Getting the result/output of a template

Hello,

I am trying to get the output of a template file and save it as HTML. The following is my approach:

1) I have a page template, called page-template.php.
2) In my plugin.php I have

add_action('edit_post', 'static_post');
add_action('publish_post', 'static_post');

function static_post($post_id){
	$post_type = strtolower(get_post_type($post_id));
	if($post_type == 'page'){
		$template = get_post_meta( $post_id, '_wp_page_template' );
		ob_start();
		require_once(locate_template($template[0]));
		$contents = ob_get_contents();
		custom_debug($contents);
		ob_end_clean();
	}
}

The custom_debug function writes the $contents to a .txt file for debugging.

3) The output is as follows:
Say the page-template.php contains

<?php while(have_posts()): the_post(); ?> <h2><?php the_title(); ?></h2>

The output in the debug .txt file mentioned above is only

<h2></h2>

which means that the loop is not being executed. Or the query. I am not really sure.

Any suggestions? 🙂

Thank you