[buddypress-trac] [BuddyPress] #3985: Race condition processing Ajax requests.

[buddypress-trac at lists.automattic.com]

#3985: Race condition processing Ajax requests.
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 Reporter:  gary_mazz                   |       Owner:  DJPaul
     Type:  defect (bug)                |      Status:  assigned
 Priority:  normal                      |   Milestone:  1.6
Component:  Core                        |     Version:  1.5.3
 Severity:  major                       |  Resolution:
 Keywords:  dev-feedback needs-testing  |
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Comment (by boonebgorges):

 Thanks for all your work on this, Paul. Looks pretty good, with one
 problem.

 I've applied the patch against the current trunk, with the following theme
 setups:
 1. BP-Default
 2. Child theme of BP-Default, which allows bp-default to use its native
 ajax.php and global.js (Status)
 3. A theme adapted for BP using a recent version of the BP Template Pack
 (loads ajax.php and global.js directly from bp-default, so this is
 essentially the same as 2)
 4. A theme with manually-added BP compatibility: global.js and ajax.php
 (old versions) copied into the theme, and enqueued/included manually

 As expected, 1-3 all work correctly. Since they all use ajax.php directly
 from bp-default, they all get the improvements automatically.

 In case (4), I'm getting stray '0's. (When clicking Favorite in the
 activity stream, for instance.) Basically, the problem that Paul outlines
 above. I have a feeling that this is going to affect a pretty fair number
 of folks (especially people who have done heavy customization, who are
 probably some of our eagerest users), so we should come up with some way
 to help them adjust. I have a couple of ideas:

 - Publicize the change heavily. Tell theme devs: Either you've got to copy
 over your included ajax.php with the new one, *or* you have to manually
 merge the changes in (if you have customized the file heavily, this might
 be the better option). Or, we could tell them to unhook our new admin-
 ajax.php method and manually provide their own `ajaxurl`, like we always
 have (they could fire up the deprecated function, maybe). (This latter
 idea seems bad for a number of reasons, but I'm just throwing it out
 there.)
 - Hack together a fix for these users. Since the problem is that the
 handler is not killing PHP execution before hitting the end of admin-
 ajax.php, we could rig BP to do it on behalf of the offending theme. The
 only place where we can really do it is on the `wp_ajax_` and
 `wp_ajax_nopriv_` hooks. Something like this, in one of our core files
 (*not* the theme):

 {{{
 // Only load when we detect that the old ajax.php is present
 if ( !function_exists( 'bp_dtheme_register_actions' ) ) :
         function bp_kill_ajax_output() {
                 $actions = array(
                         // List all the offending callback functions
                         'activity_mark_fav'           =>
 'bp_dtheme_mark_activity_favorite',
                         'activity_mark_unfav'         =>
 'bp_dtheme_unmark_activity_favorite'
                         // etc
                 );

                 foreach( $actions as $name => $function ) {
                         add_action( 'wp_ajax_'        . $name,
 create_function( '', 'die();' ), 9999 );
                         add_action( 'wp_ajax_nopriv_' . $name,
 create_function( '', 'die();' ), 9999 );
                 }
         }
         add_action( 'after_setup_theme', 'bp_kill_ajax_output', 20 );
 endif;
 }}}

 This is an ugly and pretty hackish solution. But: it fixes the '0' problem
 on all setups, for more graceful degradation.

 My feeling about this is that we should be as generous as possible to
 theme developers, who really got jerked around when 1.5 dropped. IMO we
 should do *both* of these routes (education as well as a fallback method).

-- 
Ticket URL: <https://buddypress.trac.wordpress.org/ticket/3985#comment:14>
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