Question

I am trying to send simple string message from my desktop app using sockets here is the server side code which sends data to the client:

    swSenderSender = new StreamWriter(tcpClients[i].GetStream());
    swSenderSender.WriteLine(From + " says: " + Message);
    swSenderSender.Flush();
    swSenderSender = null;

I have Metro application – Client side code using DataReader:

    var dr = new DataReader(socket.InputStream);
    var stringHeader = await dr.LoadAsync(4);
    int strLength = dr.ReadInt32();
    uint numStrBytes = await dr.LoadAsync((uint)strLength);
    string msg = dr.ReadString(numStrBytes);

Here is the problem. DataReader needs to know how long is the string which were send. On the other side the StreamWriter cant sand nothing different than a simple string /or string with new lane. How to connect these two codes? Or maybe there is annother way to do this. Please help. I don’t know how to format the data to be able to send it between the client and the server.

Answer 1

The normal way this problem is solved in protocols is to put the length of the message first, in a fixed-length field, say length N. If you are never going to receive more than 999 characters in a message then N=3, for example. So your receive code devolves to

receive N characters (or bytes, whatever).
decode N to get number of characters following, say M.
receive M characters.
repeat ad nauseam.