Refactoring: Do not query database when asking for Coinaverage rates, periodically get exchange list

BTCPayServer/Controllers/ServerController.cs

@@ -23,7 +23,6 @@ namespace BTCPayServer.Controllers
     {
         private UserManager<ApplicationUser> _UserManager;
         SettingsRepository _SettingsRepository;
-        private IRateProviderFactory _RateProviderFactory;
 
         public ServerController(UserManager<ApplicationUser> userManager,
             IRateProviderFactory rateProviderFactory,
@@ -31,7 +30,6 @@ namespace BTCPayServer.Controllers
         {
             _UserManager = userManager;
             _SettingsRepository = settingsRepository;
-            _RateProviderFactory = rateProviderFactory;
         }
 
         [Route("server/rates")]
@@ -47,22 +45,6 @@ namespace BTCPayServer.Controllers
 
         }
 
-        class TestCoinAverageAuthenticator : ICoinAverageAuthenticator
-        {
-            private RatesSetting settings;
-
-            public TestCoinAverageAuthenticator(RatesSetting settings)
-            {
-                this.settings = settings;
-            }
-            public Task AddHeader(HttpRequestMessage message)
-            {
-                var sig = settings.GetCoinAverageSignature();
-                if (sig != null)
-                    message.Headers.Add("X-signature", settings.GetCoinAverageSignature());
-                return Task.CompletedTask;
-            }
-        }
         [Route("server/rates")]
         [HttpPost]
         public async Task<IActionResult> Rates(RatesViewModel vm)
@@ -73,10 +55,14 @@ namespace BTCPayServer.Controllers
             rates.CacheInMinutes = vm.CacheMinutes;
             try
             {
-                if (rates.GetCoinAverageSignature() != null)
+                var settings = new CoinAverageSettings()
+                {
+                    KeyPair = (vm.PublicKey, vm.PrivateKey)
+                };
+                if (settings.GetCoinAverageSignature() != null)
                 {
                     await new CoinAverageRateProvider("BTC")
-                    { Authenticator = new TestCoinAverageAuthenticator(rates) }.TestAuthAsync();
+                    { Authenticator = settings }.TestAuthAsync();
                 }
             }
             catch
@@ -86,7 +72,6 @@ namespace BTCPayServer.Controllers
             if (!ModelState.IsValid)
                 return View(vm);
             await _SettingsRepository.UpdateSetting(rates);
-            ((BTCPayRateProviderFactory)_RateProviderFactory).CacheSpan = TimeSpan.FromMinutes(vm.CacheMinutes);
             StatusMessage = "Rate settings successfully updated";
             return RedirectToAction(nameof(Rates));
         }

BTCPayServer/HostedServices/RatesHostedService.cs

@@ -8,6 +8,7 @@ using BTCPayServer.Services;
 using BTCPayServer.Services.Rates;
 using Microsoft.Extensions.Hosting;
 using BTCPayServer.Logging;
+using System.Runtime.CompilerServices;
 
 namespace BTCPayServer.HostedServices
 {
@@ -15,41 +16,78 @@ namespace BTCPayServer.HostedServices
     {
         private SettingsRepository _SettingsRepository;
         private IRateProviderFactory _RateProviderFactory;
+        private CoinAverageSettings _coinAverageSettings;
         public RatesHostedService(SettingsRepository repo,
+                                  CoinAverageSettings coinAverageSettings,
                                   IRateProviderFactory rateProviderFactory)
         {
             this._SettingsRepository = repo;
             _RateProviderFactory = rateProviderFactory;
+            _coinAverageSettings = coinAverageSettings;
         }
+
+
+        CancellationTokenSource _Cts = new CancellationTokenSource();
+
+        List<Task> _Tasks = new List<Task>();
+
         public Task StartAsync(CancellationToken cancellationToken)
         {
-            Init();
+            _Tasks.Add(RefreshCoinAverageSupportedExchanges(_Cts.Token));
+            _Tasks.Add(RefreshCoinAverageSettings(_Cts.Token));
             return Task.CompletedTask;
         }
 
-        async void Init()
-        {
-            var rates = (await _SettingsRepository.GetSettingAsync<RatesSetting>()) ?? new RatesSetting();
-            _RateProviderFactory.CacheSpan = TimeSpan.FromMinutes(rates.CacheInMinutes);
 
-            //string[] availableExchanges = null;
+        async Task Timer(Func<Task> act, CancellationToken cancellation, [CallerMemberName]string caller = null)
-            //// So we don't run this in testing
+        {
-            //if(_RateProviderFactory is BTCPayRateProviderFactory)
+            while (!cancellation.IsCancellationRequested)
-            //{
+            {
-            //    try
+                try
-            //    {
+                {
-            //        await new CoinAverageRateProvider("BTC").GetExchangeTickersAsync();
+                    await act();
-            //    }
+                }
-            //    catch(Exception ex)
+                catch (OperationCanceledException) when (cancellation.IsCancellationRequested)
-            //    {
+                {
-            //        Logs.PayServer.LogWarning(ex, "Failed to get exchange tickers");
+                }
-            //    }
+                catch (Exception ex)
-            //}
+                {
+                    Logs.PayServer.LogWarning(ex, caller + " failed");
+                    try
+                    {
+                        await Task.Delay(TimeSpan.FromMinutes(1), cancellation);
+                    }
+                    catch (OperationCanceledException) when (cancellation.IsCancellationRequested) { }
+                }
+            }
+        }
+        Task RefreshCoinAverageSupportedExchanges(CancellationToken cancellation)
+        {
+            return Timer(async () => 
+            {
+                var tickers = await new CoinAverageRateProvider("BTC").GetExchangeTickersAsync();
+                await Task.Delay(TimeSpan.FromHours(5), cancellation);
+            }, cancellation);
+        }
+
+        Task RefreshCoinAverageSettings(CancellationToken cancellation)
+        {
+            return Timer(async () =>
+            {
+                var rates = (await _SettingsRepository.GetSettingAsync<RatesSetting>()) ?? new RatesSetting();
+                _RateProviderFactory.CacheSpan = TimeSpan.FromMinutes(rates.CacheInMinutes);
+                if (!string.IsNullOrWhiteSpace(rates.PrivateKey) && !string.IsNullOrWhiteSpace(rates.PublicKey))
+                {
+                    _coinAverageSettings.KeyPair = (rates.PublicKey, rates.PrivateKey);
+                }
+                await _SettingsRepository.WaitSettingsChanged<RatesSetting>(cancellation);
+            }, cancellation);
         }
 
         public Task StopAsync(CancellationToken cancellationToken)
         {
-            return Task.CompletedTask;
+            _Cts.Cancel();
+            return Task.WhenAll(_Tasks.ToArray());
         }
     }
 }

BTCPayServer/Hosting/BTCPayServerServices.cs

@@ -109,7 +109,8 @@ namespace BTCPayServer.Hosting
             services.AddSingleton<BTCPayServerEnvironment>();
             services.TryAddSingleton<TokenRepository>();
             services.TryAddSingleton<EventAggregator>();
-            services.TryAddSingleton<ICoinAverageAuthenticator, BTCPayCoinAverageAuthenticator>();
+            services.TryAddSingleton<CoinAverageSettings>();
+            services.TryAddSingleton<ICoinAverageAuthenticator, CoinAverageSettings>();
             services.TryAddSingleton<ApplicationDbContextFactory>(o => 
             {
                 var opts = o.GetRequiredService<BTCPayServerOptions>();

BTCPayServer/Services/Rates/CoinAverageRateProvider.cs

@@ -59,41 +59,11 @@ namespace BTCPayServer.Services.Rates
 
     public class RatesSetting
     {
-        private static readonly DateTime _epochUtc = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
         public string PublicKey { get; set; }
         public string PrivateKey { get; set; }
         [DefaultValue(15)]
         [JsonProperty(DefaultValueHandling = DefaultValueHandling.Populate)]
         public int CacheInMinutes { get; set; } = 15;
-
-        public string GetCoinAverageSignature()
-        {
-            if (string.IsNullOrEmpty(PublicKey) || string.IsNullOrEmpty(PrivateKey))
-                return null;
-            var timestamp = (int)((DateTime.UtcNow - _epochUtc).TotalSeconds);
-            var payload = timestamp + "." + PublicKey;
-            var digestValueBytes = new HMACSHA256(Encoding.ASCII.GetBytes(PrivateKey)).ComputeHash(Encoding.ASCII.GetBytes(payload));
-            var digestValueHex = NBitcoin.DataEncoders.Encoders.Hex.EncodeData(digestValueBytes);
-            return payload + "." + digestValueHex;
-        }
-    }
-    public class BTCPayCoinAverageAuthenticator : ICoinAverageAuthenticator
-    {
-        private SettingsRepository settingsRepo;
-
-        public BTCPayCoinAverageAuthenticator(SettingsRepository settingsRepo)
-        {
-            this.settingsRepo = settingsRepo;
-        }
-        public async Task AddHeader(HttpRequestMessage message)
-        {
-            var settings = (await settingsRepo.GetSettingAsync<RatesSetting>()) ?? new RatesSetting();
-            var signature = settings.GetCoinAverageSignature();
-            if (signature != null)
-            {
-                message.Headers.Add("X-signature", signature);
-            }
-        }
     }
 
     public interface ICoinAverageAuthenticator

BTCPayServer/Services/Rates/CoinAverageSettings.cs

@@ -0,0 +1,42 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Net.Http;
+using System.Security.Cryptography;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace BTCPayServer.Services.Rates
+{
+    public class CoinAverageSettings : ICoinAverageAuthenticator
+    {
+        private static readonly DateTime _epochUtc = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
+
+        public (String PublicKey, String PrivateKey)? KeyPair { get; set; }
+        public string[] AvailableExchanges { get; set; } = Array.Empty<string>();
+
+        public Task AddHeader(HttpRequestMessage message)
+        {
+            var signature = GetCoinAverageSignature();
+            if (signature != null)
+            {
+                message.Headers.Add("X-signature", signature);
+            }
+            return Task.CompletedTask;
+        }
+
+        public string GetCoinAverageSignature()
+        {
+            var keyPair = KeyPair;
+            if (!keyPair.HasValue)
+                return null;
+            if (string.IsNullOrEmpty(keyPair.Value.PublicKey) || string.IsNullOrEmpty(keyPair.Value.PrivateKey))
+                return null;
+            var timestamp = (int)((DateTime.UtcNow - _epochUtc).TotalSeconds);
+            var payload = timestamp + "." + keyPair.Value.PublicKey;
+            var digestValueBytes = new HMACSHA256(Encoding.ASCII.GetBytes(keyPair.Value.PrivateKey)).ComputeHash(Encoding.ASCII.GetBytes(payload));
+            var digestValueHex = NBitcoin.DataEncoders.Encoders.Hex.EncodeData(digestValueBytes);
+            return payload + "." + digestValueHex;
+        }
+    }
+}

BTCPayServer/Services/SettingsRepository.cs

@@ -8,6 +8,7 @@ using Microsoft.EntityFrameworkCore;
 using BTCPayServer.Models;
 using Microsoft.EntityFrameworkCore.Infrastructure.Internal;
 using Newtonsoft.Json;
+using System.Threading;
 
 namespace BTCPayServer.Services
 {
@@ -51,6 +52,22 @@ namespace BTCPayServer.Services
                     await ctx.SaveChangesAsync();
                 }
             }
+
+            IReadOnlyCollection<TaskCompletionSource<bool>> value;
+            lock (_Subscriptions)
+            {
+                if(_Subscriptions.TryGetValue(typeof(T), out value))
+                {
+                    _Subscriptions.Remove(typeof(T));
+                }
+            }
+            if(value != null)
+            {
+                foreach(var v in value)
+                {
+                    v.TrySetResult(true);
+                }
+            }
         }
 
         private T Deserialize<T>(string value)
@@ -62,5 +79,35 @@ namespace BTCPayServer.Services
         {
             return JsonConvert.SerializeObject(obj);
         }
+
+        MultiValueDictionary<Type, TaskCompletionSource<bool>> _Subscriptions = new MultiValueDictionary<Type, TaskCompletionSource<bool>>();
+        public async Task WaitSettingsChanged<T>(CancellationToken cancellation)
+        {
+            var tcs = new TaskCompletionSource<bool>();
+            using (cancellation.Register(() =>
+             {
+                 try
+                 {
+                     tcs.TrySetCanceled();
+                 }
+                 catch { }
+             }))
+            {
+                lock (_Subscriptions)
+                {
+                    _Subscriptions.Add(typeof(T), tcs);
+                }
+#pragma warning disable CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed
+                tcs.Task.ContinueWith(_ =>
+                 {
+                     lock (_Subscriptions)
+                     {
+                         _Subscriptions.Remove(typeof(T), tcs);
+                     }
+                 }, TaskScheduler.Default);
+#pragma warning restore CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed
+                await tcs.Task;
+            }
+        }
     }
 }

BTCPayServer/Views/Server/Rates.cshtml

@@ -29,7 +29,7 @@
                 <label class="sr-only" asp-for="PrivateKey"></label>
                 <input asp-for="PrivateKey" style="width:50%;" class="form-control" placeholder="Private key" />
                 <span asp-validation-for="PrivateKey" class="text-danger"></span>
-                <p class="form-text text-muted">You can find the information on <a href="https://bitcoinaverage.com/en/apikeys">bitcoinaverage api key page</a></p>
+                <p class="form-text text-muted">You can find the information on <a target="_blank" href="https://bitcoinaverage.com/en/apikeys">bitcoinaverage api key page</a></p>
             </div>
             <div class="form-group">
                 <label asp-for="CacheMinutes"></label>