information of PHP

 PHP(personal home page)

PHP may be a general scripting language particularly suited to internet development.  it had been originally created by Danish-Canadian coder Rasmus Lerdorf in 1994. The PHP reference implementation is currently made by The PHP cluster. PHP originally stood for private Home Page, however it currently stands for the algorithmic initialism PHP: machine-readable text Preprocessor.

PHP code is sometimes processed on an online server by a PHP interpreter enforced as a module, a daemon or as a typical entryway Interface (CGI) workable. On an online server, the results of the taken and dead PHP code – which can be any variety of information, like generated HTML or binary image information – would type the complete or a part of Associate in nursing hypertext transfer protocol response. Numerous internet guide systems, online page management systems, and internet frameworks exist which might be used to orchestrate or facilitate the generation of that response. In addition, PHP is used for several programming tasks outside of the net context, like standalone graphical applications [9] and robotic drone management. whimsical PHP code can even be taken and dead via command-line interface (CLI).

The standard PHP interpreter, power-driven by the Iranian Engine, is free package free below the PHP License. PHP has been wide ported and may be deployed on most internet servers on nearly each software system and platform, freed from charge.

The PHP language evolved while not a written formal specification or customary till 2014, with the first implementation acting because the de facto customary that different implementations aimed to follow. Since 2014, work has gone on to form a proper PHP specification.

As of January 2021, seventy two of PHP websites use out of print versions of PHP, i.e. PHP 7.2 or lower, that aren't any longer supported by The PHP Development Team. an oversized extra fraction uses PHP seven.3, that is just (up to December six, 2021) "supported for vital security problems solely."[13] Over four-hundredth of all PHP websites use version five.6 or older,[14] that not even Debi an supports (Debi an nine supported version seven.0 and 7.1)

Early history:

PHP development began in 1994 once Rasmus Lerdorf wrote many Common entrance Interface (CGI) programs in C that he won’t to maintain his personal homepage. He extended them to figure with net forms and to speak with databases, and known as this implementation "Personal Home Page/Forms Interpreter" or PHP/FI.

PHP/FI can be wont to build straightforward, dynamic net applications. To accelerate bug news and improve the code, Lerdorf ab initio declared the discharge of PHP/FI as "Personal Home Page Tools (PHP Tools) version one.0" on the Usenet discussion cluster comp.infosystems.www.authoring.cgi on Gregorian calendar month eight, 1995. This unharness already had the fundamental practicality that PHP has nowadays. This enclosed Perl-like variables, type handling, and therefore the ability to imbed hypertext mark-up language. The syntax resembled that of Perl, however was easier, a lot of restricted and fewer consistent.

Example of PHP program:

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

<!--getenv HTTP_USER_AGENT-->

<!--if substr $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 objects:

Basic object-oriented programming practicality was other in PHP three and improved in PHP four. This allowed for PHP to achieve more abstraction, creating inventive tasks easier for programmer’s victimization the language. Object handling was utterly rewritten for PHP five, increasing the feature set and enhancing performance. In previous versions of PHP, objects were handled like price sorts. the downside of this methodology was that code had to create significant use of PHP's "reference" variables if it wished to change AN object it had been passed instead of making a replica of it. Within the new approach, objects square measure documented by handle, and not by price.

PHP five introduced non-public and guarded member variables and strategies, alongside abstract categories, final categories, abstract strategies, and final strategies. It additionally introduced a typical means of declaring constructors and destructors, kind of like that of different object-oriented languages like C++, and a typical exception handling model. What is more, PHP five other interfaces and allowed for multiple interfaces to be enforced. There square measure special interfaces that permit objects to move with the runtime system. Objects implementing Array Access are often used with array syntax and objects implementing Iterator or Iterator Aggregate are often used with the for each language construct. There’s no virtual table feature within the engine, therefore static variables square measure sure with a reputation rather than a reference at compile time.

If the developer creates a replica of AN object victimization the reserved word clone, the Avestan engine can check whether or not a __clone () methodology has been outlined. If not, it'll decision a default __clone () which is able to copy the object's properties. If a __clone () methodology is outlined, then it'll be accountable for setting the mandatory properties within the created object. For convenience, the engine can provide a operate that imports the properties of the supply object, therefore the technologist will begin with a by-value duplicate of the supply object and solely override properties that require to be modified.

The visibility of PHP properties and strategies is outlined victimization the keywords public, private, and guarded. The default is public, if solely power unit is used; power unit may be a equivalent word for public. Things declared public are often accessed everyplace. Protected limits access to familial categories (and to the category that defines the item). Non-public limits visibility solely to the category that defines the item. Objects of constant sort have access to every other's non-public and guarded members although they're not constant instance.

PHP configuration:

PHP may be an all-purpose scripting language that's particularly suited to server-side internet development, during which case PHP typically runs on an internet server. Any PHP code during a requested file is dead by the PHP runtime, sometimes to make dynamic website content or dynamic pictures used on websites or elsewhere. It may be used for command-line scripting and client-side graphical program (GUI) applications. PHP is deployed on most internet servers, several in operation systems and platforms, and might be used with several electronic information service management systems (RDBMS). Most internet hosting suppliers support PHP to be used by their purchasers. it's accessible freed from charge, and therefore the PHP cluster provides the entire ASCII text file for users to create, customize and extend for his or her own use.

When mistreatment PHP for command-line scripting, a PHP command-line interface (CLI) possible is required. PHP supports an interface server application programming interface (SAPI) since PHP four.3.0. the most focus of this SAPI is developing shell applications mistreatment PHP. There square measure quite few variations between the interface SAPI and alternative SAPIs, though they are doing share several of a similar behaviors.

PHP includes a direct module interface referred to as SAPI for various net servers; just in case of PHP five and Apache two.0 on Windows, it's provided in style of a DLL file referred to as php5apache2.dll, that could be a module that, among alternative functions, provides Associate in Nursing interface between PHP and also the net server, enforced in an exceedingly type that the server understands. This manner is what's called a SAPI.

There square measure completely different sorts of SAPIs for numerous net server extensions. as an example, additionally to those listed on top of, alternative SAPIs for the PHP language embody the Common entry Interface (CGI) and command-line interface (CLI).

PHP can even be used for writing desktop graphical interface (GUI) applications, by mistreatment the PHP-GTK extension. PHP-GTK isn't enclosed within the official PHP distribution, associate in nursing as an extension it are often used solely with PHP versions five.1.0 and newer. The foremost common manner of putting in PHP-GTK is compilation it from the ASCII text file.

When PHP is put in and employed in cloud environments, code development kits (SDKs) square measure provided for mistreatment cloud-specific options. For example:

Amazon net Services provides the AWS SDK for PHP

Windows Azure are often used with the Windows Azure SDK for PHP.

Numerous configuration choices square measure supported, touching each core PHP options and extensions. Configuration file php.ini is looked for in numerous locations, betting on the manner PHP is employed. The configuration file is split into numerous sections, whereas a number of the configuration choices are often additionally set at intervals the online server configuration.