Hedwig 🦉💬

Hedwig, the messenger is an asynchronus web-server to support chat-applications having multiple rooms/groups, each having two or more participants.

Hedwig is built using FastAPI and websockets. MongoDB is used as the persistent storage, whereas Redis is used as the caching layer for messages - its Pub/Sub feature is used for triggering sending/receiving of messages.

Flow-Diagram

Use-Case

Ideal use-case of Hedwig would be when you have to add chat-rooms in various parts of your app or website, which is not chatting platform per se.
Hedwig opens a new webosocket connection for every chat room. This has been done intentionally so that resources are not wasted (in maintaining websocket-connections) when chatting features are not being used.

Usage

• Install the dependencies (mentioned in pyproject.toml and poetry.lock)
  If you're using poetry, just run poetry install
• The project needs a mongoDB server and a Redis server running.
  Hedwig picks up these environment variables: MONGODB_URI, REDIS_URL
  You can also just create a .env file and add them like these so you don't have to set them again and again

MONGODB_URI=...
REDIS_URL=...

• Run the server

uvicorn main:app

• Create a chat-room by making a POST request on /chat-room/create
• Open a websocket connection and chat on /chat-room/{chat_room_id}/chat?user_id={user_id}
  • Incoming Messages Format:

    {
      "time": timestamp,
      "text": "text message"
    }

  • Outgoing Messages Format:

    {
      "user": "user_id",
      "time": timestamp,
      "text": "text message"
    }