MACROMEDIA COLDFUSION MX 61-DEVELOPING COLDFUSION MX Develop Manual page 29

To extend the capabilities of a web server, you use a web application server, a software program that
extends the web server's capabilities to do tasks such as those in the preceding list.
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:
The user requests a page by typing a URL in a browser, and the web server receives the request.
1
The web server looks at the file extension to determine whether a web application server must
2
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.
About Internet applications and web application servers 29