HTTP Server (node:http)

Node.js · Reference cheat sheet

📋 Overview

node:http (and node:https) provide low-level servers and clients. Frameworks like Express/Fastify wrap these primitives.

🔧 Core concepts

API	Role
`http.createServer`	Create server
`IncomingMessage` (`req`)	Request stream + headers
`ServerResponse` (`res`)	Writable response
`server.listen`	Bind port/host
`http.request` / `fetch`	Outbound HTTP

Header tip	Detail
Set before body	Call `writeHead` or `setHeader` early
`Content-Type`	Required for correct client parsing
Keep-alive	Default in modern Node

💡 Examples

Plain text server:

import http from "node:http";

http
  .createServer((req, res) => {
    res.writeHead(200, { "Content-Type": "application/json" });
    res.end(JSON.stringify({ path: req.url }));
  })
  .listen(9000, "0.0.0.0");

Read POST body:

async function readBody(req) {
  const chunks = [];
  for await (const c of req) chunks.push(c);
  return Buffer.concat(chunks).toString("utf8");
}

Global fetch (Node 18+):

const res = await fetch("https://example.com");
const text = await res.text();

⚠️ Pitfalls

Forgetting to end() the response leaves the client hanging.
Unbounded body reads enable memory DoS — enforce size limits.
req.url includes query string; parse with URL + host header carefully.

HTTP Server (node:http)

HTTP Server (node:http)

📋 Overview

🔧 Core concepts

💡 Examples

⚠️ Pitfalls

🔗 Related

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