CoinPayments

A PHP implementation of CoinPayments API wrapped up into a simple to use class.

#Introduction# This is a two file class with simplicity at its core. I wanted to create a simple to use IPN that works with both paypal and bitcoin, because they are the most requested payment systems. Before you continue reading this, you should head over to https://www.coinpayments.net/merchant-tools-ipn#setup and make sure your account is ready to use with thew IPN. You do not need to setup a IPN url on coinpayments, you can do it in the code.

#How to Use#

This class is very simple to use, you need to simply include the coinPayments.class.php file and initialize it.

require 'src/coinPayments/coinPayments.class.php';

$cp = new \MineSQL\coinPayments();

$cp->setMerchantId('your_merchant_id_on_coinpayments');
$cp->setSecretKey('your_secret_key_you_defined_in_account_settings_on_coinpayments');

Now the coinpayments class is ready to do one of two things, either create a payment or recieve a callback notification.

##Creating A New Payment##

...

$productName = "A Test Product";
$currency    = "usd";
$price       = 15.00;
// This should be a unique identifier to differentiate payments in your database 
// so you can use it in your IPN to verify that price and currency are the same (more on this later)
$passthruVar = 'asd234sdf';
// The callback url that coinpayments will send a request to so you can validate the payment
$callbackUrl = 'http://localhost/coinPaymentsCallback.php';

$button = $cp->createPayment($productName, $currency, $price, $passthruVar, $callbackUrl);

echo $button;

Next, You need to know how to complete the callback (or IPN).

... initalize the class and set your merchantID and SecretKey like above


$passthruVar = $_POST['custom'];
// Now you can get the payment information from storage to get the price of the product and the currency

if($cp->validatePayment($price, $currency)){
  // the payment was successful
} else {  
  // The payment did not correctly validate, all errors are caught into an error array
  print_r($cp->getErrors());
}

In order for the payment to actually validate in the class, the request has to be verified through either HMAC or httpauth. Both work seemlessly in the application and is totally plug and play, the source does not need to be modified.

Then it needs to validate that the actual currency and currency paid are the same, so that is why you need to log the payment into some sort of database so you can fetch it when verifying the payment.It also validates that the amount paid by the buyer clears, and that the status coinpayments sends is either 100 or 2 (https://www.coinpayments.net/merchant-tools-ipn#statuses). If all of these challenges are passed then the payment was successful. If there are errors in payment verification the errors are descriptive and not number based.

##Misc.## You can modify the payment button very easily by editing the CPHelper.class.php file under the createButton method. In the future I might make it more dynamic, but for now it will need to be edited.

#Closing# This class is made to be extremely simple to use. If you find any issues with it or want to help develop it further send a pull request and I will most likely allow it.