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What is backend?

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  • Skill path

    AI-Assisted Back-End Development

    Learn back-end development with AI tools. Build APIs, work with Node.js, and manage databases using AI coding agents for faster workflows.
    • Includes 2 Courses
    • With Certificate
    • Intermediate.
      4 hours

HTML Front-End

The front-end refers to the part of web apps visible to users, handled in their browsers. This includes elements like HTML for structure, CSS for styling, and JavaScript for functionality. Meanwhile, the back-end handles the server-side processes, managing data and responding to requests.

<!DOCTYPE html>
<html lang="en">
<head>
   <meta charset="UTF-8">
   <title>Front-End Development</title>
   <style>
       body {
           font-family: Arial, sans-serif;
           background-color: #f4f4f9;
       }
   </style>
</head>
<body>
   <h1>Hello, World!</h1>
   <p>This is a simple HTML page demonstrating front-end basics.</p>
   <button onclick="alert('Hello, Front-End!')">Click me!</button>
</body>
</html>

Web Server Basics

A web server listens for client requests over a network and returns responses. Typically, these servers use the HTTP protocol to send requested resources like HTML pages, images, or files. Understanding these basic functions of a web server helps in designing efficient network communication.

```python
# Simple HTTP server in Python
import http.server
import socketserver


PORT = 8000


Handler = http.server.SimpleHTTPRequestHandler


with socketserver.TCPServer(("", PORT), Handler) as httpd:
    print(f"Serving at port {PORT}")
    httpd.serve_forever()
```

Server-Side Logic

The back-end of web applications handles server-side logic, processing requests and managing data interactions. This ensures dynamic responses are generated for clients effectively. Node.js is often used for this purpose, working seamlessly with databases like MongoDB or MySQL.

const http = require('http');
const server = http.createServer((req, res) => {
  if (req.url === '/') {
    res.write('You have reached the server-side logic page');
    res.end();
  }
});
server.listen(3000);
console.log('Listening on port 3000...');

Database Management

Databases store and manage data for web apps efficiently. Relational databases organize data into tables, facilitating easy access and manipulation using queries. Non-relational databases store data differently, like key-value pairs or documents, offering flexibility for unstructured data.

--Example of a relational database query:
SELECT * FROM users WHERE status = 'active';


--Example of non-relational database entry using JSON-like format:
{
   "key": "user123",
   "value": {
      "name": "John Doe",
      "status": "active"
   }
}

Understanding Web APIs

A web API enables communication between a client interface and a server by following a specific set of rules. Through a process called the HTTP request-response cycle, clients can retrieve, update, or manipulate data on the server side. This interaction is essential for dynamic web applications that rely on external data.

GET /api/data HTTP/1.1
Host: example.com
Accept: application/json


HTTP/1.1 200 OK
Content-Type: application/json
{
    "data": [
        {"id": 1, "name": "John Doe"},
        {"id": 2, "name": "Jane Smith"}
    ]
}

Python Authentication

Authentication ensures only legitimate users can access specific features in an application by verifying their identity, often using credentials, like usernames and passwords.

from getpass import getpass


# Placeholder user credentials for demonstration
USERNAME = "user123"
PASSWORD = "securepass"


username_input = input("Enter your username: ")
password_input = getpass("Enter your password: ")


if username_input == USERNAME and password_input == PASSWORD:
    print("Access granted.")
else:
    print("Access denied.")

Authorization Concepts

Authorization is critical for controlling access. Once a user proves their identity, authorization determines what they can do. It’s like having different keys for different doors based on your role!

// Example of authorization check
const user = {
  role: 'admin',
  permissions: ['view-dashboard', 'edit-user'],
};


function authorize(action) {
  if (user.permissions.includes(action)) {
    return `Access granted for ${action}`;
  } else {
    return `Access denied for ${action}`;
  }
}


console.log(authorize('edit-user'));  // Outputs: Access granted for edit-user
console.log(authorize('delete-user')); // Outputs: Access denied for delete-user

Tech Stack Overview

A technology stack is an essential part of web development. It combines programming languages, frameworks, databases, and tools to create a cohesive environment for building web applications. Understanding how each component interacts can enhance productivity and efficiency.

Learn more on Codecademy

  • Skill path

    AI-Assisted Back-End Development

    Learn back-end development with AI tools. Build APIs, work with Node.js, and manage databases using AI coding agents for faster workflows.
    • Includes 2 Courses
    • With Certificate
    • Intermediate.
      4 hours
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