Recently 23hq contacted us so they can implement the multiple file upload feature of Flash Player 8. Finally, the result is a cool way of provinding the users the ability to upload single or multiple photo uploads and at the same time allowing them to preview uploaded photos, tag them while the remaining at still being uploaded. You will be experiencing the cool combination of Flash and Ajax.

23hq have a an article describing their new feature in details, Flashy Uploads. Test out their Upload Feature or keep a tap of their discussion on the topic.

The first part in the client side of AjaxCFC is to include the javascript files.

_ajaxConfig = {'_cfscriptLocation':'echoTest.cfc', '_jsscriptFolder':'js'};

_ajaxConfig will store the location of the listener CFC and location of the “js” folder which is included in the ajax.zip file that comes with AjaxCFC. The use of _cfscriptLocation variable is optional as you may specify the CFC location directly in the Ajax call.

You will have an ajax calling function and a call-back function; however, none of them are mandatory, because depending on your needs you may not need to know the result of your call, or you may not need to enclose your ajax call in a function.

To invoke an ajax component you need to use DWREngine._execute which my colleague, Ashish has already explained.

The call-back function will always take one argument, which is the return of the method called within the CFC object.

AjaxCFC will allow you to return almost all simple or complex object to the JavaScript callback function: strings, numbers, arrays, structures and queries.

We have a preferance of structures over the other objects. The callback function will always take one argument, which is the return value of the invoked CF function.

The JavaScript function will receive the number or string just like any regular JavaScript call.

To retrieve the recordcount, you can loop your data through a built-in function, result.getRowCount(), which will return the equivalent to query.recordcount. You can always use sDumper(result) to show you exactly what is being sent back to your handler.

With AjaxCFC, a generic ColdFusion Component using the facade pattern was created which contains all the methods for the Messaging System. It made it so easy for me that I had to just take care of the functionality of a single method; DWREngine._execute() with the respective arguments. This is the method which handles passing of the data and also the method calls to ColdFusion. The arguments required are also quite simple and easy even for a newbie to understand.

Looking at the method signature of the function;

DWREngine._execute(_ajaxConfig.cfscriptLocation, null, ‘CFmethodName’, args, callBackFunction);

Though you can pass multiple arguments, my preference is to use a value object instead. Let us look at some points in respect to the particular Module of the RIA which I am currently working.

1. The _ajaxConfig.cfscriptLocation is the actual path to the CFC which contains the methods I need to call for my mailing system.
2. The second argument is the script name to be executed. This argument is null most of the times.
3. The CFmethodName is the name of the method you want to call from the CFC.
4. The fourth parameter to this function is the arguments you wish to pass to the CFmethod. You can pass more than one arguments or even a value object.
5. The callBackFunction is the function in JavaScript in your CFM which will always take a single argument which is the return result you get from your CFC.

Well, the bottomline is that in order to use our CFC with the AjaxCFC framework, all I had to do was extend my CFC to the ajax.cfc which comes along with the framework.

Implementing AjaxCFC into my application, not only made things faster and easier for me but also enriched the end user experience for our module, the Messaging System. Thanks to Rob Gonda, now I am looking forward to incorporate AjaxCFC with the Model-Glue framework which I have used for Live Speed Dating.

Note:
The client side part of AjaxCFC was tackled by one of my colleague, Manaswinee. She will very soon be having an article on the same. Keep an eye on her article to get an insight on the callback functions and how the data is handled at the client side.