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I have a site on my webhotel I would like to run some scheduled tasks on. What methods of achieving this would you recommend?
What I’ve thought out so far is having a script included in the top of every page and then let this script check whether it’s time to run this job or not.
This is just a quick example of what I was thinking about:
if ($alreadyDone == 0 && time() > $timeToRunMaintainance) {
runTask();
$timeToRunMaintainance = time() + $interval;
}
Anything else I should take into consideration or is there a better method than this?
That's what cronjobs are made for. man crontab assuming you are running a linux server. If you don't have shell access or no way to setup cronjobs, there are free services that setup cronjobs on external servers and ping one of your URLs.
I'm answering this now because no-one seems to have mentioned this exact solution.
On a site I'm currently working on, we've set up a cron job using cPanel, but instead of running the PHP Interpreter directly (because we're using CodeIgniter and our code is mapped to a controller function, this probably isn't a great idea) we're using wget.
wget -q -O cron_job.log http://somehost/controller/method
-q is so that wget won't generate any output (so you won't keep getting emails). -O cron_job.log will save the contents of whatever your controller generates to a log file (overwritten each time so it won't keep growing).
I've found this to be the easiest way of getting 'proper' cron working.
If you have a cPanel host, you can add cron jobs through the web interface.Go to Advanced -> Cron Jobs and use the non-advanced form to set up the cron frequency. You want a command like this:
/usr/bin/php /path/to/your/php/script.php
Have you ever looked ATrigger? The PHP library is also available to start creating scheduled tasks without any overhead.
Disclaimer: I'm among their team.
if you're wondering how to actually run your PHP script from cron, there are two options: Call the PHP interpreter directly (i.e., "php /foo/myscript.php"), or use lynx (lynx http://mywebsite.com/myscript.php). Which one you choose depends mostly on how your script needs its environment configured - the paths and file access permissions will be different depending on whether you call it through the shell or the web browser. I'd recommend using lynx.
One side effect is that you get an e-mail every time it runs. To get around this, I make my cron PHP scripts output nothing (and it has to be nothing, not even whitespace) if they complete successfully, and an error message if they fail. I then call them using a small PHP script from cron. This way, I only get an e-mail if it fails. This is basically the same as the lynx method, except my shell script makes the HTTP request and not lynx.
Call this script "docron" or something (remember to chmod +x), and then use the command in your crontab: "docron http://mydomain.com/myscript.php". It e-mails you the output of the page as an HTML e-mail, if the page returns something.
#!/usr/bin/php
<?php
$h = #file_get_contents($_SERVER['argv'][1]);
if ($h === false)
{
$h = "<b>Failed to open file</b>: " . $_SERVER['argv'][1];
}
if ($h != '')
{
#mail("cron#mydomain.com", $_SERVER['argv']['1'], $h, "From: cron#mydomain.com\nMIME-Version: 1.0\nContent-type: text/html; charset=iso-8859-1");
}
?>
If you want to avoid setting up cron jobs and whatnot (though I'd suggest it's a better method), the solution you've provided is pretty good. On a number of projects, I've had the PHP script itself do the check to see whether it's time to run the update.
The down-side (okay, one of the down sides) is that if no one is using the app during a certain period then the script won't run.
The up-side is that if no one is using the app during a certain period then the script won't run. The tasks I've got it set up to do are things like "update a cache file", "do a daily backup" and whatnot. If someone isn't using the app, then you aren't going to need updated cache files, nor are there going to be any database changes to backup.
The only modification to your method which I'd suggest is that you only run those checks when someone successfully logs in. You don't need to check on every page load.
Cron is a general purpose solution for scheduling problems. But when you go big and schedules go high in frequency, there can be reliability/overlapping issues. If you see such problems, consider something like supervise or more sophisticated monit.
If you using cpanel u should add this like:
/usr/local/bin/php -q /home/yoursite/public_html/yourfile.php
I would outsource the cronjobs with www.guardiano.pm and call a url every X minute. When your url (i.e www.yoursite.com/dothis.php) is called than you execute some code. If you don't want to let the web request the page when you want you can allow only request in POST and send some parameter that only you know with guardiano.pm
Thats what I would do because I do that on my pet projects. Have fun!
The method you are using is fine, if you don't want to use cronjobs or anything external, but these can be heavy to check each time a page loads.
At first, some cronjobs can probably be replaced. For example if you have a counter for how many users have registered on your website, you can simply update this number when a user registers, so you don't have to use a cronjob or any scheduled task for this.
If you want to use scheduled tasks, I suggest you to use the method you are using right now, but with a little modification. If you're site has enough hits on a day, you can simply make the tasks run (or the tasks check function run) only for 1% or maybe 0.01% of the hits instead of all of them, the percentage you should use depends on the page hits you have and how many times you want to run the task. So, simply add a randomizer to achieve this feature.
You could simply use a function like this;
if(rand (1, 100) <= 1) { // 1, 100 is used to generate a number between 1 and 100. 1 is for one percent.
// Run the tasks system
}
Command line PHP + cron would be the way I would go. It's simple and should fit the bill. It is usually installed with PHP as a matter of course.
If you do not have the option to setup a cronjob you can call the script with cUrl (as alternative to wget - same functionality). Just do a scheduled task on your local machine that executes the cUrl function.
If you want something more abstract, you might consider using something like a PHP scheduler.
For example:
https://github.com/lavary/crunz
https://github.com/peppeocchi/php-cron-scheduler
And also, to parse the cron expression, you could use an existing library such as https://github.com/mtdowling/cron-expression. It provides a lot of useful methods to help you figure out information of a cron job.
Hope that helps.
I just can't figure this out.
I have a script that gets data from Facebook API and this script runs all the time. (using set_time_limit(0); )
However, sometimes the Facebook API gives errors and stops the script. Therefor, I would like to have a cron task every 5 minutes or so that checks to see if the script is still running and if not, starts it again.
I tried several things but it looks like I cannot run a exec() command from a cron job because of different user rights or something? How would you guys do this?
I use CentOS and PHP 5.3+
Set up the cron under a different user (say, root), which will get around any rights issues. However, PeeHaa makes a good point: if this is a cron script, there's no reason to use exec, as exec's job is to send commands out to the OS... these commands can be run directly from the crontab rather than having cron execute a php file.
You may want to look into creating a Daemon which is better suited to running a script continuously. You can create one using PHP with this PEAR package System_Daemon
If this process runs very frequently, run it in an endless loop and just sleep it. No need for crontabs.
while(true) {
//magical code stuff
sleep(60);
}
I have written a PHP script which generates an SQL file containing all tables in my database.
What I want to do is execute this script daily or every n days. I have read about cron jobs but I am using Windows. How can I automate the script execution on the server?
You'll need to add a scheduled task to call the URL.
First of all, read up here:
MS KB - this is for Windows XP.
Second, you'll need some way to call the URL - i'd recommend using something like wget - this way you can call the URL and save the output to a file, so you can see what the debug output is. You can get hold of wget on this page.
Final step is, as Gabriel says, write a batch file to tie all this up, then away you go.
e: wget is pretty simple to use, but if you have any issues, leave a comment and I'll help out.
ee: thinking about it, you don't even really need a batch file, and could just call wget directly..
add a scheduled task to request the url. either using a batch file or a script file (WSH).
http://blog.netnerds.net/2007/01/vbscript-download-and-save-a-binary-file/
this script will allow you to download binary data from a web source. Modify it to work for you particular case. This vbs file can either be run directly or executed from within a script. Alternately you do not have to save the file using the script, you can just output the contents (WScript.Echo objXMLHTTP.ResponseBody) and utilize the CMD out to file argument:
cscript download.vbs > logfile.log
save that bad boy in a .bat file somewhere useful and call it in the scheduler: http://lifehacker.com/153089/hack-attack-using-windows-scheduled-tasks
Cron is not always available on many hosting accounts.
But try this:
http://www.phpjobscheduler.co.uk/
its free, has a useful interface so you can see all the scheduled tasks and will run on any host that provides php and mysql.
You can use ATrigger scheduling service. A PHP library is also available to create scheduled tasks without overhead. Reporting, Analytics, Error Handling and more benefits.
Disclaimer: I was among the ATrigger team. It's a freeware and I have not any commercial purpose.
Windows doesn't have cron, but it does come with the 'at' command. It's not as flexible as cron, but it will allow you to schedule arbitrary tasks for execution from the command line.
Yes, You can schedule and execute your php script on windows to run automatically. In linux like os u will have cron but on windows u can schedule task using task scheduler.
If your code is in remote hosted server then create a cron-job for the same.
Else if in local then use a scheduled task in windows.Its easy to implement.I am having servers with so many scheduled tasks running.
I am working on a site that require a php script running on a server without any request,
it is a bot script that keeps (not full time but at least once a day) checking client accounts and send alert messages to clients when something happens.
any ideas are appreciated.
Assuming you need to do this on linux, you may run any php script from the browser and from the CLI as well.
You may run a simple php script:
<? echo "Ana are mere"; ?>
like this:
php -f ./index.php
Be careful about file-permissions, and any bug that may creep inside your code, memory leaks or unallocated variables will become VERY visible now, as the process will run continuously.
If you dont want it running in the background all the time, take a look at crontab (http://unixgeeks.org/security/newbie/unix/cron-1.html) to be able to start jobs regularly.
-- edit--
take a look at php execute a background process and PHP: How to return information to a waiting script and continue processing
Basically you want to start a background process, and you may do this by either using exec() or fsockopen() or a file_get_contents() on your own script probably in this order, if don't have access to exec, or socket functions.
Also take a look at http://us2.php.net/manual/en/function.session-write-close.php so the "background script" won't "block" the request and http://us2.php.net/manual/en/function.ignore-user-abort.php
Use a cron job to do it http://www.cronjobs.org/
You can automatically call a script at any interval you like indefinitely. Your hosting provider should support them if they are good.
You should also consider putting a unique key on the end of the page
ie. www.yoursite.com/cronjob.php?key=randomstring
and then only run the script if the key is correct, to prevent bots and other users from running the script when you don't want it run.
If you can't create a cron job, then create a page that does what you want and create a scheduled task on another machine (maybe your PC?) that just goes out and hits that page at a certain time every day.
It's really a hack, but if you absolutely can't set up a cron job, it would be an option.
As Evernoob and Quamis said, you want to have a cron job (UNIX/Linux/Mac OS) or a scheduled task (MS Windows). Furthermore, you can either have the PHP script run using the PHP command line interface (CLI), in which case you can invoke the PHP executable and then your script name. As an alternate, you can use a tool like wget (availble on all platforms) to invoke the PHP script as if someone had typed the URL in the location bar of a web browser.
A php script could not be used like you imagine here. Because it's executed through apache after a request from somewhere.
Even if you do while(1) in your script, apache/php will automaticly stop your script.
Responding to your comment, yes you'll need ssh access to do this, except if your web interface allow you to add cronjob.
Maybe you can write a service which can be executed with a program on another server and do the job.
If you have no access to the server the easiest way would probably be to hit it through the browser, but that would require you or an external script hitting the URL at the same interval each day when you wanted it to one. You may also be able to setup a Selenium test suite that runs locally on a schedule and hits the page. I'm not 100% if that's possible with Selenium though, you may need some 3rd-party apps to make it happen.
Something else you could try would be to see about using PHP's Process Control Functions (link). These will let you create a script that is a deamon and runs in the background. You may be able to do this to keep the script running on the server and firing off commands at programmed intervals. You will still need some way to get it running the first time (browser request or via command line) though.
I have a site on my webhotel I would like to run some scheduled tasks on. What methods of achieving this would you recommend?
What I’ve thought out so far is having a script included in the top of every page and then let this script check whether it’s time to run this job or not.
This is just a quick example of what I was thinking about:
if ($alreadyDone == 0 && time() > $timeToRunMaintainance) {
runTask();
$timeToRunMaintainance = time() + $interval;
}
Anything else I should take into consideration or is there a better method than this?
That's what cronjobs are made for. man crontab assuming you are running a linux server. If you don't have shell access or no way to setup cronjobs, there are free services that setup cronjobs on external servers and ping one of your URLs.
I'm answering this now because no-one seems to have mentioned this exact solution.
On a site I'm currently working on, we've set up a cron job using cPanel, but instead of running the PHP Interpreter directly (because we're using CodeIgniter and our code is mapped to a controller function, this probably isn't a great idea) we're using wget.
wget -q -O cron_job.log http://somehost/controller/method
-q is so that wget won't generate any output (so you won't keep getting emails). -O cron_job.log will save the contents of whatever your controller generates to a log file (overwritten each time so it won't keep growing).
I've found this to be the easiest way of getting 'proper' cron working.
If you have a cPanel host, you can add cron jobs through the web interface.Go to Advanced -> Cron Jobs and use the non-advanced form to set up the cron frequency. You want a command like this:
/usr/bin/php /path/to/your/php/script.php
Have you ever looked ATrigger? The PHP library is also available to start creating scheduled tasks without any overhead.
Disclaimer: I'm among their team.
if you're wondering how to actually run your PHP script from cron, there are two options: Call the PHP interpreter directly (i.e., "php /foo/myscript.php"), or use lynx (lynx http://mywebsite.com/myscript.php). Which one you choose depends mostly on how your script needs its environment configured - the paths and file access permissions will be different depending on whether you call it through the shell or the web browser. I'd recommend using lynx.
One side effect is that you get an e-mail every time it runs. To get around this, I make my cron PHP scripts output nothing (and it has to be nothing, not even whitespace) if they complete successfully, and an error message if they fail. I then call them using a small PHP script from cron. This way, I only get an e-mail if it fails. This is basically the same as the lynx method, except my shell script makes the HTTP request and not lynx.
Call this script "docron" or something (remember to chmod +x), and then use the command in your crontab: "docron http://mydomain.com/myscript.php". It e-mails you the output of the page as an HTML e-mail, if the page returns something.
#!/usr/bin/php
<?php
$h = #file_get_contents($_SERVER['argv'][1]);
if ($h === false)
{
$h = "<b>Failed to open file</b>: " . $_SERVER['argv'][1];
}
if ($h != '')
{
#mail("cron#mydomain.com", $_SERVER['argv']['1'], $h, "From: cron#mydomain.com\nMIME-Version: 1.0\nContent-type: text/html; charset=iso-8859-1");
}
?>
If you want to avoid setting up cron jobs and whatnot (though I'd suggest it's a better method), the solution you've provided is pretty good. On a number of projects, I've had the PHP script itself do the check to see whether it's time to run the update.
The down-side (okay, one of the down sides) is that if no one is using the app during a certain period then the script won't run.
The up-side is that if no one is using the app during a certain period then the script won't run. The tasks I've got it set up to do are things like "update a cache file", "do a daily backup" and whatnot. If someone isn't using the app, then you aren't going to need updated cache files, nor are there going to be any database changes to backup.
The only modification to your method which I'd suggest is that you only run those checks when someone successfully logs in. You don't need to check on every page load.
Cron is a general purpose solution for scheduling problems. But when you go big and schedules go high in frequency, there can be reliability/overlapping issues. If you see such problems, consider something like supervise or more sophisticated monit.
If you using cpanel u should add this like:
/usr/local/bin/php -q /home/yoursite/public_html/yourfile.php
I would outsource the cronjobs with www.guardiano.pm and call a url every X minute. When your url (i.e www.yoursite.com/dothis.php) is called than you execute some code. If you don't want to let the web request the page when you want you can allow only request in POST and send some parameter that only you know with guardiano.pm
Thats what I would do because I do that on my pet projects. Have fun!
The method you are using is fine, if you don't want to use cronjobs or anything external, but these can be heavy to check each time a page loads.
At first, some cronjobs can probably be replaced. For example if you have a counter for how many users have registered on your website, you can simply update this number when a user registers, so you don't have to use a cronjob or any scheduled task for this.
If you want to use scheduled tasks, I suggest you to use the method you are using right now, but with a little modification. If you're site has enough hits on a day, you can simply make the tasks run (or the tasks check function run) only for 1% or maybe 0.01% of the hits instead of all of them, the percentage you should use depends on the page hits you have and how many times you want to run the task. So, simply add a randomizer to achieve this feature.
You could simply use a function like this;
if(rand (1, 100) <= 1) { // 1, 100 is used to generate a number between 1 and 100. 1 is for one percent.
// Run the tasks system
}
Command line PHP + cron would be the way I would go. It's simple and should fit the bill. It is usually installed with PHP as a matter of course.
If you do not have the option to setup a cronjob you can call the script with cUrl (as alternative to wget - same functionality). Just do a scheduled task on your local machine that executes the cUrl function.
If you want something more abstract, you might consider using something like a PHP scheduler.
For example:
https://github.com/lavary/crunz
https://github.com/peppeocchi/php-cron-scheduler
And also, to parse the cron expression, you could use an existing library such as https://github.com/mtdowling/cron-expression. It provides a lot of useful methods to help you figure out information of a cron job.
Hope that helps.