[Note]asp.net request with the iis

before
going further, I want to talk about two important conceptions: kernel model and
user model, which are two application running mode that the windows provides
for the application.

The operation
system code runs in the kernel mode and the user custom application runs in the
user model, but if a user application tries to work directly with the hardware,
this action will be done in the kernel mode for protecting the OS components
from being damaged by user application

The reason
why I am talking about those two modes is there is a new feature added in the
iis 6 which is called http.sys and running in the kernel mode.

Now
get back to the topic. When a user type http:://myserver/myapplication/mypage.aspx
in the address bar. So what will happen in the next before he od she gets the
response.

I don’t
want to detail it anymore, because it is really a big hit. Below is a brief
description on this issue.

l User types
the link above and click Enter key.

l The request
reaches the iis and is caught by http.sys(in the kernel mode)

l The http.sys
forwards the request to the very application pool where the “myapplication” is
configured under(now is in the user model)

l There is
a corresponding worker process called “w3wp.exe” for each application pool. So the
current “w3wp.exe” will load ASP.NET ISAPI “aspnet_isapi.dll”

l The ISAPI will load the Http
Runtime

l Http
Runtime creates the HttpContent

l The request
will be passed into the Http pipeline where the http modules and the http
handlers are located.

l http
modules are executed before the request hits the http modules

l the
page life cycle starts after the request leaves the piple.