IPC Publish - Subscribe model

Communication schema

Server creates two types of communication tunnels:

• Main tunnel to handle users login / register requests
• Private tunnel with each client where the communication between server and client occurs.

IPC codes:

Code	Description	Source	Tunnel
random generated	User register / login request	Client	Main tunnel
received from user	User id assignment	Server	Main tunnel
1	User send message request	Client	Private tunnel
2	Incoming message	Server	Private tunnel
3	New topic subscription	Client	Private tunnel
4	Block user request	Client	Private tunnel
5	Unblock user request	Client	Private tunnel

Build

Server

gcc server.c -o s.out -Wall -lpthread

Client

gcc client.c -o c.out -Wall -lpthread

Todo list:

Server side:

• User login / registration
• Server message request handler
• Saving changes to clients.data file
• Server subscription request handler
• Block request handler
• Unblock request handler
• Blocking client on too many login attempts

Client side:

• User login / registration
• User send message request
• User subscription request
• Block user request
• Unblock user request
• waitForUserInput() function implementation
• Client behaviour on login block
• Improve UI

Updates:

29.01.2021 v2

• Cleaned files
• Added variable logging in server

29.01.2021 v1

• Checking whether serverData directory exists. If not, it's being created
• Blocking user on too many failed login attempts
• Cleaned up warnings during compilation
• Added sync message receiver

28.01.2021 v1

• Added unblock functionality
• Improved UI
• Used new IPC code "5"
• Improved waiting for user input thanks to ignoring newline character in scanf inputs using %*c

27.01.2021 v1

• Fixed checkIfBlocked function
• Implemented user blocking funtion - client side
• Implemented user blocking funtion - server side
• Used new IPC code "4"

26.01.2021 v2

• Moved structures to separate header file
• Waiting for user input is kinda working. But only for main thread. The trick for other threads is to tell user to type 0 to conitnue
• !BUGFIX! Messages are not being trimmed no more (fix from 26.01.2021)

26.01.2021

• !BUG! Messages are being trimmed after last space. Client-side error caused by scanf splittin message on white spaces. Need to think of a solution to that
• Subscription requests and handling are probably fully working at this point. Need to test more in the future