Creating and Running a Koa.js Project

What is Koa.js?

Koa.js is a next-generation Node.js web framework developed by the Express.js team. It aims to be a smaller, more expressive, and more powerful foundation for building web applications and APIs. Koa.js leverages modern JavaScript (such as async/await), making it easier to write middleware and handle requests.

Main Features and Advantages of Koa.js

• Concise and Modern: Utilizes async/await syntax, making asynchronous operations more intuitive.
• Middleware Mechanism: Koa.js processes requests and responses through a middleware stack, providing great flexibility.
• Lightweight: The core is minimal, containing only the most basic features, and middleware can be added as needed.
• High Performance: Due to its concise design and modern asynchronous handling, Koa.js offers very high performance.

Using Koa.js can help developers quickly build high-performance web applications and APIs.

Creating and Running a Koa.js Project Using ServBay

In this article, we'll use ServBay's Node.js environment to create and run a Koa.js project. We'll use ServBay's 'Host' feature to set up a web server and use reverse proxy to access the project.

Creating a Koa.js Project

1. Initialize the Project

   First, make sure you have installed the Node.js environment provided by ServBay. Then, use the following commands to initialize a new Koa.js project:

   cd /Applications/ServBay/www
   mkdir servbay-koa-app
   cd servbay-koa-app
   npm init -y
   npm install koa

2. Create the Application File

   In the project's root directory, create an app.js file and add the following code:

   const Koa = require('koa');
   const app = new Koa();
   
   app.use(async ctx => {
     ctx.body = 'Hello ServBay!';
   });
   
   const port = process.env.PORT || 3000;
   app.listen(port, () => {
     console.log(`Server running on port ${port}`);
   });

Entering Development Mode

1. Run the Development Server

   Start the development server and specify a port (e.g., 8585):

   PORT=8585 node app.js

   This will start a local development server and expose port 8585.

2. Configure ServBay Host Reverse Proxy

   Use ServBay's 'Host' feature to access the development server through a reverse proxy. In ServBay's 'Host' settings, add a new reverse proxy:

   • Name: My first Koa.js dev site
   • Domain: servbay-koa-test.dev
   • Host Type: Reverse Proxy
   • IP: 127.0.0.1
   • Port: 8585

   For detailed settings, refer to Adding Node.js Development Website.

3. Access Development Mode

   Open a browser and visit https://servbay-koa-test.dev to see the project in real time. Since ServBay supports custom domain names and free SSL certificates, you will enjoy higher security.

Deploying a Production Version

1. Prepare Production Environment

   Ensure your project can run correctly in a production environment. Typically, Koa.js projects do not require special build steps, but you may need to set some environment variables or perform other configurations.

2. Run the Production Server

   Start the production server and specify a port (e.g., 8586):

   PORT=8586 NODE_ENV=production node app.js

3. Configure ServBay Host Reverse Proxy

   Use ServBay's 'Host' feature to access the production server through a reverse proxy. In ServBay's 'Host' settings, add a new reverse proxy:

   • Name: My first Koa.js production site
   • Domain: servbay-koa-test.prod
   • Host Type: Reverse Proxy
   • IP: 127.0.0.1
   • Port: 8586

4. Access Production Mode

   Open a browser and visit https://servbay-koa-test.prod to see the production version. Through ServBay's custom domain names and free SSL certificates, your site will have higher security and credibility.

Database Connection

ServBay provides support for Redis, MariaDB, PostgreSQL, and MongoDB databases. Here are examples of how to connect to these databases.

1. Connecting to MongoDB

   Install mongoose:

   npm install mongoose

   Then import and connect in the project:

   const mongoose = require('mongoose');
   
   mongoose.connect('mongodb://localhost/servbay-koa-app', { useNewUrlParser: true, useUnifiedTopology: true });

2. Connecting to Redis

   Install redis:

   npm install redis

   Then import and connect in the project:

   const redis = require('redis');
   const client = redis.createClient();
   
   client.on('error', function (err) {
     console.log('Error ' + err);
   });

3. Connecting to MariaDB

   Install mariadb:

   npm install mariadb

   Then import and connect in the project:

   const mariadb = require('mariadb');
   const pool = mariadb.createPool({
     host: 'localhost', 
     user: 'root', 
     password: 'password',
     database: 'servbay_koa_app'
   });
   
   pool.getConnection()
     .then(conn => {
       console.log("Connected to MariaDB");
       conn.release(); //release to pool
     })
     .catch(err => {
       console.log("Not connected due to error: " + err);
     });

4. Connecting to PostgreSQL

   Install pg:

   npm install pg

   Then import and connect in the project:

   const { Pool } = require('pg');
   const pool = new Pool({
     user: 'user',
     host: 'localhost',
     database: 'servbay_koa_app',
     password: 'password',
     port: 5432,
   });
   
   pool.connect((err, client, done) => {
     if (err) throw err;
     console.log('Connected to PostgreSQL');
     done();
   });

Through these steps, you have successfully created and run a Koa.js project, using ServBay's features to manage and access your project while connecting to multiple databases.