I want to understand plugin implementation of custom posts / taxonomies / metaboxes

Question

I want to find a long-term GUI/plugin-based solution to working with custom posts types, custom taxonomies, and custom fields/metaboxes.

To this end I have been reviewing all the major custom post-type related plugins. A long list. I have discovered something which I am confused about, hence my question. I was not able to find an answer to this question after much research online.

I notice that NONE of the plugins I have installed appear to be cross compatible. If I create a custom type in one, it will not show up in ANY of the others. If I create a custom taxonomy in one plugin it will (in most cases) show up as being assignable to a custom post type created in a different plugin… which makes sense to me. But it will not show up as editable in any other custom-type plugin. The same goes for custom fields/metaboxes.

Having read through the custom types info in the Wordpress Codex this behaviour doesn't make sense to me. I have, perhaps wrongly, assumed these plugins are adding code to the functions.php file, and that each plugin would be able to access the code of the other.

My concern is that if I use a particular custom types (etc.) plugin and then later on it is not updated to support future WP versions, I may end up losing all my custom-types/taxonomies/fields functionality. I would then have to set up all the types, etc., again using a more current plugin. A few of the plugins I've seen have an export and perhaps an import feature. But as far as I can tell this is for exporting and importing the data of that particular plugin (although I am not 100% certain about that).

Is my concern a valid one? Or am I missing an essential point somewhere? If I set up a lot of custom content using a plugin, and that plugin ceases to function down the road, will I have to set everything up again?

Answer 1

Let's start by looking at the Action Reference page in Codex: Actions Run During a Typical Request.

When a page is loaded on the front or back end, WordPress goes through the load process- loading its own code, loading plugins, the theme, calling each action in sequence.

You can see in the second and third actions where it registers the native types- post, page, etc..

The environment is built this way for each request- a post type exists for the life of a request, and disappears if the plugin that registered it is deactivated.

However, the actual data- your posts, taxonomy terms, custom field values- are all safely stored in the database. If you were to register the post type with another plugin using the same name, your post type would appear and be usable again.

So, in short, as long as a plugin adheres to the WordPress API, you aren't in danger of losing that data