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DEVELOPING
COLDFUSION 9 APPLICATIONS
Developing CFML Applications
Las
t
upda
te
d 8/5/2010
When ColdFusion receives a request, it instantiates the Application CFC and runs the Application.cfc code in the
following order:
•
CFC initialization code at the top of the file
•
onApplicationStart
, if not run before for this application
•
onSessionStart
, if not run before for this session
•
onRequestStart
•
onRequest
, or the requested page if there is no onRequest method
•
onRequestEnd
The following methods are triggered by specific events:
•
onApplicationEnd
•
onSessionEnd
•
onMissingTemplate
•
onError
The
onApplicationEnd
and
onSessionEnd
methods do not execute in the context of a page request, so they cannot
access request variables or display information to the user. The
onMissingTemplate
method is triggered when a URL
specifies a CFML page that does not exist. The
OnError
method does not always execute in the context of a request;
use its
Event
argument to determine the context.
Managing the application with Application.cfc
Use the
onApplicationStart
and
onApplicationEnd
methods to configure and manage the application; that is, to
control resources that are used by multiple pages and requests and must be consistently available to all code in your
application. Such resources include data sources, application counters such as page hit variables, or style information
for all pages.
The
onApplicationStart
method executes when ColdFusion gets the first request for a page in the application after
the server starts. The
onApplicationEnd
method executes when the application server shuts down or if the
application is inactive for the application time-out period.
The following are some of the ways you use these methods. For more information, see entries for onApplicationStart
and onApplicationEnd in the
CFML Reference
.
Defining application utility functions
Functions that you define in Application.cfc and do not place in a shared scope are, by default, available only to other
methods in the CFC.
If your Application.cfc implements the
onRequest
method, any utility functions that you define in Application.cfc are
also directly available in to the target page, because Application.cfc and the target page share the Variables scope.
onRequestEnd
All pages and CFCs in the request have been processed: equivalent to the OnRequestEnd.cfm page.
onMissingTemplate
When ColdFusion receives a request for a nonexistent page.
onError
When an exception occurs that is not caught by a try/catch block.
Method
When run
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