Issue #3155966 by mglaman, pixelwhip: ResourceResponseFactory to return a...

Issue #3155966 by mglaman, pixelwhip: ResourceResponseFactory to return a CacheableResourceResponse if request is cacheable

jsonapi_resources.info.yml

 name: 'JSON:API Resources'
 description: "This module let's you define custom resources at routes of your choice that use existing resource types."
-core_version_requirement: ^8.8 || ^9 || ^10
+core_version_requirement: ^9.1 || ^10
 type: module
 dependencies:
   - drupal:jsonapi

src/Unstable/ResourceResponseFactory.php

@@ -75,21 +75,20 @@ final class ResourceResponseFactory {
 
     $includes = $this->getIncludes($request, $data);
 
-    // \Drupal\jsonapi\ResourceResponse no longer implements
-    // CacheableResponseInterface in Drupal 9.1.
-    // Drupal\jsonapi\CacheableResourceResponse has ben added for cacheable
-    // responses. Keep compatibility with Drupal < 9.1.
-    // See https://www.drupal.org/node/3163310
     $document = new JsonApiDocumentTopLevel($data, $includes, $links, $meta);
-    $response = class_exists('\Drupal\jsonapi\CacheableResourceResponse') ?
-      new CacheableResourceResponse($document, $response_code, $headers) :
-      new ResourceResponse($document, $response_code, $headers);
-    // Make sure that different sparse fieldsets are cached differently.
-    $cache_contexts[] = 'url.query_args:fields';
-    // Make sure that different sets of includes are cached differently.
-    $cache_contexts[] = 'url.query_args:include';
-    $cacheability = (new CacheableMetadata())->addCacheContexts($cache_contexts);
-    $response->addCacheableDependency($cacheability);
+
+    if ($request->isMethodCacheable()) {
+      $response = new CacheableResourceResponse($document, $response_code, $headers);
+      // Make sure that different sparse fieldsets are cached differently.
+      $cache_contexts[] = 'url.query_args:fields';
+      // Make sure that different sets of includes are cached differently.
+      $cache_contexts[] = 'url.query_args:include';
+      $cacheability = (new CacheableMetadata())->addCacheContexts($cache_contexts);
+      $response->addCacheableDependency($cacheability);
+    }
+    else {
+      $response = new ResourceResponse($document, $response_code, $headers);
+    }
     return $response;
   }