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
  • Voice chat in room
  • 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

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

• Tech Stack

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

• Infra

  • Use docker to deploy to PaaS platform like Railway or Fly
  • Use GitHub Actions + AWS Lightsail to deploy backend server
  • Backend service cluster, auto scaling, load balancing, etc.
    • Backend service use Elixir libcluster to build cluster
    • Frontend app use the client load balance strategy
    • 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