Have script run some code every 24hrs...

[cgm225]

I have a script that is used multiple times a day.  However, I want to have a block of it only run every 24hrs.  Has anyone written anything like this before?  Could you help me code this?  I am guessing I need to store a date in a flat file or database entry?

 

Thank you all in advance!

 

 

[trq]

You will need to setup a cron job (search the board) to run your script at a specified time.

[cgm225]

I don't have access to setup a cron job or cron tab job..  so is there another way to do this?

[haku]

I don't think there is. PHP is a passive language rather than active, in that it won't do anything without some sort of input from a user (or a cron job).

 

[cgm225]

I was thinking (though I did not know exactly how to do it), that a time could be posted to a text file or database, to which a script could then reference.  If the current time is >=24hrs past the posted time, then the script could run, and while doing so, update the posted time with the current time.. and so on and so fourth it would go..

 

Is that possible?

[haku]

Yes, you could do that. But the script wouldn't run at exactly the 24 hour mark, rather it would run the first time it was triggered after 24 hours had passed. If this isn't a problem, and you have no access to cron jobs, this is probably your best option.

[cgm225]

Yes, that is what I want.. so how could I code that?  (also, thanks again for the help!)

[haku]

Honestly, you code it exactly how you said it. Create a column in a database that holds the time, and then choose a script (or all your scripts) and add a query at the top of them that checks the time stored in that column in the database, and if that time has been reached, launches the script (you can do this with an include function, just make sure the script has no output or the person viewing the script will be a little confused). Have the script that calls the other script then insert the current time in the database.

[marklarah]

If your site gets regular visits, you could just everytime a user does something on your site, make t run a checking script.

[haku]

That will work, although it adds a lot of extra overhead to your site. I would set it to run only on one script, but one that is used fairly regularly. That way you don't have an unnecessary call to the database every single time a person accesses a page on your site.

[eddierosenthal]

you need to have a piece of code that will sleep for 24 hours then wake up, do it's thing, and call itself.

you should be able to call it; with 'exec' or 'system' or 'pcntl_fork'  depending on  your OS, and whether or not

you are running apache or not.

you will need to see which version of fork you need for your os and your web server.

it's definitely not a database type of application you need .

google for fork and php and see what you come up with.

there are people on this board who will write the code for you, nice i am, not that nice.

 

 

[haku]

Nice or not, thats a good piece of advice. I knew about Cron jobs myself, but this is the first time I've heard of this fork.

[laffin]

That will work, although it adds a lot of extra overhead to your site. I would set it to run only on one script, but one that is used fairly regularly. That way you don't have an unnecessary call to the database every single time a person accesses a page on your site.

 

this is easily avoided, by having a db entry of lastrun time, a simple check if it's been over 24 hrs (or if the date is different) than it's time to run again.

 

 

[haku]

That's what I was saying would add a lot of extra overhead to your site. If you have ever script querying the database every time to see if its time to run that script, then the number of unnecessary queries to the database is equal to one less than your entire queries for a day. That's why it would be better to add that check to a script that is run somewhat frequently, but not all the time. It cuts down a lot of unnecessary queries.

[litebearer]

a possible alternative:

 

Presuming -

1 - the script is not hosted on your own computer

2 - you leave your home computer on 24/7

 

if so then simply use a scheduling program to run the script at the appointed time via your browser.

 

I do this to gather data and generate reports each morning, so they are ready from me to read when I get up.

[cgm225]

My home computer is not on 24/7, and I do not have cron job/cron tab access.

 

However, I am interested in how using fork would work.  I am not asking for you to code this for me, but could you give a general piece of example code to help me understand how that would accomplish what I am looking to do?

[redarrow]

 

read this all you need to no ok....

 

http://www.sitepoint.com/article/introducing-cron

 

regards redarrow always program the safe way..........

[eddierosenthal]

here's a couple of links for explaining the ins and outs of using php for forking -

i think you would have to use these hands on to get the feel of them.

i've done a lot of this stuff in C when i had root, but that is a different story ...

http://www.van-steenbeek.net/?q=php_pcntl_fork

and http://us.php.net/exec

 

i can't remember where i googled for this but here is a cut and paste job from an excellent article

sorry i cannot give credits to author right now . please google for more.

Instead of forking your PHP script you can exec() another process to run in the background. This obviously isn’t the same as forking, but it is about as close as you can get when running as an Apache module. While reading through the comments on the PHP exec() page I was able to piece together enough information to make execing a background process work. Here’s an example:

 

exec("/usr/local/bin/myprog 2>/dev/null >&- < &- >/dev/null &”);

 

This will execute /usr/local/bin/myprog and redirect STDOUT and STDERR to /dev/null and run the process in the background. You can even pass arguments to your program like this:

 

$safe_arg["arg_1"] = escapeshellarg($arg_1);

$safe_arg["arg_2"] = escapeshellarg($arg_2);

exec("/usr/local/bin/myprog {$safe_arg["arg_1"]} {$safe_arg["arg_2"]} 2>/dev/null >&- < &- >/dev/null &”);