Add Akismet "X-akismet-pro-tip" support

[netweb]

Via ​#BuddyPress6594

See the "spam response example" on ​http://akismet.com/development/api/#comment-check and ​http://blog.akismet.com/2014/04/23/theres-a-ninja-in-your-akismet/

TL;DR: If the X-akismet-pro-tip header is set to discard, then Akismet has determined that the comment is blatant spam, and you can safely discard it without saving it in any spam queue.

[Otto42]

Part of the problem making this difficult is that the Akismet code in bbPress is silently discarding the header information coming from Akismet.

​https://bbpress.trac.wordpress.org/browser/trunk/src/includes/extend/akismet.php#L429

The header information we want is in $response[0], which is not saved.

Additionally, the action hooks in this code are, well, kind of bizarre.

​https://bbpress.trac.wordpress.org/browser/trunk/src/includes/extend/akismet.php#L193

I can think of no sane reason to call do_action_ref_array() here, while passing it the $post_data array. The post data will not be in array form and also will be in a random order. It can't really be manipulated at all this way. This needs to be a do_action, not a do_action_ref_array. As it stands, this filter is currently unusable.

If these were done correctly, then either a separate plugin or a simple check of the headers could set the post_status to "trash" before the post was inserted.

Header check would likely go here:
​https://bbpress.trac.wordpress.org/browser/trunk/src/includes/extend/akismet.php#L196

Alternatively, if one wanted to wipe the post out entirely, before it ever saved to the database, then bbPress would need an alteration in these two places:

​https://bbpress.trac.wordpress.org/browser/trunk/src/includes/topics/functions.php#L341
​https://bbpress.trac.wordpress.org/browser/trunk/src/includes/replies/functions.php#L393

To allow something like a "false" coming back from this filter to bail and skip the wp_insert_post() call entirely.

[Otto42]

First draft for a patch. Saves the header data, eliminates the useless do_action_ref_array call and replaces with a filter, adds post data to the spam check action

[Otto42]

First draft for a patch. Saves the header data, eliminates the useless do_action_ref_array call and replaces with a filter, adds post data to the spam check action. This would make it possible for another plugin to get the headers from the akismet call and take some kind of action based on them.

[Kenshino]

Hey @Otto42 @netweb,

Can we get some focus on this? Akismet is doing nothing for all the University Spam that we are getting at W.org and it seems we're simply using most of our time to handle that nowadays.

I can only imagine how hard they're spamming other bbPress sites.

[johnjamesjacoby]

In 7126:

Akismet: add support for request headers.

This commit stops discarding the header information coming back from Akismet, and instead allows it to be filtered as needed.

In trunk, for 2.7.

Props Otto42.

See #2853.

[johnjamesjacoby]

In 7127:

Akismet: add support for request headers.

This commit stops discarding the header information coming back from Akismet, and instead allows it to be filtered as needed.

In branches/2.6, for 2.6.6.

Props Otto42.

See #2853.

[stephdau]

Happy dance (re: commit)!