Apple Support App - Get HMAC Token

General information for the website: We provide all sorts of Apple device lookup services
Kind of development: Customization of existing website
Description of requirements/features: I have been debugging the Apple Support app on iPhone, with the use of Fiddler (routing my iPhone traffic through my PC via proxy) and there is a POST URL which I would like to use. Making this request is fine, although it requires two headers to function properly, which are called the X-HMAC-TOKEN and X-HMAC-TS (timestamp).

For now, I've been just copying these into my code, but each token only lasts about 5 hours, before they stop working.

I imagine that some sort of session needs to be established in order to be able to generate these (as I did have to be signed in with an Apple ID), and so this is what I am looking to get, with a PHP solution - a method that authenticates/initialises a session and returns these headers.
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