Getting A Random Date Between Two Given Dates In ColdFusion

<cffunction
	name="RandDateRange"
	access="public"
	returntype="date"
	output="false"
	hint="Returns a random date between the two passed in dates. If either of the two dates has a time value, the resultant time will also be randomized.">

	<!--- Define arguments. --->
	<cfargument
		name="DateFrom"
		type="date"
		required="true"
		hint="The min date of the date range."
		/>

	<cfargument
		name="DateTo"
		type="date"
		required="true"
		hint="The max date of the date range."
		/>

	<cfargument
		name="IncludeRandomTime"
		type="boolean"
		required="false"
		default="false"
		hint="Will include the time in the date randomization even if neither passed-in dates have a time."
		/>

	<!--- Define the local scope. --->
	<cfset var LOCAL = StructNew() />


	<!---
		Check to see if we are going to randomize time.
		If either of the passed in dates has a non-12 AM
		time, then we are going to include a random time.
		We will know if a date is include if the either
		date does not equal its Fixed value.
	--->
	<cfif (
		(ARGUMENTS.DateFrom NEQ Fix( ARGUMENTS.DateFrom )) OR
		(ARGUMENTS.DateTo NEQ Fix( ARGUMENTS.DateTo )) OR
		ARGUMENTS.IncludeRandomTime
		)>

		<!---
			Get the difference in seconds between the two
			given dates. Once we have this value, we can
			pick a random mid point in this span of seconds.
		--->
		<cfset LOCAL.DiffSeconds = DateDiff(
			"s",
			ARGUMENTS.DateFrom,
			ARGUMENTS.DateTo
			) />

		<!---
			Now that we know the second difference between the
			two dates, we can easily use RandRange() to get a
			random second span that we will add to the start
			date to give us a random mid date.
		--->
		<cfset LOCAL.Date = (
			ARGUMENTS.DateFrom +
			CreateTimeSpan(
				0, <!--- Days. --->
				0, <!--- Hours. --->
				0, <!--- Minutes --->

				<!---
					Now, let's pick the random number of
					seconds for this added time span.
				--->
				RandRange(
					0,
					LOCAL.DiffSeconds
					)
				)
			) />

		<!---
			Now that we have the randome date/time value, we
			need to format it using both the date and the time.
			We cannot just send back the DateFormat() (as in the
			other case) since that would strip out the time.
		--->
		<cfreturn
			DateFormat( LOCAL.Date ) & " " &
			TimeFormat( LOCAL.Date )
			/>

	<cfelse>

		<!---
			We are not going to include a random time.
			Therefore, we can just get a random integer
			to represent the date (no time). Since date/time
			values can be represented as float values, we
			can just use RandRange() to get a random
			integer which we will then convert back to a
			date/time value. DateFormat() will convert it back
			to a date value with zero time.
		--->
		<cfreturn
			DateFormat(
				RandRange(
					ARGUMENTS.DateFrom,
					ARGUMENTS.DateTo
					)
				)
			/>

	</cfif>
</cffunction>

<!--- Select 5 random dates. --->
<cfloop
	index="intI"
	from="1"
	to="5"
	step="1">


	<!---
		Get the random date. Since these values do not include
		time, this will only select random dates with no time.
	--->
	<cfset dtRandDate = RandDateRange(
		"05/01/2007",
		"05/20/2007"
		) />

	<!--- Output the date. --->
	#dtRandDate#<br />

</cfloop>

<!--- Select 5 random dates. --->
<cfloop
	index="intI"
	from="1"
	to="5"
	step="1">


	<!---
		Get the random date. Since these values do not include
		time, they should only return random dates. However,
		since we are passing in the flag for time randomization,
		then this will select random dates and times.
	--->
	<cfset dtRandDate = RandDateRange(
		"05/01/2007",
		"05/20/2007",
		true
		) />

	<!--- Output the date. --->
	#dtRandDate#<br />

</cfloop>

<!--- Select 5 random dates. --->
<cfloop
	index="intI"
	from="1"
	to="5"
	step="1">


	<!---
		Get the random date. Since at least one of these
		passed-in date values has a time portion, then the
		UDF will automatically use time randomization even
		though no flag was sent.
	--->
	<cfset dtRandDate = RandDateRange(
		"05/01/2007 10:00 AM",
		"05/01/2007 05:00 PM"
		) />

	<!--- Output the date. --->
	#dtRandDate#<br />

</cfloop>