Re: Re: Event Handling

On Mon, 2010-03-15 at 14:40 +0530, Midhun Girish wrote: > ok so we have a script which checks if any cars have arrived within > last 10 minutes... if yes, a mail will be send..... suppose the server > fails for 30 minutes.... so when the cron comes next time, we will > have to check for cars which arrived within last 40 minutes and not > 10.. right... so how will we set a time limit in the script? its > variable na.. but the flag is ok.. you can send a mail to all db > entries which have flag 0 and then update the flag to 1. > > > Midhun Girish > Development Lead > MobAlive Technologies > > > > On Mon, Mar 15, 2010 at 2:29 PM, Ashley Sheridan > <ash@ashleysheridan.co.uk> wrote: > > > On Mon, 2010-03-15 at 14:28 +0530, Midhun Girish wrote: > > > hey ash, > > > > do we need both of those checks ? ie the time and the flag? i think they > > both do the same thing ie prevent duplicates.. am i right? and i think flag > > would be a more reliable method coz it will ensure that the email will be > > send even if the cron fails to execute for some time,.... > > > > Midhun Girish > > Development Lead > > MobAlive Technologies > > Trivandrum > > > > > > On Mon, Mar 15, 2010 at 2:13 PM, Ashley Sheridan > > <ash@ashleysheridan.co.uk>wrote: > > > > > On Mon, 2010-03-15 at 18:07 +1030, David Robley wrote: > > > > > > > Alex Major wrote: > > > > > > > > > Greetings all, > > > > > > > > > > I'm currently looking at building a web application, however > > > > > I've run > > > into > > > > > an area of development I've not come across before. The web > > > > > site in its > > > > > basic form allows users to send cars from a point and then the car > > > > > will > > > > > arrive at another point. When the car is set on its way, the start > > > time, > > > > > travel duration and end time are all known and stored in a MySQL > > > database, > > > > > what I would like to happen is that an event is triggered on the > > > > > server > > > at > > > > > the end time and then an e-mail is sent to the user. This should > > > > > happen > > > > > regardless of whether someone is browsing the website or not. > > > > > > > > > > I don't believe that I'll be able to solely use PHP, I > > > > > have spent the > > > > > afternoon trying to look at potential solutions but I have to admit > > > I've > > > > > drawn a blank. Google hasn't been helpful (64 pages so far), > > > > > as any > > > > > searches related to "event handling" bring up a load of > > > > > JavaScript > > > > > tutorials/help for 'onclick' events etc. I have searched > > > > > through the > > > PHP > > > > > documentation and found "libevent" > > > > > (http://www.php.net/manual/en/book.libevent.php ), I don't > > > > > believe > > > that is > > > > > what I require (although in all honesty the lack of documentation > > > > > on it > > > > > means I'm quite in the dark as to its purpose). Another > > > > > potential > > > > > candidate I came across was a PHP/Java bridge > > > > > (http://php-java-bridge.sourceforge.net/pjb/ ), whereby I could use > > > the > > > > > java virtual machine, register events with it and then callback PHP > > > > > scripts, although this seems extremely long winded. > > > > > > > > > > I was hoping that someone might have some experience with this kind > > > > > of > > > > > issue and could point me in the right direction. I'm sure > > > > > I've missed > > > > > something right in front of me. > > > > > > > > > > Alex. > > > > > > > > I think what you want is something to trigger a php script every > > > > $period-of-time; if your host supports it, cron is the means of > > > > executing > > > > an application at regular intervals down to a minute granularity. There > > > are > > > > some web-based cron services also, but they may not have the same > > > > granularity as a locally based cron. > > > > > > > > > > > > Cheers > > > > -- > > > > David Robley > > > > > > > > "Wow!" barked Tom, with a bow. > > > > Today is Prickle-Prickle, the 1st day of Discord in the YOLD 3176. > > > > > > > > > > > > > > > > > You could store the end times in the database, and cron can run a script > > > that will check each of these times to find any that are within x > > > minutes that an email hasn't been sent out for. You'll need an > > > extra > > > field to indicate whether an email has been sent or not. > > > > > > Thanks, > > > Ash > > > http://www.ashleysheridan.co.uk > > > > > > > > > > > > > > Consider a cron script that runs every 10 minutes. You'll want > to check the db for cars that are due to arrive within just > over 10 minutes. The flag is there more for you own > clarification that the email has been sent. What if the cron > fails, or you restart your server, or the script your cron > calls is just running a little slowly? > > > > Thanks, > Ash > http://www.ashleysheridan.co.uk > > > > > Just search for anything that has a date previous to the current (indicating the car arrived) Thanks, Ash http://www.ashleysheridan.co.uk