My custom title gets duplicated at every save or post update

Question

I have a problem, my custom title keeps getting added at every time I save the post..

First I created a Custom Post Type called 'imac' plus a front-end form for posting in this Post Type, only before saving I would like to change the ['post_title'] based on the Custom Fields people fill out on the front-end form aswel.

Every post people create front-end will get a 'pending' post_status but as soon as I press Publish or edit the post later and press update the title gets added too. for example: example.com/imac-lala-blabla/ becomes after a second save: example.com/imac-lala-blabla-lala-blabla/

Can somebody help me please.

function modify_imac_title( $post_id ) {

// ['post_title'] create $vars for custom title setup

    $ghz = get_post_meta( $post_id, 'imac_processor', true );
    $strip_ghz = preg_replace( '/z.*$/', 'z', $ghz );
    $ram = get_post_meta( $post_id, 'imac_ram', true );
    $hd = get_post_meta( $post_id, 'imac_harddrive', true );
    $model = get_post_meta( $post_id, 'imac_model', true );

    global $wpdb;

    $wpdb->update( $wpdb->posts,
                    array(
                        'post_title' => get_the_title( $post_id ).' '.$strip_ghz.' '.$ram.'GB '.$hd.' '.$model
                    ),
                    array( 'ID' => $post_id )
                ); 

}
add_action( 'save_post_imac', 'modify_imac_title' );

Answer 1

First of: Your custom title suffix getting duplicated might not be what you want to happen, but is expected behavior as per your code sample.

The save_post action hook runs everytime a post (or page) is created or updated. Hence your callback runs everytime.

Let me offer two solutions:

1 Use the wp_insert_post action instead

The wp_insert_post action is called with the same parameters as the save_post action (the post ID for the post being created), but is only called for new posts and only after save_post has run.

Note that, this hook does not have a posttype-specific equivalent, and hence you'd have to check for the type inside the callback function.

function modify_imac_title( $post_id ) {

    if ( 'imac' === $_POST['post_type'] ) {

        // do your thing

    }

}
add_action( 'wp_insert_post', 'modify_imac_title' );

2. Add a boolean post_meta

Add a boolean post_meta that signifies, whether the title modification has run already.

function modify_imac_title( $post_id ) {

    $title_modified = get_post_meta( $post_id, 'title_modified', true );

    if ( ! $title_modified ) {

       update_post_meta( $post_id, 'title_modified', true );

       // do your thing

    }

}
add_action( 'save_post_imac', 'modify_imac_title' );

Answer 2

I can't comment yet, so I ll try to guess that the one that is getting duplicated is the post and not just the post title.

Try this:

function modify_imac_title( $post_id ) {

// ['post_title'] create $vars for custom title setup

$ghz = get_post_meta( $post_id, 'imac_processor', true );
$strip_ghz = preg_replace( '/z.*$/', 'z', $ghz );
$ram = get_post_meta( $post_id, 'imac_ram', true );
$hd = get_post_meta( $post_id, 'imac_harddrive', true );
$model = get_post_meta( $post_id, 'imac_model', true );

global $wpdb;
        remove_action( 'save_post_imac', 'modify_imac_title');
$wpdb->update( $wpdb->posts,
                array(
                    'post_title' => get_the_title( $post_id ).' '.$strip_ghz.' '.$ram.'GB '.$hd.' '.$model
                ),
                array( 'ID' => $post_id )
            ); 
        add_action( 'save_post_imac', 'modify_imac_title');
}
add_action( 'save_post_imac', 'modify_imac_title' );