Transcript Presentation - CF Conf Central

CFCs in Practice
Raymond Camden ([email protected])
Senior Developer, Mindseye Technologies
Agenda
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Quick Intro to ColdFusion Components (CFCs)
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CFC Coding Details and Tips
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CFC “Issues”
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CFC Examples
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Q&A
CFCs in a Nutshell
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A new way to encapsulate code.
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Collection of methods with built in security
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Quick and Easy Web Services
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Pseudo-Object Oriented (No, it’s not really OO)
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New tags: <cfcomponent>, <cfproperty>,
<cffunction>, <cfreturn>
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CFC Example
<cfcomponent>
<cffunction name="sayHello">
<cfif hour(now()) lt 12>
<cfreturn "Good Morning">
<cfelseif hour(now()) lt 18>
<cfreturn "Good Afternoon">
<cfelse>
<cfreturn "Good Evening">
</cfif>
</cffunction>
</cfcomponent>
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CFC Example (2)
<cfinvoke component="simple" method="sayHello"
returnVariable="greeting">
<cfoutput>#greeting#</cfoutput>
<p>
<cfset greeter = createObject("component","simple")>
<cfoutput>#greeter.sayHello()#</cfoutput>
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CFC Tips: Constructors
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CFCs do not have a formal constructor…
However – any code not inside a method is run when
the CFC is instantiated (created or called remotely).
Generates white space! Use output=false in
<cfcomponent> (also in <cffunction>)
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CFC Tips: Let’s Talk about Data

This
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Accessible to caller code
Shows up in dump, but not getMetaData()
Unnamed “private” scope
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Not accessible to caller code
Accessible to children
Not like Variables, can’t be dumped. (Fixed in RedSky)
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Method arguments
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Method temporary variables (var scope)
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CFC Methods
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Default access is public – change to private
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Specify all attributes, even optional ones:
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access (important for security!)
returnType (important for validation!)
output (controls white space!)
hint
roles
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CFC Methods (2)

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returnType should be one of:
any
numeric
array
query
binary
string
boolean
struct
date
uuid
guid
variableName
Or must be the name of a CFC type
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Watch out for structure instead of struct,
number instead of numeric, etc.
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CFC Methods (3)
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Output versus Return
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Outputting from the method will not work for Flash Remoting
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Use the var scope
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This is intentional: Use the var scope
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Applies to UDFs as well!
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<cfproperty> - What does it really do?
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It does NOT create variables.
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It does NOT validate variables.
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It does create entries in the meta data.
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It helps define the WSDL returned by a web service
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CFC “Issues”
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<cfinclude> inside a method will not have access to Arguments
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<cftransaction> and CFCs
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ArgumentCollection and <cfinvoke>
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Cached CFCs lose access to output, other scopes
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You can’t duplicate (correctly) or serialize (correctly) a CFC
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Undefined arguments show up in arguments struct
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Web Services Gotchas…
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No optional arguments allowed for methods
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AXIS limitation
Caching of Arguments
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Fixed by using CF Admin to refresh the WS
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CFC Examples
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Session Tracker
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Unit Tester (from DRK3)
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Nathan Dintenfass’ Descriptor
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Questions and Resources
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www.cfczone.org
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cfcdev mailing list
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Macromedia DevNet Articles
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http://www.macromedia.com/devnet/mx/coldfusion/cfcs.html
CFDJ Articles
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