Creating a JSON response

Routes can also return JavaScript Object Notation (JSON) responses. A JSON response is often used for building API routes since it is an interchange format that is supported by all programming languages. This allows exposing data to be consumed by a third-party consumer.

In this recipe, we will create a route that returns a JSON response containing information about the Drupal site.

How to do it…

1. First, we need to create the src/Controller directory in the module’s directory. We will put our controller class in this directory, which gives our controller class the Controller namespace:

   mkdir -p src/Controller

2. Create a file named SiteInfoController.php in the Controller directory. This will hold our SiteInfoController controller class.
3. Our SiteInfoController class will extend the ControllerBase base class provided by Drupal core:

   <?php

   namespace Drupal\mymodule\Controller;

   use Drupal\Core\Controller\ControllerBase;

   use Symfony...