fixed close nil pointer

backend/services/spider_handler/spider.go

@@ -125,12 +125,12 @@ func (s *SpiderSync) Download() {
 	defer session.Close()
 
 	f, err := gf.OpenId(bson.ObjectIdHex(fileId))
-	defer utils.Close(f)
 	if err != nil {
 		log.Errorf("open file id: " + fileId + ", spider id:" + spiderId + ", error: " + err.Error())
 		debug.PrintStack()
 		return
 	}
+	defer utils.Close(f)
 
 	// 生成唯一ID
 	randomId := uuid.NewV4()

backend/utils/helpers.go

@@ -36,8 +36,10 @@ func GetMessage(message redis.Message) *entity.NodeMessage {
 }
 
 func Close(c io.Closer) {
-	err := c.Close()
-	if err != nil {
+	if c == nil {
+		return
+	}
+	if err := c.Close(); err != nil {
 		//log.WithError(err).Error("关闭资源文件失败。")
 	}
 }