A server and client using TCP connections over sockets, built in Racket.
The server uses only one extra library called racket/tcp. It is a loop in which the first line is a blocking statement that accepts incoming connections off of the listener. Once a new connection arrives, it creates a new thread so that it can service multiple clients at once. Inside the thread are the different functions as well as the various thread-specific variables such as name and buffer. Inside each thread there is another loop that runs after a blocking read statement that returns a line after a return-linefeed is received that will parse the received line and perform the action required. Once the ‘adios’ string is received, the loop is exited and the connection is closed.
The client is much simpler than the server. It connects to the server using tcp-connect and then creates a thread for reading data sent from the server. This thread essentially just waits for a return-linefeed and then displays whatever it has received to the console. After that thread has been created, the client enters a read from keyboard loop that blocks on a read statement and then sends the received string to the server. If that string is ‘adios’ it will also kill the thread and close the connection to the server.