[RESOLVED] Paypal Passing Variables Back

ElectricRain

So I have a simple shop site, and I pass ppl to paypal to pay, and then paypal sends them back... now in order to get the details of that transaction Im going to want to know the invoice number that paypal sends me back... does anyone know how they pass that back? Ie is it in the address bar or as $_POST from a form? Someone must have done this before?

If not, is there some other way I can get this information back.. I just need some unique identifier for that transaction so I can print out information about it n send emails to the seller/ buyer.

Any help would be much appriciated on this one! I emailed paypal of course, but they dont reply, and their help is not overly helpful... in fact they dont seem to say ANYTHING about htis atall. Grr.

dream_scape

Have you visited the PayPal developer center? It has info, documentation, SDKs, and same code on all of that.

https://developer.paypal.com/

bpat1434

Of course, I think you're talking about IPN (Instant Payment Notification) in which case, the site is: paypal.com/ipn

These two PDFs should be of help too:
Paypal Web Payments Standard Integration (page 96)
Order Management Integration Guide (page 24)

That should be all the info you need about IPN and how to use it....

~Brett

jazz_snob

get an SDK at https://developer.paypal.com
modify it to your liking

IPN uses a return page, which paypal will make POST request to. Usually unique fields are $POST['invoice'] which is a value you specify...but if you send users directly to paypal I guess that could be blank. $POST['txn_id'] is unique paypal transaction id.

use their sandbox...when its online it very helpful

MarkR

There are two methods, one is IPN - which is a callback - and the other (I forget what it's called - PDT or something?) contains data posted back to your site after a purchase, which goes via the user's browser.

For maximum safety, you should implement both of them, and register the transaction on whichever one happens first (they can occur in either order).

IPN is more reliable, because Paypal will retry the IPN until it succeeds. Note that in order to handle IPN, you need to do a postback from the postback, to validate that the request is really from Paypal. You MUST implement this.

The paypal developer documentation contains all of this, and their "sandbox" site supports IPNs (Although it's occasionally a bit slow), which you can use to test your code (of course the sandbox does not handle real money).

Mark

ElectricRain

Wow.. they have everything. I read the first integration guide, although I must have been asleep when I was at the IPN section because I missed the link to the other one. Thanks so much. The world makes sense again.