You'll Learn:
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What PHP is
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About PHP's history
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What improvements can be found in PHP 5
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Some options that add features to your PHP binary
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Some reasons you should choose to work with PHP
Welcome to PHP! you will look at almost
every element of the PHP language. But first, you will explore PHP as a
product its history, features, and future.
What PHP is:
PHP is officially
known as PHP: Hypertext Preprocessor. It is a server-side scripting language
often written in an HTML context. Unlike an ordinary HTML page, a PHP script is
not sent directly to a client by the server; instead, it is parsed by the PHP
engine. HTML elements in the script are left alone, but PHP code is interpreted
and executed. PHP code in a script can query databases, create images, read and
write files, talk to remote servers—the possibilities are endless. The output
from PHP code is combined with the HTML in the script and the result sent to the
user.
PHP is also installed as a command-line application, making it
an excellent tool for scripting on a server. Many system administrators now use
PHP for the sort of automation that has been traditionally handled by Perl.
What Need Does PHP Fulfill?
There have been scripting solutions for
as long as there has been a World Wide Web. As the need to create sites with
dynamic content has grown in recent years, so has the pressure to create robust
environments quickly and efficiently. Although C can be a great solution for
creating fast server tools, it is also hard to work with and can easily produce
security holes if not carefully deployed. Perl, a language originally developed
for text processing naturally met the demand for dynamic Web environments. Much
easier to deploy safely than C, its slower performance has always been more than
balanced by the comparatively fast development cycle it offers. Even more useful
has been the increasing availability of a large number of stable code libraries
for Perl.
So where does PHP fit in? PHP was written especially for the
Web. Many of the issues and problems faced by Web programmers are addressed
within the language itself. Whereas a Perl programmer must use an external
library or write code to acquire data submitted by the user of a Web page, PHP
makes this data automatically available. Whereas a Perl programmer must install
modules to enable her to write database-driven environments, PHP bundles a
powerful SQL database library and provides built-in support for a whole range of
third-party databases. In short, because PHP has been created for Web
programmers, it has a set of functions for almost any typical problem you might
encounter, from managing user sessions to handling XML documents.
So, do we have to pay for this ease of use with even slower
performance? Not at all. PHP is designed to run as a module with many server
applications, which means that there are none of the start-up overheads
associated with CGI scripts. The fact that many typical tasks are handled by PHP
means that developers are freed from reliance on utility libraries that can slow
things down.
