README

paypal-ewp

A PHP library for generating encrypted PayPal buttons (EWP)

Prerequisites

To use this library you should first follow the instructions given by PayPal on generating a merchant certificate and key pair and obtaining PayPal's public certificate.

You'll need the following data to generate a button:

• Your Certificate ID issued by PayPal after you uploaded your certificate
• The path to your certificate in PEM format on disk
• The path to your private key in PEM format on disk
• The passphrase for your private key (if you set one)
• The path to PayPal's public certificate in PEM format on disk
• The HTML Variables you wish to add to your button

Installation

The recommended way to install this library is via Composer:

composer require pkerrigan/paypal-ewp ^1

Usage

Below is a complete example which generates an encrypted button for submitting a shopping cart:

<?php
 
use Pkerrigan\PaypalEwp\PaypalCertificate;
use Pkerrigan\PaypalEwp\MerchantCertificate;
use Pkerrigan\PaypalEwp\ButtonGenerator;
 
$buttonGenerator = new ButtonGenerator();
 
$paypalCert = new PaypalCertificate('/path/to/certs/paypal-cert.pem');
 
$merchantCert = new MerchantCertificate(
    'MY_CERTIFICATE_ID',
    '/path/to/certs/merchant-cert.pem',
    '/path/to/certs/merchant-key.pem',
    'MY_KEY_PASSPHRASE' //This argument can be omitted if you have no passphrase
);
 
$buttonVariables = [
    'cmd' => '_cart',
    'upload' => '1',
    'amount_1' => '1.00',
    'item_name_1' => 'Test Item',
    'business' => 'test@example.org',
    'currency_code' => 'GBP'
];
 
$encryptedCart = $buttonGenerator->encrypt($paypalCert, $merchantCert, $buttonVariables);
 
?>
 
<form action="https://www.paypal.com/cgi-bin/webscr" method="post">
    <input type="hidden" name="cmd" value="_s-xclick">
    <input type="hidden" name="encrypted" value="<?= $encryptedCart; ?>">
    <input type="submit" value="Proceed to checkout">
</form>