Problem
How to generate a valid UUID from a string, such as a combination of two other UUIDs. This is useful for creating a single unique identifier from another set of unique identifiers.
Solution
The solution is actually rather simple, simply create a HASH() of the input string and then format it so that it is a valid CF UUID.
Detailed explanation
Creating a hash of the incoming string will return a 32-character string that contains valid UUID characters, but is not in a UUID format. After we have hash()'d the incoming string, we do a simple formatting of the hash value.
Proper UUIDs use the first character of the third character block to identify what type of UUID has been generated. Because this is a UUID generated from a hash, this value is set to a "3".
<cffunction name="createUUIDFromString" access="public" output="false" returntype="string">
<cfargument name="value" type="string" required="true" />
<cfset var hashString = hash( arguments.value ) />
<cfset var newUUID = left(hashString,8) & "-" & mid(hashString,9,4) & "-" & "3" & mid(hashString,13,3) & "-" & right(hashString,16) />
<cfreturn newUUID />
</cffunction>
This is very useful for uniting two unique identifiers into a new one. For instance, if you had product code X and shopping cart Y, you could combine ID's X + Y = unique id. The hash value of a specific string of characters will always be the same, so this string will always return the same UUID. The caveat is that you can't reverse engineer the new UUID; in other words, you can't get ID X or Y back out of the new UUID.
Note that the incoming string can be anything from "Please make this a UUID" to existing UUIDs to integers to ... well, you get the idea.
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