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Lazy, serializing objects with a flow network with protobuf-net

We are developing a WCF service for streaming large amounts of data, so we decided to use the WCF Streaming function in conjunction with protobuf-net .

Context:

In general, the idea is to serialize objects in the service, write them to the stream, and send them. At the other end, the caller will receive a Stream object and can read all the data.

Currently, the service method code looks something like this:

public Result TestMethod(Parameter parameter)
{
    // Create response
    var responseObject = new BusinessResponse { Value = "some very large data"};

    // The resposne have to be serialized in advance to intermediate MemoryStream
    var stream = new MemoryStream();
    serializer.Serialize(stream, responseObject);
    stream.Position = 0;

    // ResultBody is a stream, Result is a MessageContract
    return new Result {ResultBody = stream};
}

The BusinessResponse object is serialized into a MemoryStream and returned from the method. On the client side, the call code is as follows:

var parameter = new Parameter();

// Call the service method
var methodResult = channel.TestMethod(parameter);

// protobuf-net deserializer reads from a stream received from a service.
// while reading is performed by protobuf-net, 
// on the service side WCF is actually reading from a 
// memory stream where serialized message is stored
var result = serializer.Deserialize<BusinessResponse>(methodResult.ResultBody);
return result;

, serializer.Deserialize() , methodResult.ResultBody, WCF MemoryStream, TestMethod.

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, , - MemoryStream . , .

:

, Custom ( TestMethod()) , ( "BusinessResponse" ). , WCF Read() , , protobuf-net, , .

, . , - , , .

- , protobuf-net?

+5
1

, , , .

public class PullStream : Stream
{
    private byte[] internalBuffer;
    private bool ended;
    private static ManualResetEvent dataAvailable = new ManualResetEvent(false);
    private static ManualResetEvent dataEmpty = new ManualResetEvent(true);

    public override bool CanRead
    {
        get { return true; }
    }

    public override bool CanSeek
    {
        get { return false; }
    }

    public override bool CanWrite
    {
        get { return true; }
    }

    public override void Flush()
    {
        throw new NotImplementedException();
    }

    public override long Length
    {
        get { throw new NotImplementedException(); }
    }

    public override long Position
    {
        get
        {
            throw new NotImplementedException();
        }
        set
        {
            throw new NotImplementedException();
        }
    }

    public override int Read(byte[] buffer, int offset, int count)
    {
        dataAvailable.WaitOne();
        if ( count >= internalBuffer.Length)
        {
            var retVal = internalBuffer.Length;
            Array.Copy(internalBuffer, buffer, retVal);
            internalBuffer = null;
            dataAvailable.Reset();
            dataEmpty.Set();
            return retVal;
        }
        else
        {
            Array.Copy(internalBuffer, buffer, count);
            internalBuffer = internalBuffer.Skip(count).ToArray(); // i know
            return count;
        }
    }

    public override long Seek(long offset, SeekOrigin origin)
    {
        throw new NotImplementedException();
    }

    public override void SetLength(long value)
    {
        throw new NotImplementedException();
    }

    public override void Write(byte[] buffer, int offset, int count)
    {
        dataEmpty.WaitOne();
        dataEmpty.Reset();

        internalBuffer = new byte[count];
        Array.Copy(buffer, internalBuffer, count);

        Debug.WriteLine("Writing some data");

        dataAvailable.Set();
    }

    public void End()
    {
        dataEmpty.WaitOne();
        dataEmpty.Reset();

        internalBuffer = new byte[0];

        Debug.WriteLine("Ending writes");

        dataAvailable.Set();
    }
}

, ( ). , , . , . ;-) End, , Read , , .

. :

    // create a large object
    var obj = new List<ToSerialize>();
    for(int i = 0; i <= 1000; i ++)
        obj.Add(new ToSerialize { Test = "This is my very loooong message" });
    // create my special stream to read from
    var ms = new PullStream();
    new Thread(x =>
    {
        ProtoBuf.Serializer.Serialize(ms, obj);
        ms.End();
    }).Start();
    var buffer = new byte[100];
    // stream to write back to (just to show deserialization is working too)
    var ws = new MemoryStream();
    int read;
    while ((read = ms.Read(buffer, 0, 100)) != 0)
    {
        ws.Write(buffer, 0, read);
        Debug.WriteLine("read some data");
    }
    ws.Position = 0;
    var back = ProtoBuf.Serializer.Deserialize<List<ToSerialize>>(ws);

, :-) .

,

+2

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