httpcb/app/controllers/AuthController.php

<?php

namespace App\Controller;

use App\Controller\ControllerBase,
    App\Model\Data\User,
    App\Form\Login as LoginForm,
    App\Form\Registration as RegistrationForm;

use Httpcb\OAuth\UserData\UserDataInterface;

class AuthController extends ControllerBase
{
    public function initialize()
    {
        // We need event manager here from DI.
        $eventManager = $this->di->get('eventsManager');
        $this->setEventsManager($eventManager);
    }

    public function indexAction()
    {
        $form = new LoginForm();

        if ($this->request->isPost()) {
            $data = $this->request->getPost();
            if ($form->isValid($data)) {

                $email = $form->getValue('Email');
                $passwd = $form->getValue('Password');

                // Perform login
                if ($this->auth->login($email, $passwd)) {
                    $this->response->redirect('/');
                } else {
                    $this->flash->message('error', "Invalid credentials");
                }
            } else {
                $msg = '<ul>';

                foreach($form->getMessages() as $message) {
                    $msg .= '<li><strong>' . $message->getField() . '</strong> '. $message->getMessage() . '</li>';
                }

                $msg .= '</ul>';
                $this->flash->message('error', $msg);
            }
        }

        $this->view->form = $form;
    }

    public function oauthAction($provider_name)
    {
        $client = $this->getDI()->get('oauth', [ $provider_name ]);

        $code = $this->request->get('code');
        $state = $this->request->get('state');

        // Have code. Authenticate and fetch data.
        if (strlen($code) > 0) {

            try {
                // NOTE: Should pass $state here also.
                $data = $client->authenticate($code);

                // If user is authed already, we connect.
                $user = $this->auth->getUser();
                if ($user) {

                    $name = ucfirst($provider_name);
                    $user->{'set' . $name . 'Id'}($data->getId());
                    $user->save();

                    $this->getEventsManager()->fire('user:onOAuthConnected', $user, $data);

                    $this->flash->message('success', sprintf("OAuth provider <strong>%s</strong> was connected!", $name));
                    $this->response->redirect('/settings');
                }
                // Perform Auth.
                else {
                    $result = $this->auth->loginOauth($data);

                    if ($result === false) {

                        if (User::findFirstByUsernameOrEmail($data->getEmail())) {
                            $this->flash->error('The email address is already in use.');
                            $this->response->redirect('/login');
                            return;
                        }

                        $this->session->set('auth:register:data', $data);
                        $this->response->redirect(['for' => 'user-register']);
                        return;
                    }

                    // User is logged in.
                    $this->response->redirect('/');
                }
            } catch(\Exception $e) {
                $this->flash->message('error', 'Failed to authenticate.');
                if ($this->auth->getUser()) {
                    $this->response->redirect('/settings');
                } else {
                    $this->response->redirect('/login');
                }
            }
        }
        // No code
        else {
            // redirect to provider and acquire code.
            $this->response->redirect($client->getAuthorizationUrl(), true);
        }
    }

    public function registerAction()
    {
        $data = $this->session->get('auth:register:data');
        if (!($data instanceof UserDataInterface)) {
            $this->response->redirect('/');
            return;
        }

        $user = new User();
        $user->assign($data->toArray(), null,
            [ 'email', 'username', 'firstname', 'lastname' ]);

        $form = new RegistrationForm($user);

        if ($this->request->isPost()) {

            $formData = $this->request->getPost();
            if ($form->isValid($formData)) {
                $user->setOAuthId($data->getProvider(), $data->getId());
                if ($user->save()) {
                    $this->auth->systemLogin($user);
                    $this->flash->success('User successfully created. Now add your first callback!');
                    $this->response->redirect('/callback/new');
                } else {
                    $this->flash->error('Could not create user');
                }
            }
            $form->setEntity($formData);
        } else {
            $form->isValid($data->toArray());
        }

        $this->view->provider = $data->getProvider();
        $this->view->form = $form;
    }

    public function logoutAction()
    {
        $this->auth->clearIdentity();
        $this->response->redirect('/');
    }
}