JohnReedLOL / C-client-server-real-time-character-by-character-chat

This terminal chat app differs from the usual chat apps in that it allows the other person to see what you are typing as you type it, in real time, rather than after you hit *enter*. It has a customization that makes it play a bell noise in the terminal when you hit the "@" character. The other person is supposed to type when they hear the bell.

C client server real time character-by-character chat

This terminal chat app differs from the usual chat apps in that it allows the other person to see what you are typing as you type it, in real time, rather than after you hit enter. It works on Mac, Linux like Ubuntu Linux, and also in the Termux terminal on Android which you can download from the F-Droid open source app store. This terminal app does not work on Window or iPhone by default, although if you are tech-savvy you may be able to figure out a way to get it working on a Windows computer, for example with a set up virtual machine or Cygwin. This terminal app has a customization that makes it play a bell noise in the terminal when you hit the "@" character, but the bell noise doesn't play on Android in the Termux terminal. The other person is supposed to type when they hear the bell. To make the C code take each character as it is typed rather than after the user hits enter I had to turn on raw mode as described in this StackOverflow question. The code is written in 2017 compliant C, C17, and is based off https://www.binarytides.com/programming-udp-sockets-c-linux/ . I compile the code with the gcc compiler.

Usage:

The server takes a port number to listen on. First compile and run the server in the terminal like so, this example uses port number 8000:

$ gcc server.c -o server
$ ./server 8000

The client takes a port number (the port number that the server is listening on) and the ip address of the server. Compile and run the client in the terminal like so:

$ gcc client.c -o client
$ ./client 8000 127.0.0.1

In the above example, I used the localhost IP address 127.0.0.1 but you can use any reachable IP address that the server runs on. Note that this program does not support IPv6, only IPv4. If the client and server are on the same Wi-Fi network they can connect with each other using a local IP address, which usually starts with "192.168" on home Wi-Fi networks. You can use the included bash script get_local_ip.sh to get your local IP address. Note that this real time chat uses UDP sockets instead of TCP sockets so if there are dropped packets they will not be resent. This app is optimized for latency and UDP has less lag than TCP. Note that each device has to run both a client and a server because text only goes in one direction, from the client to the server, so you need both to send text in both directions.