free4chat

free4.chat is a real-time audio chat service. It is designed by the local first and privacy first principle, and is very easy to use.

:warning: This project is just using for technical test purpose, use at all your risk!

:warning: There is freedom of speech, but I cannot guarantee freedom after speech. (- Idi Amin)

Features

• Real-time Communicating
  • [x] Voice chat in room
  • [x] Text chat in room, can sent text or emoji
  • [ ] Persist text messages to browser localStorage
  • [ ] Can send arbitrary data by WebRTC datachannel 🚩
  • [ ] Room permission setting, like public/private type setting
  • private room can't been seen on room discovery, and it needs password to enter. The password is End-to-End Encryption, server only need check the answer which given by the client like the PoW in blockchain.
  • [ ] Public rooms discovery, like hot room list or filter rooms by type/tag
• Real-time Collaborating
  • [ ] User real-time collaboration, like whiteboard, you draw I guess, etc.
  • [ ] Use CRDT to impelement real-time collaboration
    • https://github.com/derekkraan/delta_crdt_ex
    • https://github.com/electric-sql/vaxine
    • https://github.com/liveblocks/liveblocks
    • https://github.com/yjs/yjs
  • [ ] Whiteboard
    • https://github.com/tldraw/tldraw
• Real-time Contesting
  • [ ] AI Robot user, like game robot who can play or facilitate game
  • robot use Web Speech API to play with user in room
    • Azure Text to speech service.
  • robot can play some voice games like language learning, technical interview, etc.
    • Gartic Phone - The Telephone Game
    • ESL Game - Not only practicing English speaking
    • Gartic.io - Draw, Guess, WIN
    • Get to know someone in 17 seconds
  • AI + Voice
    • Deep learning models are changing the world
    • @midjourney can generate fatastic image from text
    • @GitHubCopilot can generate context-awared code from short code segment
    • @OpenAI GPT-3 model can generate text paragraph from short sentence segment
    • Voice conversation from text?

Architecture

• Common

  • [x] Use WebSocket to replace http protocol of JSON-RPC
  • Compatibility
  • [ ] Make Safari(WebKit) compatibility better

• Tech Stack

  • [x] Use Elixir/Phoenix to rewrite the backend code
  • [x] Use Recat/Next.js to rewrite the frontend code

• Infra

  • [x] Use docker to deploy to PaaS platform like Railway or Fly
  • [x] Use GitHub Actions + AWS Lightsail to deploy backend server
  • [x] Backend service cluster, auto scaling, load balancing, etc.
  • Backend service use Elixir libcluster to build cluster
  • Frontend app use the client load balance strategy
  • [x] TURN cluster scale
    • Fix by start turn before the libcluster, still wait the upstream library to fix it normally

  • [ ] Room process rebalance, that means if the node where room in is offline, then the room process can rebalance to another node, the rebalance can use Consistent hashing to implement

    • For now, we just ignore this issue, because it can be resolved by reconnect another node and create the room again
    • Some Elixir simple approaches
    • Swarm
    • Horde
    • A complex approach is use Riak Core which implement the Consistent hashing and can rebalance the process by VNode
    • NkDIST, a Erlang distributed registration and load balancing lib which is base on Riak Core

    • Tinode chat solve this issue by implementing the Raft Consensus Algorithm

      More

      - https://github.com/tinode/chat/issues/28 - https://github.com/tinode/chat/issues/279 - https://github.com/tinode/chat/blob/master/server/topic_proxy.go - https://github.com/tinode/chat/blob/master/server/cluster.go - https://github.com/tinode/chat/blob/master/server/cluster_leader.go - https://github.com/tinode/chat/blob/master/server/ringhash/ringhash.go
  • [ ] Security enhancement, like coturn TLS setup, end-to-end encryption, etc.
  • [ ] TURN enable TLS
  • [ ] Privacy enhancement.
  • [ ] IPV6 support.

Documentation

https://dev-notes.free4.chat/

Contribution

If you are interested in webRTC, peer-to-peer(P2P), real-time collaboration(CRDT), distributed system or robot design, you can join this project and contact with me by twitter.

Thanks

• free4.chat Elixir version is build on the top of Membrane Framework, thanks for their heart of open source.
• free4.chat Golang version is build on the top of Kraken, Mornin, coturn and Pion, thanks for their heart of open source.
• These websites also inspired me:
  • Random voice and text chat rooms that you’ll love. | Speakrandom
  • Practice Speaking English Online Free - Language Practice Community
  • Agora Real-Time Voice and Video Engagement
  • An open network for secure, decentralized communication - Matrix
  • Introduction to Realtime Web Applications
  • Gather | Building better teams, bit by bit