fwcd / distributed-chat

Distributed peer-to-peer messaging app using Bluetooth LE mesh networks

Distributed Chat

A distributed chat messenger that uses Bluetooth LE mesh networks.

• Fully decentralized architecture, no server or Internet connection required
• Message caching, delayed transmission
• Public and private end-to-end-encrypted messaging channels
• Voice messages, image, file and contact attachments
• Full simulation environment with configurable nodes, links and much more included
• Cross-platform, portable core

Components

The project consists of the following components:

• DistributedChat: The abstract application, platform-independent, transport-independent (uses interface for broadcasting/receiving messages)
• DistributedChatApp: The iOS implementation, uses Bluetooth LE as transport, does not require a server
• DistributedChatCLI: The CLI implementation, uses either HTTP/WebSockets as transport with the simulation server or Bluetooth LE (WIP)
• DistributedChatSimulationProtocol: The high-level JSON-based protocol used between CLI and simulation server
• DistributedChatSimulationServer: The companion server for the CLI, relays messages between connected CLI nodes, provides web-interface for configuring links between nodes
• Scripts: Scripts for launching CLI instances conveniently and for testing the BLE transport

The dependency graph between these packages looks like this:

             +-----------------+  +-----------------------------------+
             | DistributedChat |  | DistributedChatSimulationProtocol |
             +-----------------+  +-----------------------------------+
                      ^                      ^
                      |                      |
           +----------+-------------+   +---------+
           |                        |   |         |
+--------------------+ +--------------------+ +---------------------------------+
| DistributedChatApp | | DistributedChatCLI | | DistributedChatSimulationServer |
+--------------------+ +--------------------+ +---------------------------------+

 \__________________/   \______________________________________________________/
       iOS only                     cross-platform, for testing

Building and Running

First, make sure to have Swift 5.7+ or newer installed. Recent versions for Ubuntu and macOS can be found here.

Simulation Server

To run the simulation server, navigate into the directory DistributedChatSimulationServer and execute:

swift run

The web interface should now be accessible at http://localhost:8080.

CLI

To start a single instance of the CLI, make sure that the simulation server is running, navigate into DistributedChatCLI and execute:

swift run DistributedChatCLI --name Alice

You can substitute any name for Alice. Once the CLI has started, the chosen name should show up as a node in the simulation server's web interface.

For convenience, there is a bash script for starting multiple instances of the CLI together in a single tmux session. To use it, navigate into the root directory of this repository and run

Scripts/start_clis Alice Bob Charles Dave

...or however many clients you want to start. To stop all clients at once, press Ctrl + B then type :kill-session and press enter.

iOS app

Building and running the iOS app is only possible on macOS, so make sure to have the following available:

• Xcode 14.1+
• Swift 5.7 (should be included with Xcode)
• optionally an iOS device

The open the DistributedChatApp subdirectory in Xcode and build/run the project.

distributed-chat's Issues

Android App - UUID for crossplatform communications

I am trying to develop an Android app based on the code provided, however, I am struggling to ensure communications between iOS and Android with UUID and channels key.

Share sheets in iOS app

Support share sheets by wrapping UIActivityViewControllers (see here).

Set up CI

Set up a CI build using GitHub Actions.

Persistence on iOS

Persist chats, attachments, profile data and settings in the iOS app.

Implement iOS app

Implement the iOS App using SwiftUI and CoreBluetooth.

Parallel central and peripheral mode currently does not work with Bluetooth LE transport on Linux

Find out why acting as both a central and a peripheral in the CLI's BluetoothLinuxTransport causes the peripheral to be non-discoverable.

Add an Android app

A long-term goal would be to have an Android app too that integrates the DistributedChat package with a platform-specific UI. There are a few challenges with this approach, however:

• Building the Swift compiler for Android is possible, but non-trivial (official docs are here)
• Integrating the ChatController may require wrapping it into C-compatible structures for interfacing with the JVM world (Java, Kotlin, ...)
  • This requires using the Android NDK and JNI

A UI could be written using a high-level framework for Kotlin, e.g. Jetpack Compose which is similar to SwiftUI.

Add BLE transport for Linux to CLI client

Investigate where BluetoothLinux could be used to implement a BLE-based transport that is compatible with the iOS/CoreBluetooth version.

add Siri command to record and send voice chat

Nice work would be nice if you added Siri command to record and send voice chat messages
and then make them auto playable on receive so it can work like Team speak for gamers just a thought

iOS Notifications

Implement local system-wide and in-app notifications for the iOS app.