Apache

Apache (Apache HTTP Server) is an open-source, cross-platform software for hosting and supporting a web server.

What is Apache used for?

The software allows you to:

• open dynamic PHP pages;
• distribute the load coming to the server;
• ensure server fault tolerance;
• Practice running PHP scripts and setting up a server.

How Apache Came to Be

Apache is an abbreviation for “A patchy server.” The name comes from the program’s origins. In the first half of the 1990s, the NCSA HTTPd web server was popular. When its developer left the project, development of the software slowed significantly. NCSA HTTPd had many bugs. Other developers began fixing them and applying their own patches. A patch is a piece of code, information, or software module that addresses developer errors. Another name for it is a patch.

What is a web server?

The server program acts as an intermediary between the server computer and the user’s browser. Upon receiving a request from the client, it finds the required page in the website’s directory and sends it back. The browser parses the received file and converts it into the web page displayed to the user. The workflow is as follows:

1. The server runs on a port (usually 80, 8080, or 8000, but sometimes others) that is open to third-party client programs, including the user’s browser.
2. When a request is received on one of the ports, the program compares it with internal instructions and rules and decides whether to execute it or not.
3. If the web server rules prohibit the request, the user will see an error code (404) or a denial of access to data.
4. After the server program has executed the request (successfully or with an error), it goes into standby mode.

Data exchange between a web server and a browser is carried out using the HTTP (HyperText Transfer Protocol). Later, it became possible to transfer all types of files. Today, an improved version, HTTPS, is used, encrypting traffic between the client and the server.

How Apache Works

Apache works on a modular principle. The core is installed first, and then the necessary modules are enabled based on the needs of the task.

Core

The Apache web server core includes core functionality—configuration file processing, the HTTP protocol, and a module loading system. It is written entirely in ASF, using the C programming language. The Apache core can operate without modules, but its functionality will be limited.

System of modules

Modules are separate software units. They connect to the web server core and expand its functionality. Modules are used to solve highly specialized problems, such as programming language support, bug fixes, security enhancements, authentication, and so on. Currently, there are over 500 modules available for the Apache web server. They can be included with the software during installation or loaded later via a configuration file.

Configuration system

This is a set of text commands for changing kernel parameters or adding new modules. Thanks to them, Apache can operate at several levels:

• The entire server. This level implements the web server’s overall operation and processes all incoming requests. These commands are specified in the httpd.conf file;
• A virtual host. A computer can host multiple websites managed by a single web server. Each website is assigned a separate virtual host. When a user requests a request, the system determines which host to send it to, where to retrieve the data, how to process it, and so on. These commands are specified in the extra/httpd-vhosts.conf configuration files.
• Catalog. The configuration file at this level (.htaccess) controls user access to data in the catalog. For example, it prevents illegal downloading of product lists or financial reports from an online store website.

The Apache server evaluates these rules for every request, so new directives are executed immediately after changes are made. Configurations can be edited in text configuration files or using the command line.

Advantages of Apache

Flexibility. Multiple configuration files that control web server operation at various levels, as well as modules, allow you to customize Apache to meet specific needs.

Cross-platform. Apache runs on computers running Microsoft Windows, MacOS, Linux, specialized network BSDs, and Novell NetWare. The web server’s functionality and administration remain the same across different operating systems; only the installation process and file directory locations differ.

Accessibility. Apache is open-source software. This means anyone can study, modify, and use the web server to solve their own problems.

Functionality. The core’s capabilities can be extended using Apache modules. Some are included with the installation package, while others can be downloaded separately. 

 documentation, modular kits, scenarios, and practical use cases have been released by the official developer and third-party experts. For virtually any problem a user might encounter while using the software, there’s a ready-made solution available online.

Scalability. Apache can power everything from a lightweight single-page landing page to a large-scale online store or information portal. If the load on a physical server increases, you can install a second Apache server on a different computer, connect the same website to it, and distribute the traffic between the two web servers.

Programming language support. Apache is written in C++, but numerous modules add support for various programming languages ​​and development systems. These include Python, PHP, Ruby (apache-ruby), Tcl, Perl, and ASP (apache-asp). Apache supports FastCGI and CGI mechanisms, allowing it to run programs in almost all programming languages, including C, C++, sh, Lua, and JavaScript. 

Apache Disadvantages

Performance. Because the system accesses configuration files for every request, processing time increases. This becomes noticeable under heavy server load—the Apache-based site processes each connection in turn, and at such times, it begins to noticeably slow down. However, this drawback can be partially mitigated by disabling unused modules.

Vulnerability. The core system has undergone numerous security checks, unlike third-party modules. Furthermore, the more functional blocks connected, the more complex the configuration and the higher the risk of a critical error.

Configuration file syntax. When working with them, users constantly deal with a large number of variables. This makes management and configuration difficult for beginners. To mitigate this, a special free tool, Apache GUI, can be used.

How to work on Apache

One of the simplest and most common ways to set up a web server with Apache is to use the MAMP software package. It includes Apache itself, a database manager, a PHP engine, and other components. It works as follows:

1. The user downloads the MAMP package version for their OS from the official website and installs the web server on the computer.
2. After installation, he launches the program and enters the Start command.
3. The system will inform the user that the server is running, display its address, and the directory where the files are located (all of this can be left as default or configured manually).
4. On the http://localhost/MAMP page, the user can view all information about the web server, including keys and database administration tools.

MAMP makes it easy to set up a local web server, but it won’t be visible from the internet unless you have a dedicated public IP address from your ISP. Setting up a website visible from the outside world is more complex and time-consuming.