Building Web Applications with Express

Topic Outline (30-min)

1. Introduction to Express:

   • Installing and Setting Up:

     • Install Express using npm:

       bash코드 복사npm install express

     • Create a new file named app.js and initialize Express:

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

   • Basic Structure of an Express App:

     javascript코드 복사app.get('/', (req, res) => {
         res.send('Welcome to Express!');
     });
     
     const PORT = 3000;
     app.listen(PORT, () => {
         console.log(`Server running on http://localhost:${PORT}`);
     });

2. Routing in Express:

   • Defining GET, POST, PUT, DELETE Routes:

     javascript코드 복사app.get('/users', (req, res) => res.send('Retrieve all users'));
     app.post('/users', (req, res) => res.send('Create a new user'));
     app.put('/users/:id', (req, res) => res.send(`Update user with ID ${req.params.id}`));
     app.delete('/users/:id', (req, res) => res.send(`Delete user with ID ${req.params.id}`));

   • Route Parameters and Query Strings:

     javascript코드 복사app.get('/products/:id', (req, res) => {
         res.send(`Product ID: ${req.params.id}`);
     });
     
     app.get('/search', (req, res) => {
         const query = req.query.q;
         res.send(`Search query: ${query}`);
     });

3. Middleware in Express:

   • Built-in Middleware:

     • Use middleware to parse JSON request bodies:

       javascript코드 복사app.use(express.json());

   • Custom Middleware:

     • Create a custom middleware to log requests:

       javascript코드 복사app.use((req, res, next) => {
           console.log(`${req.method} ${req.url}`);
           next();
       });