This expert AI assistant guide walks you through integrating "Sign in with SSO" functionality into an existing PHP application using SSOJet as an OIDC identity provider.

1. Prerequisites

An existing PHP 8.0+ application with a login page.
Composer for dependency management.
An active SSOJet account.
SSO Connection Setup Guide
Required package: jumbojett/openid-connect-php.

2. Implementation Steps

Step 1: Create Application in SSOJet

Log in to the SSOJet Dashboard.
Navigate to Applications.
Create a new application (e.g., "MyPHPApp", type Regular Web App).
Configure the callback URI (e.g., http://localhost:8000/callback.php).
Retrieve Client ID and Client Secret.
Copy the Issuer URL from the Advanced > Endpoints section.

Step 2: Modify the Existing PHP Project

Substep 2.1: Install Dependencies

composer require jumbojett/openid-connect-php

Substep 2.2: Configure Environment

Create a config.php file:

<?php
// config.php
return [
    'issuer_url'    => 'https://auth.ssojet.com',
    'client_id'     => 'your_client_id',
    'client_secret' => 'your_client_secret',
    'redirect_uri'  => 'http://localhost:8000/callback.php',
];

Substep 2.3: Update Login Page/UI

Modify your login page (login.php):

<!-- login.php -->
<?php session_start(); ?>
<!DOCTYPE html>
<html>
<head><title>Sign In</title></head>
<body>
<div class="login-container">
    <h1>Sign In</h1>

    <?php if (isset($_GET['error'])): ?>
        <p style="color: red;">Authentication failed. Please try again.</p>
    <?php endif; ?>

    <form id="loginForm" method="POST" action="auth.php">
        <div>
            <label for="email">Email</label>
            <input type="email" id="email" name="email" required />
        </div>
        <div id="passwordField">
            <label for="password">Password</label>
            <input type="password" id="password" name="password" required />
        </div>
        <input type="hidden" id="isSSO" name="is_sso" value="false" />
        <button type="submit" id="submitBtn">Sign In</button>
    </form>

    <button type="button" onclick="toggleSSO()">Sign in with SSO</button>
</div>
<script>
function toggleSSO() {
    const f = document.getElementById('isSSO');
    const p = document.getElementById('passwordField');
    const b = document.getElementById('submitBtn');
    if (f.value === 'false') {
        f.value = 'true'; p.style.display = 'none';
        document.getElementById('password').removeAttribute('required');
        b.textContent = 'Continue with SSO';
    } else {
        f.value = 'false'; p.style.display = 'block';
        document.getElementById('password').setAttribute('required','true');
        b.textContent = 'Sign In';
    }
}
</script>
</body>
</html>

Substep 2.4: Update Backend Logic

1. Auth Handler (auth.php):

<?php
// auth.php
session_start();
require_once 'vendor/autoload.php';

use Jumbojett\OpenIDConnectClient;

$config = require 'config.php';
$isSSO = $_POST['is_sso'] ?? 'false';
$email = $_POST['email'] ?? '';

if ($isSSO === 'true') {
    $oidc = new OpenIDConnectClient(
        $config['issuer_url'],
        $config['client_id'],
        $config['client_secret']
    );
    $oidc->setRedirectURL($config['redirect_uri']);
    $oidc->addScope(['openid', 'profile', 'email']);

    // Store email for login_hint
    $_SESSION['login_hint'] = $email;

    $oidc->authenticate();
    // The library handles the redirect automatically
} else {
    // Existing password login logic here
    error_log('Processing traditional login...');
    header('Location: /dashboard.php');
    exit;
}

2. Callback Handler (callback.php):

<?php
// callback.php
session_start();
require_once 'vendor/autoload.php';

use Jumbojett\OpenIDConnectClient;

$config = require 'config.php';

try {
    $oidc = new OpenIDConnectClient(
        $config['issuer_url'],
        $config['client_id'],
        $config['client_secret']
    );
    $oidc->setRedirectURL($config['redirect_uri']);
    $oidc->addScope(['openid', 'profile', 'email']);
    $oidc->authenticate();

    // Get user info
    $name = $oidc->requestUserInfo('name');
    $email = $oidc->requestUserInfo('email');
    $sub = $oidc->requestUserInfo('sub');

    // TODO: Create a session for the user
    $_SESSION['user'] = [
        'sub'   => $sub,
        'name'  => $name,
        'email' => $email,
    ];

    error_log('Authenticated User: ' . json_encode($_SESSION['user']));
    header('Location: /dashboard.php');
    exit;
} catch (Exception $e) {
    error_log('OIDC Callback Error: ' . $e->getMessage());
    header('Location: /login.php?error=oidc_failed');
    exit;
}

Step 3: Test the Modified Connection

Start your application: php -S localhost:8000.
Navigate to http://localhost:8000/login.php.
Click "Sign in with SSO", enter a test email, and submit.
You should be redirected to SSOJet, then back to /dashboard.php.

3. Additional Considerations

Security: Store secrets outside the web root. Use HTTPS in production.
Session Management: Use secure session configuration in php.ini.
Styling: Adapt the HTML to match your application's design system.

4. Support

Contact SSOJet support: Reach out if you have integration questions.
Library Documentation: Refer to the openid-connect-php documentation.