The plugin will do two things: set up an ActivityPub server running on the Wordpress instance, and transform the Wordpress web interface (both admin and public, e.g. comments) into an ActivityPub client.
I want to offload as much of the object storage as possible to existing Wordpress capabilities. This means that instead of storing separate objects for blog posts, comments, users, etc., the server translates the data already in the WP database to the correct JSON representation on-demand when it needs to interact with these objects. However, there may be some additional metadata that the server needs to associate with the existing representations, which can be done using linking tables (post_id -> recipients, etc.).
Collections (inboxes, outboxes, likes, follows, etc.) will probably need to have their own tables in the DB, since there’s not an obvious analog to these in classic WP.
I want the object created by the plugin to be compatible with Mastodon, whic