Multisite taxonomies/terms for users

[schuhwerk]

Hello! Me again. Thanks for your work! 👋

Tldr.: Are you interested integrating user- and blog-terms (assigning multisite-terms not only to posts, but to sites and users)? You can find the implementation for users here.

And the longer version:
I was working on adding multisite-taxonomies to network-users for the last few days:

$taxonomy_slug = 'job';
$object_type   = 'user';
register_multisite_taxonomy( $taxonomy_slug, $object_type, $args );

The taxonomy-selectbox appears on the profile-page of a user.
Everything works the same as before for other taxonomies.

But why?

We are a big university (with ~20k people) which is grouped into many faculties, wich are subgrouped into organisations, and sub-communities (of students and teachers).
Imagine a big category-tree-structure (with ~300 entries), let's call them affiliations.
We want to assign those terms to users, blogs and also posts and make the right blogs/posts visible/filterable for the right group of people.

Why not use regular WordPress taxonomies?

We use the same tree of taxonomies three times: for users, blogs, and posts.
I wrote a library to sync terms between taxonomies (and everything is working fine), but it is not a pleasure to work with:

• "Show all blogs, which are assigned to the current user's faculty". This requires you to:
  • switch to the blog, where your affiliations live.
  • get_the_user's affiliations. Map them to the blog-affiliation's term id
  • Query the other taxonomy for the blog_ids
  • switch back
• Managing terms/taxonomies, which affect the whole network should not live in a blog (but in the network-admin).
• The WordPress structure for taxonomies is quite smart and flexible, but it can not be used to share terms between different object-types (unless you are willing to support your own WordPress fork). Multisite-taxonomies looks like a perfect place to start.

Issues

• When I assign a term to a user, the blog_id is also assigned, which does not make sense in my use-case. This could lead to confusion (or be nice in other use-cases).
• Same for blogs.
• There is currently no page when clicking on the number below "Count" in the network-taxonomy-admin interface ![[Pasted image 20230202142810.png]]
• ID-collisions:

  $object_types = array( 'user', 'post' );
  register_multisite_taxonomy( $taxonomy_slug, $object_types, $args );

  If you assign multiple object_types (that do not have unique ids) to a taxonomy you will not be able to distinguish, if a term has been assigned to the user with the id "1" or the post with the id "1". So I disabled it (for now). Looking ahead (not part of this issue/question): wp_multisite_term_multisite_taxonomy could be used to create unique multisite_term_multisite_taxonomy_id s for (non-post) object_types.

Chances

• Central role/capability management (just add a multisite_term_meta with capabilities to a user_multisite_term)
• Multisite-categories for blogs.
• Longer-term (also looking ahead): Assign (multiple) terms to terms 🤯

What do you think? - Should I create a PR? - Or should it just live in our fork?
Thanks for your time!