Chat server and client in C using ipc's

This project is an assignment for PSiW at PUT. This repository contains source code to client and server programs.

Compilation

The make file allows for easy compilation by typing in the terminal command:

make

It creates two executable files in bin/ directory - client and serv.

Additionally, it has a feature that kills all message queues and currently running programs when typed into the terminal:

make kill

It is important to use this feature after exiting all programs, otherwise the chat will not work properly after restarting. Keep in mind that this command removes all IPCs in your system, so if you use any IPCs unrelated to this app, they will be removed. DON'T use this command if you want to keep other IPCs.In such case, you need to manually remove IPCs created by serv and client programs and kill any remaining processes of serv or client.

Running

In order to connect a client to the server, you must first run the serv binary and then run up to 16 instances of client binary. After having succesfully connected to the server, client prints out a quick list of available actions that can be performed within the application.

Directories

Src directory includes source codes of client and server which are the backbone of the whole project. The main loop is implemented in them.

Lib directory contains libraries used in project. They include declarations of functions and data structures used in main loop.

There are definitions of the above are contained in def directory.

Protocol

Communication between components takes place by sending data structures, called queries, through message queues between the client and the server. Each of queries has its own unique number (id) - which is the process identifier obtained by getpid() function, message and type. The server knows how to process a particular message thanks to the type of query. The initiation of sending the first query to the server takes place when the user enters his name, then the server reads the message type and recognizes it as ENTER_QUERY. Next it checks whether the entered name is available and if so, it registers the user in the system. After this process, the terminal window displays instructions and a list of commands that can be used, such as joining a channel, leaving a channel, sending a private or public message, displaying a list of channels with users and leaving a chat. After entering any command, exactly as before a query of a certain type is sent to the server, which processes the command accordingly, often using functions from serv_utils.c - e.g. joining a channel, leaving a channel, listing users etc. The client uses function defined in client_utils.c such as displaying chat instructions or getting the current time.
Structures used to manage channels:

User - conatains the username and his unique id.
Channel - contains channel name, user count and array of user structures.

Authors