How do I configure the REST API?

Question

A couple months back I successfully setup a development site to learn about the Drupal 8 REST API with version 8.0.x using the REST UI module for configuration. When I heard about the improvements to the REST Services in Drupal 8.2 I was pretty excited (from my understanding it is now possible to access configuration data such as content types and taxonomy terms) so I setup a new install using version 8.2.1. However, understanding the configuration for 8.2 is pretty daunting, and since it's so new there are very little resources around the setup and configuration.

I was able to locate this resource and I imported the example configuration provided, but was still unsure on how to configure other REST Endpoints.

I used the default configuration provided in the above resource. It looks like this:

langcode: en
status: true
dependencies:
 module:
   - basic_auth
   - hal
   - node
id: entity.node
plugin_id: 'entity:node'
granularity: resource
configuration:
 methods:
   - GET
   - POST
   - PATCH
   - DELETE
 formats:
   - hal_json
 authentication:
   - basic_auth

• How do I edit the configuration once it's imported via the configuration manager?
• Where can I find the available plugin_id's so that I can configure other resources? Where can I learn more about plugins?
• How would I begin to implement my own REST endpoint?

I know this is a lot to ask, but at the time of writing there is little to no information covering these topics so I figure other people might be confused as well. I would like to create a guide on this, but that would first require that I understand it first.

Answer 1

I search a lot too after 8.2x and this is how i got it working :

Example for a custom user ressource :

myModule/config/install

rest.resource.user.rest_ressource.yml

langcode: en
status: true
dependencies:
  module:
    - basic_auth
id: user.rest_ressource
plugin_id: 'user_rest_ressource'
granularity: resource
configuration:
  methods:
    - GET
  formats:
    - json
  authentication:
    - basic_auth

In myModule/src/Plugin/rest/resource

UserRestRessource.php

<?php

namespace Drupal\myModule\Plugin\rest\resource;

use Drupal\Core\Session\AccountProxyInterface;
use Drupal\rest\Plugin\ResourceBase;
use Drupal\rest\ResourceResponse;
use Symfony\Component\DependencyInjection\ContainerInterface;
use Psr\Log\LoggerInterface;


/**
 * Provides a resource to get view modes by entity and bundle.
 *
 * @RestResource(
 *   id = "user_rest_ressource",
 *   label = @Translation("User Rest"),
 *   uri_paths = {
 *     "canonical" = "/api/user/getInfo"
 *   }
 * )
 */
class UserRestRessource extends ResourceBase {

  /**
   * A current user instance.
   *
   * @var \Drupal\Core\Session\AccountProxyInterface
   */
  protected $currentUser;

  /**
   * Constructs a Drupal\rest\Plugin\ResourceBase object.
   *
   * @param array $configuration
   *   A configuration array containing information about the plugin instance.
   * @param string $plugin_id
   *   The plugin_id for the plugin instance.
   * @param mixed $plugin_definition
   *   The plugin implementation definition.
   * @param array $serializer_formats
   *   The available serialization formats.
   * @param \Psr\Log\LoggerInterface $logger
   *   A logger instance.
   * @param \Drupal\Core\Session\AccountProxyInterface $current_user
   *   A current user instance.
   */
  public function __construct(
    array $configuration,
    $plugin_id,
    $plugin_definition,
    array $serializer_formats,
    LoggerInterface $logger,
    AccountProxyInterface $current_user) {
    parent::__construct($configuration, $plugin_id, $plugin_definition, $serializer_formats, $logger);

    $this->currentUser = $current_user;

  }

  /**
   * {@inheritdoc}
   */
  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
    return new static(
      $configuration,
      $plugin_id,
      $plugin_definition,
      $container->getParameter('serializer.formats'),
      $container->get('logger.factory')->get('restimadiff'),
      $container->get('current_user')
    );
  }

  /**
   * Responds to GET requests.
   *
   * 
   *
   * @throws \Symfony\Component\HttpKernel\Exception\HttpException
   *   Throws exception expected.
   */
  public function get() {

      $responseResource=new ResourceResponse(
          array()

      );  
    return $responseResource;
  }

}

Answer 2

Since posting this, the documentation on drupal.org/docs/8/ has been updated appropriately.