如何让控制器在 Symfony 4 中返回响应？答案

【问题标题】：How can I make the controller return a response in Symfony 4?如何让控制器在 Symfony 4 中返回响应？
【发布时间】：2018-07-13 06:47:11
【问题描述】：

我根据本教程在 Symfony 4 中安装了 DataTableBundle：https://omines.github.io/datatables-bundle/#quickstart

 <?php

namespace App\Controller;

use Symfony\Bundle\FrameworkBundle\Controller\Controller;
use Omines\DataTablesBundle\Adapter\ArrayAdapter;
use Omines\DataTablesBundle\Column\TextColumn;
use Omines\DataTablesBundle\Controller\DataTablesTrait;
use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\Routing\Annotation\Route;

class DataTableController extends Controller
{

  /**
  * @Route("/")
  */

  use DataTablesTrait;

  public function showAction(Request $request)
  {
    $table = $this->createDataTable()
    ->add('firstName', TextColumn::class)
    ->add('lastName', TextColumn::class)
    ->createAdapter(ArrayAdapter::class, [
      ['firstName' => 'Donald', 'lastName' => 'Trump'],
      ['firstName' => 'Barack', 'lastName' => 'Obama'],
    ])
    ->handleRequest($request);

    if ($table->isCallback()) {
      return $table->getResponse();
    }

    $this->render('list.html.twig', ['datatable' => $table]);
  }
}

但我收到 Symfony 的错误消息：

未捕获的 PHP 异常 LogicException：“控制器必须返回一个响应（给定空值）。您是否忘记添加退货声明在你的控制器的某个地方？”在 /Users/work/project/vendor/symfony/http-kernel/HttpKernel.php 第 165 行

我试图改变这一行：

$this->render('list.html.twig', ['datatable' => $table]);

进入这个：

return $this->render('list.html.twig', ['datatable' => $table]);

然后我得到一个空白页，上面写着Loading...，没有别的。

list.html.twig：

<!-- in the <head> section -->
<link rel="stylesheet" type="text/css" href="https://cdn.datatables.net/v/dt/jq-3.2.1/dt-1.10.16/datatables.min.css"/>


<!-- Insert this where you want the table to appear -->
<div id="presidents">Loading...</div>

<!-- before the closing <body> tag -->
<script type="text/javascript" src="https://cdn.datatables.net/v/dt/jq-3.2.1/dt-1.10.16/datatables.min.js"></script>


<!-- Insert this at the end of your body element, but before the closing tag -->
<script src="{{ asset('bundles/datatables/js/datatables.js') }}"></script>
<script>
$(function() {
    $('#presidents').initDataTables({{ datatable_settings(datatable) }});
});
</script>

Services.yaml：

# Put parameters here that don't need to change on each machine where the app is deployed
# https://symfony.com/doc/current/best_practices/configuration.html#application-related-configuration
parameters:
    locale: 'en'

services:
    # default configuration for services in *this* file
    _defaults:
        autowire: true      # Automatically injects dependencies in your services.
        autoconfigure: true # Automatically registers your services as commands, event subscribers, etc.
        public: false       # Allows optimizing the container by removing unused services; this also means
                            # fetching services directly from the container via $container->get() won't work.
                            # The best practice is to be explicit about your dependencies anyway.


    # makes classes in src/ available to be used as services
    # this creates a service per class whose id is the fully-qualified class name
    App\:
        resource: '../src/*'
        exclude: '../src/{Entity,Migrations,Tests,Kernel.php}'

    # controllers are imported separately to make sure services can be injected
    # as action arguments even if you don't extend any base controller class
    App\Controller\:
        resource: '../src/Controller'
        tags: ['controller.service_arguments']

    # add more service definitions when explicit configuration is needed
    # please note that last definitions always *replace* previous ones

【问题讨论】：

您是否像这里提到的那样将配置部分添加到您的 config.yml 中？ omines.github.io/datatables-bundle/#configuration。因为被寻址的表有一个默认模板，这将导致将html代码注入到list.html.twig中的占位符#presidents
@KlausSchürg 我将它添加到我的 service.yaml 中，但这不起作用，所以我删除了它。我想我没有 config.yaml
如果我将它添加到 services.yaml 我得到错误The configuration key "language_from_cdn" is unsupported for definition "datatables" in "/Users/work/project/config/services.yaml". Allowed configuration keys are "alias", "parent", "class", "shared", "synthetic", "lazy", "public", "abstract", "deprecated", "factory", "file", "arguments", "properties", "configurator", "calls", "tags", "decorates", "decoration_inner_name", "decoration_priority", "autowire", "autoconfigure", "bind" in /Users/work/project/config/services.yaml (which is loaded in resource "/Users/work/project/config/services.yaml").
在打开呈现的 html 的源代码时，您是否安装了资产并且它们是否可用？可能只是js没有加载？
很高兴听到这个消息 :-) 周末愉快...

标签： php symfony return-value

【解决方案1】：

缺少回报确实是问题所在。有一个带有“正在加载...”字样的空白页面的原因将位于您的 list.html.twig 中。但是要解决这个问题，你必须提供更多的代码。

【讨论】：