Node.js is a JavaScript runtime environment that runs on the server and can be used to build efficient and scalable network applications. As an open source platform, Node.js has the world's largest development community, and its rich modular library allows developers to easily build various types of server applications, including Web server (Web server), API server, real-time Applications etc. This article will introduce how to build a Node.js-based HTTP server locally.
1. Preparation work
Before we start building the server, we need to do some preparation work. First, we need to install Node.js. You can download the Node.js installation package from the official website of Node.js (https://nodejs.org/). After the installation is complete, enter node -v on the command line. If the version number appears, Node.js has been installed correctly.
2. Create a working directory
We need to first create a working directory to store server files. At the command line, enter mkdir node-http-server to create a directory named node-http-server.
3. Create server file
In the node-http-server directory, we need to create a server.js file. Using a text editor, enter the following code:
const http = require('http'); const port = 3000; const server = http.createServer((req, res) => { res.statusCode = 200; res.setHeader('Content-Type', 'text/plain'); res.end('Hello World!'); }); server.listen(port, () => { console.log(`Server running at http://localhost:${port}/`); });
This code creates an HTTP server that listens on port 3000 and returns a "Hello World!" response when a request is received. Run this code and you will see the "Server running at http://localhost:3000/" prompt message on the console. Type http://localhost:3000/ into your browser and you should see a "Hello World!" response.
4. Add an HTML page
We can modify the server.js file to return an HTML page. In the node-http-server directory, create the index.html file and enter the following code:
<!DOCTYPE html> <html> <head> <title>Node.js HTTP server</title> </head> <body> <h1>Hello World!</h1> </body> </html>
Then, modify the server.js file and enter the following code:
const http = require('http'); const fs = require('fs'); const port = 3000; const server = http.createServer((req, res) => { res.statusCode = 200; res.setHeader('Content-Type', 'text/html'); fs.readFile('index.html', (err, data) => { if (err) { res.statusCode = 500; res.end('Error loading index.html'); } else { res.end(data); } }); }); server.listen(port, () => { console.log(`Server running at http://localhost:${port}/`); });
This code passes fs The module reads the index.html file and sends it to the client as a response. We can enter http://localhost:3000/ in the browser and see the index.html page.
5. Use third-party packages
The Node.js community has many third-party packages that can help us do our jobs better. For example, we can use the Express framework to build more complex web applications. In the node-http-server directory, use the command line to enter npm init, and then enter the information as prompted to generate a package.json file. Next, use the command line to enter npm install express --save to install the Express framework.
In the server.js file, introduce the Express module, and then use the following code to create an HTTP server based on Express:
const express = require('express'); const app = express(); const port = 3000; app.get('/', (req, res) => { res.send('Hello Express!'); }); app.listen(port, () => { console.log(`Server running at http://localhost:${port}/`); });
This code uses the Express framework to create an HTTP server that listens When receiving a GET request from the "/" path, a "Hello Express!" response is returned. Enter http://localhost:3000/ in your browser and you should see the "Hello Express!" response.
Summary
This article introduces how to build a Node.js-based HTTP server locally. We started by installing Node.js, learned how to create a working directory, server files and HTML pages, and created a more complex HTTP server using the third-party framework Express. After mastering these basic operations, we can further explore Node.js and build more complex applications.
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