Right way to include blog-header.php?

Question

I have a voting system on a custom post which uses AJAX, and I have a file that handles the AJAX request. This file is inside a sub folder named php of my theme. Hence the structure is:

../wp-content/themes/my-theme/php/ajax-handler.php

I use the following line to include the blog-header.php file:

include('../../../../wp-blog-header.php');

This works fine, but with debug mode on, I see warnings telling me that WP failed to open the stream as the file blog-header.php is non-existent.

So I tried this:

define('WP_USE_THEMES', false);

require('../../../../wp-blog-header.php');

Warnings gone, but $wpdb not recognized.

Any ideas on how to make this work without the warnings?

Answer 1

The "right way" is to not include it at all and use WordPress provided means for AJAX in themes and plugins.