Thanks, Jeff, for illustrating just how flexible and multi-facetted REBOL really is Compared to your example I can see how uneconomical my attempt was. The timeout check was required, though, on a particular site prone to long loading times - but I'm beginning to see how the check could be done more eloquently. Much appreciated. REBOL ROCKS! -andre ps sorry, i seem to have messed the thread heading! >> sites: [ >> "Site 1" http//www.site1.com "1" >> "Site 2" http//www.site2.com "1" >> "Page2" http//www.site1.com/page2.htm "1" >> ] >> >> while [ true ][ >> foreach [name url status] sites [ >> start: fourth now >> either error? try [read url][ >> if status = "1" [ >> message: reform ["Rebol Alert:" name "is down!"] >> send [EMAIL PROTECTED] message >> change status "0"] >> ] >> [change status "1"] >> stop: fourth now >> if stop - start >= 0:00:45 [ >> if status = "1" [ >> message: reform ["Rebol Alert:" name "timed out!"] >> send [EMAIL PROTECTED] message ; >> ] >> ] >> ] >> print reform [fourth now "Pausing for 5 min"] >> wait 0:05:00 ; ------------ //change to suite your needs >> ] > > Another approach: > sites: [ > http://www.worldrps.com > http://www.theonion.com > http://www.rebol.org > http://www.doesnotexist.com > http://www.neitherdoesthis.com > ] > total-no-go: copy [] > forever [ > no-go: copy [] > foreach site sites [ > all [not exists? site append no-go site] > ] > if not empty? no-go: difference no-go total-no-go [ > send [EMAIL PROTECTED] reform ["These sites down:" no-go] > ] > total-no-go: union total-no-go no-go > wait 00:05:00 > ] > EXISTS? works for urls. The UNION and DIFERENCE functions let you > see pretty quickly when something new has entered a set of items, in > this case the set of missing sites. Like Andre's code, the above will > only send mail the first time a site goes down (but the above code > doesn't deal with time out errors, as Andre's does (-:). Using > DIFFERENCE you can also then restrict further checking of urls to only > those sites you haven't found to be down previously. > > (ie: sites: difference sites total-no-go). > There's so many ways to do things in REBOL. It's just t00 k00l! :) > -jeff
