how to delete all users and posts based on 'user_meta'?

Question

I have developed a small wordpress application where It has Institutes(wp user), Trainers(wp user), Trainees(wp user), courses(custom post) and notifications(custom post). All the application is working fine but If I delete an institute all the information belongs to that institute like Trainers, Trainee, notifications & courses should also be deleted. While I was creating the 'institute' user I am storing the all the related info like first name, last name in wordpress table 'wp_users' and 'institute name' is storing as 'user meta' with key 'inistitute_name' in 'wp_usermeta' table like below is my code:

  $user_data = array(
            'ID' => '',
            'user_pass' => '',
            'user_login' => $first_name,
            'user_email' => $user_email,
            'first_name' => $first_name,
            'last_name' => $last_name,
            'role' => 'admin'//get_option('default_option')
        );
        $random_password = wp_generate_password(8,false);
        $user_id = wp_insert_user( $user_data );
        update_user_meta( $user_id, 'inistitute_name',$insititute_name );

While creating Trainer (or) Trainee my code is like below:

  $user_data = array(
               'ID' => '',
               'user_pass' => '',
               'user_login' => $first_name,
               'user_email' => $trainer_email,
               'first_name' => $first_name,
               'last_name' => $last_name,
               'role' => 'trainer'
         ); 
        $random_password = wp_generate_password(8,false);
        $user_id = wp_insert_user( $user_data );
        update_user_meta( $user_id, 'inistitute_name',$this->institute_name[0] );
        wp_set_password($random_password, $user_id);

While creating courses my code is like below:

  $user_ID = get_current_user_id();
  $institute_name = get_user_meta($user_ID, 'inistitute_name', true);
  $post = array(
            'post_title'    => $title,
            'post_content'  => $description,
            'post_status'   => 'publish', 
            'post_type' => "courses"  
        );
  $id = wp_insert_post($post);
  update_post_meta( $id, 'inistitute_name', $institute_name );

Suppose let us say if a institute 'abcd' is deleted then all the information like 'trainer', 'trainee', 'courses' & 'notifications' associated with that institute should also be deleted based on a 'user_meta' field. Is it possible to delete? (or) did I do any mistake? can anyone tell me what was I doing wrong?

Update:

  add_action( 'delete_user', 'cyb_delete_institute_info' );
function cyb_delete_institute_info( $id ) {

$user = get_userdata( $id );

if( ! empty( $user ) && in_array( "admin", (array) $user->roles ) ) {

    // Deleted user is admin, check `institute_name` meta field
    $institute_name = get_user_meta( $id, 'inistitute_name', true );

    if( ! empty( $institute_name ) ) {
        // Deleted user is an admin and has `institute_name` meta,
        // so, it is a "Institute" user

        // Get posts to delete
        $posts_args = array(
            'post_type' => 'notifications',
            'meta_query' => array(
                'key'   => 'inistitute_name',
                'value' => $institute_name
            ),
        );

global $wpdb;
$querystr = "DELETE FROM $wpdb->wp_dxwe_posts LEFT JOIN $wpdb->wp_dxwe_postmeta ON $wpdb->wp_dxwe_postmeta.post_id = $wpdb->posts.ID WHERE $wpdb->wp_dxwe_postmeta.meta_key = 'inistitute_name' AND 
        $wpdb->wp_dxwe_postmeta.meta_value = '$institute_name' AND $wpdb->wp_dxwe_posts.post_type = 'courses' ";
$wpdb->query( $querystr );

        $posts_args2 = array(
            'post_type' => 'courses',
            'meta_query' => array(
                'key'   => 'inistitute_name',
                'value' => $institute_name
            ),
        );

        $query = new WP_Query( $posts_args );
        $query2 = new WP_Query( $posts_args2 );
        $posts_to_delete = $query->get_posts();
        $posts_to_delete2 = $query2->get_posts();

        foreach( $posts_to_delete as $post ) {
            wp_delete_post( $post->ID );
        }

        foreach( $posts_to_delete2 as $post ) {
            wp_delete_post( $post->ID );
        }

        // Get users to delete
        $users_args = array(
            'role__in'       => array( 'trainer', 'trainee' ),
            'meta_query' => array(
                'key'   => 'inistitute_name',
                'value' => $institute_name
            ),
        );
        $query = new WP_User_Query( $users_args );
        $users_to_delete = $query->get_results();

        foreach( $users_to_delete as $user ) {
            wp_delete_user( $user->ID );
        }

    }

}
}

I was writing 2 separate WP_Query's to delete custom post_type's separately but din't work either. same result only notifications deleting correctly but for courses other institute courses also getting deleted.

Answer 1

Because "institute" is a user and you want to perform some actions when it is deleted, you could use delete_user action (as we need information of the deleted user, deleted_user may not work, not sure about this but delete_user should work for sure). In that hook you can get all users and posts based on inistitute_name meta field and delete them.

Seeing your code, "Institute" user type can be identified by user role (you assing admin) and user meta inistitute_name. So, in delete_user action you can check if the deleted user is and admin and if it has institute_name assigned, in that case, the deleted user is a "institute" and you can get all other associated users and posts.

add_action( 'delete_user', 'cyb_delete_institute_info' );
function cyb_delete_institute_info( $id ) {

    $user = get_userdata( $id );

    if( ! empty( $user ) && in_array( "admin", (array) $user->roles ) ) {

        // Deleted user is admin, check `inistitute_name` meta field
        $institute_name = get_user_meta( $id, 'inistitute_name', true );

        if( ! empty( $institute_name ) ) {
            // Deleted user is an admin and has `institute_name` meta,
            // so, it is a "Institute" user

            // Get posts to delete
            $posts_args = array(
                'post_type' => array( 'courses', 'notifications' )
                'meta_query' => array(
                    'key'   => 'inistitute_name',
                    'value' => $institute_name
                ),
            );

            $query = new WP_Query( $posts_args );
            $posts_to_delete = $query->get_posts();

            foreach( $posts_to_delete as $post ) {
                wp_delete_post( $post->ID );
            }


            // Get users to delete
            $users_args = array(
                'role__in'       => array( 'trainer', 'trainee' ),
                'meta_query' => array(
                    'key'   => 'inistitute_name',
                    'value' => $institute_name
                ),
            );
            $query = new WP_User_Query( $users_args );
            $users_to_delete = $query->get_results();

            foreach( $users_to_delete as $user ) {
                wp_delete_user( $user->ID );
            }

        }

    }
}

Note: not tested, just written here as sample code.