CentralAuth OAuth2 Provider for league/oauth2-client

A lightweight, focused OAuth 2.0 provider for integrating CentralAuth with the PHP League's league/oauth2-client. It wraps CentralAuth-specific behavior so your application code stays clean and portable.

---

🎯 Live Demo

A demo implementation is available at https://php-example.centralauth.com (source code).

---

✨ Features

• Authorization Code flow (incl. PKCE support inherited from base library)
• CentralAuth-specific user info retrieval
• Automatic Basic auth header for user info (clientId:clientSecret)
• Adds ?domain= query parameter to user info endpoint
• Custom headers automatically included: auth-ip, user-agent
• Small surface area – minimal assumptions, easy to extend

---

✅ Requirements

Component	Version
PHP	7.4+ (works on 8.x)
league/oauth2-client	^2.8

---

📦 Install

composer require centralauth/oauth2-centralauth

---

🔧 Configuration Options

Option	Required	Description
client_id	Yes	CentralAuth OAuth client ID
client_secret	Yes	CentralAuth OAuth client secret
redirect_uri	Yes	Your app callback URL (must match configured value)
authorization_url	Yes	CentralAuth login/authorization endpoint
token_url	Yes	CentralAuth token/verify endpoint
resource_owner_details_url	Yes	CentralAuth user info endpoint
domain	No	Overrides domain passed as ?domain= (defaults to redirect_uri)

---

🚀 Quick Start

use CentralAuth\OAuth2\Client\Provider\CentralAuth;

session_start(); // required for state persistence

$provider = new CentralAuth([
  'clientId' => getenv('CENTRALAUTH_CLIENT_ID'),
  'clientSecret' => getenv('CENTRALAUTH_CLIENT_SECRET'),
  'redirectUri' => 'https://your-app.example/oauth/callback',
  'authorization_url' => 'https://centralauth.com/login',
  'token_url' => 'https://centralauth.com/api/v1/verify',
  'resource_owner_details_url' => 'https://centralauth.com/api/v1/userinfo'
]);

if (!isset($_GET['code'])) {
  $authUrl = $provider->getAuthorizationUrl();
  $_SESSION['oauth2state'] = $provider->getState();
  header('Location: ' . $authUrl);
  exit;
}

if (empty($_GET['state']) || $_GET['state'] !== ($_SESSION['oauth2state'] ?? null)) {
  unset($_SESSION['oauth2state']);
  exit('Invalid state');
}

$token = $provider->getAccessToken('authorization_code', [
  'code' => $_GET['code']
]);

$resourceOwner = $provider->getResourceOwner($token);
$user = $resourceOwner->toArray();

// Use $user['email'], $user['id'], etc.

---

🧠 Why Not GenericProvider?

CentralAuth requires a non-standard user info retrieval pattern:

1. HTTP Method: POST
2. Body: raw access token string (not JSON, not form-encoded)
3. Headers:
   • Authorization: Basic base64(clientId:clientSecret)
   • auth-ip: <requester IP>
   • user-agent: <browser UA>
4. ?domain= query parameter appended to the user info URL

GenericProvider would require re-implementing this logic inline for every project—this package encapsulates it cleanly.

---

👤 Resource Owner

Example returned fields:

{
  "id": "12345",
  "email": "user@example.com",
  "gravatar": "https://www.gravatar.com/avatar/..."
}

Provided helpers:

$owner = $provider->getResourceOwner($token);
$owner->getId();
$owner->getEmail();
$owner->getGravatar();
$owner->toArray();

---

⚠️ Error Handling

checkResponse() normalizes HTTP errors. An IdentityProviderException is thrown containing:

• Exception message (error / error_description / raw body)
• HTTP status code
• Original response instance

Wrap sensitive operations:

try {
  $token = $provider->getAccessToken('authorization_code', ['code' => $_GET['code']]);
} catch (\League\OAuth2\Client\Provider\Exception\IdentityProviderException $e) {
  // Log and surface user-friendly message
}

---

🧪 Testing

This library includes comprehensive PHPUnit tests covering all functionality:

Quick Test Validation

For a quick syntax and structure check:

./test-runner.sh

Test Commands

# Run all tests (44 tests, fast and clean)
composer test

# Run only unit tests (37 tests)
composer test-unit

# Run only integration tests (7 tests)  
composer test-integration

# Generate coverage report (requires Xdebug or PCOV)
composer test-coverage

Test Coverage

The test suite includes:

• Unit tests: Individual class and method testing (CentralAuth, CentralAuthResourceOwner)
• Integration tests: Complete OAuth2 workflow testing
• Error handling: Various error scenarios and edge cases
• No external dependencies: All HTTP calls are mocked for reliable testing

For detailed testing instructions, see TESTING.md.

---

🛡 Security

Do NOT publish real credentials in code or VCS. Report vulnerabilities privately.

---

📄 License

Released under the MIT License.

---

📚 Documentation

For complete CentralAuth documentation and API reference, visit the official docs.