Question

ServiceStack服务中是否有任何机制可以返回流/大二进制数据？ WCF的MTOM支持很难但在返回大量数据时却没有文本转换开销。

Answer 1

我喜欢服务堆栈，这个litle代码足以从内存流中返回Excel报告

public class ExcelFileResult : IHasOptions, IStreamWriter
{
    private readonly Stream _responseStream;
    public IDictionary<string, string> Options { get; private set; }

    public ExcelFileResult(Stream responseStream)
    {
        _responseStream = responseStream;

        Options = new Dictionary<string, string> {
             {"Content-Type", "application/octet-stream"},
             {"Content-Disposition", "attachment; filename=\"report.xls\";"}
         };
    }

    public void WriteTo(Stream responseStream)
    {
        if (_responseStream == null) 
            return;

        _responseStream.WriteTo(responseStream);
        responseStream.Flush();
    }
}

Answer 2

从鸟瞰图ServiceStack可以返回以下任何一个：

任何DTO对象 - ＆gt;序列化为Response ContentType
用于自定义HTTP响应的HttpResult，HttpError，CompressedResult（IHttpResult）

以下类型未转换并直接写入响应流：

字符串
流
IStreamWriter
byte [] - 使用application/octet-stream内容类型。

详细信息

除了返回普通的C＃对象之外，ServiceStack还允许您返回任何 Stream 或IStreamWriter（这对您写入响应流的方式更加灵活）：

public interface IStreamWriter
{
    void WriteTo(Stream stream);
}

两者都允许您直接写入Response OutputStream而无需任何额外的转换开销。

如果要在同一时间自定义HTTP标头，只需实现IHasOptions，其中任何字典条目都写入Response HttpHeaders。

public interface IHasOptions
{
    IDictionary<string, string> Options { get; }
}

除此之外，IHttpResult允许甚至更精细地控制HTTP输出，您可以在其中提供自定义Http响应状态代码。您可以参考HttpResult对象的实现，以实现上述接口的实际实现。

Answer 3

我有类似的要求，这也要求我跟踪流式文件下载的进度。我大致这样做了：

<强> 服务器侧

服务：

public object Get(FooRequest request)
{
    var stream = ...//some Stream
    return new StreamedResult(stream);
}

StreamedResult类：

public class StreamedResult : IHasOptions, IStreamWriter
{
    public IDictionary<string, string> Options { get; private set; }
    Stream _responseStream;

    public StreamedResult(Stream responseStream)
    {
        _responseStream = responseStream;

        long length = -1;
        try { length = _responseStream.Length; }
        catch (NotSupportedException) { }

        Options = new Dictionary<string, string>
        {
            {"Content-Type", "application/octet-stream"},
            { "X-Api-Length", length.ToString() }
        };
    }

    public void WriteTo(Stream responseStream)
    {
        if (_responseStream == null)
            return;

        using (_responseStream)
        {
            _responseStream.WriteTo(responseStream);
            responseStream.Flush();
        }
    }
}

<强> 客户端

string path = Path.GetTempFileName();//in reality, wrap this in try... so as not to leave hanging tmp files
var response = client.Get<HttpWebResponse>("/foo/bar");

long length;
if (!long.TryParse(response.GetResponseHeader("X-Api-Length"), out length))
    length = -1;

using (var fs = System.IO.File.OpenWrite(path))
    fs.CopyFrom(response.GetResponseStream(), new CopyFromArguments(new ProgressChange((x, y) => { Console.WriteLine(">> {0} {1}".Fmt(x, y)); }), TimeSpan.FromMilliseconds(100), length));

“CopyFrom”扩展方法直接从这个项目的源代码文件“StreamHelper.cs”中借用：Copy a Stream with Progress Reporting（感谢Henning Dieterichs）

感谢mythz和ServiceStack的任何贡献者。伟大的项目！

ServiceStack是否支持二进制响应？

3 个答案:

详细信息