Custom POST Resource Not Working but GET is I created a custom resource and my GET Resource works but my POST does not:

&lt;?php

namespace Drupal\xeno_dashboard\Plugin\rest\resource;

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

/**
 * Provides a resource to get view modes by entity and bundle.
 *
 * @RestResource(
 *   id = "snap_shots_resource",
 *   label = @Translation("Snap shots resource"),
 *   uri_paths = {
 *     "canonical" = "/snapshots"
 *   }
 * )
 */
class SnapShotsResource 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-&gt;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-&gt;getParameter('serializer.formats'),
      $container-&gt;get('logger.factory')-&gt;get('xeno_dashboard'),
      $container-&gt;get('current_user')
    );
  }

  /**
   * Responds to entity GET requests.
   * @return \Drupal\rest\ResourceResponse
   */
  public function get() {
    $response = ['message' =&gt; 'Hello, this is a rest service'];
    return  new ResourceResponse($response);
  }

  /**
   * Responds to entity POST requests.
   * @return \Drupal\rest\ResourceResponse
   */
  public function post() {
    $response = ['message' =&gt; 'Hello, this is a POST response!'];
    return  new ResourceResponse($response);
  }

}


This is the response from the POST:

{
    "message": "No route found for \"POST /snapshots\": Method Not Allowed (Allow: GET, HEAD)"
}
This is the code we are using to determine the POST path:


    $create_path = isset($definition['uri_paths']['create']) ? $definition['uri_paths']['create'] : '/' . strtr($this-&gt;pluginId, ':', '/');
    // BC: the REST module originally created the POST URL for a resource by
    // reading the 'https://www.drupal.org/link-relations/create' URI path from
    // the plugin annotation. For consistency with entity type definitions, that
    // then changed to reading the 'create' URI path. For any REST Resource
    // plugins that were using the old mechanism, we continue to support that.
    if (!isset($definition['uri_paths']['create']) &amp;&amp; isset($definition['uri_paths']['https://www.drupal.org/link-relations/create'])) {
      $create_path = $definition['uri_paths']['https://www.drupal.org/link-relations/create'];
    }


This would mean it is /snap_shots_resource as path, but you probably want to set a 'create' uri path to the value you want.