check if a draft has been moved there from publish to draft

Question

I am writing a plugin, part of the functionality does functions on hook: publish_to_draft

I then later want to re-publish that post and trigger specific functionality to see if it has previously been published.

i.e. draft_to_publish

Now whilst I already have functionality for this, what I can't tell is the difference between a post that is just a draft going to publish or a previously published post that has been moved back to draft.

This is important because it is used for integration and I need to run that functionality on that action.

Can I use the_date() for this?

Cheers Dan

Answer 1

As far as I can see, you won't get any indication a post was previously published, as wordpress remembers only the old versus new transitions.

I recommend you add some meta data, that is use add_action('publish_post', 'your_function') (or similar) to do update_post_meta($post->ID, 'post_published', 'on').

That way, every post gets an indicator when it's published - and you can then use the condition if (get_post_meta($post->ID, 'post_published', true)=='on') in your 'draft_to_publish' actions.

Answer 2

The hook publish_postwas also fired, if a published posts was updated. Use the hook transition_post_status for the hint, if the post was published. The hook have params. The action transition_post_status (as defined at http://codex.wordpress.org/Post_Status_Transitions) sends three parameters, $new_status, $old_status, $post.

add_action( 'transition_post_status', 'your_function', 10, 3 );
function your_function( $new_status, $old_status, $post ) {

   if ( 'draft' === $old_status && 'publish' ==== $new_status ) {
      // your todos
   }
}

Alternativly have WordPress a hook for the change from status to another status, also a example.

add_action( 'draft_to_publish', 'your_callback' );
function your_callback() {
    // Code here
}

See also this codex page to this topic and examples.