History of PHP

Originally started in 1994 as a replacement for various Perl scripts used to maintain his Personal Web Page (thus the acronym PHP) by the Danish/Greenlandish programmer Rasmus Lerdorf, the project has since grown into an open source community effort. Initial uses of PHP were limited to basic tasks such as counting how many visitors a web site had received, the introduction of PHP/FI (The FI stands for Form Interpreter) added additional functionality including implementation for the C programming language.

In addition to the inclusion of C support, PHP/FI also introduced native support for database communications. These two features have become the bedrock for future versions of PHP and together allowed the relatively swift and easy construction of dynamic web sites. While sites created with PHP at that time may be considered simple by modern standards were still leaps and bounds more impressive than static content and certainly helped to pave the way for the internet to flourish and grow as a medium.

In 1995 Lerdorf made the project public in an effort to improve the PHP code base in both reliability and scope. This release would eventually be known as PHP 2. At the time Perl was still the preeminent language for performing the tasks that PHP was seeking to perform and PHP had yet to reach a point where it had the same scope, depth, and consistency offered by Perl.

PHP 3 began in 1997 when a pair of Israeli developers at Technion IIT decided to rewrite the parser. The two would later form Zend Technologies, a company named after blending their two names: Zeev (Suraski) and Andi (Gutmans). The company would eventually produce the Zend Engine, the first public version of which powered PHP 4 upon its release in 2000.

The successor to Zend Engine is the Zend Engine II which was the basis for PHP 5. PHP 5, released in 2004, is perhaps the most radical and some consider long overdue revamp to PHP as it finally brings true Object Oriented Programming (OOP) to developers who have long since grown used to writing object oriented code.

PHP/FI

PHP/FI, which stood for Personal Home Page / Forms Interpreter, included some of the basic functionality of PHP as we know it today. It had Perl-like variables, automatic interpretation of form variables and HTML embedded syntax. The syntax itself was similar to that of Perl, albeit much more limited, simple, and somewhat inconsistent.

By 1997, PHP/FI 2.0, the second write-up of the C implementation, had a cult of several thousand users around the world (estimated), with approximately 50,000 domains reporting as having it installed, accounting for about 1% of the domains on the Internet. While there were several people contributing bits of code to this project, it was still at large a one-man project.

PHP/FI 2.0 was officially released only in November 1997, after spending most of its life in beta releases. It was shortly afterwards succeeded by the first alphas of PHP 3.0.

Example #1 Example PHP/FI Code

<!--include /text/header.html-->

<!--getenv HTTP_USER_AGENT-->
<!--ifsubstr $exec_result Mozilla-->
  Hey, you are using Netscape!<p>
<!--endif-->

<!--sql database select * from table where user='$username'-->
<!--ifless $numentries 1-->
  Sorry, that record does not exist<p>
<!--endif exit-->
  Welcome <!--$user-->!<p>
  You have <!--$index:0--> credits left in your account.<p>

<!--include /text/footer.html-->

PHP 3

PHP 3.0 was the first version that closely resembles PHP as we know it today. It was created by Andi Gutmans and Zeev Suraski in 1997 as a complete rewrite, after they found PHP/FI 2.0 severely underpowered for developing an eCommerce application they were working on for a University project. In an effort to cooperate and start building upon PHP/FI's existing user-base, Andi, Rasmus and Zeev decided to cooperate and announce PHP 3.0 as the official successor of PHP/FI 2.0, and development of PHP/FI 2.0 was mostly halted.

One of the biggest strengths of PHP 3.0 was its strong extensibility features. In addition to providing end users with a solid infrastructure for lots of different databases, protocols and APIs, PHP 3.0's extensibility features attracted dozens of developers to join in and submit new extension modules. Arguably, this was the key to PHP 3.0's tremendous success. Other key features introduced in PHP 3.0 were the object oriented syntax support and the much more powerful and consistent language syntax.

The whole new language was released under a new name, that removed the implication of limited personal use that the PHP/FI 2.0 name held. It was named plain 'PHP', with the meaning being a recursive acronym - PHP: Hypertext Preprocessor.

By the end of 1998, PHP grew to an install base of tens of thousands of users (estimated) and hundreds of thousands of Web sites reporting it installed. At its peak, PHP 3.0 was installed on approximately 10% of the Web servers on the Internet.

PHP 3.0 was officially released in June 1998, after having spent about 9 months in public testing.

PHP 4

By the winter of 1998, shortly after PHP 3.0 was officially released, Andi Gutmans and Zeev Suraski had begun working on a rewrite of PHP's core. The design goals were to improve performance of complex applications, and improve the modularity of PHP's code base. Such applications were made possible by PHP 3.0's new features and support for a wide variety of third party databases and APIs, but PHP 3.0 was not designed to handle such complex applications efficiently.

The new engine, dubbed 'Zend Engine' (comprised of their first names, Zeev and Andi), met these design goals successfully, and was first introduced in mid 1999. PHP 4.0, based on this engine, and coupled with a wide range of additional new features, was officially released in May 2000, almost two years after its predecessor, PHP 3.0. In addition to the highly improved performance of this version, PHP 4.0 included other key features such as support for many more Web servers, HTTP sessions, output buffering, more secure ways of handling user input and several new language constructs.

Today, PHP is being used by hundreds of thousands of developers (estimated), and several million sites report as having it installed, which accounts for over 20% of the domains on the Internet.

PHP's development team includes dozens of developers, as well as dozens others working on PHP-related projects such as PEAR and the documentation project.

PHP 5

PHP 5 was released in July 2004 after long development and several pre-releases. It is mainly driven by its core, the Zend Engine 2.0 with a new object model and dozens of other new features.