Topic 8 – Part 6: Payment Methods

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Nice to see you again in this series of Magento tutorial. Today I will write about Payment Methods – the last stage of checkout process. As we know, once customer details are filled in and the chosen shipping method, the payment method forms will be shown for customer to select. After a customer selects a payment method, the checkout will progress through the payment method’s function. It can be the request via an API, authorization or offline payment. My tutorial today will introduce how to add a custom payment method for Magento?

1. Declare custom payment method by configuration

To add your custom payment method, you need to declare with Magento’s system. Thus you can add the code below to your module configuration (config.xml).

<config>
...
<default>
<payment>
<[custom_payment]>
<active>1</active>
<model>[custom_module]/method_[payment_model]</model>
<order_status>pending</order_status>
<title>Custom Payment Method</title>
<allowspecific>0</allowspecific>
...
</[custom_payment]>
</payment>
</default>
</config>

In this configuration, you see the tag model, this is the configuration of the payment adaptor model.

2. Write adaptor model for custom payment method

Firstly, you have to write your custom model corresponding to the configuration above. This model needs to be extended from class Mage_Payment_Model_Method_Abstract. This model class is similar to the following:

class [Custom_Module]_Model_Method_[Payment_Model] extends Mage_Payment_Model_Method_Abstract
{
/** form block and info block for custom payment method */
protected $_formBlockType = '[custom_module/form_block]';
protected $_infoBlockType = '[custom_module/info_block]';

/** Payment method features */
protected $_isGateway                   = true;
protected $_canOrder                    = false;
protected $_canAuthorize                = false;
protected $_canCapture                  = true;
protected $_canCapturePartial           = false;
protected $_canRefund                   = true;
...

public function authorize(Varien_Object $payment, $amount) {
// authorize payment
}

public function capture(Varien_Object $payment, $amount) {
// capture payment
}

public function order(Varien_Object $payment) {
// void payment
}

public function refund(Varien_Object $payment, $amount) {
// refund payment
}
...
}

Above are some basic methods that the system calls when the order is processed. Thus they are key functions of a payment method. If payment method uses a gateway, some function can send request to the gateway to collect information for processing order.

3. Store payment’s information

Payment model is the abstract of an instance payment method and it works with database. Payment model can be Mage_Sales_Model_Order_Payment or Mage_Sales_Model_Quote_Payment depending on checkout stage. And the database is stored corresponding with tables sales_flat_order_payment and sales_flat_quote_payment. However,  Quote_Payment doesn’t have any method to process the order. You can view more details in the Magento’s source code and database.

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