Extending the iis to give more functionality

ISAPI extensions

ISAPI filters

CHI and other extensions

Difference between extension and filters

Client sends the request to server, http listener identifies the website and sends the request to app pool and placed in the queue of the worker process

And worker process works on the request

Before worker process executes the request, filters will be executed

Filters are written in internet service application programming interface(ISAPI)

Filters take the request and will modify that one, and change the url

Here no processing is done… Filters will do the preprocessing the request and they can preview the result after that request is processed.

in case of request for static page, then iis need no help, it will take the page from disk and put it in memory and sends to client thru network

in case of dynamic pages, where php, asp.net code needs to be executed, then here extensions come into picture

When the php file is accessed, then iis loads the php extension and this extension will execute the script and give it back to iis and then iis will give to client

There can be loading of multiple extensions as it request are for of diff types

Filters is of isapi only

But extensions are of types

1. isapi

2.cgi

3. fast CGI

do any these configurations at server level

Go to iis and server, modules, all these are used for the iis to extend iis functionality

Handler mappings: here we can configure the extensions of IIS

Here we can have the handlers that handles the requests coming from clients

Here we can see the details

asp,cgi,handler mappings,fast cgi,modules,isapi filters,isapi and cgi restrictions, handler mappings

Regards,

Chaitanya