Node.js - Building a serever

Node comes with its own http built-in module

using http module

const http = require('http'); // grab the 'http' module

const server = http.createServer( ()=> {
    //console.log('headers', request.headers)
    console.log('method', request.method)
    console.log('url', request.url)

    const user = {
        name: 'John',
        hobby: 'Skating'
    }

    response.statusCode = 200;
    response.setHeader('Content-Type', 'application/json');
    response.end(JSON.stringify(user));
})

server.listen(3000);

• const http = require('http');: grab the buit-in http module
• http.createServer( (req, res) ⇒ {…} ): The createServer() method of http creates a new HTTP server and returns it.
• server.listen(3000): open a port 3000

Run the file

$ node server.js

1. Go to localhost:3000 (nothing seems to happen)
2. Back to terminal: server.js is running in Node
   

Add params: request & response

const http = require('http'); 

// create server
const server = http.createServer( (request, response)=> {
    console.log('headers', request.headers);
    console.log('methods', request.method);
    console.log('url', request.url);
    
    response.setHeader('Content-Type', 'text/HTML');
    response.end('<h1>Helllloooooo</h1>');
});

server.listen(3000);

request

對方要求進入 web server，關於使用者的詳細資訊物件 (e.g. request.url)

response

• response.statusCode
• response.setHeader('Content-Type', 'application/json')
• response.end()

相關 API 語法

const http = require("http");

// create server
http.createServer(function(req,res){
 res.writeHead(200,{"Content-Type":"text/plain"})
 res.write("Hello")
 res.end()
}).listen(8080);

Another way: take out the function

const requestListener = async(req, res)=>{
    console.log(req.url);
    res.end();
}

const server = http.createServer(requestListener);
server.listen(8080);

• header info
  • .writeHead( 200, {"Content-Type":"text/plain"} )
    • 200: statusCode
    • {"Content-Type":"text/plain"}
  • .setHeader('Content-Type', 'text/HTML')
• .write
• .end() - 結束這次的請求
• .listen(8080) - 開啟一個 port

port

127.0.0.1:3000

• 127.0.0.1 - 由自己的電腦所開啟的 web server 伺服器 (localhost)
  • :3000 - 伺服器其中一個軟體，佔據電腦裡其中一個 port 3000
  • :21 - ftp
  • :3389 - 遠端桌面

Run the file

Use nodeman we've set before:

$npm start

Visit localhost:3000:

• Status Code: 200
• Content-Type: text/HTML

Back to terminal & check the request:

Example: Grab a JSON file

const http = require('http'); // grab the http module

const server = http.createServer( (request, response)=> {   
    //create an object
    const user = {
      name: 'John',
      hobby: 'skating'
    } 
    
    // set content-type to JSON
    response.setHeader('Content-Type', 'application/JSON');
    
    // turn the object into JSON
    response.end(JSON.stringify(user)); 
})

server.listen(3000);