I figured out the GET request and have the OAuth 2.0 account from Google setup properly, have the credentials and everything else.
However I struggle turning my logic now into a PHP script so I can effectively use it as a WordPress plugin to retrieve Google Shopping orders from the merchant center into WooCommerce.
Sadly Googles Documentation is inconsistent. I tried this under 'Authorization Example': https://developers.google.com/shopping-content/v2/how-tos/authorizing
However then I spotted the google-api-php-client that another documentation said was required: https://github.com/googleapis/google-api-php-client
I downloaded the library as I'm not working with a composer but rather directly in the source code since I intend to put it directly on the server as a call out within WordPress.
I put the library within my ChildTheme unzipped as google-api-php-client-2.2.2
Which meant that the required path became:
require_once '/wp-content/themes/<childtheme>/google-api-php-client/vendor/autoload.php';
And the response I get is: '...failed to open stream...'
The original request that I want to make use of:
GET https://www.googleapis.com/content/v2/<merchant_id>/orders
Postman initiates via 'Request Token' the screen that allows to put in all the information required. I however struggle figuring out how to start an OAuth 2.0 request via PHP.
The desired output is to launch an OAuth 2.0 Request so I can continue to get my orders displayed from the Google Merchant Center under the Google Shopping (also known as 'Google Express') on my WordPress site in the admin backend.
