Introduce a capability for previewing posts

[johnbillion]

In order to preview an unpublished post (ie. draft or pending), a user needs the edit_posts capability for that post type (src).

There is a valid use case where a site requires a user role which has the capability to preview unpublished posts but not edit them, for example for editorial review/sign-off, layout review, early access, etc.

You can ​get around this by using a combination of the posts_results and the_posts filters, but this isn't very future-proof because the post results skip a bunch of logic that occurs between those two filters.

A preview_post meta capability and a preview_posts primitive capability could be introduced and implemented wherever the edit_posts capability is used in regard to previewing unpublished posts. By default, it will simply map to the edit_posts capability.

Thoughts?

[morganestes]

I think this could definitely be useful, especially with publishing shops that may not want to rely on a plugin for their editorial flow.

For implementation, would this be a checkbox on the user's profile page that is set by someone with a specific (filterable) capability (read-only for everyone else, maybe?) or would it be enabled through a hook, or some other way I haven't thought of?

[DrewAPicture]

Replying to morganestes:

I think this could definitely be useful, especially with publishing shops that may not want to rely on a plugin for their editorial flow.

For implementation, would this be a checkbox on the user's profile page that is set by someone with a specific (filterable) capability (read-only for everyone else, maybe?) or would it be enabled through a hook, or some other way I haven't thought of?

I think the most elegant way to do it would be to just give it to users who current have edit_posts by default, along the lines of the sub-cap concept (see the customize cap), thereby making it possible to programmatically remove the cap rather than add it.

[johnbillion]

This turns out to be more complicated that it first seems.

After patching several places in core with a preview_post capability check, I realised that previewing draft posts is a very different action to previewing changes to published posts, but they're both called previews.

We might need a collection of caps such as preview_published_posts, preview_others_posts, etc.

[johnbillion]

#22968 was marked as a duplicate.

[archon810]

@johnbillion Will you have time to tackle this again properly any time soon? It'd be a great feature for multi-user Wordpress installations everywhere.

[johnbillion]

I'd love to, but I won't have time to tackle it in the next few months due to other commitments.

[flixos90]

All of these are part of a larger goal.