TCP/UDP Protocol Implementation

This project implements a client-server application for message distribution. It consists of a Server that receives messages via UDP and forwards them to active TCP Subscribers based on topic subscriptions.

Features

• I/O Multiplexing: Both Server and Subscriber use poll() for efficient handling of multiple connections and input sources.
• UDP Protocol Parsing: The server parses binary UDP payloads containing various data types:
  • INT (Integer)
  • SHORT_REAL (Short Real, 2 decimals)
  • FLOAT (Float, variable precision)
  • STRING (Text)
• Wildcard Subscriptions:
  • +: Matches exactly one hierarchy level (e.g., upb/+/temperature).
  • *: Matches zero or more hierarchy levels (e.g., upb/precis/*).
• TCP Client Feedback: Subscribers receive and display messages in real-time and provide local feedback for subscription commands.

Architecture

• server.cpp: Manages the UDP socket, TCP listener, and all connected clients. It stores subscriptions and routes incoming UDP messages to the matching TCP clients.
• subscriber.cpp: Connects to the server, sends its ID, and allows the user to issue subscribe/unsubscribe commands via stdin while listening for incoming messages.
• helpers.h: Contains common includes, macros (like DIE for error handling), and protocol constants.
• Makefile: Script to compile the project.

Build

To compile both the server and the subscriber:

make

To clean up the executables:

make clean

Usage

1. Run the Server

Start the server on a specific port.

./server <PORT>

Example:

./server 12345

2. Run the Subscriber

Start a subscriber with a unique ID, connecting to the server's IP and Port.

./subscriber <ID_CLIENT> <IP_SERVER> <PORT_SERVER>

Example:

./subscriber C1 127.0.0.1 12345

3. Subscriber Commands

Once the subscriber is running, you can use the following commands in its terminal:

• Subscribe to a topic:

  subscribe <topic>
  

  • Example: subscribe upb/precis/temperature
  • Example (Wildcard): subscribe upb/+/temperature

• Unsubscribe from a topic:

  unsubscribe <topic>
  

• Exit:

  exit
  

  (Or simply close the server/subscriber with Ctrl+C, though strictly exit is the command).