On Tue, Aug 20, 2013 at 8:15 AM, Andreas Petersson <andreas@petersson.at> wrote:

I was just reviewing the integration work to integrate the Payment
Protocol into our products. Is there any notion of a standardized
invoice serialisation? If i pay for two Burgers and one Club Mate, how
would my Bitcoin Wallet be able to know that?

No. There are XML-based (shudder) standards for electronic invoicing that include all sorts of bells and whistles; the PaymentDetails message could easily encapsulate one of them in an 'invoice' field extension. Or we could reinvent the wheel and come up with our own, but I'd rather use an existing standard (or maybe a subset of an existing standard).

I didn't want to wade into that swamp for the 1.0 version of the payment protocol.

Right now, i would simply
put that into "memo" and come up with my own serialisation mechanism.

"Two Burgers, one Club Mate" seems pretty user-friendly.

Second, is there a way to communicate acceptance levels of TX
(unconfirmed, 1 conf, 6 conf) maybe using several PaymentACK?

No, because the Payment->PaymentACK communication round-trip is done in one, non-persistent http request-response round-trip.

I don't think we want to allow merchants to push messages to the wallet (wouldn't take long for merchants to use the opportunity to push annoying advertising at me, I think), and I don't think we want wallets to poll the merchant. Although maybe a payment protocol version 2.0 feature could be a PaymentACK extension that says "ask me how the transaction is going at THIS URL in THIS many minutes."

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Gavin Andresen