You sad you put the json in wp-includes
, but in the url you wrote wp-content
. So I give you the code for getting the server path for both folders:
// wp-includes
$file = ABSPATH . WPINC . '/json/users.json';
// wp-content
$file = WP_CONTENT_DIR . '/json/users.json';
You can find many WordPress constants (like ABSPATH
, WPINC
and WP_CONTENT_DIR
on http://wpengineer.com/2382/wordpress-constants-overview/