MACROMEDIA ColdFusion MX, Develop Manual, Page: 328 / 860

328 Chapter 15: Using Persistent Data and Locking
Enabling session variables in your application
You must also enable session variables in the
cfapplication
tag in your Application.cfm file. Do
the following in the Application.cfm file to enable session variables:
•
Set
sessionManagement="Yes"
•
Use the
name
attribute to specify the application's name.
•
Optionally, use the
sessionTimeout
attribute to set an application-specific session time-out
value. Use the
CreateTimeSpan
function to specify the number of days, hours, minutes, and
seconds for the time-out.
The following sample code enables session management for the GetLeadApp application and sets
the session variables to time out after a 45-minute period of inactivity:
<cfapplication name="GetLeadApp"
sessionmanagement="Yes"
sessiontimeout=#CreateTimeSpan(0,0,45,0)#>
Storing session data in session variables
Session variables are designed to store session-level data. They are a convenient place to store
information that all pages of your application might need during a user session, such as shopping
cart contents or score counters.
Using session variables, an application can initialize itself with user-specific data the first time a
user accesses one of the application’s pages. This information can remain available while that user
continues to use that application. For example, you can retrieve information about a specific user’s
preferences from a database once, the first time a user accesses any page of an application. This
information remains available throughout that user’s session, thereby avoiding the overhead of
retrieving the preferences repeatedly.
Standard session variables
If you use ColdFusion session variables, the Session scope has four built-in, read-only variables
that your application can use. If you use J2EE session management, the Session scope has two
built-in variables. Generally, you use these variables in your ColdFusion pages only if your
application supports browsers that do not allow cookies. For more information on supporting
browsers that do not allow cookies, see
“Using client and session variables without cookies”
on page 319 . The following table describes the built-in session variables.
Variable Description
Session.CFID ColdFusion session management only: the client ID, normally stored on the
client system as a cookie.
Session.CFToken ColdFusion session management only: the client security token, normally
stored on the client system as a cookie.