Step 3. Creating a gateway class

Lets create a eZPaypalGateway class for our gateway. Since it should redirect a customer to the paypal site, our class should be inherited from eZRedirectGateway. Add these lines to 'ezpaypalgateway.php'.

    include_once( 'kernel/shop/classes/ezredirectgateway.php' );
    
    define( "EZ_PAYMENT_GATEWAY_TYPE_PAYPAL", "ezpaypal" );
    
    class eZPaypalGateway extends eZRedirectGateway
    {
        function eZPaypalGateway()
        {
        }
    }

Now we need to override createRedirectionUrl function. This function should return a string with key-value pairs for POST request. Some values are hard-coded and some are taken from ini file. Add these lines to 'ezpaypalgateway.php' to eZPaypalGateway class.

    function &createRedirectionUrl( &$process )
    {
        $paypalINI      =& eZINI::instance( 'paypal.ini' );
    
        $paypalServer   = $paypalINI->variable( 'ServerSettings', 'ServerName');
        $requestURI     = $paypalINI->variable( 'ServerSettings', 'RequestURI');
        $business       = urlencode( $paypalINI->variable( 'PaypalSettings', 'Business' ) );
        
        $processParams  =& $process->attribute( 'parameter_list' );
        $orderID        = $processParams['order_id'];

        $indexDir       = eZSys::indexDir();
        $localHost      = eZSys::hostname();
        $localURI       = eZSys::serverVariable( 'REQUEST_URI' );
        
        $order          =& eZOrder::fetch( $orderID );
        $amount         = urlencode( $order->attribute( 'total_inc_vat' ) );
        
        include_once( 'lib/ezlocale/classes/ezlocale.php' );
        $locale         =& eZLocale::instance();
        $currency       = urlencode( $locale->currencyShortName() );

        $maxDescLen     = $paypalINI->variable( 'PaypalSettings', 'MaxDescriptionLength');
        $itemName       = urlencode( $this->createShortDescription( $order, $maxDescLen ) );
                
        $accountInfo    = $order->attribute( 'account_information' );
        $first_name     = urlencode( $accountInfo['first_name'] );
        $last_name      = urlencode( $accountInfo['last_name'] );
        $street         = urlencode( $accountInfo['street2'] );
        $zip            = urlencode( $accountInfo['zip'] );
        $state          = urlencode( $accountInfo['state'] );
        $place          = urlencode( $accountInfo['place'] );
        $image_url      = "http://$localHost" . urlencode( $paypalINI->variable( 'PaypalSettings', 'LogoURI' ) );
        $background     = urlencode( $paypalINI->variable( 'PaypalSettings', 'BackgroundColor' ) );
        $pageStyle      = urlencode( $paypalINI->variable( 'PaypalSettings', 'PageStyle' ) );
        $noNote         = urlencode( $paypalINI->variable( 'PaypalSettings', 'NoNote' ) );
        $noteLabel      = ($noNote == 1) ? '' : urlencode( $paypalINI->variable( 'PaypalSettings', 'NoteLabel' ) );
        $noShipping     = 1;

        $url =  $paypalServer  . $requestURI    .
                "?cmd=_ext-enter"               .
                "&redirect_cmd=_xclick"         .
                "&business=$business"           .
                "&item_name=$itemName"          .
                "&custom=$orderID"              .
                "&amount=$amount"               .
                "¤cy_code=$currency"      .
                "&first_name=$first_name"       .
                "&last_name=$last_name"         .
                "&address1=$street"             .
                "&zip=$zip"                     .
                "&state=$state"                 .
                "&city=$place"                  .
                "&image_url=$image_url"         .
                "&cs=$background"               .
                "&page_style=$pageStyle"        .
                "&no_shipping=$noShipping"      .
                "&cn=$noteLabel"                .
                "&no_note=$noNote"              .
                "¬ify_url=http://$localHost" . $indexDir . "/paypal/notify_url/".
                "&return=http://$localHost"     . $indexDir . "/shop/checkout/" .
                "&cancel_return=http://$localHost" . $indexDir. "/shop/basket/";
                
        return $url;
    }

And these to 'paypal.ini'

    [ServerSettings]
    #ServerName=https://www.paypal.com
    ServerName=https://www.sandbox.paypal.com
    RequestURI=/cgi-bin/webscr
    
    [PaypalSettings]
    # max length of description of the order
    # everything that exceeds will be truncated 
    MaxDescriptionLength=127
    
    # field: "business"
    # e-mail of receiver
    Business=my_business@coolmail.net
    
    # field: "no_note" 
    # prompt to include a note. 0 - prompt, 1 - dont prompt
    NoNote=0
    
    # field: "cn"
    # label that will appear above the note field
    # maximum 40 characters
    NoteLabel=Some Label
    
    # field: "page_style"
    PageStyle=
    
    # field: "cs" 
    # background color if PageStyle not set. 0 - white, 1 - black.                            
    BackgroundColor=0
    
    #filed: "image_url" (URI to the logo image (150 x 50 pixels))
    LogoURI=/var/shop/images/logo.png

Note that in the 'Business' field you should point you merchant account(a test account, for example).
Note that for testing we are using www.sandbox.paypal.com site. In life you should use www.paypal.com.

When a callback will be called we need to know what order we should process and what workflow should continue. For these purposes eZPaymentObject is served. It stores in database information about order and workflow.
Lets create our payment object. Add these lines to 'ezpaypalgateway.php' to eZPaypalGateway class.

    function &createPaymentObject( &$processID, &$orderID )
    {
        return eZPaymentObject::createNew( $processID, $orderID, 'Paypal' );
    }

Don't forget to include to 'ezpaypalgateway.php' necessary file:

include_once( 'kernel/shop/classes/ezpaymentobject.php' );

To make our gateway visible for eZPublish workflow system add this line somewhere in 'ezpaypalgateway.php'

eZPaymentGatewayType::registerGateway( EZ_PAYMENT_GATEWAY_TYPE_PAYPAL, "ezpaypalgateway", "Paypal" );

We are almost finished. Now we need to hanle callback.