class ResourceBase

abstract class ResourceBase extends PluginBase implements ContainerFactoryPluginInterface, ResourceInterface {
    
    /**
     * The available serialization formats.
     *
     * @var array
     */
    protected $serializerFormats = [];
    
    /**
     * A logger instance.
     *
     * @var \Psr\Log\LoggerInterface
     */
    protected $logger;
    
    /**
     * 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.
     */
    public function __construct(array $configuration, $plugin_id, $plugin_definition, array $serializer_formats, LoggerInterface $logger) {
        parent::__construct($configuration, $plugin_id, $plugin_definition);
        $this->serializerFormats = $serializer_formats;
        $this->logger = $logger;
    }
    
    /**
     * {@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('rest'));
    }
    
    /**
     * Implements ResourceInterface::permissions().
     *
     * Every plugin operation method gets its own user permission. Example:
     * "restful delete entity:node" with the title "Access DELETE on Node
     * resource".
     */
    public function permissions() {
        $permissions = [];
        $definition = $this->getPluginDefinition();
        foreach ($this->availableMethods() as $method) {
            $lowered_method = strtolower($method);
            $permissions["restful {$lowered_method} {$this->pluginId}"] = [
                'title' => $this->t('Access @method on %label resource', [
                    '@method' => $method,
                    '%label' => $definition['label'],
                ]),
            ];
        }
        return $permissions;
    }
    
    /**
     * {@inheritdoc}
     */
    public function routes() {
        $collection = new RouteCollection();
        $definition = $this->getPluginDefinition();
        $canonical_path = $definition['uri_paths']['canonical'] ?? '/' . strtr($this->pluginId, ':', '/') . '/{id}';
        $create_path = $definition['uri_paths']['create'] ?? '/' . strtr($this->pluginId, ':', '/');
        $route_name = strtr($this->pluginId, ':', '.');
        $methods = $this->availableMethods();
        foreach ($methods as $method) {
            $path = $method === 'POST' ? $create_path : $canonical_path;
            $route = $this->getBaseRoute($path, $method);
            // Note that '_format' and '_content_type_format' route requirements are
            // added in ResourceRoutes::getRoutesForResourceConfig().
            $collection->add("{$route_name}.{$method}", $route);
        }
        return $collection;
    }
    
    /**
     * Provides predefined HTTP request methods.
     *
     * Plugins can override this method to provide additional custom request
     * methods.
     *
     * @return array
     *   The list of allowed HTTP request method strings.
     */
    protected function requestMethods() {
        return [
            'HEAD',
            'GET',
            'POST',
            'PUT',
            'DELETE',
            'TRACE',
            'OPTIONS',
            'CONNECT',
            'PATCH',
        ];
    }
    
    /**
     * {@inheritdoc}
     */
    public function availableMethods() {
        $methods = $this->requestMethods();
        $available = [];
        foreach ($methods as $method) {
            // Only expose methods where the HTTP request method exists on the plugin.
            if (method_exists($this, strtolower($method))) {
                $available[] = $method;
            }
        }
        return $available;
    }
    
    /**
     * Gets the base route for a particular method.
     *
     * @param string $canonical_path
     *   The canonical path for the resource.
     * @param string $method
     *   The HTTP method to be used for the route.
     *
     * @return \Symfony\Component\Routing\Route
     *   The created base route.
     */
    protected function getBaseRoute($canonical_path, $method) {
        return new Route($canonical_path, [
            '_controller' => 'Drupal\\rest\\RequestHandler::handle',
        ], $this->getBaseRouteRequirements($method), [], '', [], [
            $method,
        ]);
    }
    
    /**
     * Gets the base route requirements for a particular method.
     *
     * @param $method
     *   The HTTP method to be used for the route.
     *
     * @return array
     *   An array of requirements for parameters.
     */
    protected function getBaseRouteRequirements($method) {
        $lower_method = strtolower($method);
        // Every route MUST have requirements that result in the access manager
        // having access checks to check. If it does not, the route is made
        // inaccessible. So, we default to granting access to everyone. If a
        // permission exists, then we add that below. The access manager requires
        // that ALL access checks must grant access, so this still results in
        // correct behavior.
        $requirements = [
            '_access' => 'TRUE',
        ];
        // Only specify route requirements if the default permission exists. For any
        // more advanced route definition, resource plugins extending this base
        // class must override this method.
        $permission = "restful {$lower_method} {$this->pluginId}";
        if (isset($this->permissions()[$permission])) {
            $requirements['_permission'] = $permission;
        }
        return $requirements;
    }

}