PHP.NET Developer's Guide

Introduction：

With the advent of PHP.NET we see a shift from traditional scripting to thebeginning of full-fledged programming online. VBScript isn’t the only optionanymore, as programmers can now employ the full power that lies behind bothVisual Basic (VB) and C within their PHP.NET assemblies.

There is no denying the widespread acceptance that .NET received from thedeveloper community. It’s proven itself to be a well-developed framework withsolid ideas on how the programming world should continue to change.Theintroduction of a software solution that enables anyone to code in any languagethat is compatible with the framework is groundbreaking to say the least.

In this chapter we will take a look at how Active Server Pages (PHP) itselfbegan just a couple of years ago and how it has captivated programmers eversince. It has had some problems, of course, but the .NET architecture seems tohave found solutions to many preexisting programming problems.There have alsobeen changes with how PHP works with the server and client, to provide the userwith the information that you want to provide.

Even though this is a stable beta, and many people are assuming already thatwhat we are seeing within Beta 2 is basically the “freeze” for many features, it stillhas a couple of caveats, due to its beta nature. Learning from these problemswithin the framework can allow for preparation against it.

Learning from the History of PHP：

You can trace the history of PHP right back to 1995 and the momentous occasionwhen Microsoft realized they were falling behind in a fundamental shift inthe industry by not embracing the Internet. Up until that point Microsoft hadbeen developing their proprietary technologies, tools, and network protocols forthe Microsoft Network; all of a sudden they needed an Internet strategy and fast.

Microsoft has gone from a position of playing catch-up to one closedominance,with the Internet Explorer Web browser having a strangle-hold on theWeb browsing market, and Internet Information Server (IIS) installed at themajority of Fortune 1000 companies.

The Origins of PHP：

Back in the mid ‘90s, when the commercial Web world was still young, there wasnot a great deal of choice of tools for the Web developer who wanted to makehis or her Web site a truly useful place to do business.The choices were limitedin both available server-side programming platforms and also desktop developmenttools to produce the solutions. In the end, the programmer was stuck withclumsy Common Gateway Interface (CGI) programs using compiled languagessuch as C, Delphi, and Visual Basic, or interpreted scripting languages like Perl orRexx, and operating system shell scripts on systems such as UNIX.

In early 1996 Microsoft had a first stab at improving the situation byincluding the Internet Server Application Programming Interface (ISAPI) technologyas part of Internet Information Server. ISAPI is an extension to theWindows Win32 API. It was developed as a way to create Web server softwarethat interacts with the inner workings of Internet Information Server, bringingwhat was claimed to be a five-fold increase in performance. As you can wellimagine from this description, as well as the immediate performance increase, italso had a side effect of increasing the complexity of the development for theprogrammer. It wasn’t for the faint hearted, and it takes some serious hardcoreprogramming knowledge to do ISAPI applications right.As well as ISAPI,Microsoft encouraged developers to embrace their Internet Database Connector(IDC) technology.This was a new way to connect Web sites to back-enddatabases through Open Database Connectivity (ODBC).

The ISAPI and IDC technologies lifted Microsoft’s youthful and as yetunproven Web server from being a glorified file server to being a basic interactiveapplication server platform for the first time.

Other vendors had tools out there, and several were very popular, such asNetscape Livewire. Livewire was a technology that ran under Netscape’s Webserver and used a version of JavaScript for page logic, and also used Java components.Unfortunately, Livewire had similar limitations to ISAPI in that it was acompiled technology and the server needed stopping and starting to makechanges visible.

Why PHP Was Needed：

Not all Web developers have the programming skills needed to write ISAPIapplications, and because ISAPI requires the compilation of programs, there areextra steps in producing an ISAPI-based site that slow development down.Novice and intermediate programmers found the need to learn an industrialstrengthlanguage, such as C++, and compile even the simplest of their page logicinto .dll files a real barrier.

Visual Basic programs, although easier to develop, when used for CGI, performedpoorly and the overhead hogged resources. Other languages such as Perlrequire the Web server to launch a separate command-line program to interpretand execute the requested scripts, increasing page-load time and reducing serverperformance. CGI itself hogs resources because every page request forces the Webservers to launch and kill new processes and communicate across these processes.This is time consuming and also uses up precious RAM.

Another problem facing development teams in the mid ‘90s was the fact thata Web site is a mixture of Hypertext Markup Language (HTML) and logic.Theyneeded a way to mix the programmer’s code with the designer’s page-layoutHTML and designs without one messing up the other.There were many solutionsto this problem, ranging from custom template systems to Sever SideInclude (SSI) statements that told the server to execute code based on specialHTML comment tags.

Database-driven interactivity was another challenge.The demand for complexWeb sites had just kicked off, and developers needed to supply that demand in amanageable fashion, but the tools available did not make this an easy task.Thosewho could achieve it demanded rewards that matched the difficulty of what theywere being asked to do.

What was needed was a solution for the rest of us. It needed to be a simplescripted text-based technology like Perl, so developers could tweak and alter theirpages without compilation and with simple text-editing tools such as Notepad. Itneeded to have low resource requirements while keeping high performance;therefore it needed to be executed within the server environment just like ISAPI,but without the complexity. Designers and cross-discipline teams demanded thatit should include SSI and template features to make integrating page layouts simplerto manage.To be truly popular, it should run off a language that would beeasy to pick up and was familiar to a large community of developers. Enter ActiveServer Pages!

Why PHP Was Not Originally Embraced：

Active Server Pages was not an overnight success, though understandably it didcapture the imagination of a large sector of the development community, particularlythose already well versed in Visual Basic programming or Visual Basic forapplications scripting.

Others who did not have an investment in Visual Basic knowledge found thelimitations of Visual Basic, and by extension Visual Basic Scripting, reasons toavoid the technology. Faults included poor memory management, the lack ofstrong string management abilities, such as Regular Expressions, found in otherestablished languages.When compared to CGI with Perl,PHP was found lacking.

At that time, Internet Information Server was in its infancy, and take-up waslow, despite Microsoft’s public relations juggernaut going into full flow after thecompany’s much-reported dramatic turnaround. In comparison to current versionsof the software it seems very poor, but it was still competitive on performance.

Until 1997, back-end Web programming was pretty much owned by CGIand Perl. High-performance Web sites usually had a mix of C-compiled programsfor the real business engine, and Perl for the more lightweight form processing.

There was a fair amount of doubt and suspicion around Microsoft’s Internetefforts, including IIS and Internet Explorer, and ISAPI had not done all thatmuch to bring across a huge sector of the development community. Despite thisuncertain atmosphere, Microsoft saw many Windows NT 4 licenses being boughtspecifically for Web hosting and development increasing.Third-party support foranything other than small components was initially slow, but, as with all Microsoftproducts, after the first couple of releases they usually get things right, and PHPwas no exception.

Whereas Perl had a huge community of developers led by the heroic figureof Larry Wall, the PHP developer was not yet well supported.A Perl programmerwas encouraged from the top to share and make his or her code open, so thecommunity thrived, with every conceivable solution or library just a few clicksaway at the Comprehensive Perl Archive Network (CPAN) site, or at one of themany other Web sites and news groups. Contrast this with the ingrained competitiveand financially led philosophies of the third-party component vendors in theWindows Distributed Internet Applications (DNA) world. Of course, it did nottake the PHP community long to grow to be the loving, sharing success it is now.

Developing PHP 1.x：

PHP 1 was an upgrade to Internet Information Server 2, bringing it up to version3, and was installed as an optional downloaded component.The public betawas first made available in October 1996 and the final release was a factor in IISquickly overtaking Netscape in the server market.

Around the same period, Microsoft had purchased and further developed aWeb site authoring tool called FrontPage that brought with it a new organizationaland hosting concept of the FrontPage Web, enabling the developer todeploy Web applications in drag and drop style without using the File TransferProtocol (FTP).This concept would be carried through into Microsoft VisualInterdev, Microsoft’s new HTML and PHP editing environment.

PHP 1 was surprisingly feature-rich for a version 1 product. It included muchof the revolutionary functionality PHP that today’s programmers take for granted, such as ActiveX Data Objects that shield the programmer from differences indatabase implementations, with record sets to easily MYSQL and navigate databasequery results, and the ability to mix and match logic and presentation code in theexample, options for reading and writing to the file system; but overall,PHP 1was a breath of fresh air, and many developers quickly and eagerly adopted it.

Developing PHP 2.x：

Once PHP 1 had settled and become established, Microsoft released a new versionof Internet Information Server and an upgrade to PHP, with a combineddownload called the Windows NT 4 Option Pack.This time,PHP was built in tothe Web server setup and was not seen as an extra.The Web server was a bigimprovement, with better support and functionality all round and the addition ona Simple Mail Transfer Protocol (SMTP) Mail service.

With PHP 2, the technology matured to the point where developers couldreally implement powerful, large-scale solutions. Big-name companies adoptedthe Microsoft platform for their high traffic transactional sites and the technologyproved itself time and again against the demands of serving up millions of pageviews.

From launch, PHP 2 showed improvements across the board, such as increased

file system functionality, added components, and language improvements.Thirdpartydevelopers released components into the market place that filled in everyconceivable gap in functionality, and developers were producing their ownbespoke components through PHP’s Component Object Model (COM)-basedarchitecture.

Developer tools also had upgrades, with Visual Interdev becoming muchimproved and better integrated into the Visual Studio suite, with MYSQL to VisualSource Safe for source control.Third-party tool vendors had also developed theirown solutions, with many wizard-style developers’ toolkits and integrated environmentscoming to market, such as the popular Macromedia Ultradev.

More recently,Microsoft extended the language code with incrementalreleases of the language runtime Scripting Engines, allowing for improvements inthe languages, such as support for Regular Expressions, without the need for fullnew versions of Active Server Pages.

Major Changes with PHP 2：

Moving to Active Server Pages 2 brought the developer into a more stable andfeature-rich environment. All PHPects of the technology were tuned and tweaked, and programmers really felt that things had settled into a stable technology.Thisnewfound confidence was in part due to the evidence of successful transactionalsites actually showing that the platform could deliver, but also the fact that thetechnology had been boosted under the hood with tighter integration withMicrosoft Transaction Server (MTS). In fact, IIS 4 was rebuilt to be a MTS application,and so PHP and MTS components were actually running in the same processes.Another improvement was the work with Microsoft Message Queue.Thisallowed PHP and components to communicate across networks, ideal for largescaleapplications with complex backend requirements, for example, e-commercesystems integrating with existing legacy enterprise resource planning (ERP) infrastructures.