PHP: Hypertext Preprocessor (the name is a recursive acronym) is a widely used, Open Source general-purpose scripting language that was originally designed for web development to produce dynamic web pages.
For this purpose, PHP code is embedded into the HTML source document and Interpreted by a web server With a PHP processor module, which generates the web page document.
PHP is free software released under the PHP License, which is incompatible with the GNU General Public License (GPL).
What can PHP do?
Anything! PHP is mainly focused on server-side scripting, so you can do anything any other CGI program can do, such as collect form data, generate dynamic page content, or send and receive cookies.
PHP can be used on all major operating systems, including Linux, many UNIX variants (including HP-UX, Solaris and OpenBSD), Microsoft Windows, Mac OS X, RISC OS, and probably others. PHP has also support for most of the web servers today. This includes Apache, Microsoft Internet Information Server, Personal Web Server, Netscape and iPlanet servers, Oreilly Website Pro server, Caudium, Xitami, OmniHTTPd, and many others. For the majority of the servers PHP has a module, for the others supporting the CGI standard, PHP can work as a CGI processor.
PHP now focuses mainly on 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 Active Server Pages, 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, Symfony, CodeIgniter, and Zend Framework, offering features similar to other web application frameworks.
What is the history of PHP?
PHP originally stood for personal home page.It began in 1994 as a set of Common Gateway Interface (CGI) binaries written in the C programming language by the Danish/Greenlandic programmer Rasmus Lerdorf.
PHP was originally created by Rasmus Lerdorf in 1995. Lerdorf initially created these Personal Home Page Tools to replace a small set of Perl scripts he had been using to maintain his personal homepage.
The tools were used to perform tasks such as displaying his resume and recording how much traffic his page was receiving.
Zeev Suraski and Andi Gutmans, two Israeli developers at the Technion IIT, rewrote the parser in 1997 and formed the base of PHP 3, changing the language’s name to the recursive initialism PHP: Hypertext Preprocessor. Suraski and Gutmans then started a new rewrite of PHP’s core, producing the Zend Engine in 1999.On May 22, 2000, PHP 4, powered by the Zend Engine 1.0, was released.
On July 13, 2004, PHP 5 was released, powered by the new Zend Engine II.PHP 5 included new features such as improved support for object-oriented programming, the PHP Data Objects extension, and numerous performance enhancements.
PHP currently does not have native support for Unicode or multibyte strings. Unicode support will be included in PHP 6 and will allow strings as well as class, method and function names to contain non-ASCII characters.
PHP 6 is under development alongside PHP 5. Major changes include the removal of register_globals, magic quotes, and safe mode.The reason for the removals was that register_globals had given way to security holes, and magic quotes had an unpredictable nature, and was best avoided.
The National Vulnerability Database stores all vulnerabilities found in computer software. Most of these PHP-related vulnerabilities can be exploited remotely: they allow crackers to steal or destroy data from data sources linked to the webserver (such as an SQL database), send spam or contribute to Dos attacks using malware, which itself can be installed on the vulnerable servers.
PHP stores whole numbers in a platform-dependent range. This range is typically that of 32-bit signed integers. Unsigned integers are converted to signed values in certain situations.
PHP has a native Boolean type that is similar to the native Boolean types in Java and C++.Using the Boolean type conversion rules, non-zero values are interpreted as true and Zero as false, as in Perl and C++.
The null data type represents a variable that has no value. The only value in the null data type is NULL.
Arrays can contain elements of any type that PHP can handle, including resources, objects, and even other arrays.
PHP also supports strings, which can be used with single quotes, double quotes, or heredoc syntax.
Basic object-oriented programming functionality was added in PHP 3 and improved in PHP 4. Object handling was completely rewritten for PHP 5, expanding the feature set and enhancing performance.In the new approach, objects are referenced by handle, and not by value.
PHP 5 introduced private and protected member variables and methods, along with abstract classes and final classes as well as abstract methods and final methods. It also introduceda standard way of declaring constructors and destructors, similar to that of other object-oriented languages such as C++, and a standard exception handling model.Furthermore, PHP 5 added interfaces and allowed for multiple interfaces to be implemented.
In order to speed up execution time and not have to compile the PHP source code every time the webpage is accessed, PHP scripts can also be stored in binary format using PHP compilers such as phc and roadsend.
Code optimizers aim to reduce the runtime of the compiled code by reducing its size and making other changes that can reduce the execution time with the goal of improving performance. The nature of the PHP compiler is such that there are often opportunities for code optimization, and an example of a code optimizer is the eAccelerator PHP extension.
PHP includes free and open source libraries with the core build. PHP is a fundamentally Internet-aware system with modules built in for accessing FTP servers, many database servers,embedded SQL libraries such as embedded PostgreSQL, MySQL and SQLite, LDAP servers, and others. Zend provides a certification exam for programmers to become certified PHP developers.
Is PHP used in STL?
Yes. PHP is used for all the websites belonging to STL and related companies. PHP has also been used to develop Aid Coordination and Monitoring system (ACOM) for the Ministry of Finance Uganda. PHP is also being used to develop HR5 and BOSA.