens, writes the session cookie, and completes sign-in.

Default Callbacks

The handler uses the initialized Express config callbacks if they are provided.

Callback	Default behavior
onSignIn	Calls res.end()
onError	Logs the error message and returns 500 with an empty response body

Failure Behavior

• If thunderID() has not been mounted first, the handler logs an error and returns 500
• If sign-in fails, the handler calls onError
• If the original request URL already contains an error parameter, the underlying client rejects the request

Notes

• The session cookie is set during the authorization redirect and callback flow
• The underlying Express client uses the configured sessionCookie settings when writing the cookie

Related APIs

• thunderID()
• handleSignOut()
• Redirect Flow