Generating a Decrypted Memento for a Transfer Decorator
In my last blog post, I discussed how to efficiently handle multiple encrypted fields while using Transfer. The key was using onMissingMethod in the Transfer decorator. However, what about when we use the memento with Transfer's getMemento() method? This approach can be especially handy to quickly transfer an object's properties when using web services to Flex or AJAX front ends.
For reference, here was the object definition we were using in our sample Transfer configuration.
-
<object name="Reg" table="Regs" decorator="MyProj.com.Reg">
-
<id name="ID" column="RegID" type="numeric" />
-
<property name="FName" type="string" column="RegFName" />
-
<property name="LName" type="string" column="RegLName" />
-
<property name="LastMod" type="date" column="RegLastMod" />
-
<property name="Expires" type="date" column="RegExpires" nullable="true" />
-
<property name="EncHome" type="string" column="regHome" />
-
<property name="EncWork" type="string" column="regWork" />
-
<property name="EncMobile" type="string" column="regMobile" />
-
<property name="EncSMS" type="string" column="regSMS" />
-
</object>
The process is very simple. Recall that we prefixed our Transfer properties with "Enc" to know which fields are encrypted. Let's create a getDecryptedMemento() method. It will loop through all of the keys in the memento, which is just a struct, and decrypt any of the encrypted fields, saving them as new keys in the struct (i.e. "EncHome" is decrypted as "Home" in the struct).
Something like this will do the trick:
-
<cffunction name="getDecryptedMemento" access="public" returntype="struct" output="false">
-
<cfset var memento=getMemento()>
-
<cfset var key="">
-
<cfset var newkey="">
-
<cfloop index="key" list="#StructKeyList(memento)#">
-
<cfif Left(key,3) is "Enc">
-
<cfset newkey=RemoveChars(key,1,3)>
-
<cfset memento[newkey]=decryptValue(memento[key])>
-
</cfif>
-
</cfloop>
-
<cfreturn memento>
-
</cffunction>
Not much to it. Note that we would use the same decryption function as we are using in onMissingMethod for the dynamic accessors. I'm calling it decryptValue() for this sample.
In the end, our getDecryptedMemento() method returns a memento that looks just like the Transfer-generated getMemento() output, with decrypted versions of the encrypted fields!