Public posts - preventing duplicate form submissions

Question

I'm creating a public form on a page that allows non-registered (public) visitors to create posts of a custom post type.

I'm using nonces, which I naiveley thought would expire once they were used. This doesn't appear to be the case.

This post seems to address the issue by creating a meta field and verifying that it doesn't exist before creating the post.

Is there a best practice that prevents double-form submissions (that doesn't require writing a meta field?)

T

Answer 1

Don't know if it's best practice but i had a similar issue and I ended up checking by custom sql query to check if the title already exists in my post type and filtered duplicate posts and i hooked that to wp_insert_post_data filter hook.

add_filter('wp_insert_post_data','prevente_duplicates');
function prevente_duplicates($data,$postarr){
    $count = $wpdb->get_results($wpdb->prepare("SELECT count(id)
            FROM $wpdb->posts
            WHERE post_type = 'MY_POST_TYPE_NAME'
            AND post_title = '%s'",$data['post_title']));
    if ($count > 0 ){
        return false;
    }
    return $data;
}