WinRT - TCP clients?

Question

I am building an IRC client in the new WinRT (.NET 4.5) framework for Windows 8 Metro applications.

However, I have some issues. I've already figured out that I need to use a StreamSocket to read TCP data, but I may be doing something wrong.

The reason I believe this is because I am not receiving any data.

Below you see my code. I haven't been able to find any code samples on the web regarding this.

class IRCClient
{
    private StreamSocket tcpClient;
    public string Server = "holmes.freenode.net";
    public int Port = 6665;

    public IRCClient()
    {
        tcpClient = new StreamSocket();
    }

    public async void Connect()
    {
        await tcpClient.ConnectAsync(
                         new Windows.Networking.HostName(Server), 
                         Port.ToString(), 
                         SocketProtectionLevel.PlainSocket);

        DataReader reader = new DataReader(tcpClient.InputStream);
        string data = reader.ReadString(reader.UnconsumedBufferLength);

        MessageDialog dialog = new MessageDialog(data);            
    }
}

Data is always an empty string following that code. Furthermore, UnconsumedBufferLength always returns 0.

How come?

Answer 1

You need to tell the DataReader to read bytes from the stream before you interpret them (ReadString just interprets the bytes already read).

So, if you want to read a string of 20 bytes, do this:

DataReader reader = new DataReader(tcpClient.InputStream);
await reader.LoadAsync(20);
string data = reader.ReadString(reader.UnconsumedBufferLength);

If you want to read a string up to 20 bytes, do this:

DataReader reader = new DataReader(tcpClient.InputStream);
reader.InputStreamOptions = InputStreamOptions.Partial;
await reader.LoadAsync(20);
string data = reader.ReadString(reader.UnconsumedBufferLength);

See this video for more info: http://channel9.msdn.com/Events/BUILD/BUILD2011/PLAT-580T

Note that DataReader does not give you message boundaries; it's just a more convenient way of waiting for and reading binary data from a stream. You still need message framing.