I am talking about, how for instance article is going to be published exactly in 16:00? There's a cron that checking the schedule posts every minute?

I am asking because i wish to write crawler, which will bring content from specific website every time this website will publish a brand new content.

Exactly the same example we have seen in the search engines readers, each new article out of your activated websites, readers can have immediately

Thanks!

Whenever a user visits the website (any user), a pseudo-cron job runs. Essentially, every PHP page is connected to some cron-like atmosphere that executes code when known as.

I only say "pseudo" since you can't distinguish it from the real one. The only method you are able to tell is always to see the web page to check on for brand new content, triggering the task (which happens while you request the page).

For the crawler, why must you crawl it? Just download the Feed (most styles support it). It consists of all the recent posts inside a nice format.

As @Blender noted, the occasions are triggered with a psuedo-cron process which runs whenever a user accesses the house page. It'll execute scheduled actions as lengthy his or her scheduled the years have passed.

You are able to hook your personal actions into this method. See these pages around the WordPress Codex around Wordpress-Cron, particularly this one about arranging occasions.