Node.js Lesson 6: HTTP Server

Node.js can create HTTP servers without any external library. This is the foundation of web development with Node — understanding it makes Express (next lesson) much clearer.

Your First HTTP Server

const http = require("http");

const server = http.createServer((req, res) => {
  // req = request (what the client sent)
  // res = response (what we send back)
  
  res.writeHead(200, { "Content-Type": "text/html" });
  res.end("<h1>Hello from Node.js server!</h1>");
});

server.listen(3000, () => {
  console.log("Server running at http://localhost:3000");
});

// Run: node server.js
// Open: http://localhost:3000

Handling Different Routes

const http = require("http");

const server = http.createServer((req, res) => {
  const url = req.url;
  const method = req.method;
  
  if (url === "/" && method === "GET") {
    res.writeHead(200, { "Content-Type": "text/html" });
    res.end("<h1>Home Page</h1>");
  } else if (url === "/about" && method === "GET") {
    res.writeHead(200, { "Content-Type": "application/json" });
    res.end(JSON.stringify({ page: "about", version: "1.0" }));
  } else {
    res.writeHead(404, { "Content-Type": "text/plain" });
    res.end("404 Not Found");
  }
});

server.listen(3000, () => console.log("http://localhost:3000"));