Backend side of a Chat application made with Express, PostgreSQL and Websocket and RabbitMQ.

The system is composed of 3 microservices:

• ws-server: handles ws connections and broadcasts messages to connected users, publishes incoming messages to the RabbitMQ message queue for later process;
• msg-api: simple API to retrieve old messages (GET method) stored in PostgreSQL db and store them trough POST method;
• msg-store-worker: worker that consumes the message queue and stores them by POSTing to msg-api;

The servers connects to a PostgreSQL database available locally to store all incoming messages and allow the frontend to fetch them. When launched, it connects to PostgreSQL and listens to incoming Websocket connections from clients. It then broadcasts incoming messages to all the other clients connected to form a group chat.

Run

npm install

to install the npm packages.

PostgreSQL and RabbitMQ can be installed either locally or made available in a container easily using the docker-compose.yaml file in the root of the project.

If using the latter, be sure to have Docker installing and running on your system.

Create in the root folder a file called .env, writing the variables copying the contents of .env.example. You can of course also change their values.

To generate the JWT_SECRET you can use

"ts-node-dev \"./src/services/generateJWTSecret.ts\""

It will generate 32 random bytes in hex form and make with it a 64 length string.

First, be sure PostgreSQL is installed and running on your computer. If instead of using a local instance you are using Docker, just run

docker-compose up

from the root of the project.

Then, run prisma migrate to have your local db in sync with the schema

npx prisma migrate dev

Launch the microservices with

ts-node-dev \"./src/ws-server.ts\"

ts-node-dev \"./src/msg-api.ts\"

ts-node-dev \"./src/msg-store-server.ts\"