如何使用Amazon S3 ResponseStream返回FileResult？

Question

使用AWSSDK.S3 nuget包，我试图返回从S3存储桶检索到的文件。我的出发点是基于此SO answer中给出的示例。

例控制器代码：

public FileResult GetFile(Guid id) 
{ 
    // no using block as it will be disposed of by the File method 
    var amazonResponse = _foo.GetAmazonResponseWrapper(_user, id); 
    // set Response content-length header 
    // set Response content-type header 

    var bufferSize = 1024; 
    var buffer = new byte[bufferSize]; 
    int bytesRead; 

    while ((bytesRead = amazonResponse.ResponseStream.Read(buffer, 0, buffer.Length)) > 0 && Response.IsClientConnected) 
    { 
     Response.OutputStream.Write(buffer, 0, bytesRead); 
     Response.OutputStream.Flush(); 
     buffer = new byte[bufferSize]; 
    }   

    // this will not work (can't read from this stream) 
    return File(Response.OutputStream, "text/plain", "bar.txt"); 
} 

如果我写一个MemoryStream我创建并在while循环使用，我会得到一个文件，但不会有任何内容。

我发现文件中获得内容的唯一方法是调用.ToArray()在流像这样：

return File(memStream.ToArray(), "text/plain", "foo.txt"); 

是否有实际流的文件浏览器的方式，而不加载到Web服务器的内存？

Answer 1

只是传递着

public FileResult GetFile(Guid id) { 
    // no using block as it will be disposed of by the File method 
    var amazonResponse = _foo.GetAmazonResponseWrapper(_user, id); 
    return File(amazonResponse.ResponseStream, "text/plain", "bar.txt"); 
} 

您已经表明，你可以从响应流中读取的数据流。然后只传递响应流，文件结果将读取它并返回响应。