PayPal IPN simulator - how to generate INVALID response? - paypal

I'm using Paypal IPN simulator to test changes. I'm trying to generate an INVALID response.
I select
Transaction type: Cart Checkout
payment_status: Denied, Failed or Expired.
However all of these generate a notification call with response VERIFIED
update didn't read close enough. Documentation says: PayPal sends a single word back, which is either VERIFIED if the message originated with PayPal or INVALID if there is any discrepancy with what was originally sent. So if I just browse to my IPN URL directly, I will get an INVALID response from Paypal because the call to IPN did not originate with PayPal.

Regarding your update: close, but not exactly.
IPN will return VERIFIED or INVALID depending on whether or not it recognizes the POST data you're sending as having originated from PayPal.
So yes, if you browse to your IPN URL directly and it directly POST's no data / dummy data to PayPal, then yes, we won't recognize it as having originated from us and we'll return INVALID.
For example, this link will return INVALID:
https://www.paypal.com/cgi-bin/webscr?cmd=_notify-validate&dummy_data=true

Related

PayPal IPN Processing

I have implemented an IPN listener in VBScript/Classic ASP.
From my side, it seems to work perfectly.
When it is called, it sends the message back to Paypal appending cmd=_notify-validate. It then checks the response for objHttp.status = 200 and objHttp.responseText = "VERIFIED" then adds the order to my database.
However Paypal are sending me emails;
Subject: PayPal Instant Payment Notification Warning
Instant Payment Notifications sent to the following URL(s) are failing:
According to IPN Testing
Every listener must include code that handles the "error notification" IPN messages.
Either way you should follow the steps in the IPN troubleshooting tips step by step.
Here is a few I've picked out that should help.
Check the URLs listed in your IPN history to ensure that PayPal is posting each IPN to your listener.
Check your web server's access and error logs.
Check your programming language's error log.
Verify that your IPN listener is responding to all messages, even those you do not intend to process.
Further to the OPs comments
the code samples Paypal give, in which this step isn't performed. Is this step required?
it sounds like you are missing Step 2 from the workflow in the documentation
2. After receiving the IPN message from PayPal, your listener returns an empty HTTP 200 response to PayPal. Otherwise, PayPal resends the IPN message.
Judging by the PHP sample as well both seem to send the verification first, which doesn't tally with the workflow suggested by the documentation.
In which case you should just be able to do
Response.Status = "200 OK"
after the rest of the code, make sure nothing else is written back using Response.Write() so the server response is blank, you could even use
Call Response.Clear()
before setting the Response.Status to make sure nothing else has been written from the Response buffer. This will only work however if Response.Buffer has been set to True beforehand (usually at the beginning of the script).

PayPal IPN Failing

I got an email from paypal saying:
>Hello <>,
>Please check your server that handles PayPal Instant Payment
>Notifications (IPN). IPNs sent to the following URL(s) are failing:
>
>url--
>
>If you do not recognize this URL, you may be using a service provider
>that is using IPN on your behalf. Please contact your service provider
>with the above information. If this problem continues, IPNs may be
>disabled for your account.
>
>Thank you for your prompt attention to this issue.
>
>
>Thanks,
>
>PayPal
Is anyone familiar with this? We got 1 payment that made through today, it updated the database and all but still I am concern if this email will be a threat to our website.
I tested the IPN url using the IPN stimulator and it worked fine. Should I need to change my IPN setting? Some forums are saying to turn off the IPN notifications. Should I assume that this is coming from the server refusing to accept the Paypal IPN? I'm so confused on what to do with this problem, let alone my client also knows.
I checked my site error logs but I couldn't find any new errors related to the my paypal IPN listener.
thanks,
If the warning message you are receiving is showing "url--", you may want to double check:
- the value set up in your PayPal Profile > Instant Payment Notification
- or the value you have inserted in your integration in the variable "notify_url" (if you are using Website Payment Standard or "PAYMENTREQUEST_n_NOTIFYURL" (if you are using API).
When you receive an IPN warning message, I'd recommend to check your IPN history (in your PayPal account) to check what is the HTTP response that your server is returning to PayPal.
You can test your IPN listener here
Find IPN overview here

What is the PayPal IPN reply url?

In its guide, PayPal specifies the following:
The API operation initiates a payment on PayPal.
PayPal sends your IPN listener a message that notifies you of the event
Your listener sends the complete unaltered message back to PayPal; the message must contain the same fields in the same order and be encoded in the same way as the original message
PayPal sends a single word back, which is either VERIFIED if the message originated with PayPal or INVALID if there is any discrepancy with what was originally sent
What is the URL where we need to send the reply specified by step 3? Is this something we need to obtain from the HTTP request?
Guide: https://www.x.com/developers/paypal/documentation-tools/ipn/integration-guide/IPNIntro
The URLs are shown in the examples. There's one for the sandbox, and one for the real service. Append the received parameters to the end of the url to complete it.
https://www.sandbox.paypal.com/cgi-bin/webscr?cmd=_notify-validate&...
https://www.paypal.com/cgi-bin/webscr?cmd=_notify-validate&...

PayPal Instant Payment Notification (IPN) Issue: PayPal sends VERIFIED response but has FAILED status in IPN History. 404 Error

PayPal is sending the VERIFIED message to my IPN listener but my IPN History shows a FAILED status. The IPN History also shows a 404 error. The code I am using for my listener can be found here: https://cms.paypal.com/cms_content/US/en_US/files/developer/IPN_PHP_41.txt. I am testing this with sandbox. How can I be receiving a VERIFIED response from Paypal but yet the IPN History shows a failed STATUS with a 404 error? Shouldn't PayPal be sending an INVALID response since the IPN History status is failed?
VERIFIED has nothing to do with how the transactions appear in your ipn history. How you respond to the original ipn post is what determines what shows in your ipn history.
If your ipn history says it's receiving a 404 response, then you need to check your ipn script and stop sending a 404 response.
If it were any other error, since you are using PayPal's script, I would bet you didn't change the environment variable/the URLs to match your environments. With a 404 though, you're telling the client (paypal in this case) that the page they want doesn't exist, even if you're still reading the data

Identity Token is NOT required for PayPal's Payment Data Transfer (PDT)?

I've setup a PayPal site which uses IPN and I was having trouble getting PayPal to send the GET variables to the return URL that I had specified. It was sending the user's browser to the return URL, but nothing was being passed via GET or POST.
I changed one setting in the PayPal business account: "Payment Data Transfer (optional)" to On which generated an "Identity Token" on the PayPal website.
I also got an automated email from PayPal saying:
---------- Forwarded message ----------
From: service#paypal.com <service#paypal.com>
Subject: Payment Data Transfer (PDT) Has Been Enabled
This email is to inform you that you have successfully enabled Payment Data Transfer.
PDT's primary function is to display payment transaction details to buyers when they are redirected back to your site upon payment completion. However, there are cases, such as with pending transactions, where you won't receive notification of all transactions. For this reason, PayPal strongly recommends that you also enable Instant Payment Notification (IPN).
To learn more about enabling and setting up IPN:
https://www.paypal.com/us/cgi-bin/?cmd=p/xcl/rec/ipn-intro-outside
To learn more about Payment Data Transfer, including setup instructions and a complete list of variables:
https://www.paypal.com/us/cgi-bin/?cmd=p/xcl/rec/pdt-intro-outside
Sincerely,
PayPal
Clicking on the second link and clicking on "Technical Overview" (https://www.paypal.com/us/cgi-bin/webscr?cmd=p/xcl/rec/pdt-techview-outside) shows:
Your POST should be sent to
https://www.paypal.com/cgi-bin/webscr.
You must post the transaction token
using the variable "tx" and the value
of the transaction token previously
received (e.g.
"tx=transaction_token"), and the
special identity token using the
variable at and the value of your PDT
identity token (e.g.
"at=identity_token"). You will also
need to append a variable named "cmd"
with the value "_notify-synch", for
example "cmd=_notify-synch", to the
POST string.
However, I am NOT passing the Identity Token at all, yet everything is working fine!
(a) Is this a problem?
(b) Why is it working if the documentation implies that it shouldn't?
(c) Is this a consequence of specifying an outdated API version (58.0)? What is the value I should be using?
In my opinion the identity token should be a required param since it is the only way Paypal can verify that the request you're making is valid. Otherwise, other people can simply guess a transaction id (even though it is not intended for their accounts) and get details for that transaction from Paypal.
I'm guessing this is a bug you're experiencing. Are you testing in the Paypal sandbox or in a live environment?
Realizing that the OP probably no longer needs an answer after 9 years, but others still might:
The POST of the transaction ID and identity token is purely for the purpose of verifying that the original transaction notification (relayed via the GET method to the merchant's Return URL) actually came from PayPal.
It is as if to say to PayPal, "My website just got this supposed confirmation that a customer paid. Here is the transaction ID and my seller ID again. Is this a legitimate match?"
In fact, at https://developer.paypal.com/docs/api-basics/notifications/payment-data-transfer/, when talking about setting up for testing, it only talks about getting your script ready to receive, parse and display the GET data. It doesn't mention the POSTing back to PayPal (though that is mentioned elsewhere). So, yes, the PDT function should work without doing the POST back to PayPal afterward and waiting for that response of SUCCESS or FAIL, but...
Anyone who knew what they were doing could go to a seller's URL and append a query string with the right combination of variables to fake the same kind of GET request that the PayPal PDT system would initially send, whether or not the transaction ID were a real one.