chat

Simple p2p cli chat application.

I wrote this application to be able to easily share links and files on the cli with others on the network, but I wanted it to be more comfortable than netcat.

Please do keep in mind, that I wrote this application solely for personal use, that means:

• I don't plan on adding any more documentation except the already extensive comments
• no tests (!)
• the application does clean up after unexpected exceptions (usually network issues), but it does not provide explanations to the user or try to recover

Table of Contents

• Features
• What is still missing?
• How does it work?
• Prerequisites
• Building
• Usage
• Installation
• TL;DR

Features

• automatically connects to other peers
• redirects stdin (or file contents) to them
• redirects their messages to stdout

That's it.

What is still missing?

• encryption
• authentication
• Oftentimes a bug causes input supplied via pipes or the -f flag to be lost

How does it work?

A short outline of what happens when starting the application:

1. A random tcp port is opened to listen for incoming connections

• for each new connection, stdin is duplicated and redirected to the connected peer
• all incoming messages are redirected to stdout

2. The application starts listening for UDP pings in a multicast group

• if a ping is received, it answers with an identification string and its tcp port via an UDP pong

3. A ping is sent to a multicast group, where other peers are listening

• other peers answer to the ping
• the application connects to every discovered peer in the same manner as in 1.

Prerequisites

You'll need the Haskell development tool stack.

Building

stack build

Usage

For chatting, just run it.

stack exec -- chat

You can use pipes to send the output of other programs to chat peers: (Currently a bug causes input supplied via pipes or the --file flag to be lost)

cat someFile | stack exec -- chat

You can directly read from files instead of stdin:

stack exec -- chat --file myFile

• you can get additional debug information by using the -d flag

Installation

The latest Linux binary can be obtained from here. Packages for Arch Linux are also available:

Pre-Built

curl -O "https://raw.githubusercontent.com/ahbnr/chat/master/archlinux/bin/PKGBUILD"
makepkg -sri PKGBUILD

From source

curl -O "https://raw.githubusercontent.com/ahbnr/chat/master/archlinux/git/PKGBUILD"
makepkg -sri PKGBUILD

TL;DR

# Download source
git clone --depth=1 https://github.com/ahbnr/chat.git
cd chat

# Download stack build tool
curl -sSLO https://get.haskellstack.org/stable/linux-x86_64.tar.gz
tar -xf linux-x86_64.tar.gz
cp stack-*/stack .
rm -rf stack-*

# Building
./stack build
./stack exec chat