Posted by F. Loogman on 11/23/07 22:10

On Wed, 14 Nov 2007 20:28:29 GMT, David Aldred wrote:

> I'm looking for a bit of input on how a particular situation is best handled
> on a small ecommerce site.
>
> The issue here is how to avoid two people buying the same time period for a
> holiday cottage, while at the same time not locking everything up while
> people fail to pay! Payment is to be handled off-site via Paypal.
>
> Say Person A wants the cottage from 21/3/08 to 28/3/08, and so does Person
> B. The easy bit is to arrange that when Person A clicks the 'pay for it
> now' button, a flag is set in the relevant record on the database so that
> if person B now tries to initiate payment, he is informed the week has been
> provisionally booked pending completion of payment - the script re-checks
> availability before actually initiating the jump to the payment processor.
>
> If we get back a 'cancelled' response from Paypal, we can remove the flag;
> if we get a payment confirmation the flag changes to 'definitely booked.
> No problem.
>
> But what if Person A gets to the payment screens, decides to change his
> mind, and simply closes his browser? Or, come to that, what if his PC
> crashes out? No response, either way, will be returned to the site from
> Paypal; so the flag stays on and the cottage is provisionally booked for
> ever......
>
> The only way I can immediately see here is to put a time limit on the
> payment process - if we haven't a completed response from the payment
> processor within (say) 20 minutes, the cottage is back to 'available'
> status. Obviously this runs the risk of Person A completing the payment
> 20.5 minutes later, and so having made the payment but not getting the
> booking. As long as it's clear enough how long they've got, though (with
> a bit of margin built in) that's probably OK - refunds just have to be
> made.
>
> However, I'm wondering if this is the right way. I've used such sites as a
> customer many times, and can't recall ever seeing anything which said 'you
> must complete payment within x minutes' - of course, they may be using an
> unadvertised timeout (presumably fairly long) - but perhaps there's a
> better way I haven't thought of??
>
> Any advice gratefully received....

If traffic to the site is low or the number of available similar cottages
is high, then this problem is non existent. I believe that "normally" a
site will allow all reservations, yet state in its terms that a
confirmation will be sent, confirming ofcourse the availability. In this
way the availability check will not cross the reservation process.

Only if availability data is present at real-time, which is not often the
case for large intermediairies, as it is for the individual supplier, the
availability check could precede the payment process.

floogman

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