[Feature]: Requesting model for Android Payments app short payment response

[bcederholm]

Feature summary

Until implemented a custom class needs to be declared.
Adyen Library version 32.1.2

Problem statement

Following documentation to implement tap-to-pay using Adyen Payment app.
https://docs.adyen.com/point-of-sale/mobile-android/build/payments-app/?tab=short-response_2

The short payment response object contains result, url, errorCondition and traceParent, following is examples on combinations of respons values.

{
"result": "Success",
"url": "https://checkoutpos-test.adyen.com/checkoutpos/v1/merchants/{MerchantId}/paymentsApps/{InstallationId}>/payments/{TransactionID}"
}

{
"result": "Failure",
"errorCondition": "Cancel"
}

{
"result": "Failure",
"errorCondition": "MessageFormat"
}

We have a .NET callback route where we deserialize this message, as there is no equivalent model in the Library we have to declare it in our code.

Proposed solution

Add the model to the library. Take no consideration to the class name.

public class TapToPayShortPaymentResponse
{
    public string Result { get; init; }
    public string Url { get; init; }
    public string ErrorCondition { get; init; }
    public string TraceParent { get; init; }
}

Alternatives considered

No response

Additional context

No response

[gcatanese]

Hey @bcederholm, thank you for reporting this.
Adding a new class with the expected schema is enough? Will your app (implementation) take care of the deserialization of the response?
I am trying to understand the flow and if we need to consider other aspects or solutions.

[bcederholm]

Hi! Following is my POC code for the pay callback, where you see the context to "JsonSerializer.Deserialize". The development is done with trial and error until succeeded, so if there are any steps that are unnecessary, could be simplified or there are any services or methods in .NET Library that could be applied instead of custom code I will welcome that info.

    [Function(nameof(PayCallback))]
    public async Task<IActionResult> PayCallback([HttpTrigger(AuthorizationLevel.Anonymous, "get", Route = "tap-to-pay/pay-callback")] HttpRequestData req)
    {
        var query = HttpUtility.ParseQueryString(req.Url.Query);
        foreach (string key in query) _logger.LogInformation("Query parameter: {Key} = {Value}", key, query[key]);

        var responseParam = query["response"];
        var securityTrailerParam = query["securityTrailer"];

        var nexoBlobString = Base64UrlDecode(responseParam);

        var securityTrailerJson = Base64UrlDecode(securityTrailerParam);
        var securityTrailer = JsonSerializer.Deserialize<SecurityTrailer>(securityTrailerJson);

        var saleToPoiMessageSecured = new SaleToPoiMessageSecured
        {
            NexoBlob = nexoBlobString,
            SecurityTrailer = new SecurityTrailer
            {
                AdyenCryptoVersion = securityTrailer.AdyenCryptoVersion,
                KeyIdentifier = securityTrailer.KeyIdentifier,
                KeyVersion = securityTrailer.KeyVersion,
                Nonce = securityTrailer.Nonce,
                Hmac = securityTrailer.Hmac
            }
        };

        var encryptionCredentialDetails = new EncryptionCredentialDetails
        {
            Password = "<REMOVED>",
            KeyVersion = securityTrailer.KeyVersion ?? 0,
            KeyIdentifier = securityTrailer.KeyIdentifier,
            AdyenCryptoVersion = securityTrailer.AdyenCryptoVersion ?? 0
        };

        var tapToPayTerminalApiCallbackResponseJson = new SaleToPoiMessageSecuredEncryptor().Decrypt(saleToPoiMessageSecured, encryptionCredentialDetails);
        _logger.LogWarning("Decoded JSON: {Json}", tapToPayTerminalApiCallbackResponseJson);

        var tapToPayTerminalApiCallbackResponse = JsonSerializer.Deserialize<TapToPayTerminalApiCallbackResponse>(tapToPayTerminalApiCallbackResponseJson,
            new JsonSerializerOptions { PropertyNameCaseInsensitive = true });

        if (tapToPayTerminalApiCallbackResponse.Result == "Failure")
        {
            return new BadRequestObjectResult(tapToPayTerminalApiCallbackResponse.ErrorCondition);
        }

        var request = new HttpRequestMessage(HttpMethod.Get, tapToPayTerminalApiCallbackResponse.Url);
        request.Headers.Add("x-api-key", EnvironmentHelper.Get("AdyenKey"));
        var response = await new HttpClient().SendAsync(request);
        var paymentDetailsResponseJson = await response.Content.ReadAsStringAsync();

        _logger.LogInformation("Full payment response: {PaymentResponse}", paymentDetailsResponseJson);

        var paymentDetails = new SaleToPoiMessageSerializer().Deserialize(paymentDetailsResponseJson);

        return new OkObjectResult("Payment processed, you can close this window.");
    }

    private static string Base64UrlDecode(string input)
    {
        var s = input.Replace('-', '+').Replace('_', '/');

        switch (s.Length % 4)
        {
            case 2: s += "=="; break;
            case 3: s += "="; break;
            case 0: break;
            default: throw new FormatException("Invalid Base64URL string.");
        }

        var bytes = Convert.FromBase64String(s);
        return Encoding.UTF8.GetString(bytes);
    }