Information on PHP

PHP is a computer scripting language, originally designed for producing dynamic web pages. It has evolved to include a command line interface capability and can be used in standalone graphical applications.

While PHP was originally created by Rasmus Lerdorf in 1995, the main implementation of PHP is now produced by The PHP Group and serves as the de facto standard for PHP as there is no formal specification. Released under the PHP License, the Free Software Foundation considers it to be free software.

PHP is a server-side scripting language for creating dynamic Web pages. PHP's programming syntax is very similar to that of Perl. Because of its elegant design, PHP makes it easy for anyone to learn. It is significantly easier than comparable Perl or ASP Code. Unlike other scripting languages, PHP supports the most common databases like Oracle, Sybase and MySQL. It is also possible to integrate external libraries to generate PDF documents or parsing XML PHP is an open-source language and is supported by a large groups of delvelopers. The code is downloadable from php.net.

PHP, known originally as Personal Home Pages, was first conceived in the autumn of 1994 by Rasmus Lerdorf. He wrote it as a way to track visitors to his online CV. The first version was released in early 1995, by which time Rasmus had found that by making the project open-source, people would fix his bugs. The first version was very straightforward and had a simple parser which recognised a few special macros and provided some of the utilities which were in common usage on homepages back then.

The parser was rewritten in mid-1995 and renamed PHP/FI version 2. The "FI" in this version stood for the Form Interpreter which Rasmus had added to PHP to cope with the growing needs of webpages. mSQL support was also added at this time. PHP/FI underwent massive growth, and other people started to contribute code to it regularly.

In mid-1997 Zeev Suraski and Andi Gutmans rewrote the main parser, and PHP shifted from being Rasmus' own to a more group orientated project. This formed the basis for PHP3, now named PHP: Hypertext Preprocessor - a recursive acronym.

PHP is a server-side scripting language whose primary purpose is to generate HTML content. Its creator, Rasmus Lerdorf defines it as "a cross-platform, HTML-embedded, server-side web scripting language" [Lerdorf 2002, p.1]. With the current direction of the Web, it is easily being adapted to writing out all forms of XML content as well. The most recent version of PHP is PHP 4.

It was originally developed as a set of server-side modules to perform some specific Web-server tasks on small, Unix-based Web servers. Since then PHP has grown beyond the work of one man writing some tools for his own use and into one of the most popular server-side scripting languages in the Web.

Three thing make PHP popular. The first is that it is easy: easy to implement, easy to learn, and easy to use. The second is that it is free. The third is that it runs on almost any Web server on almost any platform currently available.

PHP primarily acts as a filter, taking input from a file or stream containing text and/or PHP instructions and outputs another stream of data; most commonly the output will be HTML. It can automatically detect the language of the user. From PHP 4, the PHP parser compiles input to produce bytecode for processing by the Zend Engine, giving improved performance over its interpreter predecessor.

Originally designed to create dynamic web pages, PHP's principal focus is server-side scripting, and it is similar to other server-side scripting languages that provide dynamic content from a web server to a client, such as Microsoft's ASP.NET system, Sun Microsystems' JavaServer Pages, and mod_perl. PHP has also attracted the development of many frameworks that provide building blocks and a design structure to promote rapid application development (RAD). Some of these include CakePHP, PRADO, Symfony and Zend Framework, offering features similar to other web application frameworks.

PHP is both a scripting language and a collection of tools for performing various server-side functions in an HTTP, or Web, server. Since it is written as a collection of C-modules, it can go beyond server-side scripting and can also be used to execute scripts from the command line and for developing client-side GUI applications that can operate on most any platform.

The core features of PHP are built around the ability to process strings and arrays, as well as to work as an object-oriented programming language. Beyond this most of PHP is a collection of modules that can be added in on the server as needed to perform a large variety of specific tasks. In other words, it is a highly customizable application, and you can keept it small by only installing as much as you need to perform required tasks.

Database Access

One of set modules control database access. Using PHP with MySQL has become common enough that the MySQL interface is now part of core PHP instead of a plug-in module. Most other databases have modules that can be included in a PHP build to allow access. PHP can access most any SQL or ODBC database. It can both read and write information in the database.

This opens up the door for a whole variety of online business applications that require data storage on the server. Because of this, PHP is becoming an increasingly popular tool for e-commerce.

File Access

PHP can read and write files. It can also do basic file and directory maintenance. Because of this, you can use it to do such things as edit documents remotely. It can also be used to search flat file collections for the existence of a given file or for the existence of information stored in files and return the results. Information does not need to be coded into a database just to be accessible.

It can also take content and use it to generate files in various formats, including HTML and PDF. It is an incrasingly popular tool for processing XML for HTTP distribution. It can also take data and use it to generate e-mail, which is can send out through most any standard mail protocol.

Its ability to work across multiple data sources and return multiple content types makes it an ideal tool for things like search engines and message boards.

Graphics

PHP can not only manage text content, it can also manage graphic content. It can be used to create graphs and charts. It can be used to generate GIF and PNG images on the fly, allowing you, for instance, to have a button template that has the text added to it dynamically before being sent to the client. This means you don't need a new image for each button, just one image that has the text added as needed for each individual button.

Application Control

PHP started as an application control language. Specifically, it was designed to handle access logging for HTTP servers. This ability has expanded greatly and now PHP can even be used as a scripting language in such applications as Microsoft Word and Excel.

Extensible

PHP is extensible. It is written in C and the underlying source can be expanded on with new modules written in the same. It is also open source, so engaging in such expansion is permitted and encouraged.

PHP was written in the C programming language by Rasmus Lerdorf in 1994 for use in monitoring his online resume and related personal information. For this reason, PHP originally stood for "Personal Home Page". Lerdorf combined PHP with his own Form Interpreter, releasing the combination publicly as PHP/FI (generally referred to as PHP 2.0) on June 8, 1995.