Issue #1983710 by manarth: Fixed HTTP: Use 406 (Not acceptable) over 415 (Unsupported media type).

core/lib/Drupal/Core/EventSubscriber/ViewSubscriber.php

@@ -59,7 +59,7 @@ public function onView(GetResponseForControllerResultEvent $event) {
         $event->setResponse($this->$method($event));
       }
       else {
-        $event->setResponse(new Response('Unsupported Media Type', 415));
+        $event->setResponse(new Response('Not Acceptable', 406));
       }
     }
     elseif ($request->attributes->get('_legacy')) {

core/lib/Drupal/Core/Routing/MimeTypeMatcher.php

@@ -8,7 +8,7 @@
 namespace Drupal\Core\Routing;
 
 use Symfony\Component\HttpFoundation\Request;
-use Symfony\Component\HttpKernel\Exception\UnsupportedMediaTypeHttpException;
+use Symfony\Component\HttpKernel\Exception\NotAcceptableHttpException;
 use Symfony\Component\Routing\RouteCollection;
 use Symfony\Cmf\Component\Routing\NestedMatcher\RouteFilterInterface;
 
@@ -41,7 +41,7 @@ public function filter(RouteCollection $collection, Request $request) {
     }
 
     if (!count($filtered_collection)) {
-      throw new UnsupportedMediaTypeHttpException();
+      throw new NotAcceptableHttpException();
     }
 
     return $filtered_collection;

core/modules/rest/lib/Drupal/rest/Tests/ReadTest.php

@@ -60,7 +60,7 @@ public function testRead() {
 
       // Try to read the entity with an unsupported mime format.
       $response = $this->httpRequest('entity/' . $entity_type . '/' . $entity->id(), 'GET', NULL, 'application/wrongformat');
-      $this->assertResponse(415);
+      $this->assertResponse(406);
 
       // Try to read an entity that does not exist.
       $response = $this->httpRequest('entity/' . $entity_type . '/9999', 'GET', NULL, $this->defaultMimeType);

core/modules/system/lib/Drupal/system/Tests/Routing/MimeTypeMatcherTest.php

@@ -11,7 +11,7 @@
 use Drupal\simpletest\UnitTestBase;
 
 use Symfony\Component\HttpFoundation\Request;
-use Symfony\Component\HttpKernel\Exception\UnsupportedMediaTypeHttpException;
+use Symfony\Component\HttpKernel\Exception\NotAcceptableHttpException;
 
 /**
  * Basic tests for the MimeTypeMatcher class.
@@ -91,7 +91,7 @@ public function testNoRouteFound() {
       $routes = $matcher->filter($routes, $request);
       $this->fail(t('No exception was thrown.'));
     }
-    catch (UnsupportedMediaTypeHttpException $e) {
+    catch (NotAcceptableHttpException $e) {
       $this->pass('The correct exception was thrown.');
     }
   }