C# Multiple Client - Sending Nickname along with IP and port no

Question

I am working on a C# multithreaded socket program. Client side code for connecting is:

 c.Connect(ipText.Text, port);  // Can I add nickName here? probably not?
 thrReceive = new Thread(new ThreadStart(Receive)); //Receive -> accepts buffers from server
 thrReceive.Start();

Before I start with the problem, a quick view of what I want to do: All data send by a client should be directed to all other clients but not the sender, so every time a client sends data, program should go over the list of clients and send the data.

What I am struggling with is along with port and IP, I want to send a nickname to the server. After that, server will check whether the nickname is unique. If not, it will reject the connection.

I thought of a trivial solution where client sends nickname with the sentence it sends, so this is after establishing connection with server. Server keeps a list of structs, lets say struct is called "param". "param" consists of 3 variables: 1)Socket 2)bool first = true 3)string nick

Whenever a new connection is established, a new "param" is created, initiating "first" to true and "nick" to empty string, and of course the socket to the client. And the very first time the same socket sends a data via a buffer, I will extract its nickname, set "first" to false and check its uniqueness, if not unique then disconnect the socket and delete the related entry.

I believe above solution is not a good solution, nothing near good actually:) There should be some proper way, I suppose.

Answer 1

You can not send data with the connection. That means you can not reject the connection but you can send packets for authenticating on the server. Example for that:

Client connects

Server accepts

Client sends something like "Auth [username]"

Server checks if username is free

If not: Server sends something like "RejectAuth" to the client and disconnects.

If it is free: Server sends something like "AcceptAuth" and the protocol continues (Sharing information, sending data, etc.)

Note: this is not the most optimal way. You could instead of disconnecting assign a random username and send him a change request. Thats much better because its faster and the user can send new usernames and instantly check if its free.