Some may have noticed that there is a server.coldfusion.expiration variable (one of many read-only variables in the server scope, within the coldfusion structure). According to the docs, it's supposed to represent the date on which a trial edition of CFMX will expire.
But some have found (and I've confirmed) that on non-trial editions it instead reports the time that the server started. Try it youself:
It'll be a date, but is it in the future? or the past? Assuming it's the past, and you're not running on a trial edition, then it's likely the time your server had started. If you could restart your server and test again, you'll know for sure. :-)
Better formatting of the result
Now, if you want to easily determine how long the server has been up, just use the datediff function to report how many minutes there are between the time reported and the current time:
But even better, you could use one of the nifty functions available at the cflib.org that could help present the result minutes in terms of days, hours, and minutes (duration()). Assuming you included the latter in your page, you could then output the value as:
<cfset uptime = duration(server.coldfusion.expiration,now())><br>
<cfoutput>#uptime.days# Day(s) #uptime.hours# Hour(s) #uptime.minutes# Minute(s)
<br>Server started on #dateformat(server.coldfusion.expiration)# at #timeformat(server.coldfusion.expiration)#
I may put together a UDF to submit to the cflib to pull all this together, and which also checks if indeed the server being checked is a trial edition, etc. But I'll look forward to hearing people's feedback first.
Of course, it's worth pointing out that there are of course many tools that will monitor a server's uptime by watching it externally. It may also be possible to ask the operating system to report how long a given process or service has been running. I'll leave that for others to investigate.
Finally, I'll point out that there is indeed a tag in the Adobe Developers Exchange, CF_UpTimeMonger, that purports to help detect server uptime and says it works even for CF 4 and CF5. I have not explored it.