PHP: Hypertext Preprocessor
PHP is a widely used, open-source server-side scripting language primarily designed for web development. It enables developers to create dynamic web pages, interact with databases, and generate HTML content that is delivered to a user’s browser. Originally developed by Rasmus Lerdorf in the early 1990s, PHP has since evolved into a general-purpose scripting language used across the web.
Overview
PHP scripts are executed on the server, where the PHP interpreter processes the code and returns the resulting output to the user’s web browser. Its syntax is embedded directly within HTML, allowing seamless integration of server logic with structure and design. PHP is compatible with most web servers and operating systems, and it supports a wide range of database systems.
History
PHP was first created in 1994 by Danish-Canadian programmer Rasmus Lerdorf as a set of Common Gateway Interface (CGI) binaries written in C. The initial implementation was intended to track visits to his personal homepage. Over time, the language expanded into a full scripting language known as PHP/FI and later evolved under the stewardship of The PHP Group. Originally an abbreviation for “Personal Home Page,” the name later became the recursive acronym “PHP: Hypertext Preprocessor.”
Core Features
- Server-side Execution: PHP code runs on the server, generating HTML sent to the client’s browser.
- Dynamic Content: Enables the creation of web pages that change based on user input, database queries, or other logic.
- Database Integration: Supports numerous databases including MySQL, PostgreSQL, Oracle, and more.
- Cross-Platform: Works on various operating systems including Linux, Windows, and macOS.
- Open-Source: Freely available and supported by a large community of developers.
PHP also includes features common to many scripting languages, such as flexible variable handling, support for object-oriented programming, and a large ecosystem of extensions and libraries.
Syntax and Semantics
PHP’s syntax is influenced by languages such as C and Perl, with a focus on simplicity and ease of use for web developers. A typical PHP script is embedded within <?php ... ?> tags inside HTML. The language supports procedural programming and offers object-oriented features, allowing for class definitions, inheritance, and encapsulation.
Use in Web Development
PHP remains one of the most widely used languages for dynamic web development. It powers a significant portion of websites on the internet and is the foundation of many content management systems (CMS) and web applications. Popular platforms built with PHP include WordPress, Drupal, and Joomla, which manage content for millions of sites worldwide.
Major web properties such as Wikipedia and Facebook have utilized PHP in their development, often adapting or extending it to meet performance requirements.
Standardisation and Best Practices
The PHP Standard Recommendation (PSR) series provides a set of specifications published by the PHP Framework Interop Group (PHP-FIG). These recommendations help ensure interoperability across libraries and frameworks, standardising coding styles, autoloading, and common interfaces. PSRs enhance consistency and quality in PHP projects and support collaboration across the ecosystem.
Licensing and Governance
PHP is released under the PHP License, an open-source licence that permits free use and distribution of the language. The PHP Group maintains the reference implementation and oversees development, releases, and community contributions.
Implementation and Deployment
PHP is typically deployed on a web server with an interpreter module, such as Apache, Nginx, or Microsoft IIS. When a client requests a PHP page, the server invokes the interpreter, which processes the script and produces HTML output. PHP supports a command-line interface, enabling scripts to be run outside the context of a web server.
Impact and Adoption
Over its history, PHP has become one of the dominant languages in server-side web development. It has enabled millions of developers to build dynamic websites and web applications efficiently. Its simplicity, extensive documentation, and large community contribute to its enduring popularity in the web development domain.