Computer_Networks_Chat_Application

Overview

This is a multi-client chat application implemented in C++ using a server-client model. The server supports multiple clients and allows broadcasting, private messaging, and client management features using POSIX sockets and multithreading.

Features

Multi client support:

• Supports up to 5 simultaneous clients (configurable via MAX_CLIENTS)
• Extra clients are automatically closed

Non-blocking I/O with select():

• Uses select() to manage new connections and client communications, eliminating the need for multithreading on the server side

Client Alias Management:

• Each client must set an alias. If an alias is already taken, the server prompts the client for another alias.

Chat Room Join/Leave Mechanism

• Clients must explicitly join the chat room using the CONNECT command
• Users can send broadcast or private messages in the chat room

Broadcast Messaging:

• Messages sent without a command are broadcast to all clients in the chat room

Private Messaging:

• Prefix a message with @username to send a private message to one or more specific users
• The sender receives a notificationIf the recipient is not found

DISCONNECT and EXIT:

• Commands to leave the chat room or close the connection respectively

Customized terminal:

• ncurses library used for custom terminal with seperate chat and input window, along with scroll option in chat
• All client terminal related functions are included in terminal.h header file
• Collission avoided between inputs and outputs due to asynchronous behaviour

Multithreading:

• Threaded client handling in server for scalability and asynchronous inputs and outputs
• Threaded input and output handlers in client for ansynchronity

Technologies Used

• C++ (Standard Library, POSIX APIs)
• Sockets (TCP/IP)
• pthreads for multithreading
• ncurses library for customized terminal
• ANSI escape sequences for colored terminal output

Compilation

Compiling server

g++ server.cpp -o server -lpthread

Compiling serverSelect

g++ serverSelect.cpp -o server

Compiling client

g++ client.cpp -o client -lpthread -lncurses make sure client.cpp and terminal.h are in the same directory

USAGE

Starting the server

Run the server with a specified port number:

./server <port_number>

Example:

./server 4761

Connecting clients

Run the client and specify the server IP and port:

./client <server_ip> <port_number>

Example:

./client 127.0.0.1 4761

Commands

Command	Description
CONNECT	Connects the user to the chatroom
DISCONNECT	Disconnects the user from the chatroom
EXIT	Exits the chat application
@username <message>	Sends a private message to a user
<message>	Broadcasts a message to all connected users except the sender

SAMPLE IMAGES

Server

First Client

Second Client

Third Client