Internet Server Application Programming Interface: Difference between revisions

Revision as of 22:18, 20 March 2008

Revision as of 17:08, 4 April 2008

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The word "server" can refer to a computer ("box") or a piece of software (for example, ''SQL Server''). [[Microsoft]]'s web server application software is called [[Internet Information Services]], which is made up of a number of "sub-applications" and is very configurable. [[ASP.NET]] is one such slice of IIS, allowing a programmer to write web applications in his or her choice of programming language (Visual Basic, C#, J#) that's supported by the Microsoft .NET CLR. '''ISAPI''' is a much lower-level programming system, giving much better performance, at the expense of complexity. While Microsoft is generally credited with the creation of the ISAPI specification, it was actually codeveloped by Process Software and Microsoft with input from a small number of other vendors.<ref>[http://wasd.vsm.com.au/ht_root/doc/scripting/scripting_0600.html ISAPI<!-- Bot generated title -->]</ref>

==Major sites using ISAPI==

=Performance and compromise=

Before switching to ASP.Net Microsoft's [[MSDN]]-Library (msdn.microsoft.com) was fully developed with ISAPI. Ebay[[eBay]] still uses the "eBayISAPI.dll", although theyon declarethe thatback-end they are using Java-Technology powered by Sun.<ref>eBay was initially developed using Microsoft technology for both the front end and back and processing (re: The Perfect Store by Adam Cohen). They later adopted a Java application server for the request processing but the web client software still uses an ISAPI application.</ref>

==Performance and compromise==

The greatest disadvantage of developing web applications at ISAPI level is the required development time, which is at least twice as high as using ASP or PHP.{{fact|date=July 2007}} Another penalty is the lack of native support for many standard web application features such as [[Session (computer science)|Session]] handling, which are common features in technologies such as ASP and PHP.

===ISAPI for IIS 5.0 and earlier===

In contrast to [[Common Gateway Interface|CGI]] applications, an ISAPI application is fdloadedloaded into the same process space as the IIS web server. This removes the need for inter-[[Process (computing)|process]] calls allowing improved performance of ISAPI applications over CGI applications. However, if an ISAPI application [[Crash (computing)|crashes]], it can cause the whole of the web server to crash along with it.

===ISAPI for IIS 6.0===