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intermediate Phase 47 · Checkout Advanced

Payment Methods

Payment method interface, authorize/capture/void operations, payment configuration, and custom payment implementation

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Payment Method Interface

Payment Method Interface

// Magento\Payment\Api\PaymentMethodInterface
namespace Magento\Payment\Api;

interface PaymentMethodInterface
{
    /**
     * Get payment method code
     */
    public function getCode(): string;

    /**
     * Get payment method title
     */
    public function getTitle(): string;

    /**
     * Check if method is available
     */
    public function isAvailable(
        \Magento\Quote\Api\Data\CartInterface $quote = null
    ): bool;
}

Payment Information Interface

// Magento\Payment\Api\Data\PaymentInterface
namespace Magento\Payment\Api\Data;

interface PaymentInterface
{
    public function getMethod(): string;
    public function getPoNumber(): ?string;
    public function getAdditionalData(): ?array;
    public function get_cc_cid(): ?string;
    public function get_cc_exp_month(): ?string;
    public function get_cc_exp_year(): ?string;
    public function get_cc_number(): ?string;
    public function get_cc_type(): ?string;
}

Authorize, Capture, Void

Payment Action Types

// Magento\Payment\Model\Method\AbstractMethod
namespace Magento\Payment\Model\Method;

class AbstractMethod implements \Magento\Payment\Api\PaymentMethodInterface
{
    /**
     * Payment action constants
     */
    const ACTION_AUTHORIZE = 'authorize';
    const ACTION_AUTHORIZE_CAPTURE = 'authorize_capture';
    const ACTION_ORDER = 'order';

    /**
     * Authorize - verify funds, hold amount
     */
    public function authorize(
        \Magento\Payment\Api\Data\PaymentInterface $payment,
        float $amount
    ): self {
        // Call gateway to authorize
        $this->gateway->authorize($payment, $amount);

        $payment->setAuthorizationTransaction(
            $gatewayResponse->getTransactionId()
        );

        return $this;
    }

    /**
     * Capture - collect funds (requires authorization first)
     */
    public function capture(
        \Magento\Payment\Api\Data\PaymentInterface $payment,
        float $amount
    ): self {
        $this->gateway->capture($payment, $amount);

        $payment->setCaptureTransaction(
            $gatewayResponse->getTransactionId()
        );

        return $this;
    }

    /**
     * Void - cancel authorization
     */
    public function void(
        \Magento\Payment\Api\Data\PaymentInterface $payment
    ): self {
        $this->gateway->void($payment);

        $payment->setIsTransactionClosed(true);

        return $this;
    }
}

Payment Flow Examples

// Authorization only flow
$payment->authorize($paymentInfo, $amount);
// Funds are held but not captured

// Authorize + Capture flow
$payment->order($paymentInfo, $amount);
// Funds are captured immediately

// Void (cancel) flow
$payment->void($paymentInfo);
// Authorization is cancelled

Payment Configuration

System.xml Configuration

<!-- app/code/Vendor/Payment/etc/system.xml -->
<config>
    <section id="payment">
        <group id="custom_payment" translate="label" type="text" sortOrder="100" showInDefault="1" showInWebsite="1" showInStore="1">
            <label>Custom Payment</label>
            <field id="active" translate="label" type="select" sortOrder="1" showInDefault="1">
                <label>Enabled</label>
                <source_model>Magento\Config\Model\Config\Source\Yesno</source_model>
            </field>
            <field id="title" translate="label" type="text" sortOrder="10" showInDefault="1">
                <label>Title</label>
            </field>
            <field id="order_status" translate="label" type="select" sortOrder="20" showInDefault="1">
                <label>New Order Status</label>
                <source_model>Magento\Sales\Model\Config\Source\Order\Status\Newprocessing</source_model>
            </field>
            <field id="payment_action" translate="label" type="select" sortOrder="30" showInDefault="1">
                <label>Payment Action</label>
                <source_model>Magento\Payment\Model\Config\Source\Action\Order</source_model>
            </field>
            <field id="allowspecific" translate="label" type="select" sortOrder="40" showInDefault="1">
                <label>Payment from Applicable Countries</label>
                <source_model>Magento\Payment\Model\Config\Source\Allspecificcountries</source_model>
            </field>
        </group>
    </section>
</config>

Config Provider

namespace Vendor\Payment\Model\ConfigProvider;

class ConfigProvider implements \Magento\Checkout\Model\ConfigProviderInterface
{
    public function getConfig(): array
    {
        return [
            'payment' => [
                'custom_payment' => [
                    'title' => $this->getConfigData('title'),
                    'order_status' => $this->getConfigData('order_status'),
                    'payment_action' => $this->getConfigData('payment_action'),
                ],
            ],
        ];
    }
}

Custom Payment Implementation

Custom Payment Method

namespace Vendor\Payment\Model\Method;

class Custom extends \Magento\Payment\Model\Method\AbstractMethod
{
    protected $_code = 'custom_payment';
    protected $_isGateway = true;
    protected $_canAuthorize = true;
    protected $_canCapture = true;
    protected $_canVoid = true;
    protected $_canRefund = true;

    public function __construct(
        \Magento\Framework\App\Config\ScopeConfigInterface $scopeConfig,
        \Magento\Payment\Model\Method\Logger $logger,
        private GatewayInterface $gateway
    ) {
        parent::__construct($scopeConfig, $logger);
    }

    public function authorize(
        \Magento\Payment\Api\Data\PaymentInterface $payment,
        float $amount
    ): \Magento\Payment\Model\Method\AbstractMethod {
        $transactionId = $this->gateway->authorize([
            'amount' => $amount,
            'currency' => $payment->getOrder()->getCurrencyCode(),
            'card_number' => $payment->getCcNumber(),
            'card_expiry' => $payment->getCcExpMonth() . '/' . $payment->getCcExpYear(),
            'card_cvv' => $payment->getCcCid(),
        ]);

        $payment->setAuthorizationTransaction($transactionId);
        $payment->setIsTransactionClosed(false);

        return $this;
    }

    public function capture(
        \Magento\Payment\Api\Data\PaymentInterface $payment,
        float $amount
    ): \Magento\Payment\Model\Method\AbstractMethod {
        $transactionId = $this->gateway->capture([
            'authorization_id' => $payment->getAuthorizationTransaction(),
            'amount' => $amount,
        ]);

        $payment->setCaptureTransaction($transactionId);
        $payment->setIsTransactionClosed(true);

        return $this;
    }
}

Payment Gateway Interface

namespace Vendor\Payment\Gateway;

interface GatewayInterface
{
    public function authorize(array $request): string;
    public function capture(array $request): string;
    public function void(string $transactionId): void;
    public function refund(array $request): string;
}

Quiz

1. What is the difference between authorize and capture?

Question 1 options

2. What does payment_action configuration control?

Question 2 options

3. What must a payment method implement to be refundable?

Question 3 options

Flashcards

Question

What does authorize() do?

Click to reveal answer

Answer

Verifies and holds funds without collecting them

Question

What does capture() do?

Click to reveal answer

Answer

Collects previously authorized funds

Question

payment_action options?

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Answer

authorize (hold only) or authorize_capture (hold + collect)

Question

Minimum payment method flags?

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Answer

_canAuthorize, _canCapture, _canVoid, _canRefund

Revision Notes

Key Takeaways

  • 1. Payment methods implement PaymentMethodInterface for availability checks
  • 2. Authorize holds funds, capture collects them, void cancels authorization
  • 3. system.xml configures payment settings in admin
  • 4. ConfigProvider supplies payment config to checkout JavaScript
  • 5. Custom payment requires gateway interface and method class

Interview Tips

  • • Explain the authorize → capture → void payment lifecycle
  • • Discuss when to use authorize-only vs authorize-capture
  • • Describe how payment config flows from system.xml to checkout JS

Cheat Sheet

Payment Methods:
  authorize()  → hold funds
  capture()    → collect funds
  void()       → cancel hold
  refund()     → return funds

Flags:
  _canAuthorize, _canCapture, _canVoid, _canRefund

Config:
  system.xml → admin settings
  ConfigProvider → JS config
  di.xml → method registration