PHP HOW-TO

Al Dev (Alavoor Vasudevan) alavoor[AT]yahoo.com

v27.6, 05 Oct 2002

This document tells you howto develop PHP programs and also to migrate all the Windows 95 GUI applications to powerful PHP + HTML + DHTML + XML + Java applets + Javascript. The information in this document applies to all the operating sytems where PHP is ported that is - Linux, Windows 95/98/NT/ME/2000/XP, BeOS, Apple Macintosh (is the son of FreeBSD Unix??), OS/2, all flavors of Unix like Solaris, HPUX, AIX, SCO, Unixware, Sinix, BSD, SunOS, etc.. and mainframe operating systems and on all operating systems where "C" compiler is available.

1.Introduction

(The latest version of this document is at http://www.milkywaygalaxy.freeservers.com. You may want to check there for changes).

Definition: PHP is a simple, object-oriented, interpreted, robust, secure, very high-performance, architecture neutral, portable, dynamic scripting language. PHP has "class" keyword similar to Java's "class" keyword. And PHP is designed such that it is 5 times faster than Java, since there is no virtual machine. PHP is very fast becoming a standard, general purpose, object oriented scripting language. PHP is not only meant for web applications but also can be used for developing general applications.

PHP is the next big thing after HTML because today nobody writes static HTML but uses PHP (generate on the fly, embedded dynamic HTML). PHP 'kind-of' supercedes "static HTML". PHP is a very powerful scripting language. PHP will overtake PERL/Python and will replace PERL/Python. PHP is the next-generation PERL/Python scripting. PHP can do whatever PERL or Python does and actually does much more, much better and much, much cleaner.

PHP stands for 'Hypertext Pre-Processor' and is a server side HTML scripting/programming language. PHP is C-like Web scripting language runs on Apache, Netscape/iPlanet, and Microsoft IIS Web servers. PHP is a tool that lets you create dynamic web pages. PHP-enabled web pages are treated just like regular HTML pages and you can create and edit them the same way you normally create regular HTML pages. PHP lets you write simple scripts right in your HTML files much like JavaScript does, except, unlike JavaScript PHP is not browser-dependant. JavaScript is a client-side html-embedded language while PHP is a server-side language. PHP is similar in concept to Netscape's LiveWire Pro product and Microsoft's ASP and Sun Microsystem's JSP.

PHP is not only used for creating web applications, but also for creating general standalone applications.

PHP's strength are :

• PHP is the most superior technology. Other technologies PERL, Python, Tcl, VB script, ASP are older and inferior technologies. Even Java/JSP is inferior to PHP.
• Open source
• Easily learned syntax
• Broad database connectivity
• Massive library of contributed extensions
• General purpose scripting language much superior to PERL, VB script, ASP, JSP.

Why PHP ? PHP is the best because of the following reasons:

• PERL is the "ancestor" of PHP and PERL is used for a very long time (more than 25 years old?). PHP has an advantage over PERL - PHP supports client-side code and is easier to compile into a executable. User base of PERL is very large. PHP tries to imitate PERL and complement the PERL technology. PERL programmers like PHP! PHP is actually a "modern PERL", but with a different name called "PHP".
• Java is object-oriented but is very SLOW. Java programs run very slow. Also Java is immensely complex and sophosticated technology (has many layers like JVM, JIT compiler and others). And complexity and sophostication leads to problems. If there is Linux on server-side then why do you need Java in servers ? And Java is more like a system programming language and it is faster to develop in scripting languages (like PHP).
• Python is "good" but there are no C like brackets/braces which are useful for code navigation in vi editor. It is like your hand is broken if you cannot navigate rapidly the source code using vi/emacs editor's seek braces/brackets commands. PHP is technologically more advanced than Python.
• PHP is the best because it is object oriented and has the best features of C/C++/Java/PERL/Python. It can replace PERL, Python, Java, C, C++, awk, Unix shell scripting, MS Visual Basic and others!! PHP runs direct and PHP is written in C.
• Each and every computer programmer knows why PHP is the best. Ask your nearby computer programmer.
• Only PHP will prevail in the 21st and 22nd century and beyond!
• Why do think every PERL, Python and Java programmers are flocking to PHP ?? There is a very strong reason.
• Every person in the world wants PHP. PHP blast is causing shock-waves around the world!!
• The world is dominated by PHP. There is PHP everywhere and anywhere... PHP, PHP, PHP everywhere..

PHP was kept the "top secret and strictly confidential" computer language by many companies in the world, but now had become the most well-known and most widely used object oriented scripting language for web, internet, e-commerce, general purpose and business-to-business projects. Even today many competing companies keep PHP language as a highly confidential matter not disclosing to outsiders (competitors).

PHP will storm the entire world and will take the IT industry by surprise!! The power of PHP is that it is cross-platform and runs everywhere!! It runs on Linux, Windows 95/98/NT/2000/XP, Solaris, HPUX and all flavors of UNIX. PHP is write once and deploy anywhere and everywhere. It runs on many web-servers like Apache, Microsoft IIS, etc..

PHP runs 5 to 20 times faster than Java!! In actual benchmarks, PHP was about 3.7 times faster than JSP (see benchmarks ). PHP is extremely easy to use and you can develop very complex web/e-commerce/general-standalone applications very rapidly in a very short period of time. Developing applications in PHP is about TWO times faster than developing in programming language like Java (because there is no need for compilation in PHP). (In future PHP language will imitate most features of Java language and Java programmers will love PHP. And PHP will have java keywords like class, extends, interface, implements, public, protected, private etc..).

It has object oriented features and takes the best features from Java, C++, PERL and "C" languages. PHP language is a marriage of best features from Java, C++, PERL, Python and C.

PHP is the real gem of all the scripting/programming languges and will soon become the "MECCA" for programmers world-wide!! PHP has a huge user base and a large developer base as it runs on both Window95/NT/2000/XP and all flavors of UNIX'es.

A big surprise is waiting for us - Most probably PHP will be the scripting language of the 21st century!!

PHP can be compiled and optimized to make it run even faster by using the Zend Optimizer. Zend optimizer is integrated with PHP in PHP version 4.0. First, you will write your application in PHP scripting language during development, testing and debugging. Once the project is ready for deployment you will use the Zend compiler to compile the PHP to create executable which will run very fast.

You would normally use a combination of PHP (70% code) + HTML/DHTML/XML (25% code) + Javascript (5% code client side validations) for your e-commerce projects.

2.PHP runs on Microsoft Windows!!

PHP initially started on UNIX platform, but it is very portable and runs on MS Windows and MS IIS webserver. Today PHP has a large user base on MS Windows 2000/NT/95/98, You will find a huge collection of tools for PHP under MS Windows platform.

Many PHP programmers develop code on MS Windows and deploy on large linux servers like IBM mainframe running linux, Compaq DEC Alpha and Sun sparc.

A great advantage is that since PHP also runs on UNIX/Linux, developers on UNIX platform "cash on" the user base of PHP under MS windows as the PHP code developed under MS Windows can be used on UNIX/linux without any code change!!

PHP itself is written in 100% "C" langauge, and hence it runs on a very wide variety of platforms like BeOS, UNIX, MS Windows, Apple Macintosh, IBM OS/2 and on many more operating systems.

PHP is very fast and is much faster than Java. For web development, forget Java/JSP, it is PHP, PHP and PHP everywhere!! PHP is also becoming a general purpose object oriented scripting language

Mirror sites are in many countries like www.COUNTRYCODE.php.net, where COUNTRYCODE is like us, fe, sk etc.

3.1 PHP Installation on Microsoft Windows 95/98/NT/2000

PHP is IMMENSELY POPULAR on Microsoft Windows platform and is surprisingly more popular than Microsoft's own ASP web scripting language!! A major reason for popularity is that PHP is a object oriented scripting language whereas ASP is not. PHP has a large collection of re-usable classes (objects). PHP runs lot faster than ASP on MS Windows and has more features and functionalities than Microsoft ASP. PHP is much more robust, reliable and powerful than ASP. And the user base of PHP is extremely large because PHP runs on MS Windows, Linux, Mac OS and all UNIX'es. Greatest advantage of PHP is that you can develop on MS Windows and deploy on Linux or UNIX and vice versa!!

There are more PHP users under MS Windows98/NT/2000 than on any other operating system!! Because there is so much demand for PHP on MS Windows 98/NT/2000, a ready to install executable is made and you simply double-click on the exe file to automatically install PHP in just 2 minutes. Download the PHP executable install file from

3.2 Apache Webserver Quick-Install (10 seconds) on Microsoft Windows 95/98/NT/2000

You need a web-server to run the PHP on MS Windows. You can use MS IIS web server or you can use free Apache web-server for MS Windows 95/98/NT/2000. To save you lot of time here is the ready-to-install setup.exe file for apache for Windows platform:

PHPTriad which is Apache+PHP+MySQL single package is at http://www.phpgeek.com/phptriad.php and at mirrorsite. I very strongly recommend PHPTriad as it is immensely popular among MS Windows users (millions of downloads).

Apache binaries - http://httpd.apache.org/dist/httpd/binaries/win32

3.3 SQL server for Microsoft

SQL server can be on a seperate box which need not be running MS Windows. You also need a SQL server for doing web development. I recommend that you install Redhat Linux on a very old PC like (Pentium or 486 box) and install the PostgreSQL RPMs on it. You do not need any windows graphics for a database server and at console mode startup the PostgreSQL server. PostgreSQL is about 3 times faster than Oracle or MS SQL server.

The PostgreSQL support code for PHP was written by Adam Sussman asussman@vidya.com

You can also order ready-to-go cheap Linux boxes from -

You can also get PostgreSQL for Windows NT/2000 from http://www.askesis.nl.

See also the PostgreSQL howto at pgsql-howto

3.4 ASP To PHP Converter - Migration From ASP2PHP

After installing PHP, you may want to migrate all the Microsoft ASP programs to PHP. See the chapter ASP2PHP.

3.5 PHP Installation on UNIX'es and others

See the installation guide and instructions at PHP main site http://www.php.net or INSTALL file in the downloaded package itself.

3.6 PHP Installation on Apple Macintosh

Apple Macintosh is Unix like operating system. And actually it's father is FreeBSD. It picked up many titbits from other Unices and is quite powerful OS. See the Unix history at Unix Family Tree and click on the item 12 to see the Apple Mac position at Apple Mac tree.

The installation and use of PHP on Apple Mac will be very similar to that of on Unix OS.

4.Quick Start steps

To implement a project in object oriented PHP do -

5.Major Features of PHP

• Standard CGI, FastCGI and Apache module support - As a standard CGI program, PHP can be installed on any UNIX machine running any UNIX web server. With support for the new FastCGI standard, PHP can take advantage of the speed improvements gained through this mechanism. As an Apache module, PHP becomes an extremely powerful and lightning fast alternative to CGI programmimg.
• Access Logging - With the access logging capabilities of PHP, users can maintain their own hit counting and logging. It does not use the system's central access log files in any way, and it provides real-time access monitoring. The Log Viewer Script provides a quick summary of the accesses to a set of pages owned by an individual user. In addition to that, the package can be configured to generate a footer on every page which shows access information. See the bottom of this page for an example of this.
• Access Control - A built-in web-based configuration screen handles access control configuration. It is possible to create rules for all or some web pages owned by a certain person which place various restrictions on who can view these pages and how they will be viewed. Pages can be password protected, completely restricted, logging disabled and more based on the client's domain, browser, e-mail address or even the referring document.
• PostgresSQL Support - Postgres is an advanced free RDBMS. PHP supports embedding PostgreSQL "SQL queries" directly in .html files.
• RFC-1867 File Upload Support - File Upload is a new feature in Netscape 2.0. It lets users upload files to a web server. PHP provides the actual Mime decoding to make this work and also provides the additional framework to do something useful with the uploaded file once it has been received.
• HTTP-based authentication control - PHP can be used to create customized HTTP-based authentication mechanisms for the Apache web server.
• Variables, Arrays, Associative Arrays - PHP supports typed variables, arrays and even PERL-like associative arrays. These can all be passed from one web page to another using either GET or POST method forms.
• Conditionals, While Loops - PHP supports a full-featured C-like scripting language. You can have if/then/elseif/else/endif conditions as well as while loops and switch/case statements to guide the logical flow of how the html page should be displayed.
• Extended Regular Expressions - Regular expressions are heavily used for pattern matching, pattern substitutions and general string manipulation. PHP supports all common regular expression operations.
• Raw HTTP Header Control - The ability to have web pages send customized raw HTTP headers based on some condition is essential for high-level web site design. A frequent use is to send a Location: URL header to redirect the calling client to some other URL. It can also be used to turn off cacheing or manipulate the last update header of pages.
• On-the-fly GIF image creation - PHP has support for Thomas Boutell's GD image library which makes it possible to generate GIF images on the fly.
• ISP "Safe Mode" support - PHP supports an unique "Safe Mode" which makes it safe to have multiple users run PHP scripts on the same server.
• Many more new features are being added in newer releases of PHP. Visit the main web site at http://www.php.net
• It's Free! - One final essential feature. The package is completely free. It is licensed under the GNU/GPL which allows you to use the software for any purpose, commercial or otherwise.

5.1 Advantages of PHP over Java

PHP is an established server-side scripting language for creating dynamic Web pages. As a language that has been designed expressly for the Web, it brings many features that commercial entities are looking for:

• Exceptionally short learning curve
• Quick development time
• Very high performance

This is essential for companies who are faced with scarce skilled programming resources and ever-tighter time to market deadlines. In addition, PHP supports all major platforms (UNIX, Windows and even mainframes), and features native support for most popular databases. All these factors make it a very good choice for Web development: such shops working with PHP have reported being able to hire non-programmers and have them producing usable code within days. Programmers familiar with languages such as C, C++ or Java frequently find that they can begin programming in PHP within a few hours.

The fact that PHP was designed specifically for Web development gives it an edge as a development tool, as Intranet Design Magazine explains:

"PHP was built with the needs of Web developers in mind... Unlike other cumbersome, overhead-laden approaches, PHP is lightweight and focused on the Web - where it can solve complex problem scenarios quicker and more easily than comparable technologies."1

Java began its life as a programming language and was initially aimed at running client-side applications inside of Web browsers. Over the last few years, the problems associated with these "applets," as they were known, has led Sun and many other Java developers to use the language in other ways. One of the most prominent ways is in server-side programming, allowing Web sites to connect to databases and produce other server-side applications, or "servlets." Sun came out with Java Server Pages (JSP) as a means of writing servlets. JSP, like PHP, is highly portable across different platforms (even though PHP supports any 32-bit or better platform, whereas JSP supports only platforms that have a Java virtual machine available). However, a beginner with no programming background will find it exceptionally difficult to begin working with servlets,because of the complexity of the language as well as the complicated JSP system design.

JSP's performance also leaves much to be desired: a recent survey in ZDnet's eWeek online publication found that PHP is as much as 3.7 times faster than JSP. In the Web environment, this makes JSP a significantly worse solution - because it can perform less transactions per second, and features considerably slower response times.

ZDnet's eWeek also noted that

"JSP is a relatively new technology and still has clear market immaturities in terms of tools, support resources and available talent."...Because JSP is based on Java, a strongly typed language, we had to declare the types of variables we used and manually convert between types when necessary. This makes JSP the hardest of the scripting languages we tested for nonprogrammers to learn..."

Bad Points Of Java

1. The server is under your control but you will never know what the clients will be? MS Windows, Linux, Mac, Unix?? Java is designed for client side computing with "Applets", "Swing" and "AWT".

2. Java is a bad choice on the server-side! Since server OS is under your control, you need something like PHP which runs directly without any intermediate layers like Java virtual machine and JIT compiler. You simply select Linux, Unix or MSWindows on server-side and use PHP.

3. Java is very complicated due to many layers like JVM, JIT, whereas PHP is quite simple, fast and runs directly on the server operating system. This means Java technologies can never be faster than PHP!

4. Java technology is very bad choice on the server-side. When you have Linux on server which is completely under your control why do you need Java?? By the way, the browser clients never know that you are using Linux + Apache + PHP !! (The clients may think that the HTML pages are coming from MS Windows + MS IIS !! )

5. Use Java technology on the client-side. Use Java inside web browsers like Applets and other client applications like Swing, AWT and others.

PHP works with Java

It is important to note JSP is just one language with which Java objects can be accessed. PHP also can also integrate with Java, which means that it can be used as the scripting language for activating Java logic, just as much as JSP can. Unlike JSP, however, PHP also integrates with other component models, such as Microsoft's COM, and adding support for new object models is extremely easy. This means PHP's extensibility is infinite. JSP, on the other hand, is completely dependent on Java.

IBM programmer Sam Ruby uses PHP in combination with Java. Using the native Java support in PHP, Java objects can be created and used transparently, as if they were regular PHP objects.

AuctionWatch , which enables businesses of all sizes to benefit from dynamic pricing environments, has over 2.6 million unique visitors per month; 300K+ registered users; 1.2 million+ auctions launched every month. They tried to use Java, but opted for PHP because it's easier to use and much faster to develop with. For further information, please contact Ben Margolin, Director of Seller Services for AuctionWatch (ben@auctionwatch.com).

Programming consultant Reuven Lerner has made some comparisons among the languages. His view of PHP is summarized as follows:

"The language is easy to learn. Graphic artists and Web designers might claim that they are not programmers, but the fact is that they're doing increasingly large projects in JavaScript, VBScript, and other simple programming languages. PHP is much more regular and well-defined than PERL, and is much easier for new programmers to grasp than Java. Indeed, PHP seems like a server-side version of what JavaScript could have been, but isn't. Someone with little or no programming experience can learn PHP and work with it after a very short period of time. This is probably true for VBScript, but certainly not for PERL or Java....PHP is a truly remarkable and powerful system. I can see why it has become a popular system for producing Web sites.... I think that it will be a very strong competitor against Java and JSPs, and will rise significantly in my recommendations for clients and internal use."

PHP: Growing by the month

JSP enjoys the backing of Sun; hence its constant media attention. It is interesting to note that despite the lack of any publicity campaign, PHP's popularity is growing at a monthly rate of 8-11%, a percentage far greater than the Internet's 4% monthly growth -- as the demand for server-based applications has risen. More than 6.5 million sites use PHP (Netcraft May 2001 survey). PHP is used on 39% of Apache servers; PERL trails fourth, with 11% of the market. Apache maintains 59% of the Web server market; Microsoft IIS is second, with 28% of market share (E-Soft Inc./SecuritySpace's May 2001 report).

Prominent corporations using PHP include Unilever, Philips, NTT, Cisco, Japan Airlines, Air Canada, Lufthansa, GE Marketplace, Wallstreet:Online Germany; AuctionWatch, VillageVoice, Dialpad and BMC.

1. Intranet Design Magazine: PHP From an IT Manager's Perspective, Jun 4, 2000. http://linuxtoday.com/news_story.php3?ltsn=2000-06-04-002-04-NW-HL-SW

2. eWEEK: Four scripting languages speed development, October 30, 2000. http://www.zdnet.com/eweek/stories/general/0,11011,2646052,00.html

6.Brief History of PHP

PHP began life as a simple little cgi wrapper written in PERL. The name of this first package was Personal Home Page Tools, which later became Personal Home Page Construction Kit.

Old name is Professional Home Pages (PHP) and new name is PHP Hypertext Pre-Processor.

A tool was written to easily embed SQL queries into web pages. It was basically another CGI wrapper that parsed SQL queries and made it easy to create forms and tables based on these queries. This tool was named FI (Form Interpreter).

PHP/FI version 2.0 is a complete rewrite of these two packages combined into a single program. It evolved to a simple programming language embedded inside HTML files. PHP eliminates the need for numerous small PERL cgi programs by allowing you to place simple scripts directly in your HTML files. This speeds up the overall performance of your web pages since the overhead of forking PERL several times has been eliminated. It also makes it easier to manage large web sites by placing all components of a web page in a single html file. By including support for various databases, it also makes it trivial to develop database enabled web pages. Many people find the embedded nature much easier to deal with than trying to create separate HTML and CGI files.

Now PHP/FI is renamed as PHP.

7.A Simple Example

Suppose you have a form:

 <FORM ACTION="/cgi-bin/php.cgi/~userid/display.html" METHOD=POST> <INPUT TYPE="text" name="name"> <INPUT TYPE="text" name="age"> <INPUT TYPE="submit"> <FORM> 
Your display.html file could then contain something like:
 < ?echo "Hi $name, you are$ age years old!<p>" > 
It's that simple! PHP automatically creates a variable for each form input field in your form. You can then use these variables in the ACTION URL file.

The next step once you have figured out how to use variables is to start playing with some logical flow tags in your pages. For example, if you wanted to display different messages based on something the user inputs, you would use if/else logic. In our above example, we can display different things based on the age the user entered by changing our display.html to:

 <? if($age>50); echo "Hi$name, you are ancient!<p>"; elseif($age>30); echo "Hi$name, you are very old!<p>"; else; echo "Hi $name."; endif; >  PHP provides a very powerful scripting language which will do much more than what the above simple example demonstrates. See the section on the PHP Script Language for more information. You can also use PHP to configure who is allowed to access your pages. This is done using a built-in configuration screen. With this you could for example specify that only people from certain domains would be allowed to see your pages, or you could create a rule which would password protect certain pages. See the Access Control section for more details. PHP is also capable of receiving file uploads from any RFC-1867 compliant web browser. This feature lets people upload both text and binary files. With PHP's access control and logical functions, you have full control over who is allowed to upload and what is to be done with the file once it has been uploaded. See the File Upload section for more details. PHP has support for the PostgreSQL database package. It supports embedded SQL queries in your .HTML files. PHP also has support for the mysql database package. It supports embedded SQL queries in your .HTML files. 8.SOAPX4 and PhpXMLP SOAP is an XML-based protocol for messaging and RPC-style communication between two processes. The World Wide Web Consortium's XML Protocol (XP) Working Group is working on a SOAP standard, which will be called XP. The SOAPX4 (Simple Object Access Protocol) implementation for PHP is at http://dietrich.ganx4.com/soapx4. Alternate SOAP implementation is at http://sourceforge.net/projects/phpxmlp. 8.1 XML/XSLT Publishing Engine Krysalis is the XML/XSLT publishing engine, inspired from Cocoon but adapted to the PHP technology. InterAKT has developed Krysalis to achieve what the next generation of web services have to offer - the complete separation of the information, application logic and presentation layer. Krysalis is an open-source PHP development platform, based on the XML/XSLT core. It reused most of PHAkt code to create the Krysalis taglib library. Major features are: • Dynamic XML support. • Dynamic PDF generation. • Sitemap description with regular expressions. • PXP page caching. • Multiple transformation pipelines. • Multiple connection types to various databases (ADODB). Please visit the Krysalis site for more information http://www.interakt.ro/products/Krysalis. 9.PHP Libraries The PHP is a object-oriented scripting language. Hence PHP code is "classes, classes, classes and classes". When you write PHP code you must design your classes such that they are re-usable or they use existing PHP classes. There are hundreds of PHP classes already written and ready to use. There are classes for accessing databases, classes for generating XML, HTML forms, classes for creating tables, forms and other HTML objects. If you write some generic classes then please upload to sites. By year 2005, there will be more than hundred million re-usable PHP classes. Advantage of PHP classes are they provide - data hiding, inheritance, encapsulation, reliability, reusability and polymorphism. The most important PHP sites are PHP classes and PEAR as given below. 9.1 Classes and PEAR Visit the following web sites which have large collections of ready to use PHP class libraries. 9.2 Other PHP Utilities Other PHP utilities are at : • User Login sample: http://www.devshed.com/Server_Side/PHP/Commerce1 • phpPDFtable is a class written in php to ease the creation of tables in PDF files. It requires php (4.0 but should run with 3.x too), and pdflib http://sourceforge.net/projects/phppdftable • Data-Admin aims to provide a PHP based interface to Database Administration. This will not be limited to just one or two databases. Also, the underlying class library encapsulates the native PHP database calls allowing the programmer to use one set of fu http://sourceforge.net/projects/dadmin • PSlib is a PHP library for generating PostScript files. It offers an easy way of generating PostScript files: simple call PSlib functions from within your PHP script and the PS files are created on the fly http://sourceforge.net/projects/pslib • A complete collection of php scripts that work tightly together to create a highly customizable, dynamic and module oriented website http://sourceforge.net/projects/twebs • phpOpenTracker is a comprehensive solution for your site- and visitor-tracking needs. The collected data is stored in a SQL database, allowing complex, yet easy analysis. A powerful API for analysis and report generation (HTML or PDF output) is included. http://www.phpopentracker.de • PHPShopCart is a shopping-cart web application demo written in PHP and designed to connect to a MySQL database. It was written for the book, "A Guide to Databases under Linux" (Syngress Media) but is available under the GNU Public License. http://sourceforge.net/projects/phpshopcart 10.PHPGem package PHPGem is a PHP-script which accelerates the creation of PHP-scripts for working with tables. It works with different SQL-servers such as PostgreSQL, MySQL, mSQL, ODBC, and Adabas. You input a description of and parameters for your tables' fields (field name, on/off searching in the field, etc.), and PHPGem outputs another PHP-script which will work with the tables (view/add/edit/delete/duplicate entries and search). PHPGem works with multi-level nested tables. PHPGem allows you to specify a level of access for each table and for each field for each user. PHPGem also support images. PHPGem is at http://sptl.org/phpgem 11.PHP Application Servers The PHP applications are categorized into more than 60 groups in hotscripts.com site at HotScripts - PHP. You MUST visit this site before looking elsewhere. 11.1 Build PHP based corporate Intranet and Internet Visit the site corporate Intranet/Internet for a very good comparison and listing of applications. 11.2 Popular PHP Applications The most popular PHP applications in the order are: 1. PHP-Nuke and the mainsite 2. Smarty and the mainsite 3. eZ Publish and the mainsite 4. Mambo Portal/Content Mgmt and the mainsite 5. PHP Content Management System and the mainsite 6. PHP Shop and the mainsite 7. phpWebSite and the mainsite 8. myPHPCalendar and the mainsite 9. TreeMenu and the mainsite 10. Backend and the mainsite 11. Typo3 Content Mgmt and the mainsite 12. E-Guest 13. PHProjekt and the mainsite 14. Phorum and the mainsite PHP has several tools which are given below: 11.3 PHP Web Application Servers The following are available for PHP: • LogiCreate WebApp Server (for PHP) The LogiCreate system was designed primarily with open source technologies of Linux, Apache and PHP, LogiCreate provides a unique value in price/performance and costs are kept reasonable. Visit http://www.logicreate.com and click on Download button and read the white papers there. • PHP Lens http://phplens.com is a rapid application development component which allows PHP developers to dynamically and quickly create web applications that retrieve information from databases. With phpLens, data can be presented as html tables with facilities to create, edit, paginate, search and delete records. PHPLens uses ADODB. See also ADODB. • ADODB (Active Data Objects Data Base) http://php.weblogs.com/ADODB : PHP's database access functions are not standardised. Every database extension uses a different and incompatibile API. This creates a need for a database class library to hide the differences between the different databases (encapsulate the differences) so we can easily switch databases. ADODB currently support MySQL, PostgreSQL , Interbase, Oracle, MS SQL 7, Foxpro, Access, ADO, Sybase and generic ODBC. See also ADODB-manual. • Metabase (Database independent access and management) http://phpclasses.upperdesign.com/browse.html/package/20 • Binary Cloud http://www.binarycloud.com is an opensource, enterprise class web application platform It provides a complete set of core services such as authentication, permissions, database abstraction, and error handling - and a rich set of advanced tools built on that foundation. The system is deployed in a number of commercial installations and has proven to be robust, scaleable, and secure. Binarycloud is suitable for large-scale commerce and publishing projects, or anything of similar complexity. It offers some unique security features - such as selective encryption of database I/O - which make it a particularly good choice for web applications that require a high level of data security. And it's free. • PEAR (PHP Extension and Application Repository) is a code repository for PHP extensions and PHP library code similar to PERL's CPAN and is at http://lxr.php.net/source/php4/pear and pear-tutorials. • Midgard is Content management system is based on Apache and uses the PHP scripting language The main site of Midgard is at http://www.midgard-project.org PHP can be compiled with Zend compiler and optimizer http://www.zend.com. PHP runs very fast and is about 5 to 10 times faster than Java. See Midgard Installation • Ariadne http://www.muze.nl/software/ariadne is a web application system. It consists of a complete framework for the easy development and management of web applications, using PHP. The system uses a modular approach, using abstract interfaces for all transactions. This results in maximum freedom to change parts of the systems workings or add new functionality without needing to reprogram other parts • Group IT Engine http://groupit.org is a turnkey group collaboration and content management engine. It presently runs on UNIX machines using PHP and Apache. Using GroupIT you can "Categorize your content", "Organize your contents into sections", "Control access to your content" and many more additional features. • Ampoliros http://www.ampoliros.com Ampoliros is an advanced and easy to use distributed PHP Web applications platform, featuring a powerful Xml-Rpc and Soap interface. It is suitable as an Internet/Intranet development and deployment system. It has a very strong modular architecture and allows very fast deployment of web solutions. Ampoliros is backed by Solarix, which offers customization, complete Ampoliros based solutions, support, developer programs and other services. 11.4 PHP Template Engines 11.5 PHP based Web-Portal systems The following ready-made Web-Portal systems are available: • PHP Nuke Web Portal system at PhpNuke • DarkPortal is a Web portal system similar to PHPNuke. It is based on the user interface style of Slashdot and other news/portal systems. It uses a modular core as a base for adding pluggable modules to facilitate content creation and management. Its primary goals are full separation of content from code, fully modular portal plugins with standardized APIs, portability and database abstraction, user level theme selection and plugin module selection, and a modular user/group hierarchy with multiple levels of moderation and admin capabilities. Visit DarkPortal • CMS system ezPublish • Mambo is a feature-rich, dynamic portal engine/content management tool based on PHP/MySQL. It features a very powerful and extensive admin manager, and uses a modular framework for extensibility. Visit Mambo and mirror • Content Management system (CMS) PostNuke at http://postnuke.com 12.Object Oriented Features - public, private, protected PHP scripting language provides object oriented features through the class keyword. Features like public, private and protected will be supported in the future release (they are in TODO list). In the meantime, you can use the following coding conventions to distinguish between private, public and protected variables: 1. All private variables and functions always start with underscore "_" followed by lowercase letters like var$_myvar;

2. All Protected variables and functions always start with "_T" followed by lowercase letters like var $_Tmyvar; 3. All Public variables and functions do not start with underscore "_" like var$myvar;

4. All variables and functions always start with lowercase letter (no uppercase) like var $_myvar; and NOT like var$_Myvar;

class someabc {
var $_conn; // Private variable var$_Tmyvar;                   // Protected variable
var $connMYCONNECTION; // Public variable var$connToDb;                  // Public variable
var $myvar3; // Public variable var$myvarTHISTEST;             // Public variable

function _foofunction() {}      // Private function
function _Tfoofunction() {}     // Protected function
function foofunction() {}       // Public function
}


The private, protected declarations provide the encapsulation and data-hiding. But you must consider the following disadvantages of encapsulation:

• Encapsulation usually requires more code, hence it sacrifices performance especially for scripting languages like PHP

• Encapsulation requires lots of Set/Get methods for private/protected properties.

• Since encapsulation unneccessarily increases the code size, it is not recommended for scripting language like PHP.

• You can enforce a good degree of encapsulation by using the coding convention suggested in this section.

13.HTML Editor

HTML editors for PHP on Windows 95/NT/2000 are:

The best HTML editor is 1st Page 2000, and it is a excellent HTML editor.

14.IDE tools for PHP

Many HTML editors are supporting PHP. In near future every HTML editors and XML editor will be supporting PHP "Rapid Application Development" tool.

You will notice that some of the PHP editors run only on MS Windows. Yes!! there are millions of PHP developers on MS Windows platform. PHP is IMMENSELY POPULAR on Microsoft Windows platform and is surprisingly more popular than Microsoft's own ASP web scripting language!! PHP runs lot faster than ASP on MS Windows and has more features and functionalities than Microsoft ASP. PHP is much more robust, reliable and powerful than ASP. There are more PHP users under MS Windows98/NT/2000 than on any other operating system!! PHP initially started on Linux/UNIX environment but today there are more PHP developers on MS Windows platform as compared to UNIX.

14.1 PHP IDE

PHP IDE tools are at :

14.2 PHP IDE for MS Windows only

PHP IDE/editor on MS Windows platform are :

14.3 PHP IDE for both MS Windows and Linux

PHP IDE/editor for bot MS Windows and Linux platforms are :

14.4 PHP IDE for Linux only

The best IDE for PHP on linux is Coffeecup Editor as given below:

Zend is a server-side caching software speeds up Web site performance, maximizes hardware resources, and improves the online experience of customers, providing a good return on investment. Zend accelerator caches PHP scripts, helping to reduce processing time and Web server load while enabling administrators to monitor site performance in real time. Cost is $980 and supports Linux, Solaris and FreeBSD. Zends provides: • Enables IT to serve more Web site visitors with existing hardware • Speeds up Web site response time • Provides real-time performance monitoring 15.Code Protection - Encoding Source Code If you want to distribute your PHP source code to your clients, you may want to encode it to protect your code so that it cannot be viewed by the users. Use encoding to hide password, encode scripts etc. Many enterprises require securing the source code as a pre-condition for release process. Use one of the following Encoding tools: 16.Convert Microsoft ASP scripts to PHP - ASP2PHP To convert ASP scripts to PHP use this utility http://asp2php.naken.cc See also http://www.asp2php.com 17.ctags for PHP Tags are extremely valuable and are used for navigation of source code inside the editors like vi, emacs, CRiSP, NEdit etc... If you had programmed a lot in C, C++ or Java you might have used the ctags program to create tags. To see the online manual page, type 'man ctags' at linux/UNIX bash prompt. The latest version of ctags supports PHP language and is available from http://ctags.sourceforge.net. NOTE: Do NOT use the ptags given below but instead use the latest ctags which supports PHP language. The program below is just a exercise and sample and was created when older versions of ctags did not support PHP. The listing below is kept for historical reasons (a musuem). The ptags program for PHP is given below, which you can use to create the tags for PHP source code. Your productivity will improve 3 to 4 times if you use ptags. See also Vim color text editor for PHP, C, C++ at http://metalab.unc.edu/LDP/HOWTO/Vim-HOWTO.html // Save this file as ptags.cpp and compile by // g++ -o ptags ptags.cpp //***************************************************************** // Copyright policy is GNU/GPL but additional request is // that you include author's name and email on all copies // Author : Al Dev Email: alavoor[AT]yahoo.com // Usage : ptags *.php3 *.inc // This will generate a file called tags //***************************************************************** #include <iostream.h> #include <fstream> #include <stdio.h> // for sprintf #include <stdlib.h> // for system #include <string.h> // for memset #include <ctype.h> // for isspace #define BUFF_LEN 1024 #define LOCATION 9 char *ltrim(char *dd); char *rtrim(char *ee); main(int argc, char **argv) { if (argc < 2) { cerr << "\nUsage: " << argv[0] << " file .... " << endl; exit(0); } char fname[100] = "tag_file.out"; FILE *fpout; ofstream fout(fname); if (fout.fail()) { cerr << "\nError opening file : " << fname << endl; exit(-1); } //fpout = fopen(fname, "w"); for (int ii = 1; ii < argc; ii++) { /* char buff[2024]; sprintf(buff, "\\rm -f %s; ls %s > %s 2>/dev/null", outfile, argv[1], outfile); cout << "\nbuff = " << buff << endl; system(buff); fclose(fp); */ FILE *fpin = NULL; fpin = fopen(argv[ii], "r"); if (fpin == NULL) { cerr << "\nError opening file : " << argv[ii] << endl; exit(-1); } char buff[BUFF_LEN + 100]; memset(buff, 0, BUFF_LEN +10); for ( ; fgets(buff, BUFF_LEN, fpin) != NULL; ) { char aa[BUFF_LEN + 100]; char aapointer[BUFF_LEN + 100]; memset(aa, 0, BUFF_LEN +10); strcpy(aa, buff); strcpy(aapointer, ltrim(aa)); strcpy(aa, aapointer); // Remove the trailing new line.. { int tmpii = strlen(aa); if (aa[tmpii-1] == '\n') aa[tmpii-1] = 0; } //cout << "aa is : " << aa << endl; //cout << "aapointer is : " << aapointer << endl; if (strncmp(aa, "function ", LOCATION) != 0) continue; //cout << buff << endl; // Example tags file output is like - // al2 al.c /^al2()$/;"     f
{
char bb[BUFF_LEN + 100];
memset(bb, 0, BUFF_LEN +10);
strcpy(bb, & aa[LOCATION]);
char *cc = bb;
while (cc != NULL && *cc != '(')
*cc++;
*cc = 0;
cc = rtrim(bb);
//cout << "bb is : " << bb << endl;
//cout << cc << "\t" << argv[ii] << "\t" << "/^" << aa << "$/;\"\tf" << endl; fout << cc << "\t" << argv[ii] << "\t" << "/^" << aa << "$/;\"\tf" << endl;
//fprintf(fpout, "%s\t%s\t/^%s$/;\"f\n", cc, argv[ii], aa ); } memset(buff, 0, BUFF_LEN +10); } fclose(fpin); } fout.flush(); fout.close(); //fclose(fpout); // Sort and generate the tag file { char tmpaa[1024]; sprintf(tmpaa, "sort %s > tags; \\rm -f %s", fname, fname); system(tmpaa); } } char *ltrim(char *dd) { if (dd == NULL) return NULL; while (isspace(*dd)) dd++; return dd; } char *rtrim(char *ee) { if (ee == NULL) return NULL; int tmpii = strlen(ee) - 1; for (; tmpii >= 0 ; tmpii--) { if (isspace(ee[tmpii]) ) { //cout << "\nis a space!!" << endl; ee[tmpii] = 0; } } return ee; }  18.PHP documenter (like Javadoc) • The phpDocumentor is a script for creating documentation from comments in php code. It is at http://phpdocu.sourceforge.net. • The Doxygen documentation system can be used along with this Doxygen PHP PERL script. Download Doxygen and the PERL script from download page. • PHPXref is a small PERL script to make working with the source code of a large PHP site somewhat easier. Cross references functions, variables and database tables defined and used across your various PHP files Generates documentation for each function defined in the PHP files by utilizing formatted comments placed next to each function The output is a tree of HTML files that can be downloaded and browsed on a local machine without having to setup a web server, etc. It is at http://phpxref.sourceforge.net. 19.Debugging PHP You can use one of the following debuggers. List of PHP debuggers : 19.1 Debug with FILE and LINE To debug PHP programs create a file "debug2.inc" having the following functions : <?php /* define this variable, to prevent double declaration. */ if (!defined("_DEBUG2_DEFINED_")) { define("_DEBUG2_DEFINED_", 1 ); } else return; // if this file is already included then return # file name : debug2.inc # Functions for debuging the PHP source code #***************************************************************** # Copyright policy is GNU/GPL but additional request is # that you include author's name and email on all copies # Author : Al Dev Email: alavoor[AT]yahoo.com #***************************************************************** # Usage of this functions - # In your source code put something like - # debug2_(__FILE__, __LINE__, "f_somevariable",$f_somevariable);
# And this will generate output in debug.out file.

//function debug2_($fname,$lname, $debug_var,$debug_value=0) {}

// Give read, exec for all on directory /debug2_logs
// chmod a+rwx /debug2_logs
// But here you need to open the file in append mode.
$fp_debug2 = fopen("/debug2_logs/debug.out", "a"); if ($fp_debug2 == false)
{
print "<b>File open failed - global.var.inc<b>";
exit;
}

function debug2_($fname,$lname, $debug_var,$debug_value=0)
{
global $fp_debug2; //print "<br> debug_value is :$debug_value <br>";
if (!$debug_value) { fwrite($fp_debug2, "\n ". $fname ." ".$lname .": $debug_var"); } else { fwrite($fp_debug2, "\n ". $fname . " ".$lname .": $debug_var =$debug_value");
}
//print "<br> f_cookie is : $f_cookie <br>"; } // In your first page, which is generally index.php3 // truncate the debug2_logs file in beginning of code function init_debug_file() { global$fp_debug2;

$fp_debug2 = fopen("/debug2_logs/debug.out", "w"); if ($fp_debug2 == false)
{
print "<b>File open failed - global.var.inc<b>";
exit;
}
system("chmod a+rwx /debug2_logs/debug.out");
}

?>


In your PHP source code initial page which is generally index.php3, put a line like

<?php
include ("debug2.inc");

init_debug_file();
// all other commands follows here ...
// ...........
?>


To output debug values, in your PHP source code files, put debug2_() calls as illustrated below:

<?php
include ("debug2.inc");
debug2_(__FILE__, __LINE__, "f_somevariable", $f_somevariable); function aa() {$aa = 8;
debug2_(__FILE__, __LINE__, "aa", $aa); } ?>  When you run the PHP program the output will be traced in the file called debug.out giving the filename, linenumber, variable name and it's value. Use the debug2_() generously in your code. The usage of debug2_() calls in your program will NOT have any impact on the final production code and also has no impact on the performance because they will be filtered out as described below. You can use copy and paste to save time of typing debug2() calls or use the 'yank to buffer' feature of Vi editor and paste. When you are done development and testing and when you are ready to deploy on the production server, filter out the debug2_ calls from your source code. At UNIX prompt - bash$ mkdir production
bash$grep -v debug2_ filea.php3 > production/filea.php3  For a large group of files - bash$ mkdir production
bash$ls *.php3 | while read ans do grep -v debug2_$ans > production/$ans done  And now copy the files from production to the deployment area. 20.General purpose programming with PHP PHP is very powerful and is designed such that it can replace awk, sed, UNIX shell, PERL, Python, "C", C++ and Java. The object oriented features of PHP is developing very rapidly and in near future will surpass the object oriented features of Java language. All the object oriented features are implemented in PHP via class keyword just like in Java. If you build the CGI version of PHP, you can use it from the command line simply typing: php filename where filename is the file you want to parse. You can also create standalone PHP scripts by making the first line of your script look something like:  #!/usr/local/bin/php -q  The "-q" suppresses the printing of the HTTP headers. You can leave off this option if you like. If you want to use PHP as a stand-alone program, just like a shell script, "C" or PERL program, then use this technique: bash$ php -q filename.php
bash$php -h bash$ php -?
bash$/usr/bin/php -? bash$ php -i


The command php filename.php will execute the file filename.php. You are invoking the php program which you wrote in filename.php from the bash commmandline instead of from the web-browser.

On Microsoft Windows platform you will bringup a MSDOS prompt from Start->Run->cmd and put C:\Program Files\php\bin in your path environment and

C:\> php -q filename.php
C:\> php -h
C:\> php -?
or
C:\> c:\Program Files\php\bin\php filename.php


20.1 Standalone MS Windows GUI applications using PHP

Since PHP is general purpose scripting language and is like a "glue" language, you can use it develop standalone MS Windows GUI applications. PHP can be very easily combined with MS Windows C++ GUI classes to create GUI applications. And developing applications with PHP is extremely fast as it is a scripting language and it's runtime performance is also excellent as compared with other scripting languages like PERL, Visual Basic and Python.

PHP can also be used for developing standalone GUI applications for Linux/UNIX'es.

21.Web Application Standards - Fusebox

Fusebox is a FREE web application standard attempting to reduce the 70% software failure rate by creating a standard methodology for writing web applications. This development methodology works with ANY web application small and large.

22.Performance benchmarking - PHP, ASP, JSP, Coldfusion

It is very important to bear in mind that performance and running speed of the web scripting engine must be given TOP PRIORITY. That is, how many pages per second the scripting engine can pump out to the browser clients. The greater the number of pages pumped out to clients in a given period of time, then the better and more powerful the scripting engine is.

The Zdnet did a evaluation and benchmarking of 4 web scripting languages. During benchmarking, the same spec and identical cpu, memory boxes were used. Under identical conditions, it was found that PHP was the fastest - about 3.7 times faster than JSP and about 1.2 times faster than ASP. Read the report at eWeek and mirror-site The benchmark results are -

• PHP pumped out about 47 pages/second
• Microsoft ASP pumped out about 43 pages/second
• Allaire ColdFusion pumped out about 29 pages/second
• Sun Java JSP pumped out about 13 pages/second

See also PHP, ASP benchmarks at http://24.221.230.253/php-perl-benchmarks.html

Whenever you design a web site, give attention to these important points:

• Speed of web scripting engine - how many pages per second it can pump out.

• KISS policy (Keep It Simple Stupid!!) - your web page should be very simple without any fancy graphics (because web users do not want to wait for long time and they want the information very fast). And information they read is just plain text!!

23.Limitations of PHP

Everything has limitations or disadvantages and PHP is no exception. The following are the limitations of PHP (so be WARNED !!)

1. PHP is NOT 100 % pure Object Oriented scripting language. But in near future PHP may support 100% object oriented scripting (PHP may imitate most of the syntax of Java language). PHP already imitates some features of Java language. (In future PHP language will imitate most features of Java language and Java programmers will love PHP. And PHP will have java keywords like class, extends, interface, implements, public, protected, private etc..).
2. PHP will NOT give the performance of "C" or "C++" language. Because it is scripting language and is interpreted it will be a bit slower than the optimized "C++" programs. For top performance, you should use "C++" and fast-CGI with database/webserver connection pooling and use C++ compiler optimizer "-O3" options. Zend optimizer in PHP 4 will speed up the performance of PHP and bring it very close to optimized "C" code .
3. But note a point that PHP was designed for very Rapid Web-Application Development tool. If it takes about 3 months to code a web application in C++, then using PHP you can develop the same web application in just 4 days!! And with zend optimizer, the speed of execution of PHP will be very close to that of equivalent C++ program!! Hence, there is really no advantage in using C/C++ for web development. PHP itself is written in 100% "C" language.

On the other hand, PHP has lot of advantages and it's advantages outweigh it's limitations -

1. You can very rapidly develop web applications in PHP as compile and link is eliminated in PHP scripting language.
2. PHP applications are very stable and do not depend on the browser technologies unlike Javascript applications which depend on browsers. PHP will give you the freedom to select any server platform. The browser does not know that the HTML page is generated by PHP !!
3. PHP has excellent database conectivity to all SQL database servers.
4. PHP has partial support for Object oriented features
5. PHP has C++, PERL, Javascript like syntax features and has programs like 'ptags/ctags' to navigate the source code
6. PHP has Zend optimizer which speeds up the performance
7. PHP runs on all UNIX'es, linux, Windows 95/NT/2000 and is more powerful than ASP, JSP and others.
8. PHP has a very large user base and developer base.

See also Python: If you want 100% pure Object Oriented scripting language than you MUST consider Python. The 'Python' is a object oriented scripting language from ground up. You would be using the Python Web Application server called 'Zope' which is available at - http://www.zope.org and python is at http://www.python.org

24.PHP Tutorial

Visit the following PHP tutorial sites -

In this tutorial we assume that your server has support for PHP activated and that all files ending in .php are handled by PHP. If you are using Apache then you should edit httpd.conf and make appropriate changes to enable PHP.

Your first PHP-enabled page: Create a file named hello.php and in it put the following lines:

<html>
<title>
PHP Test</title>
<body>
<h1>
This is an example of php script.
<br>
Below, you will see one line saying 'Hello World' and 'foo is foobar':
</h1>
<?php
echo "Hello World";
$foo = "foobar"; echo "<br>foo is$foo";
?>
</body>
</html>


Copy this file hello.php to the directory known to Apache, like /var/www/html which is also known as DocumentRoot in httpd.conf file. Now, to run this example, bring up a web browser and type the URL http://localhost/hello.php or you can type http://127.0.0.1/hello.php. But make sure you bring up Apache web server on your system. When you run the example you will get an output like:

This is an example of php script.
Below, you will see one line saying 'Hello World' and 'foo is foobar':

Hello World
foo is foobar


If you get some errors or if you see the file with tags then your Apache Web server may not be working properly or PHP is not enabled.

Note that this is not like a CGI script. Think of it as a normal HTML file which happens to have a set of special tags available to you.

If you tried this example and it didn't output anything, chances are that the server you are on does not have PHP enabled. Ask your administrator to enable it for you.

The point of the example is to show the special PHP tag format. In this example we used < ?php to indicate the start of a PHP tag. Then we put the PHP statement and left PHP mode by adding the closing tag, ? > . You may jump in and out of PHP mode in an HTML file like this all you want.

We are going to check what sort of browser the person viewing the page is using. In order to do that we check the user agent string that the browser sends as part of its request. This information is stored in a variable. Variables always start with a dollar-sign in PHP. The variable we are interested in is $HTTP_USER_AGENT. To display this variable we can simply do:  <?php echo$HTTP_USER_AGENT; ?>


For the browser that you are using right now to view this page, this displays:

Mozilla/4.0 (compatible; MSIE 4.01; Windows 98)

There are many other variables that are automatically set by your web server. You can get a complete list of them by creating a file that looks like this:

      <?php phpinfo()?>


Then load up this file in your browser and you will see a page full of information about PHP along with a list of all the variables available to you.

You can put multiple PHP statements inside a PHP tag and create little blocks of code that do more than just a single echo.

      <?php
if(strstr($HTTP_USER_AGENT,"MSIE")) { echo "You are using Internet Explorer<br>"; } ?>  We can take this a step further and show how you can jump in and out of PHP mode even in the middle of a PHP block:  <?php if(strstr($HTTP_USER_AGENT,"MSIE"))
{
?>
<center><b>You are using Internet Explorer</b></center>
<?
}
else
{
?>
<center><b>You are not using Internet Explorer</b></center>
<?
}
?>


Instead of using a PHP echo statement to output something, we jumped out of PHP mode and just sent straight HTML. The important and powerful point to note here is that the logical flow of the script remain intact. Only one of the HTML blocks will end up getting sent to the viewer. Running this script right now results in:

You are using Internet Explorer

Dealing with Forms

One of the most powerful features of PHP is the way it handles HTML forms. The basic concept that is important to understand is that any form element in a form will automatically result in a variable with the same name as the element being created on the target page. This probably sounds confusing, so here is a simple example. Assume you have a page with a form like this on it:

      <form action="action.php3" method="POST">
Your name: <input type=text name=name>
You age: <input type=text name=age>
<input type=submit>
</form>


There is nothing special about this form. It is a straight HTML form with no special tags of any kind. When the user fills in this form and hits the submit button, the action.php3 page is called. In this file you would have something like this:
      Hi <?php echo $name?>. You are <?php echo$age?> years old.


Surprise!! The $name and$age variables are automatically set for you by PHP !!

24.1 Primer on PHP Sessions

This section is written by Ying Zhang .

Before we begin, let's quickly go over the concept of a session and the reason we need it. It's hard (for me) to define what a session is exactly, so let's use an example that should be very familiar to you -- logging in to your computer and using it every day. After you log in, your computer knows who you are. Every action that you perform is done so with your name.

So what's so special about that -- we take it for granted every time we have to login to any system. What's the big deal with doing this on the web? Well, the web (or specifically, the HTTP protocol) is connectionless. That means each request made to a web server is independent of all the other requests. Whereas your computer keeps information about you in memory and knows when you log in and out, a web server doesn't. A web server simply waits for requests and sends responses.

Let's illustrate this a little bit:

John Doe           __________         Jane Doe
1               |          |            2
3  ------------>|web server|<---------- 4
5               |__________|            6


Let's say we only have two people, John Doe and Jane Doe, accessing MyMarket, and their actions are like this:

1. John looks at the product catalog.
2. Jane looks at the product catalog.
3. John adds an item to his basket.
4. Jane adds an item to her basket.
5. John goes to the checkout.
6. Jane goes to the checkout.

Since HTTP is connectionless, each request is completely isolated from the other requests. So how does the server know who's doing what? How does the server know that actions 1, 3, 5 are from John, and actions 2, 4, 6 are from Jane? Well, to make a long story short, the web server doesn't have to know. It can continue on happily responding to requests, session management has to be done with the backend scripting language.

What we need is a way to group together requests by the same person into the same session. This is where PHP4's session management capabilities come in. It can group together requests made from the same source (eg. client's browser) into the same session, we have to provide the smarts to associate users with sessions.

In other words, PHP4's session management can tell us requests 1, 3, and 5 belong to the same session (call it session A). Our application has to know that session A is owned by John Doe.

24.2 Session Management in PHP4

PHP4 adds some session management functions that make our life easier when dealing with sessions. The ones we are interested in are:

session_start();
session_register();


session_start() is used to start up PHP4's session management capabilities; you need to call it before you use any of the other session functions. session_register() is used to tell PHP which variables to track in the session. A typical call to these functions would look like this:

session_register("SESSION");

This tells PHP to start up the session manager, and tells PHP that the variable called SESSION is a session variable. You can register as many session variables as you like, but I prefer to only register one session variable called SESSION, and anything I need persistent I put into this variable. For example, I like to say:

session_register("SESSION");
$SESSION["var1"] = 5;$SESSION["var2"] = 6;


session_register("var1");
session_register("var2");
$var1 = 5;$var2 = 6;


because after you register lots of session variables, you tend to forget what they were, well, at least I do :).

Anyhow, by now you probably want to see some code in action, so create a script called session_test.php somewhere accessible, and put into it:

<?
session_start();
session_register("SESSION");

if (! isset($SESSION)) {$SESSION["count"] = 0;
} else {
echo "<li>Waking up session $PHPSESSID";$SESSION["count"]++;
}
?>

Hello visitor, you have seen this page <?php echo $count; ?> times.<p>; <php # the <?=SID?> is necessary to preserve the session id # in the case that the user has disabled cookies ?> To continue, <A HREF="nextpage.php?<?=SID?>">click here</A> <html>  The <?=SID?> is not necessary, if --enable-trans-sid was used to compile PHP. Note: Non-relative URLs are assumed to point to external sites and hence don't append the SID, as it would be a security risk to leak the SID to a different server. 24.4 User Management and Privileges Okay, we've spend enough time on PHP4's session management, all you really need to get out of that was the two functions session_start() and session_register(). Let's get back to the issue of keeping track of users. PHP can help us keep track of sessions, and group requests from the same session together. Now, we have to do our part and associate user accounts with these sessions. We will use a variable called SESSION["user"] to keep track of user information. When a user logs in, we will put their information into this variable. As long as this variable is defined, we will assume that a user has logged in. When a user logs off, we will clear out this variable. Specifically, we will keep the following information about the user: SESSION["user"]["username"] This is the user's login ID (their nick name if you will), and it is how we tell users apart from each other. SESSION["user"]["firstname"] The user's firstname. SESSION["user"]["lastname"] The user's lastname. SESSION["user"]["email"] The user's email address. SESSION["user"]["priv"] The user's privilege level.  Let's talk a bit about the privilege levels. We are going to have two levels of security: (1) normal customers and (2) administrative users. Normal customers can use the system, browse through the catalog, and do other customer functions. Administrators can do everything a normal user can do, but also has the ability to perform system administrative functions. In real life, there are probably many more privilege levels that you want defined but we are going to keep things simple here. This is all fine and dandy, but where do we get this user information from? We need to have a way to store all the users on the system, and the perfect place for that would be in the database. We're going to create a users table to hold all our users. 24.5 Step1: Creating the Users Table Start up database server and login to database. Let's create the user table: psql> CREATE TABLE users ( -> username char(16) not null, -> password char(32) not null, -> priv char(5) not null, -> firstname varchar(64) not null, -> lastname varchar(64) not null, -> email varchar(128) not null, -> phone varchar(32) not null, -> address varchar(255) not null, -> PRIMARY KEY (username), -> UNIQUE email (email) -> );  Notice the constraints we've put on the users table, the username is the primary key (which makes sense, you should be able to identify a user record based on the username). The email address has a unique constraint as well because we don't want duplicate email addresses. Now let's add a record to create the root user with the password password: psql> INSERT INTO users VALUES ( -> 'root', -> '5f4dcc3b5aa765d61d8327deb882cf99', -> 'admin', -> 'System', -> 'Administrator', -> 'root@mymarket.com', -> '555-5555', -> '123 5 Avenue' -> );  Notice the password looks a bit wierd, 5f4dcc3b5aa765d61d8327deb882cf99. This is the MD5 hash of the the word "password", I won't go into details here, but the important thing to note is that it's a one-way algorithm and it always produces a 32 character string. That's it, we have a users table to track our users, and one administrative account so we can try logging in and out of the system using the example tar file (download the example tar file from http://www.devshed.com/Server_Side/PHP/Commerce1 ). 25.PHP Training & PHP Help Desk To obtain hands on training and to attend PHP courses: 26.Related URLs Visit following locators which are related to C, C++ - 27.Other Formats of this Document This document is published in 14 different formats namely - DVI, Postscript, Latex, Adobe Acrobat PDF, LyX, GNU-info, HTML, RTF(Rich Text Format), Plain-text, UNIX man pages, single HTML file, SGML (Linuxdoc format), SGML (Docbook format), MS WinHelp format. This howto document is located at - • http://www.linuxdoc.org and click on HOWTOs and search for howto document name using CTRL+f or ALT+f within the web-browser. You can also find this document at the following mirrors sites - The document is written using a tool called "SGML-Tools" which can be got from - http://www.sgmltools.org Compiling the source you will get the following commands like • sgml2html xxxxhowto.sgml (to generate html file) • sgml2html -split 0 xxxxhowto.sgml (to generate a single page html file) • sgml2rtf xxxxhowto.sgml (to generate RTF file) • sgml2latex xxxxhowto.sgml (to generate latex file) 27.1 Acrobat PDF format PDF file can be generated from postscript file using either acrobat distill or Ghostscript. And postscript file is generated from DVI which in turn is generated from LaTex file. You can download distill software from http://www.adobe.com. Given below is a sample session: bash$ man sgml2latex
bash$sgml2latex filename.sgml bash$ man dvips
bash$dvips -o filename.ps filename.dvi bash$ distill filename.ps
bash$man ghostscript bash$ man ps2pdf
bash$ps2pdf input.ps output.pdf bash$ acroread output.pdf &


Or you can use Ghostscript command ps2pdf. ps2pdf is a work-alike for nearly all the functionality of Adobe's Acrobat Distiller product: it converts PostScript files to Portable Document Format (PDF) files. ps2pdf is implemented as a very small command script (batch file) that invokes Ghostscript, selecting a special "output device" called pdfwrite. In order to use ps2pdf, the pdfwrite device must be included in the makefile when Ghostscript was compiled; see the documentation on building Ghostscript for details.

27.2 Convert Linuxdoc to Docbook format

This document is written in linuxdoc SGML format. The Docbook SGML format supercedes the linuxdoc format and has lot more features than linuxdoc. The linuxdoc is very simple and is easy to use. To convert linuxdoc SGML file to Docbook SGML use the program ld2db.sh and some PERL scripts. The ld2db output is not 100% clean and you need to use the clean_ld2db.pl PERL script. You may need to manually correct few lines in the document.

The ld2db.sh is not 100% clean, you will get lots of errors when you run
        bash$ld2db.sh file-linuxdoc.sgml db.sgml bash$ cleanup.pl db.sgml > db_clean.sgml
bash$gvim db_clean.sgml bash$ docbook2html db.sgml


And you may have to manually edit some of the minor errors after running the PERL script. For e.g. you may need to put closing tag < /Para> for each < Listitem>

27.3 Convert to MS WinHelp format

You can convert the SGML howto document to Microsoft Windows Help file, first convert the sgml to html using:

        bash$sgml2html xxxxhowto.sgml (to generate html file) bash$ sgml2html -split 0   xxxxhowto.sgml (to generate a single page html file)


Then use the tool HtmlToHlp. You can also use sgml2rtf and then use the RTF files for generating winhelp files.

27.4 Reading various formats

In order to view the document in dvi format, use the xdvi program. The xdvi program is located in tetex-xdvi*.rpm package in Redhat Linux which can be located through ControlPanel | Applications | Publishing | TeX menu buttons. To read dvi document give the command -

 xdvi -geometry 80x90 howto.dvi man xdvi 
And resize the window with mouse. To navigate use Arrow keys, Page Up, Page Down keys, also you can use 'f', 'd', 'u', 'c', 'l', 'r', 'p', 'n' letter keys to move up, down, center, next page, previous page etc. To turn off expert menu press 'x'.

You can read postscript file using the program 'gv' (ghostview) or 'ghostscript'. The ghostscript program is in ghostscript*.rpm package and gv program is in gv*.rpm package in Redhat Linux which can be located through ControlPanel | Applications | Graphics menu buttons. The gv program is much more user friendly than ghostscript. Also ghostscript and gv are available on other platforms like OS/2, Windows 95 and NT, you view this document even on those platforms.

To read postscript document give the command -

 gv howto.ps ghostscript howto.ps 

You can read HTML format document using Netscape Navigator, Microsoft Internet explorer, Redhat Baron Web browser or any of the 10 other web browsers.

You can read the latex, LyX output using LyX a X-Windows front end to latex.

Copyright policy is GNU/GPL as per LDP (Linux Documentation project). LDP is a GNU/GPL project. Additional requests are - Please retain the author's name, email address and this copyright notice on all the copies. If you make any changes or additions to this document then you please intimate all the authors of this document.

29.1 PostgreSQL large object Example

Submitted by: PHP code exchange px@sklar.com To get this file, in the web-browser, save this file as 'Text' type as pgsql_largeobj.lib


PX: PHP Code Exchange -
<url name="PostgreSQL" url="http://www.geocities.com/alavoor/HOWTO/pgsql/PostgreSQL-HOWTO.html">
large object access

<?
$database = pg_Connect ( "", "", "", "", "jacarta"); pg_exec ($database,  "BEGIN");
$oid = pg_locreate ($database);
echo ( "$oid\n");$handle = pg_loopen ($database,$oid,  "w");
echo ( "$handle\n"); pg_lowrite ($handle,  "foo");
pg_loclose ($handle); pg_exec ($database,  "COMMIT");
pg_close ($database); ?>  29.2 User authentication Example To get this file, in the web-browser, save this file as 'Text' type as user_pw.lib From the PHP 3 Manual: Works only if PHP is an Apache module. Instead of simply printing out the$PHP_AUTH_USER and $PHP_AUTH_PW, you would probably want to check the username and password for validity. Perhaps by sending a query to a database, or by looking up the user in a dbm file. <?php if (!$PHP_AUTH_USER)
{
Header("WWW-authenticate: basic realm=\"My Realm\"");
echo "Text to send if user hits Cancel button\n";
exit;
}
else
{
echo "Hello $PHP_AUTH_USER.<P>"; echo "You entered$PHP_AUTH_PW as your password.<P>";
}
?>


29.3 Network admin Example

To get this file, in the web-browser, save this file as 'Text' type as network.lib

PHP: network adminstrator's best friend from http://www.phpWizard.net

As a web-developer, you're probably used to such lovely tools as ping, whois, nslookup etc. But what when you need one of those utilities at a client's office and have no access to telnet? Good guess. Time to look up the functions in the "Network" section of the PHP manual.

Socket operations:

The most important function there is fsockopen(). Using this function, you can connect to any open port on a server and establish a socket connection with it. The function's syntax is as following:

        int fsockopen(string hostname, int port, int [errno], string [errstr]);


The first two arguments are obvious, the next two are optional and used for error handling. The "errno" and "errstr" should be passed by reference. "Passing by reference" means that the original variable will get modified. Normally, the content of a variable passed to a function wouldn't be modified.

So, you could use this function to open a connection to a webserver and print out the headers:

function get_headers($host,$path = "/")
{
$fp = fsockopen ("$host", 80, &$errnr, &$errstr) or die("$errno:$errstr");
fputs($fp,"GET$path HTTP/1.0\n\n");
while (!$end) {$line = fgets($fp, 2048); if (trim($line) == "")
$end = true; else echo$line;
}
fclose($fp); }  In this example you see that you can apply any file operations (fread, fwrite etc) to the the pointer you got using the fsockopen() call. Note that the example realizes a HTTP/1.0 client - it won't work with name-based virtual hosts. Finger: Naturally, you can also open connections to other ports. Writing a small finger client with PHP is trivial therefore. Let's change the example from above to query a finger daemon: function finger ($host, $user) {$fp = fsockopen($host, 79, &$errno, &$errstr) or die("$errno: $errstr"); fputs($fp, "$user\n"); while (!feof($fp))
echo fgets($fp, 128); fclose($fp);
}


Whois: Querying a whois server uses the same concept:

// domain is like "phpwizard.net"
function whois($domain,$server="whois.internic.net")
{
$fp = fsockopen ($server, 43, &$errnr, &$errstr) or die("$errno:$errstr");
fputs($fp, "$domain\n");
while (!feof($fp)) echo fgets($fp, 2048);
fclose($fp); }  Blocking and non-blocking operations: But there's a problem with all those functions. They work fine if 1. You have a connection with low latency and 2. If the server you're connecting to is up and running. If not, your script will be busy until it times out. The reason for this is that default socket connections are blocking and don't time out. You can avoid these "hanging scripts" by switching to non-blocking socket operations. The function set_socket_blocking() does just that: it set all operations on a socket (first parameter: socket pointer) to either blocking (second parameter: true) or false (second parameter: false). Using non-blocking operations, the finger function would like like this: $fp = fsockopen($host, 79, &$errno, &$errstr) or die("$errno: [ ] $errstr"); set_socket_blocking($fp, 0);
fputs($fp, "$user\n");

$stop = time() +$timeout;
while (!feof($fp) && time() <$stop )
echo fgets($fp, 128); fclose($fp);


Modifying these 3 functions to use non-blocking socket calls is left as an exercise for you.

30.Appendix B Midgard Installation

RPMs for Midgard from http://www.midgard-project.org/download/binaries currently do not include PostgreSQL , and hence you need to install from the source tar ball file .

Download the Midgard source tarball and read the INSTALL.REDHAT file -

bash# cd midgard-lib-1.4beta6
bash# ./configure --prefix=/usr/local --with-mysql=/usr/local --includedir=/usr/include/mysql --with-midgard=/usr/local --with-pgsql=/var/lib/pgsql --includedir=/usr/include/pgsql
bash# make
bash# make install
bash# ldconfig -v | grep -i midga
Copy the header files, just in case make install did not do that..
bash# cp *.h /usr/local/include

bash# cd ../mod_midgard-1.4beta5c
bash# ./configure --prefix=/usr/local --with-mysql=/usr/local --includedir=/usr/include/mysql --with-midgard=/usr --with-pgsql=/var/lib/pgsql --includedir=/usr/include/pgsql
bash# make
bash# make install
#modify apache line to correct /usr/.....
bash# vi /etc/httpd/conf/httpd.conf   (or it is /etc/apache/httpd.conf)
bash# /etc/init.d/apache restart
#apache should restart!!!

bash# cd ../midgard-php-1.4beta6
bash# ./configure '--with-apxs' '--with-mysql' '--with-pgsql' '--with-midgard' --prefix=/usr/local --with-midgard=/usr/local

bash# gvim Makefile
And add -I/usr/include/pgsql to INCLUDE variable.

Also add $(INCLUDE) to$(APXS) command as below -
libphp3.so: mod_php3.c libmodphp3-so.a  pcrelib/libpcre.a midgard/libphpmidgard.a
-@test -f ./mod_php3.c || test -L ./mod_php3.c || $(LN_S)$(srcdir)/mod_php3.c ./mod_php3.c
-@test -f ./mod_php3.c || test -h ./mod_php3.c || $(LN_S)$(srcdir)/mod_php3.c ./mod_php3.c
$(APXS) -c -o libphp3.so -I$(srcdir) $(INCLUDE) -I. -I/usr/local/include -I/usr/lib/glib/include -Wl,'-rpath /usr/local/lib' ./mod_php3.c libmodphp3-so.a$(APXS_LDFLAGS)

bash# make
bash# make install
#modify apache line to correct /usr/.....
# and add lines like these -

<IfModule mod_php4.c>
</IfModule>

bash# vi /etc/httpd/conf/httpd.conf   (or it is /etc/apache/httpd.conf)

bash# /etc/init.d/apache restart
#apache should restart!!!


30.1 Testing Midgard PHP Server

To test the installation do this - Create a file in your document root directory. I usually call it info.php and in it put this single line:

<?phpinfo()?>


Then load it up in your browser: http://localhost/info.php

You should see a nice summary page showing all sorts of information about your setup. You probably shouldn't leave this file around on a production server, but for debugging and general info during development, it is very handy.

30.2 Security OpenSSL

You may also need to get the RSA package for to enable SSL encryption from ftp://ftp.deva.net/pub/sources/crypto/rsaref20.1996.tar.Z See also OpenSSL RPM package on Linux cdrom ( http://www.openssl.org

If you do not want the SSL to be enabled (or if you face any problem), then download the source RPM of Apache-Midgard and edit the *.spec file and comment out SSL and rebuild the RPM.

31.Appendix C - Debug tool phpcodesite

<
?php
/*  phpCodeSite (Idea from CodeSite - Raize Software)
*  @version 0.1b - 20001125
*  @author Sébastien Hordeaux - <
marms@marms.com>
*  @licence GNU Public Licence
*  Main site : http://phpcodesite.phpedit.com
*/

/*
** How does it work ?
Place a CS_EnterMethod() at the beginning of each method/function
Place a CS_ExitMethod() at the beginning of each method/function
Use CS_SendError() to log an error message
Use CS_SendNote() to log a simple note message
Use CS_SendMessage() to log a message
To log variables: CS_SendVar & CS_SendArray()
To see input data (global PHP variables) use CS_SendInputData()
*/

if(defined("FLAG_PHPCODESITE_PHP")) return FALSE;
define("FLAG_PHPCODESITE_PHP", 1);

$CS_Step = 0; CS_SetEnabled(TRUE); // CS_SetEnabled(FALSE); // Switch between Enable/Disable mode function CS_SetEnabled($state){
global $CS_Enabled;$CS_Enabled = $state; CS_Write($CS_Enabled?"<
pre>":"<
/pre>");
}

//  Add a level to the reported items
function CS_IncStep(){
global $CS_Step;$CS_Step++;
}

// Remove a level to the reported items
function CS_DecStep(){
global $CS_Step;$CS_Step--;
if($CS_Step < 0)$CS_Step = 0;
}

// Log an item
function CS_Log($msg){ global$CS_Step;
for($i = 0;$i <
$CS_Step;$i++)
CS_WriteIndent();
CS_Write($msg); } // Write data to the target output function CS_Write($str){
global $CS_Enabled; if($CS_Enabled)
echo "$str"; } // Write an indent block function CS_WriteIndent(){ CS_Write("| "); } // Beginning a new method function CS_EnterMethod($methodName){
CS_Log("--> $methodName\n"); CS_IncStep(); } // Exit a method function CS_ExitMethod($methodName){
CS_DecStep();
CS_Log("<
-- $methodName\n"); } // Log a note function CS_SendNote($note){
CS_Log("[O] $note\n"); } // Send a simple message function CS_SendMessage($msg){
CS_Log("[M] $msg\n"); } // Log an error function CS_SendError($msg){
CS_Log("<
b>[E] $msg< /b>\n"); } // Log a variable function CS_SendVar($varName, $value){ if(is_array($value)){
CS_SendArray($value,$varName);
}else{
CS_Log("[L] $varName = \"$value\"\n");
}
}

// Write all global variables to the report
function CS_SendInputData(){
global $HTTP_GET_VARS,$HTTP_POST_VARS, $HTTP_COOKIE_VARS,$HTTP_SERVER_VARS, $HTTP_ENV_VARS,$HTTP_SESSION_VARS;
CS_Write("----------------------------------------------------------\n");
CS_SendArray($HTTP_GET_VARS, "HTTP_GET_VARS"); CS_SendArray($HTTP_POST_VARS, "HTTP_POST_VARS");
CS_SendArray($HTTP_COOKIE_VARS, "HTTP_COOKIE_VARS"); CS_SendArray($HTTP_SERVER_VARS, "HTTP_SERVER_VARS");
CS_SendArray($HTTP_ENV_VARS, "HTTP_ENV_VARS"); CS_SendArray($HTTP_SESSION_VARS, "HTTP_SESSION_VARS");
CS_Write("----------------------------------------------------------\n");
}

// Log an array
function CS_SendArray($array,$arrayStr = ""){
if(!empty($arrayStr)) CS_Log("\$$arrayStr"); if(count($array) == 0){
CS_Log(" = Array()\n");
}else{
CS_Write(" = Array(\n");
while(list($key2,$value2) = each($array)){ CS_WriteIndent(); if(empty($arrayStr))
CS_WriteIndent();
CS_Log("$key2"); if(!is_array($value2))
CS_Write(" => ".htmlentities($value2)."\n"); else CS_SendArray($value2);
}
CS_WriteIndent();
if(empty(\$arrayStr))
CS_WriteIndent();
CS_Log(")\n");
}
}
?>


32.Appendix D - PERL versus PHP debate

PERL (Practical Extraction and Reporting Language) is kind of ancestor of PHP. PERL is immensely powerful and is in use for a very long time, just like "C" language. PERL can do everything that "C" language does. You are better off programming in PERL than in "C" language!! Most of the "C" programmers prefer to program in PERL if speed is not that important (C programs is little faster than PERL).

PERL5 is fully OOP operational. Just because PERL can also do everything without OOP techniques does not mean it's not OOP.

Comparing PERL to PHP, in terms of readability and scalability, they are nearly equal although PHP has a slight advantage for those who insist on using only client side code. PERL is certainly easier to read than C due to it being a very high level language. As you know, the biggest obstacle to multiple developer maintenance is compilers from which PERL does not suffer.

PHP and PERL are equal in these ways:

1. High level code. English-like syntax is easy to read and logical
2. Execution speed. As raw interpreted source code, both are very fast (compared to VB and the like.)
3. Ease and speed of development. As scripts, both can be developed quickly bypassing the nasty compiler and with built-in intelligent debuggers.
4. Run anywhere. A dream these share which all other languages fail.
5. Superior text processing to all other languages.
6. Open source.
7. Both are very well supported by whole Internet community
8. Both are free.

Where PHP has an advantage over PERL:

1. Client-side code (for those who insist on such things.)
2. Easier to compile into EXE.

Where PERL might have an advantage over PHP.

1. PERL is already installed on every web server in the world automatically during setup.
2. PERL is more backward and forward compatible.
3. PERL in all it's versions is VERY stable.
4. PERL hooks into all existing dbase engines very easily. The necessary modules come with every PERL distribution. All that is required is up-to-date drivers which are easy to obtain. PERL and MySQL are made for each other.