[buddypress-trac] [BuddyPress Trac] #6327: Improved caching for group membership

[buddypress-trac]

#6327: Improved caching for group membership
--------------------------------+------------------
 Reporter:  boonebgorges        |       Owner:
     Type:  defect (bug)        |      Status:  new
 Priority:  normal              |   Milestone:  2.3
Component:  Component - Groups  |     Version:
 Severity:  normal              |  Resolution:
 Keywords:  has-patch           |
--------------------------------+------------------
Changes (by boonebgorges):

 * keywords:   => has-patch


Comment:

 [attachment:6327.patch] demonstrates what I have in mind. It does the
 following:

 * Introduces `bp_get_user_groups()`. This function fetches data about a
 user's group memberships in a cache-friendly way, and supports some
 parameters for filtering the return results.
 * Does the necessary cache invalidation. I added a few new hooks to
 `BP_Groups_Member` to support this.
 * Refactors the `groups_is_user_*()` functions to use the new function. I
 also added a couple of missing functions: `groups_is_user_invited()`,
 `groups_is_user_banned()`. These could be rewritten as a wrapper for
 `groups_is_user_status()` or something like that.
 * Refactors `BP_Groups_Group::get_group_extras()` to use the new function.
 In this case, we save not only some database overhead, but we also save a
 bunch of ugly complexity :)
 * Unit tests for the lot.

 This all works very well, and cuts down on database queries significantly,
 especially when extending with certain types of plugins.

 A couple of implementation decisions I made in the patch, which others
 might want to comment on:

 1. Cache granularity. I've chosen to cache an array of group membership
 objects in `'user_groups_' . $user_id` (bucket 'bp_groups'). It would be
 slightly more complicated, though maybe better in the long run (in terms
 of reusable cache objects), to cache only the membership IDs in
 `user_groups_$user_id`, and then to cache membership objects individually.
 This is something that could be changed later on, of course.
 2. The syntax of `bp_get_user_groups()` works like this: the `is_*`
 parameters have default boolean values, and you can pass `null` to any of
 them to disable the filters (ie, to return results that have either `true`
 or `false` for these fields). We don't really use this syntax anywhere
 else (we and WP tend to prefer a string like `'any'`), but I thought I'd
 throw it out there, just for laughs.
 3. I've only chosen a couple of places (`groups_is_user_*()` and
 `get_group_extras()`) to use the new system, though there are a couple
 other places where it could doubtless be used as well.

 Feedback welcome.

--
Ticket URL: <https://buddypress.trac.wordpress.org/ticket/6327#comment:4>
BuddyPress Trac <http://buddypress.org/>
BuddyPress Trac