Support self-service loans (transition to state 3)

[GallusMax]

PAIA currently implements transitions known from a browser session: sign in, show account details, reserve, renew, sign out.
Future applications may allow the user to register an item to her account in order to start a loan. This cannot be done with the current vocabulary.

A new verb should be introduced allowing a direct loan of an item, changing it directly from state 0 to 3. Access to this verb should be restricted to configured devices and registered accounts by an appropriate scope.

Possible naming ideas: loan or pick or hold.

Think of a mobile device capable of identfying an item and allowing for instant loan to a given account. The device could be in the hands of library personnel, or - after performing a secured personalization preventing abuse - on a patron's smartphone.
More than that the verb could as well be useful to reserve electronic media aka onleihe.

[nichtich]

This might also be handled by the existing request method, but the method may require some extensions. Before adding a new method or another kind of extension, we should clarify the use case.

Use case: A patron want's to directly put a document on loan.

The existing specification already supports the transition 0 → 3 (loan) but only if the PAIA server chooses to do so (for instance for a particular type of document like electronic documents). A new method might be needed if a patron can choose whether to order/reserve a selected document or to directly loan it. If this possibilities are disjoint, no new method is needed, is it?

[JonathanRowell]

One gets into a lot of complexity here. An issue may require an interaction with the media - 3M Demagnetization Checkout or RFID security (EAS Bit, AFI values) and the like. When the media interaction fails, then the checkout has to be reversed (in such a way that none of the holds are activated!)

[nichtich]

@JonathanRowell if self-service loan requires interaction with the media and feedback from another system, such as demagnetization, it should better not be provided as PAIA method. But there are libraries which don't require this, for instance institutional libraries where patron/colleagues can just pick up items. This might also make sense for digital objects. Without actual use case, however, I'd not add the requested feature.