Scope-specific built-in variables

ColdFusion returns variables, such as those returned in a cfdirectory or cfftp operation. A variable is usually referenced by scoping it according to its type: naming it according to the code context in which it is available; for example, Session.varname, or Application.varname. For more information on ColdFusion scopes, see Using ColdFusion Variables in ColdFusion MX Developer's Guide

You use the cflock tag to limit the scope of CFML constructs that modify shared data structures, files, and CFXs, to ensure that modifications occur sequentially. For more information, see cflock, and Using Persistent Data and Locking in ColdFusion MX Developer's Guide.

This section describes the following topics:

• Variable scope
• Caller scope
• Client variables
• Server variables
• Application and session variables

Variable scope

ColdFusion supports the Variables scope. Unscoped variables created with the cfset tag acquire the Variables scope by default. For example, the variable created by the statement <CFSET linguist = Chomsky> can be referenced as #Variables.linguist#

Caller scope

History

ColdFusion MX: The Caller scope is accessible as a structure. (In earlier releases, it was not.)

Client variables

The following client variables are reserved:

Client.CFID
Client.CFToken
Client.HitCount
Client.LastVisit
Client.TimeCreated
Client.URLToken

Server variables

Use the Server prefix to reference server variables, as follows:

Server.ColdFusion.ProductName
Server.ColdFusion.ProductVersion
Server.ColdFusion.ProductLevel 
Server.ColdFusion.SerialNumber 
Server.ColdFusion.SupportedLocales
Server.ColdFusion.AppServer
Server.ColdFusion.Expiration
Server.ColdFusion.RootDir
Server.OS.Name 
Server.OS.AdditionalInformation 
Server.OS.Version 
Server.OS.BuildNumber

Application and session variables

To enable application and session variables, use the cfapplication tag or Application.cfc. Reference them as follows:

Application.myvariable
Session.myvariable

To ensure that modifications to shared data occur in the intended sequence, use the cflock tag. For more information, see cflock.

The predefined application and session variables are as follows:

Application.ApplicationName
Session.CFID
Session.CFToken
Session.URLToken

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