Question

我正在从Amazon S3检索文件。我想将文件转换为字节，以便我可以按如下方式下载：

var download = new FileContentResult(bytes, "application/pdf");
download.FileDownloadName = filename;
return download;

我的文件在这里：

var client = Amazon.AWSClientFactory.CreateAmazonS3Client(
        accessKey,
        secretKey,
        config
        );
GetObjectRequest request = new GetObjectRequest();
GetObjectResponse response = client.GetObject(request);

我知道response.WriteResponseStreamToFile（）但我想将文件下载到常规下载文件夹。如果我将GetObjectResponse转换为字节，我可以返回该文件。我怎么能这样做？

Answer 1

以下是我为其他需要它的人找到的解决方案：

.where(m =>m.id == x.CategoryID).ToList()

GetObjectResponse response = client.GetObject(request);
using (Stream responseStream = response.ResponseStream)
{
    var bytes = ReadStream(responseStream);
    var download = new FileContentResult(bytes, "application/pdf");
    download.FileDownloadName = filename;
    return download;
}

Answer 2

另一种选择：

Stream rs;    
using (IAmazonS3 client = Amazon.AWSClientFactory.CreateAmazonS3Client())
{
    GetObjectRequest getObjectRequest = new GetObjectRequest();
    getObjectRequest.BucketName = "mybucketname";
    getObjectRequest.Key = "mykey";

    using (var getObjectResponse = client.GetObject(getObjectRequest))
    {
              getObjectResponse.ResponseStream.CopyTo(rs);
    }
}

Answer 3

我一直努力让Alex提供的更干净的方法可以工作（不确定我缺少什么），但是我想不带Erica提供的额外ReadStream方法（尽管它可以工作）...是我的伤口：

var s3Client = new AmazonS3Client(AccessKeyId, SecretKey, Amazon.RegionEndpoint.USEast1);
    using (s3Client)
    {
        MemoryStream ms = new MemoryStream();
        GetObjectRequest getObjectRequest = new GetObjectRequest();
        getObjectRequest.BucketName = BucketName;
        getObjectRequest.Key = awsFileKey;

        using (var getObjectResponse = s3Client.GetObject(getObjectRequest))
        {
            getObjectResponse.ResponseStream.CopyTo(ms);
        }
        var download = new FileContentResult(ms.ToArray(), "image/png"); //"application/pdf"
        download.FileDownloadName = ToFilePath;
        return download;
    }

Answer 4

Stream现在具有异步方法。在C＃8中，您可以执行以下操作：

public async Task<byte[]> GetAttachmentAsync(string objectPointer)
{
    var objReq = new GetObjectRequest
    {
        BucketName = "bucket-name",
        Key = objectPointer,    // the file name
    };

    using var objResp = await _s3Client.GetObjectAsync(objReq);
    using var ms = new MemoryStream();
    await objResp.ResponseStream.CopyToAsync(ms, _ct);  // _ct is a CancellationToken
    return ms.ToArray();
}

这不会在发生IO时阻塞任何线程。

如何从S3获取GetObjectResponse的字节？

4 个答案: