Imhoteph

A peer to peer chat application using libp2p Swarm and Gossipsub protocols.

Motivation

Almost all major instant messaging apps are made by big tech who have a less than stellar track record of respecting user privacy. Imhoteph aims to be reliable, scalable and at the same time respect the privacy of the user.

Tech used

• Rust nightly
• Libp2p
• Clap
• Tokio

Usage

imhoteph-cli [SUBCOMMAND]

Sub commands

• dial --id [PEER ID] --topic [TOPIC NAME] Dial the given Peer ID and subscribe to the topic
• test --id [PEER ID] --addr [PEER MULTIADDR] Test dial a the given peer id with the given multiaddr.

Working

There are several independent working parts of Imhoteph.

1. network Manages network events, establishes connections and publishes messages to the network.
2. cli Handles commands given by the user

Network Initialization

On startup two threads are spawned one for displaying the messages and notifying the user about network events the other thread manages the network Eventloop struct.

// Run the network eventloop
pub async fn run(mut self) {
        loop {
            futures::select! {
                event = self.swarm.select_next_some() => {
                        self.handle_event(event).await;
                }

                command = self.command_receiver.select_next_some() => {
                        self.handle_command(command).await;
                }
            }
        }
    }

Message Passing

The Eventloop struct has event_sender field of type mpsc::channel which is used to pass messages to other the corresponding event_listner in the Client.

Network Events

There are a number of network events in Imhoteph. Client handles the event any way it wants to, as of now it displays the output in the terminal.

async fn handle_event(event: Event) {
    match event {
        Event::NewListenAddr { addr } => {
            println!("Starting Listening at {}", addr);
        }
        Event::Subscribed { peer_id, topic } => {
            println!("Peer {} joined {}", peer_id, topic)
        }
        Event::Unsubscribed { peer_id, topic } => {
            println!("Peer {} left {}", peer_id, topic)
        }
        Event::Message {
            propagation_source,
            message,
            ..
        } => {
            println!(
                "{}: {}",
                propagation_source,
                String::from_utf8_lossy(&message.data)
            )
        }
        _ => {}
    }
}

Build from source

Download Rust

Clone the repo

git clone https://github.com/omkar-mohanty/imhoteph.git
cd imhoteph

Build Imhoteph

cargo build 

Run the application

cd target/debug
./imhoteph-cli