There's a black hole in my server (TcpClient, TcpListener)

Question

Hi,

I'm trying to build a server that will receive files sent by clients over a network. If the client decides to send one file at a time, there's no problem, I get the file as I expected, but if it tries to send more than one I only get the first one.

Here's the server code: I'm using one Thread per connected client

public void ProcessClients()
{
    while (IsListening)
    {
        ClientHandler clientHandler = new ClientHandler(listener.AcceptTcpClient());
        Thread thread = new Thread(new ThreadStart(clientHandler.Process));
        thread.Start();
    }
}

The following code is part of ClientHandler class

public void Process()
{
    while (client.Connected)
    {
        using (MemoryStream memStream = new MemoryStream())
        {
            int read;
            while ((read = client.GetStream().Read(buffer, 0, buffer.Length)) > 0)
            {
                memStream.Write(buffer, 0, read);
            }

            if (memStream.Length > 0)
            {
                Packet receivedPacket = (Packet)Tools.Deserialize(memStream.ToArray());
                File.WriteAllBytes(Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.DesktopDirectory), Guid.NewGuid() + receivedPacket.Filename), receivedPacket.Content);
            }
        }
    }
}

On the first iteration I get the first file sent, but after it I don't get anything. I've tried using a Thread.Sleep(1000) at the end of every iteration without any luck.

On the other side I have this code (for clients)

.
.
client.Connect();
foreach (var oneFilename in fileList)
    client.Upload(oneFilename);
client.Disconnect();
.
.

The method Upload:

public void Upload(string filename)
{
    FileInfo fileInfo = new FileInfo(filename);
    Packet packet = new Packet()
    {
        Filename = fileInfo.Name,
        Content = File.ReadAllBytes(filename)
    };

    byte[] serializedPacket = Tools.Serialize(packet);

    netStream.Write(serializedPacket, 0, serializedPacket.Length);
    netStream.Flush();
}

netStream (NetworkStream) is opened on Connect method, and closed on Disconnect.

Where's the black hole? Can I send multiple objects as I'm trying to do?

Thanks for your time.

Answer 1

I am guessing that if clients upload multiple files, your loop is reading the whole stream as a single file on the server side. Where's the "delimiter between files"? How does the server know where one ends and another begins?