Payment module for the Lynx framework

This module enables payments for the Lynx framework. It is possible to register additional custom payment methods.

This module currently supports the Stripe payment method. It is necessary to provide the usual Stripe keys to enable it.

An administration interface is provided thought the AdminUI module.

Installation

NOTE: The module depends on lynx-admin-ui and lynx-data-grid.

npm install lynx-payments

Usage

Initialize the module and register the payments methods:

StripePayment.setKeys(
    'pk stripe key',
    'sk stripe key'
);

PaymentsModule.register(StripePayment);

const app = new App(myConfig, [new PaymentsModule(), new PaymentsTestModule()]);

Payment methods shall also be registered on the PaymentMethodEntity (this enable dynamic activation/deactivation of a single methods). For example, for the Stripe payment method:

let p = await PaymentMethodEntity.findOne({
    where: { name: StripePayment.getName() },
});
if (!p) {
    p = new PaymentMethodEntity();
    p.name = StripePayment.getName();
    await p.save();
}

Finally, it is possible to create a new payment request as follow:

@Route('/payment/test')
export default class TestController extends BaseController {
    @Name('test-do')
    @POST('/')
    async performPayment(req: Request) {
        let p = await Payment.createPayment(
            100, // the amount of the payment
            'eur', // the selected currency for the payment
            'Checkout for order 123', // the user readable description of the payment (will be displayed to the user)
            '/payment-done', // internal callback url in order to check the payment (if success or error)
            '/my-template/layout' // the base template layout in which the payment flow will be included
        );
        return this.redirect(p.currentUrl, { uuid: p.uuid });
    }
}

At the end of the payment flow, the user will be redirect to /payment-done?uuid={{payment-uuid}}. A controller with a GET method shall be defined, in order to complete the payment flow, retrieving the Payment entity with the specified {{payment-uuid}} and checking its .status property. If the status is Status.completed, the payment is completed successfully.

Add a custom payment method

A payment method shall extends the base Payment class, providing implementations for the abstract methods. Each Payment class contains the payment and the user attributes, that are the associated PaymentEntity and UserEntity values for that particular request.

The PaymentEntity contains a customizable data attribute, can be used to store payment-specific information (for example, in the Stripe implementation, the Stripe payment id can be stored in order to have a relation). The status attribute shall be updated based on the results of the payment (for example, in the Stripe implementation, if the credit card payment failed, the status will be updated to Status.error).

Each implementation shall also have a static method, defined as getName(): string, that returns a string containing a unique id for the payment method.

The payment flow is divided in three steps:

1. The user will be asked to choose a payment method from a list. In this page, all the enabled methods from the PaymentMethod entity will be displayed. Each method is also filtered by the isAvailable(): Promise<boolean> method, in which it is possible to check if the current payment and user can authorized this method.
2. For the chosen payment method, the create(): Promise<CreateData> is executed. It should perform any initialization and return an object containing the templated for the payment method (both the html and the js scripts). This templates will be displayed to the user. At the end of the operations, a form should be posted to the checkout-result named route, with the uuid parameter.
3. In the checkout-result controller, the method updateStatus(): Promise<void> of the payment method is executed. This method shall check the payment status (for example, with the back API), and correctly update the status of the current payment.
4. Finally, the payment status is checked to create flash messages, and the user is redirected to the url specified when the payment was created.