WooCommerce 2.4 - Example of how generate an URL for the API Auth endpoint

index.php

<?php
$store_url = 'http://example.com';
$endpoint  = '/wc-auth/v1/authorize';
$params    = array(
	'app_name'     => 'My App Name',
	'scope'        => 'write',
	'user_id'      => 123,
	'return_url'   => 'http://app.com',
	'callback_url' => 'https://app.com'
);

echo $store_url . $endpoint . '?' . http_build_query( $params );