Related Topics
Express.Js Introduction
Lesson 17: Introduction to Express.js
Objective:
Introduce Express.js as a web application framework for Node.js.
Express.js, a powerful and minimalist web framework for Node.js, simplifies backend development. Let's explore its core concepts and functionalities:
Overview of Express.js and its role in backend development
- Express.js: Lightweight and flexible, it streamlines routing, middleware, and HTTP handling for Node.js.
- Backend role: Facilitates the creation of robust APIs and web applications, handling HTTP requests and responses efficiently.
Middleware and routing in Express
- Middleware: Functions executed during the request-response cycle, handling tasks like logging, authentication, etc.
- Routing: Defines endpoints and HTTP methods to handle client requests, aiding in the organization of code.
Basic server setup using Express
- Server creation: Setting up a basic Express server involves importing the framework, defining routes, and starting the server.
- Example:
```javascript
const express = require('express');
const app = express();
app.get('/', (req, res) => {
res.send('Hello, Express!');
});
app.listen(3000, () => {
console.log('Server running on port 3000');
});
```
Lesson 18: Setup Environment of Express.js
Objective:
Guide students through setting up the development environment for Express.js.
Installation and configuration of Express.js
- Installation: Use npm (Node Package Manager) to install Express.js in your project.
- Configuration: Initialize and configure Express, set up routes, and handle dependencies.
Use of tools like Nodemon for automatic server restarts
- Nodemon: A development tool that monitors changes in your source code and automatically restarts the server.
- Benefits: Saves time by eliminating the need to manually restart the server after code changes.
Folder structure and project setup
- Organized structure: Create folders for routes, controllers, models, views, and other resources to maintain a structured project.
- Example:
```
- project-root
- node_modules
- app.js
- routes
- index.js
- controllers
- mainController.js
- models
- dataModel.js
- views
- index.ejs
- public
- css
- js
```
Lesson 19: HTTP Methods
Objective:
Understand different HTTP methods and their usage in Express.js.
Overview of HTTP methods (GET, POST, PUT, DELETE)
- GET: Retrieves data from the server.
- POST: Sends data to the server to create a new resource.
- PUT: Updates an existing resource on the server.
- DELETE: Removes data from the server.
Handling different types of requests in Express
- Routing: Define routes for different HTTP methods, handling specific tasks or data manipulations.
- Middleware: Use middleware to intercept and process incoming requests before reaching the route handlers.
RESTful API principles and routing
- RESTful APIs: Follows principles like statelessness, uniform interface, and resource-based URLs for efficient and scalable APIs.
- Routing: Express allows developers to create RESTful routes that adhere to these principles.
Lesson 20: Request & Response Objects
Objective:
Explore the request and response objects in Express.js.
Accessing request parameters and body
- Request object: Contains information about the HTTP request, including query parameters, URL parameters, and request body data.
- Example:
```javascript
app.get('/users/:id', (req, res) => {
const userId = req.params.id; // Access URL parameter
const username = req.query.username; // Access query parameter
const userData = req.body; // Access request body
// Process the data
res.send('User data retrieved');
});
```
Sending different types of responses
- Response object: Allows sending various types of responses like HTML, JSON, files, etc., to the client.
- Example:
```javascript
app.get('/api/data', (req, res) => {
const data = { key: 'value' };
res.json(data); // Send JSON response
});
```
Error handling and middleware for requests and responses
- Error handling: Use middleware to catch errors and handle them gracefully, ensuring a good user experience.
- Middleware for requests and responses: Customize request and response behavior using middleware functions.
Understanding Express.js fundamentals, middleware, routing, and request/response handling lays a strong foundation for developing robust backend applications and RESTful APIs using Node.js.