Paypal IPN continuously hits my IPN page w/the same transaction - php

I just moved my server to a new host, and obviously changed the DNS for my paypal ipn page.
For some reason paypal keeps hitting my page about every 30 seconds with the same transactions over and over again.
So of course its verified then stored in the database as duplicate records.
Has anyone had this problem? Or know how to fix?

Make sure that your browser is returning 200 OK status to paypal.
Either way, you should store IPN tracking IDs (ipn_track_id) in your database and check for duplicates. This is the only guaranteed way to solve your problem.

According to PayPal's IPN documntation:
Your listener must respond to each message, whether or not you intend
to do anything with it. If you do not respond, PayPal assumes that the
message was not received and resends the message. PayPal continues to
resend the message periodically until your listener sends the
correct message back, although the interval between resent
messages increases each time. The message can be resent for up to four
days.
This resend algorithm can lead to situations in which PayPal
resends the IPN message while you are sending back the original
message. In this case, you should send your response again, to cover
the possibility that PayPal did not actually receive your response the
first time. You should also ensure that you do not process the
transaction associated with the message twice.
IMPORTANT: PayPal
expects to receive a response to an IPN message within 30 seconds.
Your listener should not perform time-consuming operations, such as
creating a process, before responding to the IPN message.
So a) is your script properly responding and b) is the notify_url parameter from your transaction different with your DNS change?

Related

Payment info using paypal

I have Integrated Paypal using php. I know there is return url ,that means when payment is received it will return to the url for our website.My Question is if payment is received and due to internet problem it does not return to our web page, how do I know that payment is received from a particular user?
If there is a network issue and PayPal cannot issue the IPN message, then according to their documentation, they will retry 15 times up to 4 days.
The IPN message service does not assume that your listener will receive all IPN messages. Because the Internet is not 100% reliable, IPNs can get lost or be delayed. To address these issues, the IPN message service includes a retry mechanism that re-sends a message at various intervals until your listener acknowledges receipt. An IPN message may be present up to four days after the original was sent. The maximum number of retries is 15.
https://developer.paypal.com/docs/classic/ipn/integration-guide/IPNIntro/
This item below might help. Instant Payment Notification should work, but in the case of a network failure, if the payment reached PayPal but the purchaser did not get back to your site to complete a purchase, then you should still receive an email from PayPal telling you that you have received a payment.
using paypal button - can my webpage tell if paypal transaction was successful or not?
You get a confirmation email with their name and email address - be aware that occasionally this may not be the user's current, most active email address. You can also log in to your PayPal dashboard to see all details as well, of course.
You can look up your payment details from the email and compare them to your own user records in your database. If the email they use for PayPal is not the same as the one they registered on your site with, you can still look up their name from the email - in practice it seems to happen extremely rarely that payments have such a problem in my personal experience
I set up a script which emails my users with a passcode to get to the online product they bought which is emailed to them so they can submit that later along with their email address. This is the first thing that happens on return to my script so at least if the site fails to respond properly they can get to what they bought later.
The script uses PHPMailer and cc's me with their passcode so I have it available to re-send to them if they write with a complaint. It doesn't help if the PayPal return for Instant Payment Notification fails completely but the other answers cover that very fully and detail the PayPal repeat attempt process well.
Instant Payment Notification scripts can be downloaded from PayPal for modification by yourself as per the article linked to above.
To be perfectly honest, this is one of PayPal Standard's largest holes. IPN is a POST callback (as is PDT) and they check to make sure they get a 200 response or else they retry (and you can use the IPN history in your PayPal account to resend missing IPNs). But this method still relies on you getting the callback in a timely manner and it's not foolproof. Worse, you need to verify the IPN call and that introduces yet another point of failure in calling PayPal to make sure they did indeed send you the IPN you got.
There's a couple of ways to deal with this
Audit your account regularly. This is a good idea in general, but for a small website this shouldn't be terribly hard. Match your invoices up to your PayPal payments. Obviously this doesn't scale well so...
Switch to Payments Pro. There's more hurdles to this (like more PCI compliance, SSL certificate, etc) but the major advantage is that the API is far less susceptible to the whims of the Internet and only involves one call for credit cards (you can ignore the IPN because the API tells you everything you need to know). The worst that can happen is you send a payment API call and fail to get a response. This is exceptionally rare as PayPal makes sure their API is 99.9% reliable (IPN relies on your server being reliable). Speaking from experience, Payments Pro has far fewer issues than IPN does.
In your application, you should have a status field for orders. If you haven't received the ipn, you wouldn't change the status to Paid.
After that, if you receive an email from Paypal that someone has paid, check the order number, and change the status manually.
how do I know that payment is received from a particular user?
Paypal will send an email both user and you.
Paypal offers 2 solutions for your problem.
PayPal IPN - it notifies the server with a POST request to a specific URL, whena transaction has been successful, declined, aborted by user and so on. Paypal provide an IPN Simulator (the worst simulator ever) in order to test its functionality. you may give it a try at : https://developer.paypal.com/developer/ipnSimulator/
Paypal WebHooks - The webhooks are the "New Kid in the Block",they are basically "user-defined HTTP callbacks that receive events for the subscribed event types. Webhooks are asynchronous, the order is not guaranteed, and idempotency may lead to the same event being sent more than once." as stated in the Paypal documentation.
You can read more about it on : https://developer.paypal.com/docs/integration/direct/rest-webhooks-overview/
For any further help, comment below and I shall try to help.
Cheers,
You have to use notify_url for this purpose
<input type="hidden" name="notify_url" value="https://domain-name.com/ipn.php">

Slow Paypal IPN by 3 seconds

I have a paypal IPN system in place. The payment system works very well, it takes t he required amount of money fine, however the IPN is just slightly off.
I've done some timestamps on the time the IPN connects to my site and the time I load the /shop/thanks page - and here is the data:
IPN:
[1416406186 // 14:09:46 19-11-14] papypal.php runtime: 1 seconds. (start time: 1416406185 / end time: 1416406186)
/shop/thanks error:
[1416406183 // 14:09:43 19-11-14] /shop/thanks error - could not display thank you message.
THREE SECONDS. If I go straight through the paypal process I get to my website 3 seconds before paypal updates me via IPN. If I go through it slowly then most likely I get correct thank you page.
I haven't encountered this problem before. What can I do to sort it out? The runtime of the paypal.php script is 1 second, so It's not like I am taking too long to update the database.
You can't. IPN is supposed to be asynchronous. You are supposed to say "thank you for your payment, we will notify you when your payment is complete."
But why?
Because let's say I decide to pay you by eCheque, ie. directly from my bank account through PayPal. eCheques may take six to ten DAYS to clear.
IPN may stand for "Instant Payment Notification", but the "Instant" part refers to when you actually get the payment, not when the user sends it to you.
Now, that being said, you might be able to adjust your IPN script to accept "Pending" status payments, and act accordingly. However, this is not necessarily a good idea because it may mislead the user into thinking their payment has completed, when in fact it may be cancelled or deemed invalid later. But that's a question for UX. Even then, you'd still have some kind of delay while the IPN system processes your notification.

PayPal IPN verification fails with unknown error

I encountered the following problem twice in the last month with PayPal IPN in live mode.
I receive an incoming IPN as usual, and all the data are correct. Then I append cmd=_notify-validate& and send the input to PayPal to verify it. The documentation says to expect VERIFIED or INVALID as response.
Instead those two times I got
<HTML><HEAD><TITLE>Error</TITLE></HEAD><BODY>
An error occurred while processing your request.<p>
Reference #…
</BODY></HTML>
with HTTP status 503. My script of course dismisses the IPN, but how should I handle this?
Normally, if the listener fails, PayPal retries to notify in an increasing interval. But I don’t receive any additional IPNs. I could save the request and verify it later on my own, but for how long does this work? I assume I have to verify it instantenously, otherwise PayPal will forget about it.
Can anybody recommend a good way of handling this?

Paypal ION different servers

so I got a guy to code this IPN feature for my website.
Basically a user pays thought the main site then it forwards the ipn stuff to another server and that server sends ipn payment to paypal. For some reason it keeps saying "retrying" under the paypal IPN history. Is paypal blocking this and does the payment have to be made from the same server? Thanks hopefully this makes sense!
IPN does not happen until after any transaction has occurred, so what you're saying here doesn't really make sense. There's no way IPN would be sending any payment to PayPal. PayPal simply POSTs transaction data to your IPN URL after the transaction has taken place.
That said, if you're seeing "retrying" in your IPN History that means your IPN script is not completing successfully, and as such, is not returning a 200 result code back to PayPal's server. You need to troubleshoot your IPN script to figure out what's failing and get it fixed.
Your web server logs should provide the information you need. If you look there you should see a log of when your IPN URL was hit and it should also provide the result including any errors that were generated from the request to that script.
I like to create a simple HTML form with the action set to my IPN URL and then include hidden fields that match the fields/values that I would expect to get from IPN. This way you can load that in a browser and submit it directly so that you can see the result on screen which can help with troubleshooting and debugging.
Keep in mind that when testing that way, though, the data is not coming from PayPal's servers, so it will not verify. You'll need to make sure your script is setup to handle this accordingly for testing purposes.

is HTTP 200 response actually necessary for IPN paypal protocol?

I'm going to implement the IPN protocol in my website, using php.
Paypal documentation note that the protocol goes as follows:
The user clicks the button.
Paypal posts my IPN listener an IPN message.
My listener has to send an empty HTTP 200 OK response.
My listener has to send the message gotten from paypal (with a preceding string) back to paypal.
Paypal sends my listener a "VERIFIED" or "INVALID" response.
Can anyone explain why the protocol demands this [3] step?
Why can't it be fulfilled just with the [4]th step?
Also, I noticed that in another chapter of paypal documantation, they skip this [3]rd step themselves (see their implementation). So I wonder, is it really necessary??
The 200 OK response will happen automatically as long as your IPN script completes successfully. This let's the PayPal server that it did indeed complete.
If PayPal's IPN server gets something other than 200 OK back from your web server it will assume your script failed and will place that IPN in a que to be re-sent. It will resend after 30 seconds, then 60 seconds, then 120 seconds, etc. until it gets that 200 OK.
This is why sometimes people end up with duplicate IPN's. If you've got something at the very bottom of your script, for example, that's failing, but all of your email notifications, database updates, etc. actually did work prior to that point, you'd end up seeing those things happen again and again because PayPal kept re-sending the IPN. This can be very messy, of course, so you want to make sure that's not happening.
Again, though, the response code gets sent back to PayPal from your web server automatically. It's not something you actually have to do within your code.

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