[wp-hackers] Filtering Themes visible for a particular network

[Andrew Nacin]

On Tue, Jul 20, 2010 at 5:59 PM, Shelby, Harper <
harper.shelby at parivedasolutions.com> wrote:

> I've been asked to implement theme filtering for a multi-network
> installation, so that network admins only see those themes which "belong" to
> them. In the existing installation (on MU 2.9.2), this was done by altering
> wpmu-themes to check for a Tags value in the theme's CSS file and filtering
> based on that. I'm trying to move this implementation into a plugin to
> reduce changes to the core code. Digging into the code, I don't see any
> action or filter hooks being called in ms-themes.php, so I suspect my best
> course of action is to move themes into network-specific subdirectories of
> wp-content/themes, then alter the include path in an admin_init hook to
> bring in the proper theme directory. Is there a better way to implement
> this, or are there any potential risks that I haven't seen in this course of
> action?
>

You can indeed register theme directories in a plugin. In fact that seems
like a very sane way of doing this (as long as you don't expect a theme to
be used across networks).