Refactor by adding extension FindPayoutHandler (#2984)

BTCPayServer/Controllers/GreenField/PullPaymentController.cs

@@ -233,7 +233,7 @@ namespace BTCPayServer.Controllers.GreenField
                 return this.CreateValidationError(ModelState);
             }
             
-            var payoutHandler = _payoutHandlers.FirstOrDefault(handler => handler.CanHandle(paymentMethodId));
+            var payoutHandler = _payoutHandlers.FindPayoutHandler(paymentMethodId);
             if (payoutHandler is null)
             {
                 ModelState.AddModelError(nameof(request.PaymentMethod), "Invalid payment method");

BTCPayServer/Controllers/InvoiceController.UI.cs

@@ -198,7 +198,7 @@ namespace BTCPayServer.Controllers
                 // TODO: What if no option?
                 var refund = new RefundModel();
                 refund.Title = "Select a payment method";
-                refund.AvailablePaymentMethods = new SelectList(options.Select(id => new SelectListItem(id.ToPrettyString(), id.ToString())));
+                refund.AvailablePaymentMethods = new SelectList(options.Select(id => new SelectListItem(id.ToPrettyString(), id.ToString())), "Value", "Text");
                 refund.SelectedPaymentMethod = defaultRefund?.ToString() ?? options.Select(o => o.CryptoCode).First();
 
                 // Nothing to select, skip to next

BTCPayServer/Controllers/PullPaymentController.cs

@@ -59,7 +59,7 @@ namespace BTCPayServer.Controllers
                            {
                                Entity = o,
                                Blob = o.GetBlob(_serializerSettings),
-                               ProofBlob = _payoutHandlers.FirstOrDefault(handler => handler.CanHandle(o.GetPaymentMethodId()))?.ParseProof(o)
+                               ProofBlob = _payoutHandlers.FindPayoutHandler(o.GetPaymentMethodId())?.ParseProof(o)
                            });
             var cd = _currencyNameTable.GetCurrencyData(blob.Currency, false);
             var totalPaid = payouts.Where(p => p.Entity.State != PayoutState.Cancelled).Select(p => p.Blob.Amount).Sum();
@@ -109,7 +109,7 @@ namespace BTCPayServer.Controllers
             
             var paymentMethodId = ppBlob.SupportedPaymentMethods.FirstOrDefault(id => vm.SelectedPaymentMethod == id.ToString());
             
-            var payoutHandler = paymentMethodId is null? null: _payoutHandlers.FirstOrDefault(handler => handler.CanHandle(paymentMethodId));
+            var payoutHandler = paymentMethodId is null? null: _payoutHandlers.FindPayoutHandler(paymentMethodId);
             if (payoutHandler is null)
             {
                 ModelState.AddModelError(nameof(vm.SelectedPaymentMethod), $"Invalid destination with selected payment method");   

BTCPayServer/Controllers/WalletsController.PullPayments.cs

@@ -196,7 +196,7 @@ namespace BTCPayServer.Controllers
             var storeId = walletId.StoreId;
             var paymentMethodId = PaymentMethodId.Parse(vm.PaymentMethodId);
             var handler = _payoutHandlers
-                .FirstOrDefault(handler => handler.CanHandle(paymentMethodId));
+                .FindPayoutHandler(paymentMethodId);
             var commandState = Enum.Parse<PayoutState>(vm.Command.Split("-").First());
             var payoutIds = vm.GetSelectedPayouts(commandState);
             if (payoutIds.Length == 0)
@@ -429,7 +429,7 @@ namespace BTCPayServer.Controllers
                     Destination = payoutBlob.Destination
                 };
                 var handler = _payoutHandlers
-                    .FirstOrDefault(handler => handler.CanHandle(item.Payout.GetPaymentMethodId()));
+                    .FindPayoutHandler(item.Payout.GetPaymentMethodId());
                 var proofBlob = handler?.ParseProof(item.Payout);
                 m.ProofLink = proofBlob?.Link;
                 vm.Payouts.Add(m);

BTCPayServer/Data/Payouts/LightningLike/LightningLikePayoutController.cs

@@ -104,7 +104,7 @@ namespace BTCPayServer.Data.Payouts.LightningLike
         public async Task<IActionResult> ProcessLightningPayout(string cryptoCode, string[] payoutIds)
         {
             var pmi = new PaymentMethodId(cryptoCode, PaymentTypes.LightningLike);
-            var payoutHandler = _payoutHandlers.FirstOrDefault(handler => handler.CanHandle(pmi));
+            var payoutHandler = _payoutHandlers.FindPayoutHandler(pmi);
 
             await using var ctx = _applicationDbContextFactory.CreateContext();
 

BTCPayServer/Extensions.cs

@@ -152,6 +152,13 @@ namespace BTCPayServer
             return transactions.Select(t => t.Result).Where(t => t != null).ToDictionary(o => o.Transaction.GetHash());
         }
 
+#nullable enable
+        public static IPayoutHandler? FindPayoutHandler(this IEnumerable<IPayoutHandler> handlers, PaymentMethodId paymentMethodId)
+        {
+            return handlers.FirstOrDefault(h => h.CanHandle(paymentMethodId));
+        }
+#nullable restore
+
         public static async Task<PSBT> UpdatePSBT(this ExplorerClientProvider explorerClientProvider, DerivationSchemeSettings derivationSchemeSettings, PSBT psbt)
         {
             var result = await explorerClientProvider.GetExplorerClient(psbt.Network.NetworkSet.CryptoCode).UpdatePSBTAsync(new UpdatePSBTRequest()

BTCPayServer/HostedServices/PullPaymentHostedService.cs

@@ -296,7 +296,9 @@ namespace BTCPayServer.HostedServices
                 if (paymentMethod.CryptoCode == payout.PullPaymentData.GetBlob().Currency)
                     req.Rate = 1.0m;
                 var cryptoAmount = payoutBlob.Amount / req.Rate;
-                var payoutHandler = _payoutHandlers.First(handler => handler.CanHandle(paymentMethod));
+                var payoutHandler = _payoutHandlers.FindPayoutHandler(paymentMethod);
+                if (payoutHandler is null)
+                    throw new InvalidOperationException($"No payout handler for {paymentMethod}");
                 var dest = await payoutHandler.ParseClaimDestination(paymentMethod, payoutBlob.Destination, false);
                 decimal minimumCryptoAmount = await payoutHandler.GetMinimumPayoutAmount(paymentMethod, dest.destination);
                 if (cryptoAmount < minimumCryptoAmount)
@@ -369,7 +371,7 @@ namespace BTCPayServer.HostedServices
                 }
                 var ppBlob = pp.GetBlob();
                 var payoutHandler =
-                    _payoutHandlers.FirstOrDefault(handler => handler.CanHandle(req.ClaimRequest.PaymentMethodId));
+                    _payoutHandlers.FindPayoutHandler(req.ClaimRequest.PaymentMethodId);
                 if (!ppBlob.SupportedPaymentMethods.Contains(req.ClaimRequest.PaymentMethodId) || payoutHandler is null)
                 {
                     req.Completion.TrySetResult(new ClaimRequest.ClaimResponse(ClaimRequest.ClaimResult.PaymentMethodNotSupported));

BTCPayServer/Services/SettingsRepository.cs

@@ -66,7 +66,7 @@ namespace BTCPayServer.Services
             return settings;
         }
 
-        private T Deserialize<T>(string value)
+        private T? Deserialize<T>(string value) where T : class
         {
             return JsonConvert.DeserializeObject<T>(value);
         }

BTCPayServer/Views/Wallets/Payouts.cshtml

@@ -1,4 +1,4 @@
-@using BTCPayServer.Client.Models
+@using BTCPayServer.Client.Models
 @using BTCPayServer.Payments
 @model PayoutsModel
 
@@ -10,7 +10,9 @@
     var paymentMethods = PayoutHandlers.GetSupportedPaymentMethods();
     
     var stateActions = new List<(string Action, string Text)>();
-    var payoutHandler = PayoutHandlers.First(handler => handler.CanHandle(PaymentMethodId.Parse(Model.PaymentMethodId)));
+    var payoutHandler = PayoutHandlers.FindPayoutHandler(PaymentMethodId.Parse(Model.PaymentMethodId));
+    if (payoutHandler is null)
+        return;
     stateActions.AddRange(payoutHandler.GetPayoutSpecificActions().Where(pair => pair.Key == Model.PayoutState).SelectMany(pair => pair.Value));
     switch (Model.PayoutState)
     {