PHP 没有 Cron 的计划任务

Question

I have shared hosting with limited privileges to make advanced setup. But I need to make some job once a time without Cron. So how can I run PHP script at scheduled time? Let's say I need to send email notification from server after 2h. My first idea to make loop until time is up, but wouldn't it drain resources unnecessarily? Second just compare server system time with desired time, but has nothing to run the script. Any idea how to solve this issue?

Answer 1

Take a look at the PHP sleep function ( https://www.php.net/manual/en/function.sleep.php )

You could potentially have a loop that would compare the current time to your desired time. If the current time still wasn't your desired time, you could sleep for x number of seconds.

*Word of caution: This method likely won't get your script to run at exactly your desired time like a cron job, but will be accurate to the amount of time you put in your sleep call in-between checks. Also, I wouldn't trust the sleep function to return at exactly your desired time (ex. if you want to wait five minutes then sleep(5*60) likely wouldn't return at exactly 5 minutes. Cron jobs would definitely be recommended if possible. *