What is Apache? A Beginner-Friendly Guide to Web Servers and How They Work

So, you want to build a website! But do words like "Web Server" and "Apache" sound a bit intimidating? Don't worry! In this article, we'll break down the basics of web servers and the mechanics of Apache in a way that's easy for web development beginners to understand, almost like we're explaining it with pictures. We'll simplify the technical jargon, so you can follow along with confidence.

And the biggest goal of this article is to give you that "Aha! So this is what it means to publish on the web!" experience. We've prepared plenty of copy-and-paste code samples, so let's get our hands dirty and master how web servers work together!

So, What Is a Web Server Anyway?

First, let's look at the role of a web server. In one sentence, it's "a computer that provides web page data in response to our requests."

It might be easier to understand with a restaurant analogy:

You (the person viewing the website): The customer
Web Browser (Chrome, Safari, etc.): The role of looking at the menu and placing an order (making a request)
Web Server: The waiter who takes the order and brings you your food (the web page data)

When you type a URL into your browser or click a link, the browser sends a request to the web server, saying, "Show me this page!" The web server receives that request and sends the HTML files, images, and other data for the web page back to the browser as a response. It's thanks to this exchange that we can browse websites.

What is "HTTP," the Rule of Communication?

For a web server and a browser to talk to each other (communicate), they need a common language they both understand—a set of "rules." That rulebook is called HTTP (HyperText Transfer Protocol).

In our restaurant analogy, this is like having a set way to order, such as saying, "I would like the steak," and a set way to be served, such as, "Here is your steak." All data is exchanged according to this HTTP protocol.

The `http://` or `https://` you see in your browser's address bar is a declaration that you'll be communicating using this protocol. (The 's' in `https` stands for Secure, meaning the communication is encrypted for better security.)

The Main Event! What is Apache?

Now, for the main topic: Apache. Apache is one of the most widely used pieces of web server software in the world. Its official name is the "Apache HTTP Server."

Think of Apache as the software that actually performs the "waiter's" role from our analogy on a computer. By installing Apache on a computer, you can make that computer function as a web server.

What's So Great About Apache?

Open-Source and Free: Anyone can use it for free and even modify it freely.
Highly Reliable and Stable: It has a long history and a proven track record of powering many websites worldwide.
A Wealth of Information: Because it's so popular, you can find a huge amount of information online about configuration and troubleshooting.
Extendable with Modules: It has a system of "modules" that allows you to add or change functionality, making it highly flexible and customizable.

[Hands-On] Let's Publish a Web Page with Apache!

Enough theory—let's get our hands dirty and experience publishing a web page! For this part, we'll assume you already have Apache installed on your computer. (We'll cover how to install it in the next article!)

Step 1: Create the HTML File to Publish

First, let's create an HTML file that contains the content for our web page. It's a very simple page that just says "Hello, world!" Save this file as `index.html`.

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>My First Apache Page</title>
</head>
<body>
    <h1>Hello, world!</h1>
    <p>This page is being served by Apache.</p>
</body>
</html>

Step 2: Check and Edit the Apache Configuration File

Next, we need to tell Apache where to find the web page files we want to publish. This is done in a configuration file named `httpd.conf`.

A particularly important setting in this file is `DocumentRoot`. This is where you specify the path to the directory (folder) where you will place your web-ready files, like the `index.html` we just created.

For example, if `DocumentRoot` is set to `/usr/local/apache2/htdocs`, you would place your `index.html` file inside the `/usr/local/apache2/htdocs` directory to make it accessible from a web browser.

Below is a snippet from an example `httpd.conf` file. You'll need to adapt the path for your own environment. ※This code is for explanatory purposes. Don't just change your own config file without understanding it!

# Listen: The port number the server will listen for requests on.
# Typically, HTTP uses port 80.
Listen 80

# DocumentRoot: The path to the directory where you'll place web content.
# Place your HTML files, etc., in this directory.
# (On Windows, this might look like "C:/Apache24/htdocs")
DocumentRoot "/usr/local/apache2/htdocs"

# Settings for the directory specified in DocumentRoot
<Directory "/usr/local/apache2/htdocs">
    # Allow settings to be overridden by .htaccess files.
    AllowOverride All
    # Allow all requests.
    Require all granted
</Directory>

[IMPORTANT] After editing the `httpd.conf` file, you must always restart Apache for the changes to take effect.

[Advanced Examples] Mastering Apache with `.htaccess`

One of Apache's most powerful features is the `.htaccess` file. While global server settings are typically handled in `httpd.conf`, the `.htaccess` file is useful when you want to add rules that only apply within a specific directory.

When running a website, you'll often have needs like "I want to redirect all non-www URLs to the www version" or "I want to password-protect a specific page." This is where `.htaccess` shines.

Example 1: Normalize URLs (Force 'www')

From an SEO (Search Engine Optimization) perspective, it's not ideal to have split URLs like `example.com` and `www.example.com`. This setting redirects all traffic to the `www.example.com` version. Create an `.htaccess` file with the following content and place it in your `DocumentRoot`.

RewriteEngine On
RewriteCond %{HTTP_HOST} ^example\.com$ [NC]
RewriteRule ^(.*)$ http://www.example.com/$1 [R=301,L]

Example 2: Password-Protect a Directory (Basic Authentication)

Use Basic Authentication when you want to restrict access to a certain directory, like a members-only area. First, place an `.htaccess` file with the following content in the directory you want to protect.

AuthType Basic
AuthName "Secret Area"
AuthUserFile /path/to/.htpasswd
Require valid-user

Next, create an `.htpasswd` file that contains the usernames and passwords for authorized users. Be sure to replace `/path/to/` with an appropriate path on your server. It's crucial to place this file in a location that is not accessible from the web.

# An example for the username "myuser" with an encrypted password
myuser:$apr1$abcdefg$hijklmnopqrstuvwxyz.

※ The `.htpasswd` file is typically generated using a special command-line tool or a web-based generator.

Example 3: Deny Access from Specific IP Addresses

This setting is for blocking annoying traffic from specific IP addresses. You specify the IP addresses you want to block.

Require all granted
Require not ip 192.168.1.100
Require not ip 10.0.0.0/8

Things to Watch Out For

Apache is very powerful, but if configured incorrectly, it can create security risks or cause your site to stop working.

Back Up Your Config Files: Before editing `httpd.conf` or `.htaccess`, always save a copy of the original file. If something goes wrong, you can quickly revert to the working version.
Permissions: Improper file and directory permissions can create risks of files being modified by outsiders or data being leaked. It's important to set the minimum necessary permissions.
Check the Logs: When something goes wrong, the first place to look is the log files. The `error_log` contains the causes of errors, and the `access_log` keeps a record of who accessed what and when. Get into the habit of checking these logs.

Conclusion

In this article, we've covered everything from the basic mechanics of a web server to the role of the popular server software, Apache, including hands-on steps to publish a simple web page and some advanced examples.

It might seem difficult at first, but the thrill of seeing your `index.html` file displayed in a browser is the first step to experiencing the joy of web development. Apache is a reliable partner that helps deliver the websites you create to people all over the world. We hope this article serves as a starting point for you to deepen your knowledge of web servers and apply it to your creative projects.

As a next step, let's try installing Apache on your own computer! The following article provides detailed installation instructions for different operating systems.

2. How to Install Apache on Windows / macOS / Linux (By OS)