HTTP and Routing¶

HTTP Module¶

The http module lets you create a basic web server without using any external frameworks.

const http = require("http");

Create a Basic Server¶

const server = http.createServer((req, res) => {
  res.write("Hello from Node.js server");
  res.end();
});

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

Handling Routes¶

Use req.url to detect the requested path and req.method to detect the HTTP method.

const server = http.createServer((req, res) => {
  if (req.url === "/") {
    res.write("Home Page");
  } else if (req.url === "/about") {
    res.write("About Page");
  } else {
    res.writeHead(404);
    res.write("Page Not Found");
  }
  res.end();
});

Sending JSON¶

if (req.url === "/api") {
  res.writeHead(200, { "Content-Type": "application/json" });
  res.end(JSON.stringify({ name: "Node", version: "1.0" }));
}

Serving HTML Files¶

const fs = require("fs");

if (req.url === "/home") {
  fs.readFile("index.html", (err, data) => {
    if (err) {
      res.writeHead(500);
      res.end("Server Error");
      return;
    }
    res.writeHead(200, { "Content-Type": "text/html" });
    res.end(data);
  });
}

Handling Query Parameters¶

const url = require("url");

const server = http.createServer((req, res) => {
  const parsedUrl = url.parse(req.url, true); // true to parse query
  const name = parsedUrl.query.name;
  res.end(`Hello ${name}`);
});

Example: Request to /greet?name=John → Response: Hello John

Setting Headers¶

res.writeHead(200, {
  "Content-Type": "text/plain",
  "Custom-Header": "value"
});

HTTP Status Codes¶

Code	Meaning
200	OK
404	Not Found
500	Internal Server Error

Summary¶

Use http.createServer() to build a server
Use req.url and req.method for routing
Use fs to serve files
Manually handle headers and status codes