LiveCode equivalent to 'cron' for automated background functions?
ambassador at fourthworld.com
Wed Nov 28 15:45:38 EST 2018
Keith Clarke wrote:
> Please can anyone steer me towards the dictionary keyword equivalent
> to ‘cron' jobs for initiating time-based background functions, along
> the lines of…
> on TimeAt pHour pMinute pSecond
> do stuff
> end TimeAt
You can do it with LC, but not as a CGI, as LC Server is most commonly
used. CGIs boot a scripting engine, the engine processes the request,
sends a reply, and dies, each time it's called. Keeps things simple and
discrete, but isn't well suited for an always-on process like a cron
Shared hosts generally don't allow always-on processes, but if you're
running on a VPS or dedicated box you have the freedom to do anything
you want. For such cases "send <msg> in <time>" works well, if you set
up the process to boot with the machine and build a means of interacting
with it while it's running.
If you've seen LiveNet you've seen it in action: I have a box in the
corner of my office that aggregates RSS feeds for our community and
packages them up and posts the result to a public server for display in
LiveNet. It's been running every few minutes without interruption for
But I did it only because it was a fun exercise at the time, and if I
had to do it over again I'd just use cron - simpler, leaner, more portable.
FWIW, cron is for periodic tasks. If you need a one-off at a specific
time see at.
But can be managed from the command line, which means you can drive them
from LC if needed through the shell function.
Fourth World Systems
Software Design and Development for the Desktop, Mobile, and the Web
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