Get All Custom Fields Attached to a Post, Page or Post  Type

The base_get_all_custom_fields() function will run a data­base query to get all cus­tom fields attached to the cur­rent page, post or post type and store them in an array. This is a lean way to retrieve all custom fields in one database query.

Add the function to a theme

Open up your themes’ functions.php file. If you don’t have one, create it. Add the following PHP function to the file:

/**
*   Get all custom fields attached to a page
*/
if ( !function_exists('base_get_all_custom_fields') ) {
    function base_get_all_custom_fields()
    {
        global $post;
        $custom_fields = get_post_custom($post->ID);
        $hidden_field = '_';
        foreach( $custom_fields as $key => $value ){
            if( !empty($value) ) {
                $pos = strpos($key, $hidden_field);
                if( $pos !== false && $pos == 0 ) {
                    unset($custom_fields[$key]);
                }
            }
        }
        return $custom_fields;
    }
}

Use the function in a theme template

Open up a WordPress theme template file such as page.php and add the following, replacing my_custom_field_value with the name of the custom field you want to display:

// Get all custom fields attached to this post and store them in an array
$custom_fields = base_get_all_custom_fields();
if( !empty($custom_fields) ) {
    print_r($custom_fields);
}
?>

<!-- Single value -->
<p><?php echo $custom_fields['page_subtitle'][0]; ?></p>

That’s it, I hope this helps someone out there!