Paypal Rest API payment verification serverside

Question

I have setup the payment on my server with paypal, after doing some check it redirects the user to paypal payment page which in turn redirect user to my website with one custom parameter 'approved'='ok' or 'nok'. Apart from this i get 3 more field in GET params ie payment-id, payerid and token on success. i want to verify whether these parameter are coming from paypal and check the payment status whether user has really paid the amount on server side only.

Will anybody help. Ready to provide more info.

My return url look like: http://localhost/test/payment.php?approved=ok&paymentId=PAY-6P3424788A4717248KYR6EPA&token=EC-0V6779052Y720131T&PayerID=JWTZXBN9AEBMC

Thanks in advance.

Answer 1

You can see transaction status after post parameters to paypal and they return the response error or success message. Here is one complete example of the payment process with recurring and after that ordinary payment:

// Parameters for SetExpressCheckout, which will be sent to PayPal

$padata['L_BILLINGAGREEMENTDESCRIPTION0']   = 'Product description';
$padata['L_BILLINGAGREEMENTDESCRIPTION0']   = $padata['L_BILLINGAGREEMENTDESCRIPTION0'] . 
' $'.$product->price.'/month';
$padata['L_PAYMENTREQUEST_0_DESC0']         = $padata['L_BILLINGAGREEMENTDESCRIPTION0'] . 
' $'.$product->price.'/month';
$padata['PAYMENTREQUEST_0_NOTIFYURL']        = 'http://site_url/paypal/ipn';
$padata['PAYMENTREQUEST_0_DESC']            = $product->name;
$padata['RETURNURL']                        = 'http://site_url/paypal/returnurl';
$padata['CANCELURL']                        = 'http://site_url/paypal/cancelurl';

$padata['PAYMENTREQUEST_0_CURRENCYCODE']    = 'USD';
$padata['PAYMENTREQUEST_0_PAYMENTACTION']   = 'SALE';
$padata['PAYMENTREQUEST_0_ITEMAMT'] = $product->price;
$padata['PAYMENTREQUEST_0_AMT']      = $product->price;
$padata['L_BILLINGTYPE0']            = 'RecurringPayments';
$padata['L_PAYMENTREQUEST_0_NAME0']  = $product->name;
$padata['L_PAYMENTREQUEST_0_NUMBER0']= '322';
$padata['L_PAYMENTREQUEST_0_QTY0']  = '1';
$padata['L_PAYMENTREQUEST_0_AMT0']   = $product->price;


$paypal_data            = http_build_query($padata);
$httpParsedResponseAr   = $this->PPHttpPost('SetExpressCheckout', $paypal_data);

//Respond according to message we receive from Paypal
if("SUCCESS" == strtoupper($httpParsedResponseAr["ACK"]) || "SUCCESSWITHWARNING" == strtoupper($httpParsedResponseAr["ACK"])){

    //Redirect user to PayPal store with Token received.
    $paypalurl ='https://www.paypal.com/cgi-bin/webscr?cmd=_express-checkout&token='.$httpParsedResponseAr["TOKEN"].'';
    header('Location: '.$paypalurl);

}else{
    echo ''.urldecode($httpParsedResponseAr["L_LONGMESSAGE0"]).'';


}

Page returnurl:

$hosteddata['L_BILLINGAGREEMENTDESCRIPTION0']   = 'Recurring Description';
$hosteddata['L_BILLINGAGREEMENTDESCRIPTION0']    = $hosteddata['L_BILLINGAGREEMENTDESCRIPTION0'] . ' $'.$pr->price.'/month';
$hosteddata['L_PAYMENTREQUEST_0_NAME0']         = $pr->name;
$hosteddata['PROFILEREFERENCE']                    = $GetExpressCheckoutDetails['L_PAYMENTREQUEST_0_NUMBER0'];
$hosteddata['PROFILESTARTDATE']                 = date('Y-m-d') . 'T' . date('H:i:s').'Z';
$hosteddata['SUBSCRIBERNAME']                    = $GetExpressCheckoutDetails['FIRSTNAME'] . ' ' . $GetExpressCheckoutDetails['LASTNAME'];
$hosteddata['TOKEN']                          = urlencode($_POST['token']);
$hosteddata['DESC']                               = $hosteddata['L_BILLINGAGREEMENTDESCRIPTION0'];
$hosteddata['AMT']                             = $pr->price;
$hosteddata['BILLINGPERIOD']                  = 'Month';
$hosteddata['BILLINGFREQUENCY']                  = '1';
$hosteddata['TOTALBILLINGCYCLES']                = '12';
$hosteddata['REGULARTOTALBILLINGCYCLES']        = '1';
$hosteddata['VERSION']                           = '74.0';
$hosteddata['MAXFAILEDPAYMENTS']              = '1';
$hosteddata['L_PAYMENTREQUEST_0_QTY0']           = '1';
$hosteddata['L_BILLINGTYPE0']                    = 'RecurringPayments';
$hosteddata['L_PAYMENTREQUEST_0_ITEMCATEGORY0']  = 'Digital';
$hosteddata['L_PAYMENTREQUEST_0_AMT0']         = $pr->price;
$hosteddata['INITAMT']                            = $pr->price;
$hosteddata['L_PAYMENTREQUEST_0_NUMBER0']     = $pr->id;
$hosteddata['PAYMENTREQUEST_0_NOTIFYURL']        = 'http://site_url/paypal/ipn';


$paypal_data = http_build_query($hosteddata);
$hosted_saas_response = $this->PPHttpPost('CreateRecurringPaymentsProfile', $paypal_data);

I used a separate method to post parameters to paypal

private function PPHttpPost( $methodName_, $nvpStr_ ) {

$api_username   = 'yourpaypal@email.com';
$api_password   = 'QWEQWEWQEQWEQEQWE';
$api_signature   = 'WQEQWEQWEQWEWQEQWEQWEQWEQWEQWE.cT';
$api_endpoint    = "https://api-3t.paypal.com/nvp";
$version     = '124.0';

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $api_endpoint);
   curl_setopt($ch, CURLOPT_VERBOSE, 1);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, FALSE);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);

curl_setopt($ch, CURLOPT_POST, 1);
 
$nvpreq = "METHOD=$methodName_&VERSION=$version&PWD=$api_password&USER=$api_username&SIGNATURE=$api_signature&$nvpStr_";

curl_setopt($ch, CURLOPT_POSTFIELDS, $nvpreq);
$httpResponse = curl_exec($ch);

    if(!$httpResponse) {
        exit("$methodName_ failed: ".curl_error($ch).'('.curl_errno($ch).')');
}

    // Extract the response details.
    $httpResponseAr = explode("&", $httpResponse);

    $httpParsedResponseAr = array();
    foreach ($httpResponseAr as $i => $value) {
        $tmpAr = explode("=", $value);
        if(sizeof($tmpAr) > 1) {
            $httpParsedResponseAr[$tmpAr[0]] = $tmpAr[1];
         }
    }

    if((0 == sizeof($httpParsedResponseAr)) || !array_key_exists('ACK', $httpParsedResponseAr)) {

        exit("Invalid HTTP Response for POST request($nvpreq) to $api_endpoint.");

    }

    return $httpParsedResponseAr;

}

Parameters for SetExpressCheckout for one time ordinary payment:

// Parameters for SetExpressCheckout for one time ordinary payment
$padata['L_BILLINGAGREEMENTDESCRIPTION0']    = 'Product descriptuion;
$padata['L_PAYMENTREQUEST_0_DESC0']            = $padata['L_BILLINGAGREEMENTDESCRIPTION0'];
$padata['PAYMENTREQUEST_0_NOTIFYURL']      = 'http://siteurl.com/paypal/ipn';
$padata['PAYMENTREQUEST_0_DESC']         = $padata['L_BILLINGAGREEMENTDESCRIPTION0'];
$padata['RETURNURL']                       = 'http://siteurl.com/paypal/returnToDownload';
$padata['CANCELURL']                        = 'http://siteurl.com/paypal/cancelurl';

$padata['PAYMENTREQUEST_0_CURRENCYCODE']    = 'USD';
$padata['PAYMENTREQUEST_0_PAYMENTACTION']  = 'SALE';
$padata['PAYMENTREQUEST_0_ITEMAMT']           = $product->price;
$padata['PAYMENTREQUEST_0_AMT']              = $product->price;
$padata['L_PAYMENTREQUEST_0_NAME0']          = $product->price;

$padata['L_PAYMENTREQUEST_0_NUMBER0']       = 'verification_id#@@#!@#!@#@!!@#ASDASD';
$padata['L_PAYMENTREQUEST_0_QTY0']            = '1';
$padata['L_PAYMENTREQUEST_0_AMT0']           = $product->price;