Migration-from-the-AuthComponent.md

Migration from the AuthComponent

Differences

• This plugin intentionally does not handle authorization. It was decoupled from authorization on purpose for a clear separation of concerns. See also Computer access control. This plugin handles only identification and authentication. We might have another plugin for authorization.
• There is no automatic checking of the session. To get the actual user data from the session you'll have to use the SessionAuthenticator. It will check the session if there is data in the configured session key and put it into the identity object.
• The user data is no longer available through the AuthComponent but is accessible via a request attribute and encapsulated in an identity object: $request->getAttribute('authentication')->getIdentity();
• The logic of the authentication process has been split into authenticators and identifiers. An authenticator will extract the credentials from the request, while identifiers verify the credentials and find the matching user.
• DigestAuthenticate has been renamed to HttpDigestAuthenticator
• BasicAuthenticate has been renamed to HttpBasicAuthenticator

Similarities

• All the existing authentication adapters, Form, Basic, Digest are still there but have been refactored into authenticators.

Identifiers and authenticators

Following the principle of separation of concerns, the former authentication objects were split into separate objects, identifiers and authenticators.

• Authenticators take the incoming request and try to extract identification credentials from it. If credentials are found, they are passed to a collection of identifiers where the user is located. For that reason authenticators take an IdentifierCollection as first constructor argument.
• Identifiers verify identification credentials against a storage system. eg. (ORM tables, LDAP etc) and return identified user data.

This makes it easy to change the identification logic as needed or use several sources of user data.

If you want to implement your own identifiers, your identifier must implement the IdentifierInterface.

Migrating your authentication setup

Adding the authentication middleware

Login action

The AuthenticationMiddleware will handle checking and setting the identity based on your authenticators. Usually after logging in, AuthComponent would redirect to a configured location. To redirect upon a successful login, change your login action to check the new identity results:

public function login()
{
    $result = $this->Authentication->getResult();

    // regardless of POST or GET, redirect if user is logged in
    if ($result->isValid()) {
        $redirect = $this->request->getQuery('redirect', ['controller' => 'Pages', 'action' => 'display', 'home']);
        return $this->redirect($redirect);
    }

    // display error if user submitted and authentication failed
    if ($this->request->is(['post']) && !$result->isValid()) {
        $this->Flash->error('Invalid username or password');
    }
}

Checking identities

After applying the middleware you can use identity data by using the identity request attribute. This replaces the $this->Auth->user() calls you are be using now. If the the current user is unauthenticaed or if the provided credentials were invalid, the identity attribute will be null.

$user = $request->getAttribute('identity');

For more details about the result of the authentication process you can access the result object that also comes with the request and is accessible on the authentication attribute:

$result = $request->getAttribute('authentication')->getResult();
// Boolean if the result is valid
debug($result->isValid());
// A status code
debug($result->getStatus());
// An array of error messages or data if the identifier provided any
debug($result->getErrors());

Any place you were calling AuthComponent::setUser(), you should now use setIdentity():

// Assume you need to read a user by access token
$user = $this->Users->find('byToken', ['token' => $token])->first();

// Persist the user into configured authenticators.
$this->Authentication->setIdentity($user);

Migrate AuthComponent settings

The huge config array from the AuthComponent needs to be split into identifiers and authenticators when configuring the service. So when you had your AuthComponent configured this way

$this->loadComponent('Auth', [
    'authentication' => [
        'Form' => [
            'fields' => [
                'username' => 'email',
                'password' => 'password',
            ]
        ]
    ]
]);

You'll now have to configure it this way:

// Instantiate the service
$service = new AuthenticationService();

// Load identifiers
$service->loadIdentifier('Authentication.Password', [
    'fields' => [
        'username' => 'email',
        'password' => 'password',
    ]
]);

// Load the authenticators
$service->loadAuthenticator('Authentication.Session');
$service->loadAuthenticator('Authentication.Form');

If you have customized the userModel you can use the following configuration:

// Instantiate the service
$service = new AuthenticationService();

// Load identifiers
$service->loadIdentifier('Authentication.Password', [
    'resolver' => [
        'className' => 'Authentication.Orm',
        'userModel' => 'Employees',
    ],
    'fields' => [
        'username' => 'email',
        'password' => 'password',
    ]
]);

While there is a bit more code than before, you have more flexibility in how your authentication is handled.

Migrating allow/deny logic

Like AuthComponent the AuthenticationComponent makes it easy to make specific actions 'public' and not require a valid identity to be present:

// In your controller's beforeFilter method.
$this->Authentication->allowUnauthenticated(['view']);

Each call to allowUnauthenticated() will overwrite the current action list.

Migrating Unauthenticated Redirects

By default AuthComponent redirects users back to the login page when authentication is required. In contrast, the AuthenticationComponent in this plugin will raise an exception in this scenario. You can convert this exception into a redirect using the unauthenticatedRedirect when configuring the AuthenticationMiddleware.

You can also pass the current request target URI as a query parameter using the queryParam option.

// in src/Application.php
use Authentication\Middleware\AuthenticationMiddleware;

public function middleware($middlewareQueue)
{
    // Various other middlewares for error handling, routing etc. added here.

    // Add the authentication middleware
    $authentication = new AuthenticationMiddleware($this, [
        'unauthenticatedRedirect' => Router::url('users:login'),
        'queryParam' => 'redirect',
    ]);

    // Add authentication
    $middlewareQueue->add($authentication);

    return $middlewareQueue;
}