Allow Ability to Disable Pingbacks and Trackbacks by Protocol

[dshanske]

Related #36576, which covers making it easier to disable sending of linkbacks by protocol in a functional manner..

The form I am thinking this would take would be a filter that filtered an array of protocols to receive and another for protocols to send, hooking this in to the various areas.

[dshanske]

The function I am thinking would be allowed_ping_protocol and would be filterable.

It would be called in wp_trackback, do_all_pings, and pingback_ping and terminate, skip, or reject if the protocol was not allowed.

[dshanske]

Add functionality to disable trackback processing

[dshanske]

In the interest of simplicity, I created a patch for an alternate solution. A hook that runs when wp-trackback is triggered that can either be used to process the trackback in lieu of the existing code(allowing it to be possibly enhanced or moved into a function attached to same, but to simply add an exit which will not process anything.

[rachelbaker]

@dshanske Looking at 37007.diff​ I noticed you aren't passing any values for the action. How would you then use this hook to determine if you would allow the trackback?

[dshanske]

Improvements suggested by @rachelbaker

[dshanske]

@rachelbaker I moved it to accommodate the 4 parameters extracted from $_POST.

[jorbin]

@rachelbaker Can you take another look at this patch?

[rachelbaker]

Included $tb_id in the action parameters

[rachelbaker]

@dshanske Looking through 37007.2.diff​ I started feeling as though this hook would be more useful if we could include a populated $td_id (the comment_post_ID). To do that, the action needs to move lower in the function to occur JUST before the trackback is added. See 37007.3.diff​ where I move the pre_trackback_post action down several lines and add the $tb_id parameter.
Would this still fit your use-case?

[dshanske]

Since the goal is to allow an easy disabling of receiving trackbacks separate from pingbacks and/or allow for an improved trackback handler that is more security sensitive, that would not interfere with that goal.

[rachelbaker]

In 38791:

Pings/Trackbacks: Add new pre_trackback_post action before a trackback is added to a post.

Props dshanske, rachelbaker.
Fixes #37007.