How to build a paypal donation system that gives points

Question

Am trying to create a way to setup the following:

1. User sends donation to paypal with info from donation site (name, email)
2. Paypal receives the donation and using the 2 variables it received (name, email) it sends them back to the donation site
3. Donation site receives variables and donation amount and changes some variables in the website to show that the user has donated some amount.

The site shows a list of users that have donated and how much they have donated which shows as points. How can I do this with paypal and php and mysql.

Answer 1

I found this tutorial, looks like what you're after.

http://tutorialzine.com/2010/05/donation-center-php-mysql-paypal-api/

Answer 2

I'd suggest looking into using PayPal Instant Payment Notifications (IPN). PayPal IPN allows you to (asynchronously) process order information while not having to depend on the buyer to return to your website to complete the order (which would be the case with PDT).

You can use IPN by setting up a script which receives this (POST) data from PayPal. In addition, you must include the following code in your button and/or API call(s):

For Website Payments Standard (where "xxxxxxxx" is the full URL to your IPN script):
<input type="hidden" name="notify_url" value="xxxxxxxx">

For Express Checkout:
Include NOTIFYURL=xxxxxxxx in your SetExpressCheckout and DoExpressCheckoutPayment API call

For Website Payments Pro
Include NOTIFYURL=xxxxxxxx in your DoDirectPayment API call

Once set up, you will receive POST data from PayPal with every transaction.
Take this data, and send it back to https://www.paypal.com/cgi-bin/webscr?cmd=_notify-validate (Live) or https://www.sandbox.paypal.com/cgi-bin/webscr?cmd=_notify-validate (Sandbox) to validate the data. If PayPal responds with VERIFIED (in the body of the page), you're sure the data is genuine IPN data coming from PayPal.

You can find sample code, documentation and further information on PayPal IPN at https://www.paypal.com/ipn

See also some IPN security best practices at https://www.x.com/developers/community/blogs/ppmtsrobertg/securing-your-instant-payment-notification-ipn-script

Answer 3

Set up Payment Data Transfer with PayPal,

PayPal PDT How To

Then on the page that receives the payment details from PayPal, calculate the number of points the person gets based off of how much money they donated (using whatever multiplier or point scheme you decide on), then log the data in a points field in the user's row of your user table in mysql.

Answer 4

Your first step is to use a paypal payments pro account. If memory serves correctly, you can only callback on pro accounts. Otherwise your paypal donation is pretty much a one way trip.

Please understand your question is very involved and is not likely going to result in a full blown example.

The best suggestion I can give is to read up on the paypal API documentation and see if the PHP API fits your needs...

https://cms.paypal.com/us/cgi-bin/?cmd=_render-content&content_ID=developer/howto_api_overview

The PHP / MySQL end of things is on you at this point. You must store user information that you would use to send and validate the successful transactions based on the paypal API results.

While this answer may not serve your situation exactly, it is at least a small point in the right direction. I would suggest taking care to consider refunds and cancelled payments. If there is anything at all to gain by accumulating these "points" you mention then you need to cover security well. Otherwise you will be gamed and could stand to lose something if this is not done correctly.

If you have anything specific to add to this question to narrow down the possible answers, let me know and I will try to update this answer with a better, more specific response.