Express

express - install (opens new window)

Install:

npm i express

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Minimal Express-Server

const express = require('express');

const app = express();

app.listen(3000)

// is the same as:
// const server = http.createServer(app);
// server.listen(3000);

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Helloworld Express (opens new window)

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

app.get('/', (req, res) => {
  res.send('Hello World!')
});

app.listen(port, () => {
  console.log(`Example app listening on port ${port}!`)
});

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create Express application (opens new window).

const express = require('express');
const app = express();

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Basic Webserver

const express = require('express');
const app = express(); //creates express-app-object

app.use(express.static(__dirname + '/public')); // public-foder

const port = process.env.PORT || 3000;

// root-folder
app.get('/', (req, res) => {
  console.log('A request was made to the root');
  res.send('A request was made to the root');
});

app.listen(port, () => {
  console.log(`Server running and listening on port ${port}`);
});

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stop running app

ctrl-c

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Requests

get - most basic request. most common. links...

post - zb. form -› secure

app.get('route', function(req, res) {});

req - contains a lot of informartion

• req.query - query-object
• User-agent - info about the browser

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Query

query-parameter extra information, that is send via the http-get-request

?variable=value-string

e.g..

http://localhost:3000/about?name=Joe&age=39

const express = require('express');
const app = express(); //creates express-app-object

const port = 3000; // use port 3000

app.listen(port, function() {
  console.log(`Server running and listening on port ${port}`);
});

// root-folder
app.get('/', function(req, res) {
  console.log('A request was made to the root');
  res.send('Hello');
});

// about-folder
app.get('/about', function(req, res) {
  console.log('A request was made to about');
  const name = req.query.name;
  if (name) {
    res.send(
      `<h1>About:</h1> 
       <p>Hello ${name}, you are ${req.query.age} old ...</p>`
    );
  } else {
    res.send(`You nameless bastard!!`);
  }
});

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