Mpad - A Decentralised Local Multiplayer Text Pad

Mpad is a desktop app (mobile/web clients planned!) which allows you to share a simple text pad with other users on a local network:

Any changes you make on one mpad instance are instantly reflected to all other pcs using a CRDT for conflict resolution via multicast.

It was borne out of a frustration to have a shared clipboard between a few laptops around the office.

Compilation

Requires rust & gtk installed (for gtk-rs), then simply:

cargo build --release

Installation

From Path

cargo install --path .

Or from Cargo:

cargo install mpad

Usage

Typing mpad in a terminal will bring up a window. Bring it up on each computer to have them participate.

Internals

Uses a slimmed down version of the existing ditto CRDT library (with an extra function or two added).

The multicast.rs does all the heavy lifting here!

• Users type something
• Updates its local CRDT using a diff
• If there are changes, submits them in partial chunks to a multicast address (currently hardcoded to 239.1.1.1:1111)
• Receives updates from the multicast address
• Merges the remote state with the local CRDT

This is exposed by a channel so it should be easy-ish to plug it into other frontends:

pub fn setup_channels() -> Result<(Sender<String>, Receiver<String>), Error>;

Where sender is where you send updates from your text pad, and receiver is where you receive updates from the wire.