 | Introduction to ISAPI |
| | |
ISAPI stands for Internet Server Application Program Interface. Simply put, it s an interface to the web server that allows you to create customized web based applications and significantly improve the web experience of your customers.
Although ISAPIs are mostly known for their use with Microsoft Internet Information Services (usually called IIS or MS-IIS), they may also be used with many other web servers, including Apache (Note: Apache supports only ISAPI extensions), Zeus, and many more.
An ISAPI functions every time the web server receives a request for information. Usually these requests come from the web browsers of users who are trying to view information on the web server, such as your web page. Each time a request is received, the ISAPI controls what information will be provided to the user s web browser. In other words, it determines what the user will see.
Because an ISAPI can increase the speed at which your web page loads, it can make your customer s visit to your web page more enjoyable and keep them coming back. And, the more enjoyable the customer s experience is, the more likely the customer is to make a purchase.
Today, most major web sites that generate heavy traffic use ISAPI plugins.
An ISAPI plugin (sets of them are referred to ISAPIs) is a program that loads into the memory when the web server is started and unloads when the web server is shut down. ISAPIs provide added functionality or customizations that are not included in the web server software package. There are two kinds of ISAPI plugins-extensions and filters.
Extensions generate content on the web server and are very similar to CGI (Common Gateway Interface) programs. In fact, ISAPI was created to provide a faster alternative to CGI.
Filters modify the behavior of the web server by filtering the content generated on the web server. They filter both outgoing and incoming content.
ISAPIs can be used as an extremely potent means of powering the entire content of a web site. They can both serve content and filter content hosted on the web server.
Many web driven applications can be accomplished using ISAPI plugins. For example, ISAPI extensions can be used to create databases to store customer information, such as billing addresses, credit card information, shipping addresses, etc. Storing such information saves customers from the inconvenience of re-entering this information each time they make a purchase.
You might also use an ISAPI extension to create a shopping cart feature on your site. This feature creates a database of products from which each item selected by the customer is retrieved and displayed on a single web page. Previous technologies made this type of application almost impossible for high-volume web sites. ISAPIs provide the necessary speed and versatility.
With ISAPI filters (such as our ISAPIZip), you can:
 Change or map URLS or headers.
Modify responses.
Run processes when a request or connection is completed.
Perform logging.
Analyze traffic.
Perform authentication tasks.
Handle encryption and compression.
Slow response time can really hurt your chances of repeat visitors to your web site. Because ISAPIs are essentially added-on as part of the web server, they are much faster than previous technologies.
One of the major downfalls of older technologies (such as CGI) is that they create a new process each time a request is received from the web server. Because they are constantly re-creating the process, these older technologies require an immense amount of server and system resources to handle the traffic. However, with ISAPIs, the resources needed are greatly reduced because the program is loaded into the memory and only one process is created. The same process is executed each time a request is made. This process reuse allows for extremely fast, resource skimpy execution and handling of data.
Another disadvantage of older web server technologies is their lack of adequate scripting technologies. ASP and PHP are actually ISAPI filters that filter through scripted web pages and execute the code they find. ISAPI filters make it possible to create a web server scripting language.
Are you ready to stop using the same old technology and make your web server better, faster, more efficient?
It s time to get ISAPI!
|
|
