Understanding The Web Application Framework; Application-Level Settings And Functions; Client, Session, Application, And Server Scope Variables - MACROMEDIA COLDFUSION 5-DEVELOPING Develop Manual

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Understanding the Web Application Framework

A ColdFusion application is a collection of application pages that work together.
Applications can be as simple as a guest book or as sophisticated as a full Internet
commerce system with catalog pages, shopping carts, and reporting. You can
combine individual applications to create advanced Web systems.
The ColdFusion Web Application Framework is based on four basic components:
With these components, you can easily combine your ColdFusion application pages
to create sophisticated Web applications.

Application-level settings and functions

ColdFusion provides application-level facilities that help you control settings,
variables, and features available across the entire application. After you define an
application, you can use the application-level features in addition to all of the other
features in ColdFusion.
You specify application-level settings in the Application.cfm and OnRequestEnd.cfm
files. Application.cfm is executed when ColdFusion starts processing each page in
your application, and OnRequestEnd.cfm is processed after all other processing is
completed for the page.

Client, Session, Application, and Server scope variables

ColdFusion provides four variable scopes that let you to maintain data that must last
beyond the scope of the current page.
Variable Scope Description
Client
Session
Application-level settings and functions
Client, Session, Application, and Server scope variables
Custom error handling
Web server security integration
Contains variables that are available for a single client browser
over multiple browser sessions in an application. Client variables
are stored as cookies, database entries, or Registry values. Client
variables can time out after an extended period.
You cannot access the Client scope as a data structure. You
should use the Client scope prefix in the variable name, but it is not
required.
Contains variables that are available for a single client browser for
a single browser session in an application. Session variables are
stored in memory and time out after a period of inactivity or when
the server shuts down.
You can access the Session scope as a data structure. You must
use the Session scope prefix in the variable name.
Chapter 12 Using the Application Framework