--- /dev/null
+<?php
+
+namespace Drupal\rest\EventSubscriber;
+
+use Drupal\Core\Entity\EntityTypeManagerInterface;
+use Drupal\Core\Routing\RouteBuildEvent;
+use Drupal\Core\Routing\RoutingEvents;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+
+/**
+ * Generates a 'create' route for an entity type if it has a REST POST route.
+ */
+class EntityResourcePostRouteSubscriber implements EventSubscriberInterface {
+
+ /**
+ * The REST resource config storage.
+ *
+ * @var \Drupal\Core\Entity\EntityManagerInterface
+ */
+ protected $resourceConfigStorage;
+
+ /**
+ * Constructs a new EntityResourcePostRouteSubscriber instance.
+ *
+ * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
+ * The entity type manager.
+ */
+ public function __construct(EntityTypeManagerInterface $entity_type_manager) {
+ $this->resourceConfigStorage = $entity_type_manager->getStorage('rest_resource_config');
+ }
+
+ /**
+ * Provides routes on route rebuild time.
+ *
+ * @param \Drupal\Core\Routing\RouteBuildEvent $event
+ * The route build event.
+ */
+ public function onDynamicRouteEvent(RouteBuildEvent $event) {
+ $route_collection = $event->getRouteCollection();
+
+ $resource_configs = $this->resourceConfigStorage->loadMultiple();
+ // Iterate over all REST resource config entities.
+ foreach ($resource_configs as $resource_config) {
+ // We only care about REST resource config entities for the
+ // \Drupal\rest\Plugin\rest\resource\EntityResource plugin.
+ $plugin_id = $resource_config->toArray()['plugin_id'];
+ if (substr($plugin_id, 0, 6) !== 'entity') {
+ continue;
+ }
+
+ $entity_type_id = substr($plugin_id, 7);
+ $rest_post_route_name = "rest.entity.$entity_type_id.POST";
+ if ($rest_post_route = $route_collection->get($rest_post_route_name)) {
+ // Create a route for the 'create' link relation type for this entity
+ // type that uses the same route definition as the REST 'POST' route
+ // which use that entity type.
+ // @see \Drupal\Core\Entity\Entity::toUrl()
+ $entity_create_route_name = "entity.$entity_type_id.create";
+ $route_collection->add($entity_create_route_name, $rest_post_route);
+ }
+ }
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public static function getSubscribedEvents() {
+ // Priority -10, to run after \Drupal\rest\Routing\ResourceRoutes, which has
+ // priority 0.
+ $events[RoutingEvents::DYNAMIC][] = ['onDynamicRouteEvent', -10];
+ return $events;
+ }
+
+}