feat: introduce new reverse_proxy_cache_control config to allow configuring specific cache control for reverse proxy

Author: 94noni

Resources/doc/reference/configuration/headers.rst

@@ -347,6 +347,39 @@ section:
 
 This example adds the header ``X-Reverse-Proxy-TTL: 3600`` to your responses.
 
+``reverse_proxy_cache_control``
+"""""""""""""""""""""
+
+**type**: ``array``
+
+The map under ``reverse_proxy_cache_control`` goes with ``ttl_header``.
+The names are specified with underscores in yaml, but translated to ``-`` for
+the ``X-Reverse-Proxy-TTL`` header.
+
+You can use the standard cache control directives:
+
+* ``max_age`` time in seconds;
+* ``s_maxage`` time in seconds for proxy caches (also public caches);
+* ``private`` true or false;
+* ``public`` true or false;
+
+.. code-block:: yaml
+
+    # app/config/config.yml
+    fos_http_cache:
+        cache_control:
+            rules:
+                -
+                    headers:
+                        reverse_proxy_cache_control:
+                            max_age: 36000
+                            public: true
+                        cache_control:
+                            no_store: true
+                            private: true
+
+This example adds the header ``X-Reverse-Proxy-TTL: max-age=36000, public`` to your responses.
+
 ``ttl_header``
 --------------
 

src/DependencyInjection/Configuration.php

@@ -337,6 +337,15 @@ private function addCacheControlSection(ArrayNodeDefinition $rootNode): void
                         ->defaultNull()
                         ->info('Specify a custom time to live in seconds for your caching proxy. This value is sent in the custom header configured in cache_control.ttl_header.')
                     ->end()
+                    ->arrayNode('reverse_proxy_cache_control')
+                        ->info('Add the specified cache control directives for reverse proxy.')
+                        ->children()
+                            ->scalarNode('max_age')->end()
+                            ->scalarNode('s_maxage')->end()
+                            ->booleanNode('private')->end()
+                            ->booleanNode('public')->end()
+                        ->end()
+                    ->end()
                     ->arrayNode('vary')
                         ->beforeNormalization()->ifString()->then(function ($v) {
                             return preg_split('/\s*,\s*/', $v);

src/EventListener/CacheControlListener.php

@@ -116,11 +116,30 @@ public function onKernelResponse(ResponseEvent $event): void
             }
         }
 
-        if (array_key_exists('reverse_proxy_ttl', $options)
-            && null !== $options['reverse_proxy_ttl']
-            && !$response->headers->has($this->ttlHeader)
-        ) {
-            $response->headers->set($this->ttlHeader, $options['reverse_proxy_ttl'], false);
+        if (!$response->headers->has($this->ttlHeader)) {
+            if (!empty($options['reverse_proxy_cache_control'])) { // new config
+                $directives = array_intersect_key($options['reverse_proxy_cache_control'], $this->supportedDirectives);
+
+                if (!empty($directives)) {
+                    $headerValues = [];
+
+                    foreach ($directives as $k => $v) {
+                        $k = str_replace('_', '-', $k);
+
+                        if (in_array($k, ['public', 'private'])) {
+                            if ($v) {
+                                $headerValues[] = $k;
+                            }
+                        } else {
+                            $headerValues[] = ' ' . $k . '=' . $v;
+                        }
+                    }
+
+                    $response->headers->set($this->ttlHeader, \trim(\implode(', ', $headerValues)), false);
+                }
+            }  elseif (array_key_exists('reverse_proxy_ttl', $options) && null !== $options['reverse_proxy_ttl']) { // BC layer
+                $response->headers->set($this->ttlHeader, $options['reverse_proxy_ttl'], false);
+            }
         }
 
         if (!empty($options['vary'])) {