User Guide

Table Of Contents
About Internet applications and web application servers 21
How a web server and web application server work together
The following steps explain how a web server and web application server work together to process
a page request:
1.
The user requests a page by typing a URL in a browser, and the web server receives the request.
2.
The web server looks at the file extension to determine whether a web application server must
process the page. Then, one of the following actions occur:
If the user requests a file that is a simple web page (often one with an HTM or HTML
extension), the web server fulfills the request and sends the file to the browser.
If the user requests a file that is a page that a web application server must process (one with
a CFM, CFML, or CFC extension for ColdFusion requests), the web server passes the
request to the web application server. The web application server processes the page and
sends the results to the web server, which returns those results to the browser. The following
figure shows this process:
Because web application servers interpret programming instructions and generate output that a
web browser can interpret, they let web developers build highly interactive and data-rich websites,
which can do tasks such as the following:
Query other database applications for data.
Dynamically populate form elements.
Dynamically generate Flash application data.
Provide application security.
Integrate with other systems using standard protocols such as HTTP, FTP, LDAP, POP,
and SMTP.
Create shopping carts and e-commerce websites.
Respond with an e-mail message immediately after a user submits a form.
Return the results of keyword searches.
Web browser
requests
a web page.
1
Web server
receives the
page request.
2
Web server instructs
application server
to process the page.
3
The application server
processes the page
and generates output.
4
The web server
sends the output
to the browser.
5