CFC Best Practices, Tips, and Tricks

Raymond Camden

jedimaster@mindseye.com

Agenda

• Basic (but real!) Examples

• Best Practices (Suggestions)

• Tips and Tricks

• Resources

Examples

• www.cflib.orgCFCs serve as DB abstraction

• ResourceBundle CFCLocalization Utility

• SimpleCMSSimple CMS based on CFCs

Best Practices

• Control white space generated by CFC

<cfcomponent displayName="Example" output="false">

<cffunction name="test" returnType="string" access="public" output="false"> <cfreturn "This is a boring function."> </cffunction> </cfcomponent>

Best Practices

• Supply Optional Attributes

<cfcomponent displayName="Example2" output="false">

<cffunction name="test" returnType="string" access="public" output="false" hint="This function does blah using Foo's logic."> <cfargument name="argone" type="string" required="true"> <cfargument name="argtwo" type="numeric" required="false" default="0"> <cfreturn arguments.argone & " with the number " & arguments.argtwo> </cffunction> </cfcomponent>

Best Practices

• Use the VAR scope!

<cfcomponent displayName="Example3" output="false">

<cffunction name="test" returnType="string" access="public" output="false"> <cfargument name="argone" type="string" required="true"> <cfset var i = 0> <cfloop index="i" from=1 to=10> ..... </cfloop></cffunction> </cfcomponent>

Understand Data Scopes

• Variables

• This

• Arguments

• Function Local

Cache CFC Instances

• CFC creation can be slow.

• Use createObject/cfobject to create an instance.

• <cfinvoke> (typically) works with new instances.

Pseudo-Constructor

• Any code not inside <cffunction>.

• Useful to initialize variables.

• BlueDragon has <cfconstructor>

Dealing with Application Variables

• Application.cfm and when it's run:Flash Remoting/WS callsSame folder

• Don't rely on it!

• Application CFC

Inheritance/Super

• Use for Is-A, not Has-AIn other words, inheritance is used when a

CFC defines as "is a" relationship with it's parent. It should not be used for simple code re-use.

• Super allows for a child method to extend a parent method.

Pass by Ref/by Value

• Values passed to CFC methods follow the same rules as values passed to UDFs.

• The following are passed by reference:StructuresQueriesOther "comlpex" objects (including CFCs)

Resources

• www.cfczone.org

• cfcdev mailing list

• Top Ten Tips article by Rob Brooks-Bilsonhttp://www.oreillynet.com/pub/a/javascript/

2003/09/24/coldfusion_tips.html?page=1

• CFC Best Practices by Nathan Dintenfasshttp://www.dintenfass.com/cfcbestpractices/