如何更新AWS S3存储桶上传的文件权限？

Question

我使用node.js使用Multipart Upload将视频上传到Amazon-S3。我正在使用this参考

默认情况下，上传的视频只能由所有者访问。

使用以下代码上传文件时

var params_to_upload_on_S3 = {                     ACL：＆＃39; public-read＆＃39;，                     斗：imageBucket，                     密钥：imgName +＆＃34; .jpg＆＃34;，                     身体：imageBuffer，                     ContentType：＆＃39;图片/ jpg＆＃39;                 }

        s3.putObject(params_to_upload_on_S3 , function (err, res) {
            if(err)
                console.log('Thumnail Upload Error'+ err);
            else 
                console.log('Thumbnail Successfully uploaded .'+ JSON.stringify(res));

            fs.unlink(imagePath, function(){
                console.log('File deleted from local storage');
            });

        });