Fellow Coder 
We use the internet every day – Browse websites, send emails, and use social media. But have you ever wondered where all this information comes from? How does a website instantly appear on our screen when we type its address into the browser? The main architect behind this is the Server. In this post, we’ll explain in simple terms what a server is and specifically how web servers work.
What is a Server Really?
In the simplest terms, a server is a special type of powerful computer or a software program that provides various services or data to other computers or devices (called clients) on a network.
Think of it like a waiter in a restaurant. Just as a waiter takes orders from customers and brings food from the kitchen, a server receives requests from your device and sends back the necessary information or files. When you send a request (Request) for a website from your phone or computer, the server accepts that request and sends the required data or files back to your device (Response).
Servers are typically much more powerful than regular computers because they need to handle requests from many users simultaneously and often need to be running 24/7.
Client-Server Model: How the Conversation Works
Most activities on the internet follow the client-server model. In this model:
- Client: This is your device (like a laptop, smartphone, tablet) and the software running on it (like a web browser – Chrome, Firefox). The client sends requests to the server for information or services.
- Server: This is the powerful computer or software that receives the client’s request, processes it, and sends the necessary data or service back to the client.
When you type a website address (like www.google.com) into your browser, your browser (the client) sends a Request via the internet to Google’s server. Google’s server receives the Request and sends the website’s data (HTML, CSS, images, etc.) back to your browser as a Response. Your browser then uses this data to display the website on your screen.
Types of Servers: Different Servers for Different Tasks
Different types of servers are used for various tasks. Some common types include:
- Web Server: Their main job is to host websites and display web pages in users’ browsers. When you visit a website, you are actually communicating with a web server. They use protocols like HTTP (Hypertext Transfer Protocol) or HTTPS to exchange data.
- Database Server: They are responsible for storing, managing, and retrieving large amounts of data. For example, Facebook stores your profile information, friends list, posts, etc., on a database server. Product information on online shopping sites is also stored on database servers.
- File Server: Used for storing and sharing files within a network. Office networks or cloud storage services (like Google Drive, Dropbox) are examples of file server usage.
- Mail Server: These servers handle sending, receiving, and storing emails (like the servers for Gmail or Outlook).
- Game Server: Used in online multiplayer games to connect players and manage game data.
How Does a Web Server Work?
Let’s look at how a Web Server works step-by-step:
- Sending the Request: You type a website address (URL – Uniform Resource Locator) into your web browser and press Enter.
- Domain Name System (DNS): Your browser first uses a DNS server to find the IP address (a unique numerical address, like 172.217.160.142) corresponding to the website’s name (domain name).
- Connection and HTTP Request: The browser establishes an internet connection with the web server at the found IP address and sends an HTTP Request. This request specifies which particular page or file is needed.
- Server Processing: The web server software (like Apache or Nginx) receives the Request. It then finds the requested files (e.g., HTML documents, images, CSS stylesheets, JavaScript files) on the server’s hard drive. If the webpage is dynamic (e.g., changes based on user login information), the server might use a scripting language (like PHP, Python) and a database to generate the page content.
- HTTP Response: The server sends the necessary files or generated data back to the browser via an HTTP Response. This response also includes a status code (e.g., 200 OK means everything is fine, 404 Not Found means the file wasn’t found).
- Rendering the Page: Your browser receives the files (HTML, CSS, JavaScript) from the server and combines them to display the complete webpage on your screen.
This entire process usually completes within a few seconds!
Some Popular Web Servers and Technologies
Many types of web server software and related technologies are used today. Some popular ones include:
- Apache HTTP Server: One of the world’s oldest and most widely used open-source web servers, known for its reliability and flexibility.
- Nginx (Engine-X): Another popular open-source web server. It’s famous for its high performance and ability to handle many simultaneous connections efficiently. It’s often used as a reverse proxy, load balancer, and HTTP cache.
- Microsoft IIS (Internet Information Services): Microsoft’s web server that comes with Windows Server operating systems.
- LiteSpeed Web Server: A high-performance web server gaining popularity as an alternative to Apache.
Some Related Technologies:
- WSGI (Web Server Gateway Interface): A standard interface for communication between web servers and web applications written in the Python programming language. Frameworks like Django or Flask use WSGI to connect with servers like Apache or Nginx.
- ASGI (Asynchronous Server Gateway Interface): The successor to WSGI, designed for asynchronous Python web applications (capable of handling multiple tasks concurrently). It’s particularly useful for WebSockets and other real-time features.
Final Words
Hopefully, I’ve been able to give you a clear idea of what a server is and, specifically, how web servers deliver our favorite websites to our screens. Servers are the unsung heroes of the internet, without which today’s digital world would be impossible. The next time you visit a website, take a moment to appreciate the complex yet amazing process happening behind the scenes!
