Question

I need some help in creating a pair of programs in Python UDPClient and UDPServer, that use the UDP protocol to communicate with each other.

Once the sockets are set up, the communication will go as follows:

1. The client reads a line of characters (data) from its keyboard and sends the data to the server.
2. The server receives the data and converts the characters to uppercase.
3. The server sends the modified data to the client.
4. The client receives the modified data and displays the line on its screen.
5. 
   

The code should have UDP_IP & UDP_Port

Testing: will be executing both programs on separate consoles. Use "localhost" as the serverName on UDPClient. Run UDPServer on one console. Then run UDPClient on another console.

Answer 1

UDP SERVER:

import socket

UDP_IP = "localhost"

UDP_PORT = 6780

serverSock = socket.socket()

serverSock.bind((UDP_IP, UDP_PORT))

serverSock.listen(5)

conn, addr = serverSock.accept()

data = conn.recv(UDP_PORT).decode()

new_data = data.upper()

conn.send(new_data.encode())

serverSock.close()

UDP CLIENT:

import socket

UDP_IP = "localhost"

UDP_PORT = 6780

message = input("Enter String: ")

clientSock = socket.socket()

clientSock.connect((UDP_IP, UDP_PORT))

clientSock.send(message.encode())

data = clientSock.recv(UDP_PORT).decode()

print(data)

clientSock.close()

Explanation:

socket.bind((UDP_IP, UDP_PORT)) will bind the ip address and port no to the socket.

socket.listen(n) will listen n requests and hold them in a queue, and drop the other requests after it.

conn.send(bytes) will take bytes like object and send it to bound address.

conn.recv(port_no) will take port_no as arg and return bytes like object

The data is sent from client to server, the server converts the string to a capital case and retransmits it back to the client.

str.encode() - (string to bytes)

bytes.decode() - (bytes to string)

These operations are required for proper communication.