User Guide

onApplicationStart 949
onApplicationStart
Description
Runs when ColdFusion MX receives the first request for a page in the application.
Syntax
<cffunction name="onApplicationStart" returnType="boolean">
...
<cfreturn Boolean>
</cffunction>
See also
onApplicationEnd
, Method summary, “Managing the application with Application.cfc” in
Chapter 13, “Designing and Optimizing a ColdFusion Application,” in Chapter 5,
“Application.CFC Reference,” in ColdFusion MX Developer’s Guide
Returns
A Boolean value: True if the application startup code ran successfully; False, otherwise. You do
not need to explicitly return a True value if you omit the
cffunction tag returntype attribute.
Usage
Use this method for application initialization code; for example, use it to set Application scope
variables, to determine whether a required data source or other resource is available, or to log the
application start. You do not have to lock the Application scope if you set Application variables in
this method, and you can reference Application scope variables as you normally do; for example,
as Application.myVariable.
This method can access the requested page’s Variables scope only if the Application.cfc file
includes an
onRequest method that calls the page.
If you call this method explicitly, ColdFusion does not start the application; it does execute the
method code, but does not lock the Application scope while the method executes.
If this method throws an uncaught exception or returns False, the application does not start and
ColdFusion MX does not process any pages in the application. In this case, ColdFusion will run
the
onApplicationStart method the next time a user requests a page in the application.
Example
The following example tests for the availability of a database. If the database is not available it
reports and logs the error, and does not start the application; if it is available, the method
initializes two Application scope variables.
<cffunction name="onApplicationStart">
<cftry>
<!--- Test whether the DB is accessible by selecting some data. --->
<cfquery name="testDB" dataSource="cfdocexamples" maxrows="2">
SELECT Emp_ID FROM employee
</cfquery>
<!--- If we get a database error, report an error to the user, log the
error information, and do not start the application. --->
<cfcatch type="database">