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Simplified PayfastPaymentConfirmationReceivedEventHandler #113

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khwezi merged 1 commits from payments into master 2026-06-13 16:27:28 +02:00
Conversation 0 Commits 1 Files Changed 2
+28 -88
2 changed files with 28 additions and 88 deletions
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LiteCharms.Features.MidrandBooks/LiteCharms.Features.MidrandBooks.csproj
+3 -3
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@@ -32,7 +32,7 @@
<!-- Quartz Scheduler-->
<ItemGroup>
<PackageReference Include="Humanizer" Version="3.0.10" />
<PackageReference Include="Meziantou.Analyzer" Version="3.0.102">
<PackageReference Include="Meziantou.Analyzer" Version="3.0.103">
<PrivateAssets>all</PrivateAssets>
<IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
</PackageReference>
@@ -136,8 +136,8 @@
<!-- Amazon S3 SDK -->
<ItemGroup>
<PackageReference Include="AWSSDK.Extensions.NetCore.Setup" Version="4.0.4.6" />
<PackageReference Include="AWSSDK.S3" Version="4.0.24.3" />
<PackageReference Include="AWSSDK.Extensions.NetCore.Setup" Version="4.0.4.7" />
<PackageReference Include="AWSSDK.S3" Version="4.0.24.4" />
<ProjectReference Include="..\LiteCharms.Features\LiteCharms.Features.csproj" />
<!-- global Usings -->
LiteCharms.Features.MidrandBooks/Payments/Events/Handlers/PayfastPaymentConfirmationReceivedEventHandler.cs
+25 -85
View File
@@ -1,17 +1,13 @@
using LiteCharms.Features.Api.Configuration;
using LiteCharms.Features.Hasher;
using LiteCharms.Features.Hasher;
using LiteCharms.Features.Mediator;
using LiteCharms.Features.MidrandBooks.Orders;
using LiteCharms.Features.MidrandBooks.Payments.Models;
namespace LiteCharms.Features.MidrandBooks.Payments.Events.Handlers;
public sealed class PayfastPaymentConfirmationReceivedEventHandler(IServiceProvider services,
IOptions<PayfastSettings> payfastOptions, ILogger<PayfastPaymentConfirmationReceivedEvent> logger) :
public sealed class PayfastPaymentConfirmationReceivedEventHandler(IServiceProvider services, ILogger<PayfastPaymentConfirmationReceivedEvent> logger) :
INotificationHandler<PayfastPaymentConfirmationReceivedEvent>
{
private readonly PayfastSettings pasfastSettings = payfastOptions.Value;
public async ValueTask Handle(PayfastPaymentConfirmationReceivedEvent notification, CancellationToken cancellationToken)
{
using var activity = MediatorTelemetry.Source.StartActivity($"Quartz: {typeof(PayfastPaymentConfirmationReceivedEvent).Name}");
@@ -23,83 +19,34 @@ public sealed class PayfastPaymentConfirmationReceivedEventHandler(IServiceProvi
var paymentService = scope.ServiceProvider.GetRequiredService<PaymentService>();
var payfastService = scope.ServiceProvider.GetRequiredService<PayfastService>();
var payload = notification.Payload ?? throw new Exception("Payload metadata context context is null.");
var payload = notification.Payload ?? throw new Exception("Payload metadata context is null.");
var dict = payload.ToParamDictionary();
var localSignature = PayfastService.GenerateSignature(dict, pasfastSettings.Passphrase);
var hashResult = hashService.DecodeLongIdHash(payload.MerchantPaymentId!);
if (hashResult.IsFailed) throw new Exception("Failed to decode application tracking hash key identifier.");
if (localSignature.IsFailed)
throw new Exception("Failed to generate local signature for incoming webhook payload.");
var orderResult = await orderService.GetOrderAsync(hashResult.Value, cancellationToken);
if (orderResult.IsFailed) throw new Exception("Target system order entity context cannot be traced.");
if (!string.Equals(localSignature.Value, payload.Signature, StringComparison.OrdinalIgnoreCase))
var paymentResult = await paymentService.GetOrderPaymentAsync(orderResult.Value.Id, cancellationToken);
if (paymentResult.IsFailed) throw new Exception("Target payment ledger entity cannot be resolved.");
var isAlreadyProcessed = await paymentService.HasLedgerEntryAsync(orderResult.Value.Id, paymentResult.Value.Id, cancellationToken);
if (isAlreadyProcessed.Value)
{
logger.LogCritical("Incoming webhook signature verification failed. Possible payload tampering.");
logger.LogWarning("Webhook reference token '{Ref}' already verified. Skipping processing routines.", payload.MerchantPaymentId);
return;
}
var hashResult = hashService.DecodeLongIdHash(payload.MerchantPaymentId!);
if (hashResult.IsFailed) throw new Exception("Failed to decode application tracking hash key identifier.");
var orderResult = await orderService.GetOrderAsync(hashResult.Value, cancellationToken);
if (orderResult.IsFailed) throw new Exception("Target system order entity context cannot be traced.");
var paymentResult = await paymentService.GetOrderPaymentAsync(orderResult.Value.Id, cancellationToken);
if (paymentResult.IsFailed) throw new Exception("Target payment ledger entity cannot be resolved.");
var isAmountValid = payfastService.ValidatePaymentAmount(orderResult.Value.Total, payload.AmountGross);
if (!isAmountValid.Value)
throw new Exception("Security validation exception: Transaction cost variance bounds breached (Price Tampering Detected).");
decimal.TryParse(payload.AmountGross, CultureInfo.InvariantCulture, out var gross);
decimal.TryParse(payload.AmountFee, CultureInfo.InvariantCulture, out var fee);
decimal.TryParse(payload.AmountNet, CultureInfo.InvariantCulture, out var net);
string status = payload.PaymentStatus ?? "UNKNOWN";
var isAlreadyProcessed = await paymentService.HasLedgerEntryAsync(orderResult.Value.Id, paymentResult.Value.Id, cancellationToken);
if (isAlreadyProcessed.Value)
{
logger.LogWarning("Webhook reference token '{Ref}' already verified. Skipping validation routines.", payload.MerchantPaymentId);
return;
}
if (notification.PerformBackgroundChecks)
{
var isHostValid = await payfastService.ValidateReferrerIpAsync(notification.RemoteIpAddress!, notification.AllowLoopback, cancellationToken);
if (isHostValid.IsFailed)
throw new Exception("Security validation exception: Webhook packet source address failed cluster validation checks.");
if (!isHostValid.Value)
throw new Exception("Security validation exception: Webhook packet source address failed cluster validation checks.");
var isAmountValid = payfastService.ValidatePaymentAmount(orderResult.Value.Total, payload.AmountGross);
if (!isAmountValid.Value)
throw new Exception("Security validation exception: Transaction cost variance bounds breached.");
var paramList = new List<string>();
foreach (var kvp in dict)
{
if (!string.IsNullOrEmpty(kvp.Value))
{
string encoded = HttpUtility.UrlEncode(kvp.Value.Trim());
string safeValue = PayfastService.PercentEncodingRegex.Replace(encoded, m => m.Value.ToLowerInvariant());
paramList.Add($"{kvp.Key}={safeValue}");
}
}
string rawParamString = string.Join("&", paramList);
var serverConfirmation = await payfastService.ValidateServerConfirmationAsync(rawParamString, isSandbox: true, cancellationToken);
if (serverConfirmation.IsFailed)
throw new Exception("Security validation exception: Payfast central handshake server rejected payload legitimacy.");
}
await payfastService.WriteLedgerEntryAsync(new CreateGatewayLedgerEntry
{
OrderId = orderResult.Value.Id,
@@ -124,31 +71,23 @@ public sealed class PayfastPaymentConfirmationReceivedEventHandler(IServiceProvi
CustomerId = orderResult.Value.CustomerId,
}, cancellationToken);
if (ledgerWriteResult.IsFailed)
throw new Exception("Failed to write ledger entry for payment confirmation.");
if (ledgerWriteResult.IsFailed) throw new Exception("Failed to write ledger entry for payment confirmation.");
var completePaymentResult = await paymentService.CompletePaymentAsync(paymentResult.Value.Id, PaymentStatuses.Paid, cancellationToken);
if (completePaymentResult.IsFailed)
throw new Exception("Failed to update payment status to 'Paid' for payment confirmation.");
if (completePaymentResult.IsFailed) throw new Exception("Failed to update payment status to 'Paid'.");
var updateOrderResult = await orderService.UpdateOrderStatusAsync(orderResult.Value.Id, OrderStatus.Completed, cancellationToken);
if (updateOrderResult.IsFailed)
throw new Exception("Failed to update order status to 'Completed' for payment confirmation.");
if (updateOrderResult.IsFailed) throw new Exception("Failed to update order status to 'Completed'.");
logger.LogInformation("Order payment verified secure and cleared successfully.");
}
else
{
LedgerStatuses ledgerStatus;
LedgerStatuses ledgerStatus = status.Equals("CANCELLED", StringComparison.OrdinalIgnoreCase)
? LedgerStatuses.Cancelled
: LedgerStatuses.Failed;
if (status.Equals("CANCELLED", StringComparison.OrdinalIgnoreCase))
ledgerStatus = LedgerStatuses.Cancelled;
else
ledgerStatus = LedgerStatuses.Failed;
var ledgerWriteResult = await paymentService.WriteLedgerEntryAsync(new CreateLedgerEntry
await paymentService.WriteLedgerEntryAsync(new CreateLedgerEntry
{
OrderId = orderResult.Value.Id,
PaymentId = paymentResult.Value.Id,
@@ -157,8 +96,9 @@ public sealed class PayfastPaymentConfirmationReceivedEventHandler(IServiceProvi
CustomerId = orderResult.Value.CustomerId,
}, cancellationToken);
logger.LogInformation("Webhook validation pipeline passed checks successfully, logged entry to ledger with status: {Status}", status);
logger.LogInformation("Webhook pipeline logged non-success entry to ledger with status: {Status}", status);
}
activity?.SetStatus(ActivityStatusCode.Ok);
}
}