如何从我的PHP应用程序安全地创建Cron作业？

Question

I am building a web app (using PHP) which needs to offer the end user the functionality to receive an update every x hours, between a range of dates. I know you can create a cron job using "shell". However, I have disabled shell in php.ini to secure my server, in the event of any malicious code finding its way on to my server. Is there a way to securely create a cron job from my app without resorting to using system commands?

Edit

In response to Halayem's comment for further clarification. A registered user in my system may set up a repeating task in my app that will send an SMS message to their mobile number every X Hours where X is a user defined time. I wish to build a secure way of implementing a cron job to automatically send the message every X Hours when the user creates the task.

Answer 1

You don't ever dynamically create new cron jobs from code, that's madness. What you do is you set up one cron job explicitly which checks every so often if there's something to do, and you keep a database of tasks that the cron job should do.

Simple example: if there's an option for your customers to receive a mail every hour, then you set up a cron job which checks your database every hour for which customers opted into receiving a mail and then sends those mails.