With Linux crontabs, you can schedule events to run once per day, month, week, etc. In Drupal, however, your hook_cron() will be run with every call to cron.php. Hopefully a cron-scheduling API is in the works, but in the meantime here's a snippet for scheduling your own hook_cron() jobs.

<?php
function YOURMODULE_cron(){
  $cron_last = db_result(db_query('select timestamp from {watchdog} where type="cron" order by timestamp desc limit 1')); 
  // Or using poormanscron.module:
  // $cron_last = variable_get('cron_last', time());

  // if( date('ym', $cron_last) != date('ym', time() ) ){ // Once per month
  if( date('ymd', $cron_last) != date('ymd', time() ) ){ // Once daily
    // Code here
  }
}
?>

Comments

Alex Andrascu’s picture

Alex Andrascu commented

If you have a site where cron runs hourly and you want to run you own module cron at let's say 19'o clock each day you'll do something like

<?php
function YOURMODULE_cron(){
  if( date('G', $time) == 19) ){ // At 19'o clock
    // Code here
  }
}
?>
anou’s picture

anou
Primary language French
Location Collonges au Mont d'Or
commented

Thanks for this but I think you wanted to write :

<?php
function YOURMODULE_cron(){
  if( date('G', time()) == 19) ){ // At 19'o clock
    // Code here
  }
}
?>

David THOMAS
http://www.smol.org

darrenwh’s picture

darrenwh commented

Actually you don't need time as its there by default

function YOURMODULE_cron(){
  if( date('G') == 19) ){ // At 19'o clock
    // Code here
  }
}
Anybody’s picture

Anybody
Primary language German
Location Porta Westfalica
commented 
function YOURMODULE_cron(){
  if( date('G') == 19){ // At 19'o clock
    // Code here
  }
}

is right.
There was one ")" too much.

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gopal6988’s picture

gopal6988 commented

Thanks really, its what i need..

tannguyenhn’s picture

tannguyenhn commented

Weekly, i want send email to clients. How can i do that ?

vipul tulse’s picture

vipul tulse commented

if (date('G')==0 && date('i')==00 && date('l')=="Monday") {
//Your code here
}

* change day according to your requirement

FranciscoLuz’s picture

FranciscoLuz commented

PHP Cron Scheduler might come handy.

Drupal in the Amazon Jungle

glass.dimly’s picture

glass.dimly commented

I wouldn't access tables from other modules, especially when variable_set and variable_get are so easy to use in d7.

mymodule_cron() {
    $last_notification = variable_get('mymodule', 0);
    if ($last_notification < strtotime('-1 week')) {
      myjob();
      variable_set('mymodule', time());

    }
}