Topic 2: Client-Server Architecture

1. Introduction to the Client-Server Model

^📌 What is a Client?

• A user’s device (computer, phone, tablet) that requests data from a server.

• Examples: Web browsers, mobile apps.

📌What is a Server?

• A powerful computer that stores and delivers content or services.

• Examples: Web servers, API servers, database servers.

📌Example:

• A client is like a customer at a restaurant, and the server is like a waiter bringing food from the kitchen.

2. Differences Between Client and Server

📌 Example

• You visit YouTube → The client sends a request.

• The YouTube server processes it and responds with videos.

3. HTTP Request/Response Cycle

📌How It Works?

• Client sends a request (e.g., GET /index.html).

• Server processes the request.

• Server responds with data

• Client displays the content.

📌 HTTP Methods

• GET → Retrieve data.

• POST → Send data (forms, logins).

• PUT → Update data.

• DELETE → Remove data.

📌Example:


• A restaurant order – You (client) order pizza (GET), the kitchen (server) prepares it, and you receive it.

4. Frontend vs Backend, Static vs Dynamic Websites

📌 Frontend (Client-Side)

• Code that runs in the browser.

• Technologies: HTML, CSS, JavaScript.

📌 Backend (Server-Side)

• Code that runs on the server.

• Technologies: Node.js, Python, PHP.

📌Static vs Dynamic Websites

📌Example:


• A static website is like a printed book, while a dynamic website is like a news website that updates regularly.

5. Basics of Web Hosting

• Web hosting stores websites for online access.

• Examples: Shared Hosting, VPS, Cloud Hosting.

• Popular Providers: GoDaddy, Hostinger, AWS, Netlify.

📌 Analogy:

• Hosting is like renting an apartment for your website.