Understanding Application And Session Timeouts In ColdFusion
Posted July 29, 2009 at 5:02 PM
Earlier today, I blogged about ColdFusion 9's new ApplicationStop() method which stops the current application, forcing OnApplicationStart() to be called on the next page request. During my exploration of this new method, I found out that the given Application was reset independently of the Session; meaning, while the Application scope was wiped out and repopulated, the existing Session scopes were left unchanged. When I observed this, I thought for sure it was a bug; but, after testing relative Application and Session timeout values, it appears to be the default behavior.
To test the inherent behavior of Application and Session timeouts, I set up a simple Application.cfc file session management:
Application.cfc
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- <cfcomponent
- output="false"
- hint="I define the application settings and event handlers.">
-
- <!---
- Define the application settings. Notice that our
- Application timeout is rather small - 10 seconds,
- while our Session timeout is larger - 5 minutes.
- --->
- <cfset this.name = hash( getCurrentTemplatePath() ) />
- <cfset this.applicationTimeout = createTimeSpan( 0, 0, 0, 10 ) />
- <cfset this.sessionManagement = true />
- <cfset this.sessionTimeout = createTimeSpan( 0, 0, 5, 0 ) />
-
- <!--- Define the request settings. --->
- <cfsetting showdebugoutput="false" />
-
-
- <cffunction
- name="onApplicationStart"
- access="public"
- returntype="boolean"
- output="false"
- hint="I initialize the application.">
-
- <!--- Initialize the application settings. --->
- <cfset application.dateInitialized = now() />
-
- <!--- Return true so that the page can load. --->
- <cfreturn true />
- </cffunction>
-
-
- <cffunction
- name="onSessionStart"
- access="public"
- returntype="void"
- output="false"
- hint="I initialize the session.">
-
- <!--- Initialize the session settings. --->
- <cfset session.dateInitialized = now() />
-
- <!--- Return out. --->
- <cfreturn />
- </cffunction>
-
- </cfcomponent>
As you can see, the application timeout is a very small number, only 10 seconds. The session timeout, on the other hand, is much larger, at 5 minutes. Each of the scopes (Application and Session) has an event handler which defines an initialization timestamp. I am using these two timestamps to track the effects of the application timeout on the session timeout in the index file:
Index.cfm
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- <cfoutput>
-
- <h1>
- Application And Session Overview
- </h1>
-
- <p>
- Application initialized:
- #dateDiff(
- "s",
- application.dateInitialized,
- now()
- )#
- seconds ago.
- </p>
-
- <p>
- Session initialized:
- #dateDiff(
- "s",
- session.dateInitialized,
- now()
- )#
- seconds ago.
- </p>
-
- </cfoutput>
As you can see, this test code simply outputs the relative age (in seconds) of each scope - Application and Session - based on the DateInitialized property defined in the Application.cfc. When I run this page for the first few time, I get the following output:
Application And Session Overview
Application initialized: 4 seconds ago.
Session initialized: 4 seconds ago.
As you can see, each scope is the same age.
Then, I waited for more than 10 seconds, waiting for the Application to timeout, and refreshed the page. Here is the output I got:
Application And Session Overview
Application initialized: 0 seconds ago.
Session initialized: 107 seconds ago.
As you can see, the Application scope timed out and refreshed itself on this subsequent page request. However, the Session scope, which had a much higher timeout, did not get altered in anyway.
When I saw the behavior of ApplicationStop(), I was sure that it was a bug; however, based on the testing above, which was done in ColdFusion 8, it appears that the complete independence of the Application scope from the Session scopes is the default behavior of the ColdFusion framework. Now, I am not suggesting that you make it a habit of keeping your session timeouts higher than your application timeouts - it wouldn't make any sense; but, this proves that the ApplicationStop() behavior in ColdFusion 9 is in proper alignment with the default ColdFusion framework behavior.
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Reader Comments
After such as you said simple Application.cfc file session management I understood, that I knew very little about it
Thanks for the article, after going through the article I could understand the difference of the scopes.
