Change update-links to be wp-cron compatible

[Otto42]

update-links.php is a file that does little other than to update the links link_updated times using pingomatic when it's called. However, there's nothing in Wordpress to run it at all. The trigger has to be external.

With the addition of wp-cron to the 2.1 line, the update-links.php file should be wrapped in a function with an action hook and included into the main source, so that wp-cron can trigger it on some basis.

Further suggestion: Rig the "track link update times" checkbox on Options->Misc to activate and deactivate this wp-cron job as needed. The checking timer can be set to, say, 1-2 hours or so. Add a filter to the timer so that it can be easily modified if needed. Or make it an option or something.

Seems like a good use of WP-Cron.

Added patch to move update links into a cron job. Features of this patch:

• Adds two new functions. One does the updating of the links, the other manages the wp-cron scheduling based on the enabling/disabling of the links update option.
• Scheduling frequency is filtered for easy plugin changing (defaults to daily).
• Both new functions are pluggable, in case a plugin wants to change how the updating or scheduling works entirely.

Makes update links functionality into a wp-cron job.

What is your plan for update-links.php ? Update it to use this function? Delete it altogether?

Delete it altogether. The only reason to have it separate is so it can be executed separately as a cron job. With wp-cron doing it, there's no reason to have it at all. And with the function being pluggable, plugins can replace it if they like.

Sounds fine. This should be good to go in after a little testing.

Sounds good. Word of warning to the testers: I've never gotten the pingomatic call to actually work. I think this is a problem with pingomatic. But, since this is the current code, it's what I used for this patch.

The patch in ticket #4231 also has this code change, but also changes the update_links code to use RSS feeds to get the last updated time instead. That code actually works because it doesn't rely on pingomatic.

Any traction on this? I really want something like this put into the core code. The patch may need to be refreshed at this point.

not even sure this is still current...

I've removed the Link update checking from core. This is better left for plugin material. See #12437