Socket Programming Client-Server Project

This project demonstrates basic socket programming using TCP and UDP protocols in Python. The project includes the following four Python scripts:

• TCP Server (tcp_server.py): A server that listens for TCP client connections, receives messages, and responds with the uppercase version of the message.
• TCP Client (tcp_client.py): A client that connects to a TCP server, sends messages, and receives modified responses.
• UDP Server (udp_server.py): A server that listens for UDP client messages and sends back the uppercase version of the message.
• UDP Client (udp_client.py): A client that sends messages to a UDP server and receives modified responses.

Project Structure

/SocketProgramming
│
├── tcp_server.py          # TCP server script
├── tcp_client.py          # TCP client script
├── udp_server.py          # UDP server script
└── udp_client.py          # UDP client script

Requirements

• Python 3.x
• No external libraries required

Instructions

1. TCP Server and Client

Running the TCP Server:

1. Open a terminal and navigate to the directory containing the tcp_server.py file.
2. Run the server with the following command:

   python tcp_server.py

   The server will start listening for incoming client connections.

Running the TCP Client:

1. In another terminal window, navigate to the directory containing the tcp_client.py file.
2. Run the client with the following command:

   python tcp_client.py

   The client will connect to the server, send messages, and receive modified responses.

2. UDP Server and Client

Running the UDP Server:

1. Open a terminal and navigate to the directory containing the udp_server.py file.
2. Run the server with the following command:

   python udp_server.py

   The server will start listening for UDP client messages.

Running the UDP Client:

1. In another terminal window, navigate to the directory containing the udp_client.py file.
2. Run the client with the following command:

   python udp_client.py

   The client will send messages to the server and receive modified responses.

Code Explanation

TCP Server (tcp_server.py):

• Creates a TCP server socket using socket.AF_INET and socket.SOCK_STREAM.
• Binds the socket to the specified IP and port.
• Waits for a client to connect, accepts the connection, and then waits for messages.
• For each received message, the server sends back the uppercase version of the message.
• The server will close the connection once the client disconnects or sends an empty message.

TCP Client (tcp_client.py):

• Creates a TCP client socket and connects to the server using socket.connect().
• Sends user input messages to the server.
• Receives and prints the server's modified response (uppercase version of the sent message).
• Closes the connection when the user types "exit".

UDP Server (udp_server.py):

• Creates a UDP server socket using socket.AF_INET and socket.SOCK_DGRAM.
• Binds the socket to the specified IP and port.
• Waits for incoming messages from clients.
• For each received message, the server sends back the uppercase version of the message.
• The server continues to run until stopped manually.

UDP Client (udp_client.py):

• Creates a UDP client socket.
• Sends user input messages to the server and waits for a response.
• Receives the server's modified response (uppercase version of the sent message).
• The client continues to send messages until the user types "exit".

Example Usage

TCP Example:

1. Start the TCP server:

   python tcp_server.py

2. In a new terminal, start the TCP client:

   python tcp_client.py

3. Input a message on the client:

   Enter your message: hello
   

   The client will receive the server's response:

   "HELLO" has been sent
   

UDP Example:

1. Start the UDP server:

   python udp_server.py

2. In a new terminal, start the UDP client:

   python udp_client.py

3. Input a message on the client:

   Enter your message: hello
   

   The client will receive the server's response:

   "HELLO" has been sent
   

Conclusion

This project demonstrates how to use Python's socket module to implement simple client-server communication using both TCP and UDP protocols. It provides a solid foundation for learning about network programming and can be expanded for more complex applications.