Anatomy of payment systems in Drupal 8

1. Anatomy of payment
systems in Drupal 8
Oleg Natalushko http://drupal.org/u/niko

2. Plan
• Current status of payments in Drupal 8.
• Common developers mistakes.
• Drupal commerce 2.x payment
• Payment
• Payment offsite API

3. About me
• More than 100 implemented drupal projects.
• 15 years experience Backend developer
• 5 years experience Drupal developer
• Maintainer of commerce interkassa
• Maintainer of Payment platon
• Maintainer of commerce probokassa
• Maintainer of Payment offsite API

4. Payment types.
• Payment emulation
• On site
• Off site

5. Drupal payment contrib.
Drupal 7
• Drupal commerce 1.x
• Payment
• Payment Gateway API
Drupal 8
• Drupal Commerce 2.x
• Payment
• Payment offsite API

6. W3C PAYMENT REQUEST API
SPECIFICATION
• Payment Request API
• Basic Card Payment
• Payment Method Identifiers
https://www.w3.org/TR/payment-request/

7. Payment
workflow

8. Real payment workflow

9. Real payment workflow
(Drupal developer think)
Checkout Payment system IPN call* Result page

10. Known contrib issues
• Partitional payment not supported
• Support only one payment instance per payment module
• Not fixed result pages
• Success URL: checkout/ORDER_ID/payment/return/ORDER_PAYMENT_REDIRECT_KEY
• Fail URL: checkout/ORDER_ID/payment/back/ORDER_PAYMENT_REDIRECT_KEY
• Payment transaction created only on success
• Send order ID to payment system
• Custom result urls used

11. Drupal commerce 2.x plan
- The payment gateway config entity + UI
- The payment gateway plugin type
- The payment type YAML plugin
- The credit_card payment type
- The payment method content entity (for storing tokenized payment
information), which uses the payment types as bundles
- The payment content entity, which uses payment types as bundles
A payment would have a workflow:
New -> Pending -> Complete -> Cancelled | (Partially) Refunded.
https://www.drupal.org/node/2711013

12. Payment method configuration

13. Payment method configuration
Payment module
•Config, Schema and Plugin
•Implement PaymentMethodConfigurationBase
• processBuildConfigurationForm() including tabs
magic
• defaultConfiguration()
• buildConfigurationForm()
• validateConfigurationForm()
• submitConfigurationForm()
• Status Selector (5 methods)
Payment Offsite API module
•Config, Schema, Plugin
•Implement PaymentMethodConfigurationBaseOffsite
• processBuildConfigurationForm()
• validateConfigurationForm()
• submitConfigurationForm()
• defaultConfiguration()

14. Payment form

15. Payment form
Payment module requirements
•Implement Routing
•Implement Redirect form controller (with
cleanup)
•Implement Access controller
•Implement signature generator
•Implement is configured checker
•Auto submit library
• Implement Operation provider (configuration
loader) getPaymentMethodConfiguration()
• Implement payment method deriver
getDerivativeDefinitions()
Payment Offsite API module
PaymentMethod plugin
•Extend PaymentMethodBaseOffsite or
PaymentMethodOffsiteSimple
•Implement
• paymentForm()
• isConfigured()
• getSignature() (simple)
•Use $this->addPaymentFormData()
•Use $this->generateForm()
•Configure auto submit via UI

16. Payment result pages
Payment
system
IPN
callback
Call Result
pages callback
Success page
Pending page
Fail page
Hidden fallback call
(optional)

17. Payment result pages
Payment module requirements
•Implement
• Routing
• Result pages controller
• Access controller
•Fallback support (optional)
Payment Offsite API module
PaymentMethod plugin
•Implement
• getResultPages()
• get<Result>Content()
• getSignature() (simple)
•Fallback call supports per result
page using getResultPages()

18. Payment IPN callback
Payment
system
IPN callback
Call IPN
Access check
Call IPN
Validate
Call IPN
Execute
Set order
internal status
according to
status mapping
Payment method plugin + configuration

19. Payment IPN callback
Payment module require
Implement
•Routing
•IPN controller
•IPN validator
•Access controller
Payment Offsite API module
Implement in PaymentMethod plugin
•ipnExecute()
•ipnValidate()
Also you could extend PaymentMethodOffsiteSimple and use
•validateEmpty()
•validateRequiredKeys()
•validateMerchant()
•validateSignature()
•validateTransactionId()
•validateAmount()
You must implement if going to use default validators:
•getMerchantIdName()
•getTransactionIdName()
•getAmountName()
•getSignatureName()
•getRequiredKeys()

20. Payment offsite API Interface
interface PaymentMethodOffsiteInterface {
public function ipnExecute();
public function ipnValidate();
public function getResultPages();
public function paymentForm();
public function isConfigured();
}

21. Payment offsite API
Simple Interface
interface PaymentMethodOffsiteSimpleInterface extends PaymentMethodOffsiteInterface {
const SIGN_IN = 'IN';
const SIGN_OUT = 'OUT';
public function getSignature($signature_type = self::SIGN_IN);
public function getMerchantIdName();
public function getTransactionIdName();
public function getAmountName();
public function getSignatureName();
public function getRequiredKeys();
}

22. Payment offsite API
• Fully compatible with Payment module
• Fallback mode support
• Multiple payment instances support
• Simplify payment method creation
• IPN and result pages callbacks
• Payment form
@Todo provide integration to commerce_payment
@see https://www.drupal.org/sandbox/niko/2685859

23. Thank you
Oleg Natalushko
Site: http://bighameleon.com
Skype: onatalushko
Phone: +380674176171
Drupal.org: https://www.drupal.org/u/niko