Question

I posted a question on how to send large objects over TCP and it seems like the primary issue is solved, but now frequently I get another exception:

Binary stream ‘0’ does not contain a
valid BinaryHeader. Possible causes
are invalid stream or object version
change between serialization and
deserialization.

The issue is still in my Receive method:

public Message Receive()
{
    if (_tcpClient == null || !_tcpClient.Connected)
    {
        throw new TransportException("Client Not Connected");
    }

    // buffers
    byte[] msgBuffer;
    byte[] sizeBuffer = new byte[sizeof(int)];

    // bites read
    int readSize = 0;
    // message size
    int size = 0;

    MemoryStream memStream = new MemoryStream();
    NetworkStream netStream = _tcpClient.GetStream();
    BinaryFormatter formatter = new BinaryFormatter();
    try
    {
        // Read the message length
        netStream.Read(sizeBuffer, 0, sizeof(int));

        // Extract the message length
        size = BitConverter.ToInt32(sizeBuffer, 0);
        msgBuffer = new byte[size];

        // Fill up the message msgBuffer
        do
        {
            // Clear the buffer
            Array.Clear(msgBuffer, 0, size);

            // Read the message
            readSize += netStream.Read(msgBuffer, 0, _tcpClient.ReceiveBufferSize);

            // Write the msgBuffer to the memory streamvb
            memStream.Write(msgBuffer, 0, readSize);

        } while (readSize < size);

        // Reset the memory stream position
        memStream.Position = 0;

        // Deserialize the message
        return (Message)formatter.Deserialize(memStream); // <-- Exception here

    }
    catch (System.Exception e)
    {
        if (_tcpClient == null || !_tcpClient.Connected)
        {
            throw new TransportException("Client Not Connected");
        }
        else
        {
            throw e;
        }
    }
}

The rest of the code relevant to this example can be found in my original question.

Does anybody know what is causing this exception and how I can avoid it?

Update

Changed the Read to read a maximum of _tcpClient.ReceiveBufferSize bytes at a time, rather than trying to read the full message size (which can be larger than the buffer size) and while the frequency of the Exception decreased slightly, it’s still occurring quite often.

Answer 1

Let me suggest you a slight simplification of your code:

public Message Receive()
{
    try
    {
        if (_tcpClient == null || !_tcpClient.Connected)
        {
            throw new TransportException("Client Not Connected");
        }

        using (var stream = _tcpClient.GetStream())
        using (var reader = new BinaryReader(stream))
        {
            int size = reader.ReadInt32();
            byte[] buffer = reader.ReadBytes(size);
            using (var memStream = new MemoryStream(buffer))
            {
                var formatter = new BinaryFormatter();
                return (Message)formatter.Deserialize(memStream);
            }
        }
    }
    catch (System.Exception e)
    {
        if (_tcpClient == null || !_tcpClient.Connected)
        {
            throw new TransportException("Client Not Connected");
        }
        throw e;
    }
}

Also if you are doing this for fun and/or education purposes then it’s ok, but in a real project you should probably consider WCF in order to transmit objects over the wire.