Intro

In case you have worries that you might not implement everything correctly from the last lecture, you can check out to the branch called 1_server. If you are good with your implementation, there is no need to check out to this branch.

The project structure should look like this:

Server

For your app, we are going to use an Express.js server, which is a minimal and flexible Node.js web application framework.

1. In the server`s src folder, create a file called index.ts.
2. Paste the following code to the file:

// Importing necessary modules
import express, {Application} from "express";
import cors from "cors";
import dotenv from "dotenv";
 
// Loading environment variables from .env file
dotenv.config();
 
// Creating an instance of the express application
const app: Application = express();
 
// Defining a default port for the server to listen to
const PORT = process.env.PORT || 5000;
 
// MIDDLEWARE
app.use(cors()); // Allow Cross-Origin Resource Sharing
app.use(express.json()); // Parse incoming request body as JSON
app.use(express.urlencoded({extended: true})); // Parse incoming request body as URL-encoded data
 
// ROUTES
 
// Starting the server and listening for incoming requests on the defined port
try {
    app.listen(PORT, (): void => {
        console.info(`Server is successfully running on port ${PORT}`);
    });
} catch (error) {
    console.error(`Error occurred: ${error.message}`);
}

Go through individual lines of code and try to understand their purpose.

3. In line 13, we are defining a default port for the server to listen to in case the environment variable PORT is not defined.
   We need to define the port in the environment variable file.
   Edit the .env file and add the following lines:

# Server configuration
PORT=5000

4. In the package.json file, find the command which starts the server.

Database

For the database, we are using PostgreSQL.
The database server is already running on the VM, so we are just going to create the database, tables and seed the tables with some data.

Before running following commands, terminate (CTRL + C) the running server in the terminal and insert the commands in the server directory

Create a database

In the terminal, run the following command:

npm run db-create

Create tables and insert data

Run the following command:

npm run db-seed

Drop database

If you corrupt the database and data in it during exposing the vulnerabilities, you can drop the database and create it again.

npm run db-drop

[Optional] Interact with the database

Summary

By following the tutorial, you should have an Express server running on port 5000 and a database with seeded data. Let's move to the next section!