PHP Introduction Introduction PHP is one of the most prevalent Web programming languages for creating dynamic Web content Its similarity to C s syntax and open source nature make PHP relatively easy to learn This document provides a brief overview of PHP several reasons for using PHP as a Web programming language and a list of minimum requirements to begin working with PHP What is PHP PHP is a scripting language created in 1994 by Rasmus Lerdorf that is designed for producing dynamic Web content PHP originally stood for Personal Home Page but as its functionality expanded it became PHP Hypertext Processor because it takes PHP code as input and produces HTML as output Although PHP is typically used for Web based applications it can also be used for command line scripting a task commonly handled by Perl as well as standalone applications possibly with a graphical user interface a task commonly handled by Python or Java NOTE This course only addresses PHP in the context of dynamic Web content creation PHP is interpreted rather than compiled like Java or C an embedded scripting language meaning that it can exist within HTML code a server side technology everything happens on the server as opposed to the Web browser s computer the client cross platform meaning it can be used on Linux Windows Macintosh etc making PHP very portable PHP does not handle client side tasks such as creating a new browser window adding mouseovers determining the screen size of the user s machine etc Such tasks are handled by JavaScript or Ajax Asynchronous JavaScript and XML do anything within the Web browser until a request from the client has been made e g submitting a form clicking a link etc Why use PHP PHP has been described as being better faster and easier to learn than the alternatives Ullman 2004 The alternatives being HTML static no database file interaction cannot handle email etc CGI Common Gateway Interface scripts Perl or C Microsoft ASP Active Server Pages or ASP NET need to learn VBScript C or another language and is limited to servers running Microsoft Windows Server Macromedia ColdFusion expensive to purchase JSP JavaServer Pages Java based so there is a higher learning curve plus you deal with the overhead of a compiled language Personal experience also suggests that JavaServer sites are slower than other sites Additionally PHP is free works on multiple platforms and is open source i e user driven development not part of a corporation These attributes combined with a large development community and the wealth of available PHP libraries make PHP an attractive choice for Web developers The Web content delivery process has the same beginning and end A user requests a URL from the Web server and HTML markup is sent to the user s browser With the static HTML delivery process the Web server sends the exact content of the requested page to the client without any additional processing With dynamic Web content creation PHP acts as a filter by processing PHP code possibly embedded within HTML markup to produce HTML markup that is ultimately sent to the user s browser PHP requirements The following elements represent the minimum requirements to begin working with PHP Concepts such as PHP installation and configuration are beyond the scope of this course 1 2 3 PHP enabled Web server On the EECS machines you can place your PHP scripts anywhere within the www home directory unlike Perl CGI scripts that must be placed in www home cgi bin However it is strongly suggested that you place your PHP scripts in your www home cgi bin directory If you are working on your own machine you will need an SFTP client to transfer your PHP scripts to the Web server Otherwise you can edit your files directly on the file system via an SSH session with a text editor e g vi emacs Web browser e g Mozilla Firefox Apple Safari Microsoft Windows Internet Explorer
View Full Document
Unlocking...