SimpleChat

About

• A simple chat app that uses websocket for real-time message routing, and rabbitmq to decouple the incoming messages and the db writes and increase throughput.
• Websocket is hosted at ws://localhost:8080/
• Simple UI can be found at localhost:3000/client for testing of functionalities

Technology

• Websocket: Real-time bi-directional networking
• RabbitMQ: Decouple message routing and db writes
• PostgreSQL: Database used to save the messages
• TypeScript: Provide typing support
• Sequelize: ORM used to connect and interact with the PostgreSQL database
• Sequelize CLI: To run the migrate files
• ts-node: Run TS scripts by compiing on the fly

Necessary Files

• .env file in root directory; variables to include
  • ENVIRONMENT

Quick Start:

# Pull postgres docker image
docker pull postgres

# Start the posgres docker container
docker run --name some-postgres -e POSTGRES_PASSWORD=password -p 5432:5431 -d postgres

# Pull rabbitmq image
docker pull rabbitmq:3-management

# Start the rabbitmq container
docker run -d --name rabbitmq -p 5672:5672 -p 15672:15672 rabbitmq:3-management

# This generates the config json file which is required when you migrate the schemas to the database
npm run script ./scripts/genConfig

# Compile typescript code into javascript
npm run build

# Create the database
npm run db:create

# Migrate schema
npm run db:migrate

# Start the server
npm run start

Test

• Open 2 pages to localhost:3000/client
• Key in the user id and recipient id on both pages, but in reverse order to talk to each other
• Click register
• Type in the text box and click send
• Start chatting away!

Tutorials:

• Websocket:
  • https://www.blackslate.io/articles/real-time-communication-with-nodejs-express-websockets
  • https://dev.to/hamzakhan/built-in-websockets-in-nodejs-2024-a-comprehensive-guide-2236
• RabbitMQ:
  • Intro: https://www.cloudamqp.com/blog/part1-rabbitmq-for-beginners-what-is-rabbitmq.html
  • Exchange Types: https://www.cloudamqp.com/blog/part4-rabbitmq-for-beginners-exchanges-routing-keys-bindings.html
  • Management Plugin: https://geshan.com.np/blog/2024/05/rabbitmq-docker/
  • https://medium.com/cwan-engineering/rabbitmq-concepts-and-best-practices-aa3c699d6f08

TODO:

• Look into whether multiple producers are needed and how to create a pool of producers to choose from
• Look into bulk inserts for the db to speed up the db inserts
• Add history api to get all the past messages