Chat Server
This is a chat server built in Golang to demonstrate how to design scalable chat services using Redis and the publisher-subscriber model.
Overview
I designed the chat server to be horizontally scalable by using Redis to store user states, including subscribed channels and login information. Additionally, the server includes authentication and a middleware for the WebSocket endpoint.
Running the Server
To run the server, you need to run the docker-compose.yaml file with the following command:
docker-compose up
Endpoints
The server supports the following endpoints:
/signup
This endpoint requires a JSON with a username and password. It returns an OTP that must be added as a query parameter when connecting to the WebSocket endpoint.
/login
This endpoint requires a JSON with a username and password. It returns an OTP that must be added as a query parameter when connecting to the WebSocket endpoint.
/community
This is a WebSocket endpoint that should be accessed via ws://localhost:8080?OTP="otp". The message to the WebSocket is in JSON format and has the following structure:
{"command":"", "content":"", "channel":"", "error":""}
The command field can be one of "SendMessage", "Subscribe" or "Unsubscribe". The channel field must be provided. By default, all users are subscribed to the "eje" channel.
Testing Horizontal Scalability
To test the horizontal scalability, create another session on your websocket client, signup and login using localhost:8081 and establish a websocket connection on ws://localhost:8081?OTP="otp". Keeping the two websocket sessions active, try sending messages.
Conclusion
With its support for authentication and scalable design, this chat server provides a solid foundation for building real-world chat applications.
