在PHP中调用Mail（）之间休眠

How would i send an email, to say 3000 recipients - with a Max 500 emails / hours on my dedicated IP? So far my thought is to send each email every 9 seconds, this would come to about 450 emails an hour... but how could i do this?

My plan for the sending of the emails would be the following...

$emails = ARRAY OF EMAILS, MYSQL RESULT
for($emails){
mail($subject,$row[email],$headers);
}

This wont work, wrong kind of statement but this concept anyway....

What I would do is :

  • create a PHP script that is launched via cron once per hour
  • this script only sends 450 e-mails, at its own speed
  • when the 450 mails are sent, the script dies
  • and some time later, it is re-launched, by cron, to send 450 other mails.

The trick is : you have to know which mails where already sent.
Ordering the mails by id in your DB, or something like that, and using limit, would be OK, I suppose

If you want to sleep for a while between mails, use the sleep function ; something between 2 and 5 seconds would probably be OK, to be sure you script the chunk of 450 mails is finished before the script is re-launched by cron.


And, thinking about it :

  • You should put some logging stuff in place : if someone complains, saying he received 10 emails, it could help you find out why.
  • I wouldn't use the mail function : there are plenty of other possibilities, using libraries that are well-tested and provide lots of functionnalities, already developped : don't re-invent the wheel ;-)

Here are a couple of libraries I can think about :

Store You messages for sending in a database, mark messages which are sent. In a cron job select some of them that are not sent, and process them. The frequency of the cron job determines the speed of sending the emails.

You could use this very handy Timer class to do the heavy lifting for you (start, stop and get the elapsed time within your loop, etc): PHPClasses: Timer.php.

Thanks for all the answers! The best way i found was actually to simply sleep() between calls using the sleep() as i tested 400 mails, this took 17 seconds :)

It is unlikely the user will send more than the 450 limit ... but if they do i have an if statement before the while() ends checking if there are more than 450 rows, if so it will sleep between each... this works without fiddly databases :)

Thanks!