Redirect Issue

Hello Everyone,

I am creating a simple plugin which use to redirect to url which you can define in edit page under custom field named ‘redirect’ , then when you view that page this will redirect to that url which you have defined in custom field, here is my code `
function custom_redirect () {
global $post;
if ( is_page() || is_object( $post ) ) {
if ( $redirect = get_post_meta($post->ID, ‘redirect’, true ) ) {

wp_redirect( $redirect );
exit;
}
}
}
add_action( ‘get_header’, ‘custom_redirect’ );`
now when i add a url then when i see it takes me to the url something like this https://localhost/wordpress/www.google.com, i can’t figure it out why its not redirecting to google.com…does anyone help me out with this..