Symfony 4 |访问通过传统用户表单传递的用户名(来自doc)

我正在学习 https://symfony.com/doc/current/security/form_login_setup.html 我想访问用户名。我想让会话存储用户名,但我不知道如何捕获登录用户的用户名。

到目前为止我已经试过了 $username = $request->get('username'); 在SecurityController中,然后尝试将会话“username”密钥设置为 $username 但它不起作用。

SecurityController。php

<?php
/**
 * Created by PhpStorm.
 * User: Adrian
 * Date: 2018-01-29
 * Time: 11:02
 */

namespace App\Controller;

use Symfony\Bundle\FrameworkBundle\Controller\Controller;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\Security\Http\Authentication\AuthenticationUtils;
use Symfony\Component\Routing\Annotation\Route;

class SecurityController extends Controller
{
    /**
     * @Route("/panel/login", name="login")
     */
    public function login(Request $request, AuthenticationUtils $authUtils) {
        $error = $authUtils->getLastAuthenticationError();
        $lastUsername = $authUtils->getLastUsername();

        return $this->render('security/login.html.twig', array(
            'last_username' => $lastUsername,
            'error'         => $error,
        ));
    }

}

登录名。html。细枝

{% block body %}
    {% if error %}
        <div>{{ error.messageKey|trans(error.messageData, 'security') }}</div>
    {% endif %}

    <form action="{{ path('login') }}" method="post">
        <label for="username">Username:</label>
        <input type="text" id="username" name="_username" value="{{ last_username }}" />

        <label for="password">Password:</label>
        <input type="password" id="password" name="_password" />

        <input type="hidden" name="_target_path" value="/panel/dashboard"/>
        {#
            If you want to control the URL the user
            is redirected to on success (more details below)
            <input type="hidden" name="_target_path" value="/account" />
        #}

        <button type="submit">login</button>
    </form>
{% endblock %}

稍后,我希望访问此用户名,如下所示:

$session = $request->getSession();
$username = $session->get('username');