Paypal IPN needed? - php

I'm doing a project involving Paypal, more specifically with the NVP API in PHP. But I just can't seem to figure what to use the IPN feature for.
I mean, when the user has been redirected to Paypal to confirm the purchase, he is redirected back to my website's "Paypal-succes-page", when the transaction is complete. And just to be sure that he actually payed i could use the "PaymentDetails" operation.
Now where does IPN fit in this process? and what is the benefit of it?
Thanks

The integrate with PayPal's services you will notice there are three main channels (and IMO it's important to know this so you can decide the benefits for your application):
IPN: Instant Payment Notification
PDT: Payment Data Transfer
PayPal's API
To use PayPal's IPN you need to add a 'listener' script (example) and add the address to your PayPal account. Whenever an event occurs PayPal will send a message directly to your server via your listener and you then update your accounts appropriately. This is especially useful for running subscription services as events will occur in the background without user intervention and you can capture successful/failed recurring payments etc.
PayPal's PDT is a system for accepting data when a user is redirected back to your site from PayPal. For example, a user clicks 'Buy', they are directed to PayPal, enter information etc. Then, once the payment has been taken, they are redirected back to your site. PayPal can pass details about the transaction including whether it was successful or not so you can display the appropriate success/failed page from your site.
PayPal's API allows you to integrate more deeply with PayPal's services, and you would use this if you were managing payments directly from your site.
These services aren't mutually exclusive, so you can use any combination with your application.
I hope this helps

The IPN feature is a very useful feature which you should use to update your database in my opinion. Sure the user is redirected to your success-page after the purchase where you can validate the payment details.
But what if he closes (by accident or not) the browser before reaching your success page? You will never know the result of the transaction and you will never update your database or process his order accordingly.
When using the IPN you can be sure that the transaction result will always reach you because PayPal will keep on making an offline request to your IPN page until it has reached your servers.

Instant Payment Notification
The typical usage of the IPN is to validate the purchase and to let your script or management system know that the transaction is complete so your system can update any records you may have for your service.
But the most important part is that the transaction is validated.

IPN send all data about transaction to your server - price, items, contacts ... so you can check, if someone don't pay you only 1$ instead of 100$ and confirm your order. It prevets thiefs, cheaters, ... USE IT! ;)

Related

PayPal REST API order workflow: Payment -> Sale -> Webhook?

I am trying to integrate the PayPal REST API into my Symfony 2 web app but I find hard to understand how exactly the complete workflow looks like:
The PayPal docs describe the following steps to accept a payment. One can use the PayPal Playground to simulate these steps:
Get an access token
Create a Payment object by querying the API
Redirect the user to the approval url received in the Payment response
After the user approved the payment on the PayPal page, he is redirected back to my page, using the success-link defined in the Payment object. Use the received information to execute the payment.
Payment is completed with status approved
From the docs: Once a payment is complete, it is referred to as a
sale. You can then look up the sale and refund it.
So far so good. BUT: Where are Webhooks used/fired in this workflow? I have defined a wildcard Webhook (accepting all possible events) in the PayPal Developer Dashboard.
My observation is, that my system receives the Webhook event 1-2 Minutes (!) after the user was redirected back to the success-link and after the payment was executed (Step 4).
Beside this long delay between executing the payment and receiving the Webhook, this workflow means, that I only receive the Webhook AFTER handling the success-link. This means, handling the success-link is absolutly necessary for the payment to be completed. Is this correct?
Do I need to use Webhooks?
I already asked this question a few days before and the answer by nifr is quite reasonable: One cannot trust the user to follow any redirect URL but should only rely on the Webhook events.
However this collides with the observations I described before, since I will never receive the Webhook without handling the redirect URL...
So, handling the PAYMENT.SALE.COMPLETED webhook event does not make a lot of sense, since this should already be done in when handling the redirect URL. Correct?
However, to handle updates on pending payments, handle refunds or reversed payments, etc. are only possible by listening on those events.
So the answer is: Only use Webhooks to get updates on payments made before. Correct?
So, the main questions are:
The 5-step process to accept payments does not say anything about using Webhooks. This does not seem to make a lot of sense, because without Webhooks one would miss update events, etc.? So, is it really possible to implement the complete payment workflow without Webhooks?
If yes, how are updates (refunds, pending, etc) handled in this case?
If no, what is the right strategy/time to fulfill the order since it take quite a long time to completly receive and handle the webhook?
i am still a newbie in PayPal world, but few days ago i integrated PayPal Plus REST API in an online Shop, and from my understanding i can tell that the workflow looks like:
create a Payment
redirect to PayPal
Payer could pay using PayPal account OR (using Bank Direct debit or Credit Card Payment without PayPal Account)
After completing the process on PayPal side, PayPal redirect the user back to your success URL.
till now the user is still not charged(you got no money). At the moment where you (in your success URL) do $payment->execute($paymentExecution,$api); , you ask Paypal to charge the amount from user. BUT also after this, you got no Money. Paypal have first to process the charging and notify you later via WebhookEvents.
the Webhook Notification (with that nasty delay) is especially important when the user pays per direct debit or Credit Card etc. Processing such Payments takes few seconds/minutes.
the redirectUrl ist absolutly necessary for charging/executing the Payment.
here on execution succeed, just to tell the user, that he finished his Job, and you can here save/capture the PaymentID/Transaction id for later usage/update via WebhookEvent Listener.
so i would recommend you to update your Database(Payment completed) only after receiving notofications via WebhookEvent Listener and not in the success RedirectUrl.

I want to use paypal payment for package sales, which paypal method woud be best?

I want package sales, when user click on purchase want to send user on paypal site, after success payment back to my site, I will update payment status if payed other wise will not update the payment status. 2nd question how will i know user payed?
PayPal IPN allows the PayPal servers to interact with yours, telling them statuses about if they've paid, missed payment or it failed etc.
https://www.paypal.com/ipn
For example, if you're using the Website Payments Standard (https://www.paypal-business.co.uk/accept-online-payments-with-paypal/index.htm) you send them to the PayPal site by sending hidden information in a form, they do their thing on PayPal and then get sent back. PayPal will then notify the server using the IPN details that were either sent or are in the account, letting the server know if it was successful or if anything else happened. Then your application that picks up the IPN, does its security checks, and then does the appropriate action (e.g. allows the item to be sent or them to login etc).
However - if you're doing subscriptions, I highly recommend not using PayPal. They suck for subscriptions.
visit the following link
http://www.evoluted.net/thinktank/web-development/paypal-php-integration
and follow the step by step guide.
If not work then ask question here.

How do I get data back from Paypal so I can alter my MySQL database accordingly?

I'm just starting out with Paypal, so this is a newbie question.
I've been going through the instructions for setting up Paypal subscription service, but I think I'm looking at the wrong thing.
What I want to acheive is to get back some kind of response from Paypal so that I can update the database on my web site to mark a registered user as having paid. Basically I have a flag in the database that says if the user is subscribed or not. I want to ensure that the user is marked as paid so long as their Paypal subscription is maintained.
While the instructions linked above do say how to set up a button to receive a payment, there's nothing there about getting any data back from Paypal.
I know there are terms like IPN and sandbox that are related to what I'm trying to do, but I can't find clear instructions for how to get started on this process. I'm just circling around and not getting anywhere.
Where do I start on setting this up? Where is there a clear beginner's tutorial?
Also, I'm using PHP/Javascript/MySQL on my website.
PayPal's IPN service is what you want to use. I've used it myself to do just what you're looking to do.
Instant Payment Notification (IPN) is PayPal's message service that
sends a notification when a transaction is affected. Once IPN is
integrated, sellers can automate their back office so they don’t have
to wait for payments to come in to trigger order fulfillment. IPN can
send notifications for these transactions:
Instant payments, including Express Checkout and direct credit card payments
eCheck payments and pending, completed, or denied status payments
Pending payments
Recurring payments and subscriptions
Authorizations
Disputes, chargebacks, reversals, and refunds
You can also view notifications on PayPal’s IPN History page and
resend them if you need to. As PayPal’s interface for handling
purchase confirmation and server-to-server communications, IPN can
also be used to manage and customize a variety of APIs and
communications, including:
Customize your website's response to customer purchases in seconds
Track customers via IPN "pass-through" variables
Notify sellers who deal mostly in software downloads and other digital, online goods
Track affiliate sales and commissions
Store transaction information in your own database
For more about IPN:
Technical Overview (link to new html version of docs on developer central)
Instant Payment Notification Guide (PDF)
Code Samples
I'm not sure if its the same thing, but I just setup my friends website with Express Checkout, and I wanted to add all paid orders to an orders table in my database.
After I call SetExpressCheckout, and the user is returned to my site after going through the purchase flow on Paypal's side,
I used the information from GetExpressCheckoutDetails.
Then, if DoExpressCheckoutPayment
is successful (also called from the "callback" page) I then do the appropriate work in my database as far as logging the order details. For you in this case, it could be updating a record for the user in the database.
Hope that helps a little.

Paypal Integration with PHP

I'm looking to implement a very simple Paypal integration whereby I can enter a valid Paypal Email address (recipient) and a dollar amount, and click "Pay." Ideally, it would send the money from my paypal account automatically via my API key.
I currently have Mass Pay set up with PHP, and it's working fine, except that it charges me 2% on every payment, and doesn't pass back the Transaction ID. It also kinda seems unnecessary since I don't need to pay multiple people at once.
Since I only need to do one transaction at a time, I'm wondering if anyone knows of a simpler Paypal API for single outgoing transactions from my account.
I've been reading the documentation all day and I've yet to find what I'm looking for.
Any advice is greatly appreciated!
PayPal has sample codes for integrating various PayPal features on it's website. This includes PHP take a look at the list of features and I'm sure what you are looking for is there.
Also from the paypal site:
PayPal receives the MassPay request and returns a response indicating
success or failure. If PayPal returns a successful response, then
PayPal processes the payments and, if you have Instant Payment
Notifications (IPN) enabled, PayPal sends a notification to the Notify
URL specified in your account profile. If you do not have IPN enabled,
you can view the details of the MassPay transaction in your PayPal
account.
This implies that in the case of mass pay you need to provide a URL where paypal sends payment notifications. Your program can probably check this url to figure out whether a payment has been made or not, I would suspect this would be the case for all payment integration. That being said I would print_r the the response from paypal, I'm sure something like a transaction id will probably be in there. In the case of DoAuthorization it does return the transaction id
In the case of mass pay it does return the transaction id if IPN is enabled

How to intergrate paypal into an application?

Im planning to allow people to create premium accounts on a site. There is a simple registration form, at the end of which I want to direct people to paypal where they will make a payment, and then be sent back to my site with their newly created account now activated (if transaction went thru).
I dont want a fully hosted solution ("Website Payments Pro"), but something where you leave the site, and then come back to it after payment.
Everything you need to get started
View sample code
View all tech docs
Download SDKs
API Reference
Using the PayPal API, you'll be able to send users to PayPal to handle payments. Once the transaction has been completed it will then send a response to a script on your site, which you can then act on accordingly. For example, update a particular user's status as 'Paid' or 'Unpaid' in your members database table.
You want to look at PayPal IPN. With that, you can send these pages URLs as hidden fields and PayPal will then return the user to the page you submitted for success, failed, IPN handler etc.
Yes that's possible, look into the "Buy now"-method on PayPal, they have an off-site payment possibility and they have on-site payment. It's up to you how much you want to spend on both time and percentage on each sale.

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