Two identical orders using Paypal IPN (Website Payments Std)?

[fredhicks]

I'm running Zen Cart v1.3.8a/v1.3.8, with minimal add-ons (I grabbed Super Orders, but that's about it in terms of any deviation from "vanilla").

I just had an event today -- two identical orders from the same customer got submitted at once (zero seconds apart), each claiming the same paypal transaction validated them as paid. In other words, two "paid" orders got entered into my system, even though I only received one payment.

I asked the customer what they did to trigger this behavior, and they explained:

Well, it might have happened because I decided to change the shipping. I did not confirm order at first because I decided I wanted the expedited shipping. I changed the shipping and then confirmed the order. Maybe that messed things up on your end. Does that help at all?

Is this a known issue? (I am not always good at coming up with the right search terms, so my apologies if I missed something.) Regardless, is there a fix? This absolutely can't happen again. I caught it because my store is pretty new (got installed in the last couple weeks) and I'm looking at every order that comes across.

[fredhicks]

This has happened a second time as of this morning -- two identical orders entered, same customer, same content, only *one* payment.

Help, please!

[DrByte]

Have you tried removing the PDT token from your IPN module settings?

[fredhicks]

Have you tried removing the PDT token from your IPN module settings?

Wouldn't that cause the module to stop working entirely? I don't understand how that's a solution.

[DrByte]

I've seen a couple cases where the PDT validation step triggered duplicate order insertion, and blanking out the token setting in your Zen Cart module settings stopped the problem.

[fredhicks]

I've seen a couple cases where the PDT validation step triggered duplicate order insertion, and blanking out the token setting in your Zen Cart module settings stopped the problem.

Okay. That seems to imply the token is not needed in order to regularly process payments. I'll give it a shot, thanks very much.

[DrByte]

Correct. The PDT token is an optional extra step which can in some cases speed up the way in which orders show up in your admin after completing a Website Payments Standard transaction.

By the way, Express Checkout is way more reliable and quick by comparison.

[fredhicks]

By the way, Express Checkout is way more reliable and quick by comparison.

Yeah, I tried to get Express Checkout to work first, and it didn't, so I configured IPN, which did.

I'll try a second run at Express Checkout sometime, but the first experience didn't leave me optimistic about my ability to figure out the arcane particulars!

[batterygenie]

Not sure if anyone else has tried this solution, but recently our site started to receive duplicate orders recently after functioning just fine for almost two years. So I found this post and removed the token as instructed. In testing the order, we found that the order number is not provided to the customer at checkout as a result of removing the token.

Seems like a catch-22 to me. We are investigating whether the other Paypal options might better suit our needs now.

[sloruss]

The double order issue has just started happening to our store after a year of successfully running ZenCart without the issue. This deserves a closer look.