Python server get recv from all clients conncted and not just from the first one that conncted

Question

The title explain everything. I made Java code that sends messgaes for the python server, but evry time, just the first message is sends because every time, java conneced again to server, and the server keeps waiting to next message from the first client that I send in the first time.

How can the server get message from all clients are connectd? and not just from one?

My python server:

    server = socket.socket()
    server.bind((socket.gethostname(), 4786))

    server.listen(5)
    (client, (ipNum, portNum)) = server.accept()

    print("Client connected")

    while True:
        message = str(client.recv(64).decode()) # Check if client send message. I want to change it to check all clients

        if(message != ""):
            print("Client: " + message)

        else:
            time.sleep(0.1)

score 0 · Accepted Answer · answered Dec 11 '20 at 10:17

Summary

The server.accept() must be called inside the loop.

TLDR

The socket server returned from the call socket.socket() is a 'listening' socket. It is not used for any data transfer but just for listening incoming connections. When the server is willing to accept incoming connection then calls server.accept(). This call waits till a client connects. When a client connects the accept wakes up and returns a socket that represents a connection to one client. This socket is then used for data send and received and should be closed when the communication with this specific client is done.

When server wants to accept connection from another client it must call server.accept() again to wait for connection from another client and use the unique client socket for each connected client.

If it sufficient to handle client sequentially then you can just move the call accept onto the loop. Furthermore you should close the client socket when the communication with the client is done.

If multiple clients can be connected in parallel then slightly more complicated design is needed. You can start a new thread for each client after accepting the connection. The thread can call recv in a loop and terminates when the client disconnects. See Multi Threaded TCP server in Python for example.

Python server get recv from all clients conncted and not just from the first one that conncted

1 Answers1