With the Xuland Flex-based social networking application I’ve been working on for the past eight months, I decided to switch things up on the back-end, most notably in the services layer where I’ve been using ColdFusion 9 for my data-access objects.

ColdFusion has been a perfect fit for Flex since I had used the software quite extensively for much of my programming career. However, as I prepare Xuland for go-live (August 13th – which also coincides with the Adobe MAX Awards deadline for entry date), I realized that without a license for the software I would be restricted to shared hosting services – a solution that would not work in the long-run, especially if Xuland were to suddenly gain popularity.

As I considered dedicated or “cloud” hosting, I would have to either buy an $8,000 ColdFusion license (umm, no) or switch to an alternative. BlueDragon piqued my interest, but it unfortunately does not yet support AMF. Without the ability to remote, my application would launch already dead in the water.

Another alternative, completely unknown to me before today, is Railo (pronounced “Rhylo” after a fictitious alien dog in Star Trek).

“Railo is a free, open-source alternative for ColdFusion application development.” It currently supports the AMF3 format (whereas in the last version it only supported AMF0) and comes shipped with its own application server and servlet engine (Caucho Resin). In fact, the Express versions can be downloaded, configured for Flex and launched within minutes. The best part is it’s completely FREE.

I’ve since switched from ColdFusion to Railo and with hardly any tweaking, Xuland was running against Railo executing the same CFC’s I had already written for ColdFusion 9. After starting the Railo service locally the first time, it automatically created the necessary Flex remoting-config and services-config XML files needed in the WEB-INF directory. Remoting worked perfectly, and I dare say it seems a bit faster (I have not run any benchmarks quite yet, however).

If you’re looking for a solution similar to this, definitely consider Railo as it works as well as ColdFusion without the sheer cost.

It’s been a couple of years since I worked with ColdFusion and Flex together, but I remember I always like the combination and chose it for my new little Xuland social networking project I’ve been working on (see previous posts).

I had to remember how the whole Flex-ColdFusion remoting setup would work again and I had to overcome a couple of hurdles. I thought I’d share the experience as it would have helped me get up to speed quickly.

Here’s a quick recap of setting up your Flex application to remote to ColdFusion:

1. Install ColdFusion (I installed mine to the default C:\ColdFusion9 directory)
2. In FlexBuilder, create a new Flex project
3. While creating the project, select an Application server type of “ColdFusion” and check the “Use remote object access service” with the “ColdFusion Flash Remoting” option selected.
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4. On the next screen, in my case I’m using a Standalone installation and had to uncheck the “Use default location for local ColdFusion server”. Of course, the root folder was C:\ColdFusion9. I clicked Validate Configuration which validated that the root folder existed.
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5. I happen to use ColdFusion primarily for access to a MySQL datasource, so I had to setup the datasource in the ColdFusion admin first (this information should be readily available anywhere)
6. Once the datasource was setup, I first created a value-object (VO) in ColdFusion to represent the object (in this case, a User) I wanted to pass back to the Flex application
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   UserVO.cfc:

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   <cfcomponent output="false" alias="com.xyz.coldfusion.vo.UserVO"> <cfproperty name="userID" type="numeric"/> <cfproperty name="username" type="string"/> <cfproperty name="password" type="string"/> </cfcomponent>

7. After the VO, I created a data-access object (DAO) to query the datasource for a user and return a UserVO to the calling Flex application
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   <cfcomponent output="yes"> <cffunction name="getUserByID" access="remote" returntype="com.xyz.coldfusion.vo.UserVO">   <cfargument name="userID" type="numeric" required="yes">   <cfquery name="getUser" datasource="xuland"> SELECT * FROM tblUsers WHERE userID = '#userID#' </cfquery>   <cfreturn getUser>   </cffunction> </cfcomponent>

8. Back in the Flex project, I setup my RemoteObject tag to point towards the ColdFusion DAO component I created in the last step:
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   <!-- Remote Services --> <mx:RemoteObject id="userService" destination="ColdFusion" source="com.xyz.coldfusion.dao.UserDAO" showBusyCursor="true">   <mx:method name="getUserByID" result="resultHandler(event)" fault="faultHandler(event)"/>   </mx:RemoteObject>

9. Create your result and fault handlers (here we just display an Alert)
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   <fx:Script> <![CDATA[ import mx.controls.Alert; import mx.rpc.events.FaultEvent; import mx.rpc.events.ResultEvent;   private function resultHandler( event : ResultEvent ) : void { Alert.show( event.result.toString() ); }   private function faultHandler( event : FaultEvent ) : void { Alert.show( event.fault.faultString ); } ]]> </fx:Script>

10. Finally create a button or method to call the service:
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    1	<mx:Button click="userService.getUserByID( 1 )"/>

Much of this logic may be abstracted off into controllers, delegates, commands or other framework-specific components but this is a fairly simple example of installing, configuring and executing a remote object service call from Flex to ColdFusion.