Load .txt file for login_message in wp-login.php

Question

How do I load the contents of a text file - or any other file, like .php - and use the test for the login_message hook that prints a message above the #login box in wp-login.php?

(BTW, this is in a child theme, if it makes a difference.)

function custom_login_message() {

$message = get_bloginfo('stylesheet_directory')."/tos.txt";
return $message;
}
add_filter('login_message', 'custom_login_message');

Right now, the function above prints out the URL of the file, not the text in the file, i.e.:

Answer 1

Use locate_template() if you want to use a file from your theme. include() or require() works too.

Sample code, tested:

add_filter( 'login_message', 'wpse_73619_include_login_message' );

function wpse_73619_include_login_message()
{
    print '<pre>';
    locate_template( 'style.css', TRUE );
    print '</pre>';
}

Answer 2

Your function just constructs the URL. You'd need to include the file to get at its contents. You may be able to do this with get_template_part. I am not sure about the hook context. However, your file would need to generate a PHP variable or it will echo immediately rather than return.

If you are using a text file, you could look into one of PHP's file functions, like get_file_contents for more complicated manipulation of the file contents before your echo/return it. Or use output buffering.