How to retrieve metadata from fragments

[yesil]

By default fragments are retrieved with .plain.html extension which returns only the fragment body, omitting the head section where inherited/fragment metadata is rendered.
For commerce, we will have promo codes in the metadata.xlsx that applies to a content tree in the fragments folder and we would like to be able to consume the promo code on the frontend.
What would be the recommended way for retrieving fragment metadata?

cc: @auniverseaway @chrischrischris

[auniverseaway]

I would probably introduce a hash util or we can start pulling the whole file as default... as long as the pages are not too big.

What data is being stored in the metadata?

[yesil]

@auniverseaway it is mainly the promocode value for now.

[honstar]

I would probably introduce a hash util or we can start pulling the whole file as default... as long as the pages are not too big.

Pulling the whole .plain.html by default would break existing fragment resolution and injection, no? A hash util sounds like a good idea though 👍