Using Application.cfc as your application controller

A few months ago, I was experimenting with Model-Glue for an application. One thing that struck me as odd was that certain events which are normally handled by the Application.cfc (onRequestStart, onRequestEnd) were handled by Model-Glue controllers.

Rather than moving custom application event handling logic in a seperate controller, why not handle them with the Application.cfc? After all, the Application.cfc framework is a well-documented, frequently used ColdFusion features which already handles many application-level events.

To that end, I've written yet another ColdFusion MVC framework I call "Boca", which is Rails-esque insofar as mapping event names to controller methods (handlers) to view pages without configuration. But what makes Boca unique (and uniquely ColdFusion) is that Application.cfc serves as the controller for all application events. A sample Application.cfc would like this:


<cfcomponent displayname="My Great Application" extends="BaseApplicationController">


<cffunction name="onApplicationStart" ...

<cffunction name="onSessionStart" ...

<!--- Custom Event Handlers --->

<cffunction name="addToCart" access="public" returntype="void">

<cfargument name="productId" type="numeric" required="true">
<!--- Do application logic here --->

</cffunction>

<cffunction name="signIn" access="public" returntype="void">

<cfargument name="username" type="string" required="true">
<cfargument name="password" type="string" required="true">
<!--- Do application logic here --->

</cffunction>


</cfcomponent>

While I cannot make the source code public, I can offer insight on how to accomplish this in your application. The secret is using the onRequest function in Application.cfc to intercept calls, call the appropriate function within the Application.cfc, and include the corrent view page(s). This can all be done in less than 100 lines of code. To reuse this filter across Application.cfc files within your site, simply extend the base component which implements the onRequest method, and don't override that method.

If, like in other MVC frameworks, the event contains the union of FORM and URL scopes, I suggest invoking the event handlers using the event as the argument collection of the handler method like so:


<cfset event = StructNew() />
<cfset StructAppend(event, URL) />
<cfset StructAppend(event, FORM) />
<cfinvoke method="#action#" argumentcollection="#event#" />

You the get better event documentation by enumerating the arguments and types for your event handler (although this is optional, since ColdFusion supports dynamic arguments, and will also preserve the name-value pairs passed in). See the sample component above for an example.

A consequence of this approach is that variables set (and not var-scoped) within the event handlers are available in the view pages included within the onRequest method (this is a well-documented Application.cfc behaviour), saving Model-Glue like usage of event and view-state components across controllers and views.