json

//[doc-seo]
{
    "Description": "Learn how to create a custom payment gateway in ABP Framework, enhancing your application's payment flexibility and integration."
}

Creating a Custom Payment Gateway

You must have an ABP Team or a higher license to use this module.

This document explains creating custom a payment gateway that's different than the existing ones in the Payment Module.

Creating Core Operations

Create MyPaymentGateway.cs in the Domain layer of your project and implement IPaymentGateway.

csharp

public class MyPaymentGateway : IPaymentGateway, ITransientDependency
  {
      private readonly IPaymentRequestRepository paymentRequestRepository;

      public MyPaymentGateway(IPaymentRequestRepository paymentRequestRepository)
      {
          this.paymentRequestRepository = paymentRequestRepository;
      }

      public async Task<PaymentRequestStartResult> StartAsync(PaymentRequest paymentRequest, PaymentRequestStartInput input)
      {
          var totalPrice = paymentRequest.Products.Sum(x => x.TotalPrice);

          var checkoutLink = // Some operations here

          return new PaymentRequestStartResult
          {
              CheckoutLink = checkoutLink + "returnUrl=" + input.ReturnUrl
          };
      }

      public async Task<PaymentRequest> CompleteAsync(Dictionary<string, string> parameters)
      {
          var token = parameters["token"]; // You can get any parameter from your gateway provides. Example: token, id, hash etc. 

          var result = ;// provider.Validate(token); Validate the payment here

          var paymentRequest = await paymentRequestRepository.FindAsync(result.Id);

          paymentRequest.SetState(PaymentRequestState.Completed); // completed or anything else according to your result.

          return paymentRequest;
      }

      public Task HandleWebhookAsync(string payload, Dictionary<string, string> headers)
      {
          // You can leave unimplemented if you not configure webhooks.
          throw new System.NotImplementedException();
      }

      public bool IsValid(PaymentRequest paymentRequest, Dictionary<string, string> properties)
      {
          // You can check some custom logic here to make this gateway available or not.
          return true;
      }
  }

You should also configure PaymentOptions for your gateway in the Domain layer of your project as shown below.

csharp

Configure<PaymentOptions>(options =>
  {
      options.Gateways.Add(new PaymentGatewayConfiguration(
          "MyGateway",
          LocalizableString.Create<PaymentResource>("MyGateway"),
          isSubscriptionSupported: false,
          typeof(MyPaymentGateway)
          ));
  });

Creating the UI

There are 2 types of pages that are supported by default. You can define a pre-payment page and post-payment page.

Create PreCheckout.cshtml and PreCheckout.cshtml.cs

html

@model PreCheckoutModel

<h3>Pre Checkout</h3>
<form method="post">
    <button class="btn btn-success" asp-page-handler="ContinueToCheckout">
        Continue to Checkout
        <i class="fa fa-long-arrow-right"></i>
    </button>
</form>

csharp

public class PreCheckoutModel : AbpPageModel
{
    [BindProperty] public Guid PaymentRequestId { get; set; }

    public virtual ActionResult OnGet()
    {
        // GET operation is not supported here. All the selected gateway requests will be sent as POST.
        return BadRequest();
    }

    public virtual async Task OnPostAsync()
    {
        // You can get the payment request from the database by using `PaymentRequestId` and render something on the UI side.
    }

    public virtual async Task<IActionResult> OnPostContinueToCheckout()
    {
        return Redirect("the-actual-checkout-link-of-gateway");
    }
}

Create PostCheckout.cshtml and PostCheckout.cshtml.cs
html
```
@model PostCheckoutModel

<h3>Operation Done</h3>
```

Configure your pages using PaymentWebOptions in Web layer of your project.

csharp

Configure<PaymentWebOptions>(options =>
{
    options.Gateways.Add(new PaymentGatewayWebConfiguration(
        name: "MyGateway",
        prePaymentUrl: "/MyGateway/PreCheckout", // This page will be opened before checkout.
        isSubscriptionSupported: false,
        postPaymentUrl: "/MyGateway/PostCheckout" // This page will be opened after checkout.
        ));
});

Your custom gateway will be listed in the public payment gateway selection page. If there is only one payment gateway, this page will be skipped.