Re: [Taler] Withdrawal Flow (was: Taler Android UX)

[Florian Dold]

On 5/1/20 5:58 PM, Torsten Grote wrote:
> Hi Florian,
> 
> I added some clarifications to the docs:
> 
> https://docs.taler.net/design-documents/004-wallet-withdrawal-flow.html
> 

Looks good to me.  Though I'd really like to see the bank-related
aspects (the three cases below) documented somewhere as well,
independent of the wallet docs.  Do you think we should document this as
part of the withdrawal flow?

> On 2020-04-24 06:14, Florian Dold wrote:
>> Another thing that's missing is the 2FA step that might happen after 
>> the user confirms withdrawal in the wallet. There are three cases:
>>
>> 1. The bank transfer happens immediately
>>
>> 2. The 2FA is "detached", i.e. you have to press "confirm" on a 
>> physical Taler ATM, or a Taler cashier has to do a final "confirm"
>> on their device.
>>
>> 3. The bank provides a confirmation_url
>>
>> Note that the wallet is able to distinguish all three cases based on 
>> the bank integration API's response.
>>
>> We could consider to include some explanation string (i18n-ized) for
>>  case 2, which we can display in the wallet UI.  Something like 
>> "Waiting for transaction confirmation (please confirm transaction on 
>> your QuuxBank ATM terminal)".
> 
> The current TransactionWithdrawal interface
> 
> https://docs.taler.net/taler-wallet.html#tsref-type-TransactionWithdrawal
> 
> includes a confirmed boolean and an optional bankConfirmationUrl which
> should cover case 1 and 3, but I wonder what to do about case 2. A
> (i18n-ized) explanation string could work, but do we generally want the
> wallet-core library provide strings for the UI?

So for this we generally use taler:// URIs when a HTTP URI is not
appropriate.  So something like:

taler://withdrawal-confirmation-instruction/Please+ask+the+cashier+to+confirm+the+transaction

(or some less unwieldy name for it ;-) )

> Or do we just say, "Waits for bank confirmation" if confirmed is false
> and there's no bankConfirmationUrl and let the user figure out what's
> next? In the case of the ATM, this should be shown on screen. In the
> case of the cashier, the user can't do anything anyway, right?

We can at least communicate to the user what the next step is supposed
to be!

- Florian