How can I run PHP script in certain interval (e.g. once a day)?

I have a php script that reads one file through http(the file is on other domain). I would like to read this file only once or twice a day, instead of connecting to it every time the website is refreshed. Is there any other way than doing it with cron? I dont want to use cron cause I prefer to setup this behaviour in the script itself .. so it is flexible, so I can use it anywhere without setting up cron every time. thanks