Using the 'draft_to_publish' hook (post status transition)

Question

I am trying to use the draft_to_publish hook (http://codex.wordpress.org/Post_Status_Transitions) to run a function when a post that is a draft becomes published. This hook does not appear to be working:

add_action('draft_to_publish', 'myFunction');

When I use this in my plug-in, myFunction is never fired. I have used/tested the function before. I know it is the hook, not the contents of myFunction.

All 'solutions' I found just link to the Codex page above. Any ideas about why this hook is not working?

Edit: Here is an example. It the email will not be sent, because the action never fires:

function myfunction () {
        $to = "recipient@example.com";
        $subject = "Hi!";
        $body = "Hi,\n\nHow are you?";
        if (mail($to, $subject, $body)) {
          echo("<p>Message successfully sent!</p>");
         } else {
          echo("<p>Message delivery failed...</p>");
         }
    }
add_action('draft_to_publish', 'myFunction');

Answer 1

You certainly have the right hook, but keep in mind that you are hooking your functionality specifically to the draft_to_publish action, i.e. to the specific case of a post-object pre-existing in the database with draft status being updated to publish. Note that this action ignores drafts which are automatically saved by Wordpress when a new post is created - these "drafts" have a post_status of auto-draft.

I'm not exactly sure how you've been debugging the issue up to this point, but if you haven't already, I would recommend verifying that the action itself is firing when you expect it to, perhaps by attaching some simple, arbitrary, and obvious function to it:

function kill_wp( $post ) {
  die( 'draft_to_publish fired for post #' . $post['ID'] . ' entitled, "' . $post['post_title'] . '"' );
}
add_action( 'draft_to_publish', 'kill_wp' );

That said, part of your problem may lie in capitalization - the action callback in your example references the function myFunction while the function that is defined has been named myfunction.

Though I am not sure as to what you are trying to accomplish, you could alternately attempt to attach your functionality to the generic action transition_post_status which gets passed the old status of the post, the new status of the post, and the post object such that you would have something similar to

function my_function( $strOldStatus, $strNewStatus, $post ) {
    if( $post['post_type'] !== 'post' )
        return;    //Don't touch anything that's not a post (i.e. ignore links and attachments and whatnot )

    //If some variety of a draft is being published, dispatch an email
    if( ( $strOldStatus === 'draft' || $strOldStatus === 'auto-draft' ) && $strNewStatus === 'publish' ) {
        $to      = 'recipient@example.com';
        $subject = 'Hi!';
        $body    = 'Hi,' . chr(10) . chr(10) . 'How are you?';

        if( wp_mail($to, $subject, $body ) ) {
            echo('<p>Message successfully sent!</p>');
        } else {
            echo('<p>Message delivery failed...</p>');
        }
    }
}
add_action('transition_post_status', 'my_function');

There are also a number of tools available that might grant you more insight into Wordpress' action execution such as the action hooks inspector for the Debug Bar plugin.