I want to scrape a page that regularly updates (adding new articles with exactly the same structure as previous ones) in order to generate an RSS feed.
I can write the code to analyse the page easily, but how do I emulate a ping i.e. when the page updates how can my php script know? Does it have to be a cron job?
(Probably a duplicate question I know, but searched for a direct answer with no luck. Closest I got was http://stackoverflow.com/questions/557598/scrape-and-generate-rss-feed, which has a scraping script but no info on how to get it to respond to changes on the page automatically)