WCF 服务端点处的空流

Question

我有 WCF 服务，我指定通过流使用它： 这是 Web.config

<services>
  <service name="StreamServiceBL">
    <endpoint address="" binding="basicHttpBinding"
      bindingConfiguration="StreamServiceBLConfiguration" contract="IStreamServiceBL" />
  </service>
</services>
<bindings>
   <basicHttpBinding>
    <binding name="StreamServiceBLConfiguration" transferMode="Streamed"/>
  </basicHttpBinding>
</bindings>

这是我发送流媒体的方式：

    private static MemoryStream SerializeToStream(object o)
    {
        var stream = new MemoryStream();
        IFormatter formatter = new BinaryFormatter();
        formatter.Serialize(stream, o);
        return stream;
    }

    private void Somewhere()
    {
        //...
        streamServiceBLClientSample.MyFunc(SerializeToStream(myObject));
    }

这就是我收到它们的方式：

[ServiceContract]
public interface IStreamServiceBL
{
    [OperationContract]
    public int MyFunc(Stream streamInput);
}

public class StreamServiceBL : IStreamServiceBL
{
    public int MyFunc(Stream streamInput)
    {
        //There I get exception: It can't to deserialize empty stream
        var input = DeserializeFromStream<MyType>(streamInput);

    }

    public static T DeserializeFromStream<T>(Stream stream)
    {
        using (var memoryStream = new MemoryStream())
        {
            CopyStream(stream, memoryStream);

            IFormatter formatter = new BinaryFormatter();
            memoryStream.Seek(0, SeekOrigin.Begin);
            object o = formatter.Deserialize(memoryStream); //Exception - empty stream
            return (T)o;
        }
    }

    public static void CopyStream(Stream input, Stream output)
    {
        byte[] buffer = new byte[16 * 1024];
        int read;
        //There is 0 iteration of loop - input is empty
        while ((read = input.Read(buffer, 0, buffer.Length)) > 0)
        {
            output.Write(buffer, 0, read);
        }
    }
}

所以我花的不是一个空流，而是一个空流。我从那里得到 CopyStream 代码：​​How to get a MemoryStream from a Stream in .NET?，我认为其中没有错误，所以据我所知，我得到了空流。

Answer 1

很难说为什么在一般情况下你会得到一个空流，但在你的示例情况下，它是非常清楚的。

如果您将方法 SerializeToStream 更新如下，一切都应该按预期工作：

private static MemoryStream SerializeToStream(object o)
{
    var stream = new MemoryStream();
    IFormatter formatter = new BinaryFormatter();
    formatter.Serialize(stream, o);
    // here we reset stream position and it can be read from the very beginning
    stream.Position = 0;  
    return stream;
}