Double RC confirmation with PayPal

Hi David,

It appears we haven't had an email, would you mind emailing again? I have a feeling I know what the issue is, however I will thoroughly investigate.

Kind Regards

Guys,

Getting a bit frustrated now. You haven't replied since December and the fault is still happening. I have negative stock following double confirmations for a paypal standard order RC13803707.

Please, get it fixed AND let us know what's happening. The suspense is killing me...

Regards,

Dave P.
Gifts for all at HoneyPotGifts

Hi,
The answer is this...

you have set up both PDT and IPN on paypal.
This is a good idea as sometimes IPN can be really slow and if IPN has not fired then the customer will see 'Not Completed' on the payment page.

PDT solves this as it also posts the result to the completion page, so if IPN has not fired then it still has the outcome.

The problem is in the very rare case where the IPN and the PDT fire at exactly the same time. Which will cause both results to trigger as essentially it all happens so quickly.

The solution is to add a wait on the confirmation page to allow the IPN to take place, for example 10 seconds.
However this means that the thousands of transactions which take place through PayPal on RomanCart each day will take 10 seconds longer.
This is not a great solution either.

You could stop this issue right away if you disable PDT. However you might then get 'Not Completed' transactions from slow IPN.
However the cause of this whole issue is that IPN is now very fast and reliable, so i'm not sure how likely this is at this time.

You could also switch off IPN and just use PDT however anyone that quits before the completion page would not have the correct order outcome.

Unfortunately there isn't a great simple answer at this time.

Many Thanks
Support

Edited by Support - 25 February 2013 at 6:58pm

Hi,
That is the problem. It can't be done as they both happen at the same time. The only solution is a delay.
Having thought about it, we will set this up as an option,
Many Thanks
Support

Edited by Support - 25 February 2013 at 7:39pm

Hi,
Absolutely not intended - apologies. It should have the tone of a 'brain dump' i.e. thinking as writing whilst perhaps not paying enough attention to how it would be read.
We are looking into this today. It gets even more complicated when you look at the code because of the way it works.
Many Thanks
Support

Author	Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic
Dave P Members Profile Find Members Posts RomanCart Guru Joined: 15 February 2004 Location: United Kingdom Status: Offline Points: 4066	Post Options Post Reply Quote Dave P Report Post Thanks(0) Quote Reply Posted: 19 December 2012 at 9:16am
	Hi Oliver, I emailed the details, any update yet on this?
	Regards, Dave P. Gifts for all at HoneyPotGifts

Support Oliver Members Profile Find Members Posts RomanCart Team Joined: 06 April 2010 Status: Offline Points: 333	Post Options Post Reply Quote Support Oliver Report Post Thanks(0) Quote Reply Posted: 19 December 2012 at 11:25am
	Hi David, It appears we haven't had an email, would you mind emailing again? I have a feeling I know what the issue is, however I will thoroughly investigate. Kind Regards

Dave P Members Profile Find Members Posts RomanCart Guru Joined: 15 February 2004 Location: United Kingdom Status: Offline Points: 4066	Post Options Post Reply Quote Dave P Report Post Thanks(0) Quote Reply Posted: 19 December 2012 at 1:08pm
	Hi Oliver, I've re-sent the details to support@romancart.com
	Regards, Dave P. Gifts for all at HoneyPotGifts

Dave P Members Profile Find Members Posts RomanCart Guru Joined: 15 February 2004 Location: United Kingdom Status: Offline Points: 4066	Post Options Post Reply Quote Dave P Report Post Thanks(0) Quote Reply Posted: 23 February 2013 at 5:40pm
	Guys, Getting a bit frustrated now. You haven't replied since December and the fault is still happening. I have negative stock following double confirmations for a paypal standard order RC13803707. Please, get it fixed AND let us know what's happening. The suspense is killing me...
	Regards, Dave P. Gifts for all at HoneyPotGifts

Dave P Members Profile Find Members Posts RomanCart Guru Joined: 15 February 2004 Location: United Kingdom Status: Offline Points: 4066	Post Options Post Reply Quote Dave P Report Post Thanks(0) Quote Reply Posted: 25 February 2013 at 6:51pm
	Any chance of an answer?
	Regards, Dave P. Gifts for all at HoneyPotGifts

Support Members Profile Find Members Posts RomanCart Team Joined: 16 March 2004 Location: United Kingdom Status: Offline Points: 10803	Post Options Post Reply Quote Support Report Post Thanks(0) Quote Reply Posted: 25 February 2013 at 6:57pm
	Hi, The answer is this... you have set up both PDT and IPN on paypal. This is a good idea as sometimes IPN can be really slow and if IPN has not fired then the customer will see 'Not Completed' on the payment page. PDT solves this as it also posts the result to the completion page, so if IPN has not fired then it still has the outcome. The problem is in the very rare case where the IPN and the PDT fire at exactly the same time. Which will cause both results to trigger as essentially it all happens so quickly. The solution is to add a wait on the confirmation page to allow the IPN to take place, for example 10 seconds. However this means that the thousands of transactions which take place through PayPal on RomanCart each day will take 10 seconds longer. This is not a great solution either. You could stop this issue right away if you disable PDT. However you might then get 'Not Completed' transactions from slow IPN. However the cause of this whole issue is that IPN is now very fast and reliable, so i'm not sure how likely this is at this time. You could also switch off IPN and just use PDT however anyone that quits before the completion page would not have the correct order outcome. Unfortunately there isn't a great simple answer at this time. Many Thanks Support Edited by Support - 25 February 2013 at 6:58pm

Dave P Members Profile Find Members Posts RomanCart Guru Joined: 15 February 2004 Location: United Kingdom Status: Offline Points: 4066	Post Options Post Reply Quote Dave P Report Post Thanks(0) Quote Reply Posted: 25 February 2013 at 7:03pm
	Perhaps you could at least stop the double confirmation from reducing the stock, by not allowing the same order number to reduce the stock more than once?
	Regards, Dave P. Gifts for all at HoneyPotGifts

Support Members Profile Find Members Posts RomanCart Team Joined: 16 March 2004 Location: United Kingdom Status: Offline Points: 10803	Post Options Post Reply Quote Support Report Post Thanks(0) Quote Reply Posted: 25 February 2013 at 7:28pm
	Hi, That is the problem. It can't be done as they both happen at the same time. The only solution is a delay. Having thought about it, we will set this up as an option, Many Thanks Support Edited by Support - 25 February 2013 at 7:39pm

Dave P Members Profile Find Members Posts RomanCart Guru Joined: 15 February 2004 Location: United Kingdom Status: Offline Points: 4066	Post Options Post Reply Quote Dave P Report Post Thanks(0) Quote Reply Posted: 26 February 2013 at 6:54am
	Ok, thanks guys. The reason both IPN and PDT are set up is because that's the way your instructions read, I've on only ever set it up the way Romancart told us merchants to set it up. Somehow, your response has a tone of suggesting that the problem is my fault
	Regards, Dave P. Gifts for all at HoneyPotGifts

Support Members Profile Find Members Posts RomanCart Team Joined: 16 March 2004 Location: United Kingdom Status: Offline Points: 10803	Post Options Post Reply Quote Support Report Post Thanks(0) Quote Reply Posted: 26 February 2013 at 8:37am
	Hi, Absolutely not intended - apologies. It should have the tone of a 'brain dump' i.e. thinking as writing whilst perhaps not paying enough attention to how it would be read. We are looking into this today. It gets even more complicated when you look at the code because of the way it works. Many Thanks Support