Pagekit\User\Controller\RegistrationController::activateAction PHP Method

    public function activateAction($username, $activation)
    {
        if (empty($username) || empty($activation) || !($user = User::where(['username' => $username, 'activation' => $activation, 'login IS NULL'])->first())) {
            App::abort(400, __('Invalid key.'));
        }
        $verifying = false;
        if ($this->module->config('require_verification') && !$user->get('verified')) {
            $user->set('verified', true);
            $verifying = true;
        }
        if ($this->module->config('registration') === 'approval' && $user->status === User::STATUS_BLOCKED && $verifying) {
            $user->activation = App::get('auth.random')->generateString(32);
            $this->sendApproveMail($user);
            $message = __('Your email has been verified. Once an administrator approves your account, you will be notified by email.');
        } else {
            $user->status = User::STATUS_ACTIVE;
            $user->activation = '';
            $this->sendWelcomeEmail($user);
            $message = $verifying ? __('Your account has been activated.') : __('The user\'s account has been activated and the user has been notified about it.');
        }
        $user->save();
        App::message()->success($message);
        return App::redirect('@user/login');
    }