Support immutable

Author: bajb

src/Resources/ResourceFactory.php

@@ -145,6 +145,8 @@ public static function create(DispatchResource $resource, $cache = true)
       $response->setEtag($resource->getHash());
       $response->setPublic();
 
+      $response->setImmutable($cache->isImmutable());
+
       //This resource should last for 1 year in cache
       $response->setMaxAge($cache->getCacheSeconds());
       $response->setSharedMaxAge($cache->getCacheSeconds());

src/ResponseCacheConfig.php

@@ -5,6 +5,7 @@ class ResponseCacheConfig
 {
   protected $_varyHeader = 'Accept-Encoding, Accept';
   protected $_cacheSeconds = 31536000;
+  protected $_immutable = true;
 
   /**
    * @return string
@@ -44,4 +45,23 @@ public function setCacheSeconds(int $cacheTimeSeconds)
     return $this;
   }
 
+  /**
+   * @return bool
+   */
+  public function isImmutable(): bool
+  {
+    return $this->_immutable;
+  }
+
+  /**
+   * @param bool $immutable
+   *
+   * @return ResponseCacheConfig
+   */
+  public function setImmutable(bool $immutable)
+  {
+    $this->_immutable = $immutable;
+    return $this;
+  }
+
 }