About

This application implements a chat client that really is no more complex than an echo client. Each client will have the ability to send text strings to the server and will also be able to see the text sent by all other clients. The application is run through console. The select call has been used to implement multiplexed I/O.

How to compile and run

Client: g++ -Wall -o client client.cpp -lpthread, followed by ./client , localhost can be used for hostname to run

Server: g++ -Wall -o server server.cpp, followed by ./server to run

Design

Server State Diagram

Client State Diagram

Pseudocode

Server.cpp – Mian

Get user args

Crete Socket

Add socket to the set of file descriptors

Listen for activity on the set – if anything happens, check if it’s a new connection request, if so create a socket and add it to the set, if not process the activity as a message

Parse the message and add the IP address for re-transmission

Send the message to everyone who is not either the listening socket or the sender

Client.cpp

Get user args

Crete Socket

Connect to the host/port

Get the user’s chat alias

Create a thread for listening to messages from the server

Poll for messages from the user and append their alias to each message

Testing

A pcap was provided in this submission of the TCP traffic for demonstration purposes in addition to the below tests.

All users can see each other’s IP addresses

Condition: Each message received should have the sender’s IP address prepended to it.

Result: Passed

A user does not receive a message from the server from themself

Condition: I should not see an IP prepended to my own messages (the server prepends an IP to all messages it relays)

Result: Passed

All users can see their chat names on each message

Condition: Each user should, in addition to seeing IP addresses, be able to read an alias for the sender

Result: Passed