Edit Static Web File Http Header Metadata of AWS S3 from SDK | SDK编程方式编辑储存在AWS S3中Web类文件的Http Header元数据

1.Motivation | 起因

A requirement from the product department requires download image from AWS S3 bucket, for achieving this requirement, I should set the image content MIME header as Content-Disposition:Attachment.

产品部门有一项需求是从S3上下载图片，为了完成这一需求，需要把图片的MIME头设为Content-Disposition:Attachment。

2.Attemption | 尝试

I tried pre-handling before upload the image file to S3 with the metadata by the following method:

尝试了以下面的方法在文件上传到S3之前进行预处理。

var request = new Amazon.S3.Model.PutObjectRequest()
{
    FilePath = @"D:SourceFile.jpg",
    BucketName = @"MyBucket",
    Key = @"Folder/NewFileName.jpg",
    ContentType= "images/jpg",
    CannedACL=S3CannedACL.PublicRead,
};
request.Metadata.Add("Cache-Control", "no-store");

But the result shows that the uploaded file is attached a strange metadata as x-amz-meta-Content-Disposition:Attachment, it's not suitable for my propose.

但结果显示上传的文件被附带了奇怪的元数据：x-amz-meta-Content-Disposition:Attachment，这并非我的本意。

3.Resolved | 解决

Finally I found that the request has a property named Header and it has the typical http header keys such as CacheControl and ContentEncoding, certainly the ContentDisposition is in it too. So I modified the assignment as follow and the requirement can be done.

最终发现，请求体中有个名为Header的属性，该属性具有一些典型的http头中的键，像CacheControl和 ContentEncoding，当然ContentDisposition也在其中。于是如下面的代码这样修改了赋值语句，就搞定了这项工作。

request.Headers.ContentDisposition = "attachment";