add cache-control and etag for video meta api

conf/app.php

@@ -64,6 +64,8 @@ $configs = array(
     'small_image_client_cache_seconds' => 600,
     //目录封面图在浏览器端缓存时长，单位：秒
     'dir_snapshot_client_cache_seconds' => 300,
+    //视频、音乐meta在浏览器端缓存时长，单位：秒
+    'meta_client_cache_seconds' => 300,
 
     //列表页缩略图尺寸设置
     'small_image_min_width' => 360,     //缩略图最小宽度设置，以确保清晰度

themes/beauty/controller/SiteController.php

@@ -805,6 +805,9 @@ Class SiteController extends Controller {
         $msg = 'OK';
         $meta = array();
 
+        $httpStatus = 200;
+        $customHeaders = array();
+
         $videoId = $this->get('id', '');
         if (empty($videoId)) {
             $code = 0;
@@ -816,13 +819,26 @@ Class SiteController extends Controller {
             $cachedData = Common::getCacheFromFile($cacheKey, $expireSeconds, $cacheSubDir);
             if (!empty($cachedData)) {
                 $meta = $cachedData;
+
+                //增加客户端缓存header
+                $etag = md5(json_encode($meta));
+                $etag_from_client = !empty($_SERVER['HTTP_IF_NONE_MATCH']) ? $_SERVER['HTTP_IF_NONE_MATCH'] : '';  //get etag from client
+                if (!empty($etag) && $etag == $etag_from_client) {
+                    $httpStatus = 304;
+                }
+
+                $meta_client_cache_seconds = FSC::$app['config']['meta_client_cache_seconds'];
+                $customHeaders = array(
+                    "Cache-Control: max-age={$meta_client_cache_seconds}",
+                    "Etag: {$etag}",
+                );
             }else {
                 $code = 0;
                 $msg = '此视频无缓存或缓存已过期';
             }
         }
 
-        return $this->renderJson(compact('code', 'msg', 'meta'));
+        return $this->renderJson(compact('code', 'msg', 'meta'), $httpStatus, $customHeaders);
     }
 
     //保存视频meta数据到缓存，支持手动生成