Start a server

The general ways to start a server.

Node

Run as:

$ node server.js

NPM

This will lookup server.js by default.

$ npm serve

HTTP

Using the Node builtin module.

See HTTP module docs.

Basic

Example based on Getting started with NodeJS for frontend developers - Part 1.

Set up HTTP server with returns a greeting as plain text.

  • server.js 
      const http = require('http')

  http.createServer((req, resp) => {
    resp.writeHead(200, { 'Content-Type': 'text/html' });
    resp.write(`<p>Hello, world! You requested ${req.url}</p>`);
    resp.end();
  }).listen(3000);

Start the app. Note you won’t see any output and this is a blocking call.

Then open the browser at:

Note that you can use any path and you’ll get the same response.

Parse the query string

Based on Node.js HTTP Module on W3 Schools.

Use the url builtin module.

var http = require('http');
var url = require('url');

http.createServer(function (req, res) {
  res.writeHead(200, { 'Content-Type': 'text/html' });

  var q = url.parse(req.url, true).query;
  var text = q.year + " " + q.month;
  res.end(text);
}).listen(3000);

Open in the browser:

Result:

2017 July

Express

Resources

See also project - MichaelCurrin/express-js-rest-quickstart. Including the notes in the docs.

Install

Install Express.

$ npm install express

Note that return is not used in examples below - just resp.send.

Basic greeting

Express starter

  • server.js 
      const express = require('express');

  const app = express();
  const port = 3000;

  app.get('/', (req, resp) => resp.send('Hello, world!'))

  app.listen(port, () => console.log(`Example app listening at http://localhost:${port}/`))

Run as:

$ node server.js
Example app listening at http://localhost:3000/

Open browser at:

Note that you’ll get an error on other paths.

Handle query parameters

Example based on Getting started with NodeJS for frontend developers - Part 2.

Add the following to base example, before .listen.

Note use of .query.

  • index.js 
      app.get('/foo', (req, resp) => {
    const { name } = req.query;
    resp.send(`Hello, ${name || world}!`);
  })

Test on:

Handle URL parameters

Add the following to base example, before .listen.

Note use of .params.

app.get('/foo/:name', (req, resp) => {
    const { name } = req.params;
    resp.send(`Hello, ${name || world}!`);
})

Test on:

Handle POST request

  • index.js 
      app.use(express.json());
  app.use(express.urlencoded());

  app.post('/foo', (req, res) => {
    res.status(201)
      .send({
        message: "Created a foo using data",
        data: req.body,
      });
  });

Handle other status codes

  • index.js 
      app.get('/admin', (_req, res) => {
      res.sendStatus(401);
  });

Static files

Serve a directory of static files.

  • index.js 
      const express = require('express');

  const app = express();
  const port = 3000;
  const staticDir = 'build';

  app.use('/', express.static(staticDir));
  app.listen(port, () => console.log(`Example app listening at http://localhost:${port}/`));