Tom Jordahl provided the answer on this for me. Here's the solution:
1) Prior to implementing this solution, it's important to realize that because
LCDS manages the data, switching datasources dynamically could potentially
cause issues if there is overlap between identifiers on the records you are
retrieving. In my case, I'm using GUID fields as primary key and identifiers
in my destinations, so this is not a problem. However, for example, if you
were to use an incrementing integer for the identifier, then you could feasibly
have LCDS managing a record, which would match identifiers with a record if you
switched datasources on the fly.
2) I'm using ColdFusion as my middle-tier layer, but this could be applied to
any form by accessing the flex.messaging.FlexContext class within your solution
of choice.
3) The solution involves extracting the ID value of Flex client which makes
calls against your Destination. Grab the identifier by calling
FlexContext.getFlexClient().getId() to get a unique key for the "session". I
use the term "session" loosely, as it's really just representative of the
particular swf instance which has been loaded with your Flex Application.
However, the ID doesn't change and persists across all calls you make against
your destinations.
4) On application load, make a call to your CF layer which gets the ID, and
sets it to the Application scope of the CF server as follows:
<cffunction name="set" access="remote">
<cfargument name="datasource" type="string" required="yes" default="">
<cfset var clientID="">
<cfscript>
clientID = CreateObject('java',
'flex.messaging.FlexContext').getFlexClient().getId();
APPLICATION[clientID] = arguments.datasource;
</cfscript>
</cffunction>
The function above receives a unique string which I want to be my datasource of
choice. You could call this "set" function again anytime to reset the
Application variable for this "session".
5) The only other thing to do, is now access this Application variable for each
datasource.
datasource="#APPLICATION[CreateObject('java',
'flex.messaging.FlexContext').getFlexClient().getId()]#"
6) The last consideration is that each connection that is made via Flex will be
setting a new variable in the Application scope on the Coldfusion server. This
is a pretty minor concern for me, and I'll just run a schedule to clear the
Application scope once a day, but if you have a high volume of users, a better
solution would have to be found.
--- In flexcoders@yahoogroups.com, Brendan Meutzner <bmeutz...@...> wrote:
>
> Hi All,
>
>
>
> I'm hitting a wall on a requirement for a Flex application which utilizes
> the LCDS version included with ColdFusion.
>
>
>
> I have the project setup to use DAO's, Assemblers and ValueObject (cfc's)
> which I call from Flex via DataService implmentation and the fill(),
> getItem(), etc... methods.
>
>
>
> I need to setup my ColdFusion layer to access multiple datasources from the
> same Flex application. However, because of the way LCDS gets called from
> Flex, it doesn't seem that Application or Session variables in ColdFusion
> persist when I set them. I was thinking I could just have the HTML (cfm)
> wrapper page for my Flex application set that, but it is not recognized when
> I go to make a fill or get call against the assembler.
>
>
>
> I thought about passing the datasource as a parameter each time a call is
> made, but while that would work when I initiate fill and get methods, the
> sync methods are "invisible" and I wouldn't be able to append an argument to
> them.
>
>
>
> So my issue is... how do I go about having ColdFusion read a dynamic
> variable to define it's datasource?
>
>
>
>
>
> Thanks in advance for the help.
>
>
>
>
>
> Brendan
>
> --
> Brendan Meutzner
> http://www.meutzner.com/blog/
> http://www.riajobs.com
>
