Re: [CFCDev] Just starting CFC's -- Session Question

St�phane Bisson Fri, 03 Oct 2003 19:16:53 -0700

> I have to throw in the obligatory and oft repeated advice that you should not be directly manipulating session variables

> inside your CFCs, generally speaking.

Nathan, do you mean that if I use session scope in my CFC instances store in the Application scope... that I should consider this like not a good practice to do!... Could you explain a bit more... I'm thinking right now of how to avoid this... and I'm not like you guys... OOP oriented!... because now! in my CFC intances... I'm using Session and Application scope (to call other services)... and it's working very find!!... but I would like to know, why it's not a good practice to do so!...

Thanks for any advice

Stephane

Buidding a Flash MX/ColdFusion MX site

----- Original Message -----

From: Nathan Dintenfass

To: [EMAIL PROTECTED]

Sent: Friday, October 03, 2003 12:21 PM

Subject: RE: [CFCDev] Just starting CFC's -- Session Question

I have to throw in the obligatory and oft repeated advice that you should not be directly manipulating session variables inside your CFCs, generally speaking. You'd be better off having your cartModule component store things as instance variables, then store an instance of the cartModule in the session. This way you preserve encapsulation because the cartModule does not need to be aware of its environment (you could, for instance, use it in the Application or Server scope if that were more appropriate in another setting). You also avoid any risk of overwriting the data inside the cart. You also don't need to be aware of how the cartModule is implemented to use it -- you can then use CFCs' strength, which is to encapsulate complexity and expose functionality through an API defined by the methods. Then if you ever need to change how a cartModule works internally your other code doesn't need to change because the API of the cartModule can stay the same.

-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]On Behalf Of Paul Giesenhagen
Sent: Friday, October 03, 2003 8:10 AM
To: [EMAIL PROTECTED]
Subject: [CFCDev] Just starting CFC's -- Session Question

I am just now starting my learning on CFC's and having issues with sessions .. it is quite frustrating.

I created a VERY simple little input for building an array populated with a struct and then sticking it into a session.

I am not getting any session information from the calling CFM page .. if I set the session inside of the CFC.

Can anyone see what I am doing wrong?

If I run cart.cfm?mode=addCart (I see the session set in the CFC -- cfdump)

AND then Run cart.cfm?mode=viewCart it says cartData is undefined in SESSION.



<cfparam name="url.mode" default="">

<cfswitch _expression_="#url.mode#">
<cfcase value="delCart">
  <cfset variables.foo = StructDelete(session, "cartData")>
</cfcase>
<cfcase value="addCart">
  <cfparam name="url.qty" default="1">
  <cfparam name="url.id" default="1">
  
  <cfinvoke component="test.components.cartModule" method="addCart"/>
</cfcase>
<cfcase value="viewCart">
  <cfdump var="#session.cartData#">
</cfcase>
</cfswitch>



<cfcomponent displayname="cartModule" hint="manages Items to the Cart">
<cffunction name="addCart" output="true" displayname="Adds Cart Stuff" hint="Adds Cart Stuff">
  <cfif IsDefined("session.cartData")>
   <cfset cartLen = ArrayLen(cart) + 1>
   <cfset cart[cartLen] = structNew()>
   <cfset cart[cartLen].qty = url.qty>
   <cfset cart[cartLen].id = url.id>
  <cfelse>
   <cfset cart = arrayNew(1)>
   <cfset cartLen = ArrayLen(cart) + 1>
   <cfset cart[cartLen] = structNew()>
   <cfset cart[cartLen].qty = url.qty>
   <cfset cart[cartLen].id = url.id>
  </cfif>
  <cfset session.cartData = cart>
  <cfdump var="#session.cartData#">
</cffunction>
</cfcomponent>

Also: If I call this component via CFOBJECT the <CFDUMP in the function doesn't display anything -- If I use <CFINVOKE it displays the dump.

Thanks

Paul Giesenhagen

QuillDesign

Re: [CFCDev] Just starting CFC's -- Session Question

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