New feature: Apps limited inventory (#961)

BTCPayServer.Tests/TestUtils.cs

@@ -44,9 +44,9 @@ namespace BTCPayServer.Tests
             formFile.ContentDisposition = $"form-data; name=\"file\"; filename=\"{fileInfo.Name}\"";
             return formFile;
         }
-        public static void Eventually(Action act)
+        public static void Eventually(Action act, int ms = 200000)
         {
-            CancellationTokenSource cts = new CancellationTokenSource(20000);
+            CancellationTokenSource cts = new CancellationTokenSource(ms);
             while (true)
             {
                 try

BTCPayServer.Tests/UnitTest1.cs

@@ -1861,7 +1861,7 @@ namespace BTCPayServer.Tests
 
         [Fact]
         [Trait("Integration", "Integration")]
-        public void CanUsePoSApp()
+        public async Task CanUsePoSApp()
         {
             using (var tester = ServerTester.Create())
             {
@@ -1972,6 +1972,49 @@ donation:
                     Assert.Equal(test.ExpectedDivisibility, vmview.CurrencyInfo.Divisibility);
                     Assert.Equal(test.ExpectedSymbolSpace, vmview.CurrencyInfo.SymbolSpace);
                 }
+                
+                
+                //test inventory related features
+                vmpos = Assert.IsType<UpdatePointOfSaleViewModel>(Assert.IsType<ViewResult>(apps.UpdatePointOfSale(appId).Result).Model);
+                vmpos.Title = "hello";
+                vmpos.Currency = "BTC";
+                vmpos.Template = @"
+inventoryitem:
+  price: 1.0
+  title: good apple
+  inventory: 1
+noninventoryitem:
+  price: 10.0";
+                Assert.IsType<RedirectToActionResult>(apps.UpdatePointOfSale(appId, vmpos).Result);
+                
+                //inventoryitem has 1 item available
+                Assert.IsType<RedirectToActionResult>(publicApps.ViewPointOfSale(appId, 1, null, null, null, null, "inventoryitem").Result);
+                //we already bought all available stock so this should fail
+                await Task.Delay(100);
+                Assert.IsType<RedirectToActionResult>(publicApps.ViewPointOfSale(appId, 1, null, null, null, null, "inventoryitem").Result);
+                
+                //inventoryitem has unlimited items available
+                Assert.IsType<RedirectToActionResult>(publicApps.ViewPointOfSale(appId, 1, null, null, null, null, "noninventoryitem").Result);
+                Assert.IsType<RedirectToActionResult>(publicApps.ViewPointOfSale(appId, 1, null, null, null, null, "noninventoryitem").Result);
+
+                //verify invoices where created
+                invoices = user.BitPay.GetInvoices();
+                Assert.Equal(2, invoices.Count(invoice => invoice.ItemCode.Equals("noninventoryitem")));
+                var inventoryItemInvoice = invoices.SingleOrDefault(invoice => invoice.ItemCode.Equals("inventoryitem"));
+                Assert.NotNull(inventoryItemInvoice);
+                
+                //let's mark the inventoryitem invoice as invalid, thsi should return the item to back in stock
+                var controller = tester.PayTester.GetController<InvoiceController>(user.UserId, user.StoreId);
+                var appService = tester.PayTester.GetService<AppService>();
+                var eventAggregator = tester.PayTester.GetService<EventAggregator>();
+                Assert.IsType<JsonResult>( await controller.ChangeInvoiceState(inventoryItemInvoice.Id, "invalid"));
+                //check that item is back in stock
+                TestUtils.Eventually(() =>
+                {
+                    vmpos = Assert.IsType<UpdatePointOfSaleViewModel>(Assert.IsType<ViewResult>(apps.UpdatePointOfSale(appId).Result).Model);
+                    Assert.Equal(1, appService.Parse(vmpos.Template, "BTC").Single(item => item.Id == "inventoryitem").Inventory);
+                }, 10000);
+                
             }
         }
 

BTCPayServer/Controllers/AppsController.Crowdfund.cs

@@ -156,7 +156,7 @@ namespace BTCPayServer.Controllers
 
             app.TagAllInvoices = vm.UseAllStoreInvoices;
             app.SetSettings(newSettings);
-            await UpdateAppSettings(app);
+            await _AppService.UpdateOrCreateApp(app);
 
             _EventAggregator.Publish(new AppUpdated()
             {

BTCPayServer/Controllers/AppsController.PointOfSale.cs

@@ -53,6 +53,7 @@ namespace BTCPayServer.Controllers
                     "  title: Fruit Tea\n" +
                     "  description: The Tibetan Himalayas, the land is majestic and beautiful—a spiritual place where, despite the perilous environment, many journey seeking enlightenment. Pay us what you want!\n" +
                     "  image: https://cdn.pixabay.com/photo/2016/09/16/11/24/darts-1673812__480.jpg\n" +
+                    "  inventory: 5\n" +
                     "  custom: true";
                 EnableShoppingCart = false;
                 ShowCustomAmount = true;
@@ -198,22 +199,11 @@ namespace BTCPayServer.Controllers
                 RedirectAutomatically = string.IsNullOrEmpty(vm.RedirectAutomatically)? (bool?) null: bool.Parse(vm.RedirectAutomatically)
                 
             });
-            await UpdateAppSettings(app);
+            await _AppService.UpdateOrCreateApp(app);
             StatusMessage = "App updated";
             return RedirectToAction(nameof(UpdatePointOfSale), new { appId });
         }
 
-        private async Task UpdateAppSettings(AppData app)
-        {
-            using (var ctx = _ContextFactory.CreateContext())
-            {
-                ctx.Apps.Add(app);
-                ctx.Entry<AppData>(app).State = EntityState.Modified;
-                ctx.Entry<AppData>(app).Property(a => a.Settings).IsModified = true;
-                ctx.Entry<AppData>(app).Property(a => a.TagAllInvoices).IsModified = true;
-                await ctx.SaveChangesAsync();
-            }
-        }
 
         private int[] ListSplit(string list, string separator = ",")
         {

BTCPayServer/Controllers/AppsController.cs

@@ -127,29 +127,25 @@ namespace BTCPayServer.Controllers
                 StatusMessage = "Error: You are not owner of this store";
                 return RedirectToAction(nameof(ListApps));
             }
-            var id = Encoders.Base58.EncodeData(RandomUtils.GetBytes(20));
+            var appData = new AppData
-            using (var ctx = _ContextFactory.CreateContext())
             {
-                var appData = new AppData() { Id = id };
+                StoreDataId = selectedStore, 
-                appData.StoreDataId = selectedStore;
+                Name = vm.Name, 
-                appData.Name = vm.Name;
+                AppType = appType.ToString()
-                appData.AppType = appType.ToString();
+            };
-                ctx.Apps.Add(appData);
+            await _AppService.UpdateOrCreateApp(appData);
-                await ctx.SaveChangesAsync();
-            }
             StatusMessage = "App successfully created";
-            CreatedAppId = id;
+            CreatedAppId = appData.Id;
 
             switch (appType)
             {
                 case AppType.PointOfSale:
-                    return RedirectToAction(nameof(UpdatePointOfSale), new { appId = id });
+                    return RedirectToAction(nameof(UpdatePointOfSale), new { appId = appData.Id });
                 case AppType.Crowdfund:
-                    return RedirectToAction(nameof(UpdateCrowdfund), new { appId = id });
+                    return RedirectToAction(nameof(UpdateCrowdfund), new { appId = appData.Id });
                 default:
                     return RedirectToAction(nameof(ListApps));
             }
-                
         }
 
         [HttpGet]

BTCPayServer/Controllers/AppsPublicController.cs

@@ -1,52 +1,41 @@
 using System;
 using System.Collections.Generic;
-using System.Diagnostics;
 using System.Globalization;
-using System.IO;
 using System.Linq;
 using System.Security.Claims;
 using System.Threading;
 using System.Threading.Tasks;
 using BTCPayServer.Configuration;
-using BTCPayServer.Data;
 using BTCPayServer.Filters;
 using BTCPayServer.ModelBinders;
 using BTCPayServer.Models;
 using BTCPayServer.Models.AppViewModels;
-using BTCPayServer.Payments;
-using BTCPayServer.Rating;
 using BTCPayServer.Security;
 using BTCPayServer.Services.Apps;
-using BTCPayServer.Services.Invoices;
-using BTCPayServer.Services.Rates;
-using Ganss.XSS;
 using Microsoft.AspNetCore.Cors;
 using Microsoft.AspNetCore.Http.Extensions;
 using Microsoft.AspNetCore.Identity;
 using Microsoft.AspNetCore.Mvc;
-using Microsoft.EntityFrameworkCore;
-using NBitpayClient;
-using YamlDotNet.RepresentationModel;
 using static BTCPayServer.Controllers.AppsController;
 
 namespace BTCPayServer.Controllers
 {
     public class AppsPublicController : Controller
     {
-        public AppsPublicController(AppService AppService,
+        public AppsPublicController(AppService appService,
             BTCPayServerOptions btcPayServerOptions,
             InvoiceController invoiceController,
             UserManager<ApplicationUser> userManager)
         {
-            _AppService = AppService;
+            _AppService = appService;
             _BtcPayServerOptions = btcPayServerOptions;
             _InvoiceController = invoiceController;
             _UserManager = userManager;
         }
 
-        private AppService _AppService;
+        private readonly AppService _AppService;
         private readonly BTCPayServerOptions _BtcPayServerOptions;
-        private InvoiceController _InvoiceController;
+        private readonly InvoiceController _InvoiceController;
         private readonly UserManager<ApplicationUser> _UserManager;
 
         [HttpGet]
@@ -132,6 +121,14 @@ namespace BTCPayServer.Controllers
                 price = choice.Price.Value;
                 if (amount > price)
                     price = amount;
+
+                if (choice.Inventory.HasValue)
+                {
+                    if (choice.Inventory <= 0)
+                    {
+                        return RedirectToAction(nameof(ViewPointOfSale), new { appId = appId });
+                    }
+                }
             }
             else
             {
@@ -139,6 +136,33 @@ namespace BTCPayServer.Controllers
                     return NotFound();
                 price = amount;
                 title = settings.Title;
+                
+                //if cart IS enabled and we detect posdata that matches the cart system's, check inventory for the items
+                if (!string.IsNullOrEmpty(posData) && 
+                    settings.EnableShoppingCart && 
+                    AppService.TryParsePosCartItems(posData, out var cartItems))
+                {
+                        
+                    var choices = _AppService.Parse(settings.Template, settings.Currency);
+                    var updateNeeded = false;
+                    foreach (var cartItem in cartItems)
+                    {
+                        var itemChoice = choices.FirstOrDefault(c => c.Id == cartItem.Key);
+                        if (itemChoice == null)
+                            return NotFound();
+
+                        if (itemChoice.Inventory.HasValue)
+                        {
+                            switch (itemChoice.Inventory)
+                            {
+                                case int i when i <= 0:
+                                    return RedirectToAction(nameof(ViewPointOfSale), new {appId});
+                                case int inventory when inventory < cartItem.Value:
+                                    return RedirectToAction(nameof(ViewPointOfSale), new {appId});
+                            }
+                        }
+                    }
+                }
             }
             var store = await _AppService.GetStore(app);
             store.AdditionalClaims.Add(new Claim(Policies.CanCreateInvoice.Key, store.Id));
@@ -164,7 +188,6 @@ namespace BTCPayServer.Controllers
             return RedirectToAction(nameof(InvoiceController.Checkout), "Invoice", new { invoiceId = invoice.Data.Id });
         }
 
-
         [HttpGet]
         [Route("/apps/{appId}/crowdfund")]
         [XFrameOptionsAttribute(XFrameOptionsAttribute.XFrameOptions.AllowAll)]
@@ -243,6 +266,15 @@ namespace BTCPayServer.Controllers
                 price = choice.Price.Value;
                 if (request.Amount > price)
                     price = request.Amount;
+                
+                
+                if (choice.Inventory.HasValue)
+                {
+                    if (choice.Inventory <= 0)
+                    {
+                        return NotFound("Option was out of stock");
+                    }
+                }
             }
 
             if (!isAdmin && (settings.EnforceTargetAmount && info.TargetAmount.HasValue && price >

BTCPayServer/HostedServices/AppInventoryUpdaterHostedService.cs

@@ -0,0 +1,134 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using BTCPayServer.Controllers;
+using BTCPayServer.Events;
+using BTCPayServer.Services.Apps;
+
+namespace BTCPayServer.HostedServices
+{
+    public class AppInventoryUpdaterHostedService : EventHostedServiceBase
+    {
+        private readonly AppService _AppService;
+
+        protected override void SubscibeToEvents()
+        {
+            Subscribe<InvoiceEvent>();
+        }
+
+        public AppInventoryUpdaterHostedService(EventAggregator eventAggregator, AppService appService) : base(
+            eventAggregator)
+        {
+            _AppService = appService;
+        }
+
+        protected override async Task ProcessEvent(object evt, CancellationToken cancellationToken)
+        {
+            if (evt is InvoiceEvent invoiceEvent)
+            {
+                Dictionary<string, int> cartItems = null;
+                bool deduct;
+                switch (invoiceEvent.Name)
+                {
+                    case InvoiceEvent.Expired:
+
+                    case InvoiceEvent.MarkedInvalid:
+                        deduct = false;
+                        break;
+                    case InvoiceEvent.Created:
+                        deduct = true;
+                        break;
+                    default:
+                        return;
+                }
+
+                
+                if ((!string.IsNullOrEmpty(invoiceEvent.Invoice.ProductInformation.ItemCode) ||
+                     AppService.TryParsePosCartItems(invoiceEvent.Invoice.PosData, out cartItems)))
+                {
+                    var appIds = AppService.GetAppInternalTags(invoiceEvent.Invoice);
+
+                    if (!appIds.Any())
+                    {
+                        return;
+                    }
+
+                    //get all apps that were tagged that have manageable inventory that has an item that matches the item code in the invoice
+                    var apps = (await _AppService.GetApps(appIds)).Select(data =>
+                    {
+                        switch (Enum.Parse<AppType>(data.AppType))
+                        {
+                            case AppType.PointOfSale:
+                                var possettings = data.GetSettings<AppsController.PointOfSaleSettings>();
+                                return (Data: data, Settings: (object)possettings,
+                                    Items: _AppService.Parse(possettings.Template, possettings.Currency));
+                            case AppType.Crowdfund:
+                                var cfsettings = data.GetSettings<CrowdfundSettings>();
+                                return (Data: data, Settings: (object)cfsettings,
+                                    Items: _AppService.Parse(cfsettings.PerksTemplate, cfsettings.TargetCurrency));
+                            default:
+                                return (null, null, null);
+                        }
+                    }).Where(tuple => tuple.Data != null && tuple.Items.Any(item =>
+                                          item.Inventory.HasValue &&
+                                          ((!string.IsNullOrEmpty(invoiceEvent.Invoice.ProductInformation.ItemCode) &&
+                                            item.Id == invoiceEvent.Invoice.ProductInformation.ItemCode) ||
+                                           (cartItems != null && cartItems.ContainsKey(item.Id)))));
+                    foreach (var valueTuple in apps)
+                    {
+                        foreach (var item1 in valueTuple.Items.Where(item =>
+                            ((!string.IsNullOrEmpty(invoiceEvent.Invoice.ProductInformation.ItemCode) &&
+                              item.Id == invoiceEvent.Invoice.ProductInformation.ItemCode) ||
+                             (cartItems != null && cartItems.ContainsKey(item.Id)))))
+                        {
+                            if (cartItems != null && cartItems.ContainsKey(item1.Id))
+                            {
+                                if (deduct)
+                                {
+                                    item1.Inventory -= cartItems[item1.Id];
+                                }
+                                else
+                                {
+                                    item1.Inventory += cartItems[item1.Id];
+                                }
+                                
+                            }
+                            else if (!string.IsNullOrEmpty(invoiceEvent.Invoice.ProductInformation.ItemCode) &&
+                                     item1.Id == invoiceEvent.Invoice.ProductInformation.ItemCode)
+                            {
+                                if (deduct)
+                                {
+                                    item1.Inventory--;
+                                }
+                                else
+                                {
+                                    item1.Inventory++;
+                                }
+                            }
+                        }
+
+                        switch (Enum.Parse<AppType>(valueTuple.Data.AppType))
+                        {
+                            case AppType.PointOfSale:
+
+                                ((AppsController.PointOfSaleSettings)valueTuple.Settings).Template =
+                                    _AppService.SerializeTemplate(valueTuple.Items);
+                                break;
+                            case AppType.Crowdfund:
+                                ((CrowdfundSettings)valueTuple.Settings).PerksTemplate =
+                                    _AppService.SerializeTemplate(valueTuple.Items);
+                                break;
+                            default:
+                                throw new InvalidOperationException();
+                        }
+
+                        valueTuple.Data.SetSettings(valueTuple.Settings);
+                        await _AppService.UpdateOrCreateApp(valueTuple.Data);
+                    }
+                }
+            }
+        }
+    }
+}

BTCPayServer/Hosting/BTCPayServerServices.cs

@@ -208,6 +208,7 @@ namespace BTCPayServer.Hosting
             services.AddSingleton<IHostedService, RatesHostedService>();
             services.AddSingleton<IHostedService, BackgroundJobSchedulerHostedService>();
             services.AddSingleton<IHostedService, AppHubStreamer>();
+            services.AddSingleton<IHostedService, AppInventoryUpdaterHostedService>();
             services.AddSingleton<IHostedService, DynamicDnsHostedService>();
             services.AddSingleton<IHostedService, TorServicesHostedService>();
             services.AddSingleton<IHostedService, PaymentRequestStreamer>();

BTCPayServer/Models/AppViewModels/ViewPointOfSaleViewModel.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
@@ -20,6 +20,7 @@ namespace BTCPayServer.Models.AppViewModels
             public ItemPrice Price { get; set; }
             public string Title { get; set; }
             public bool Custom { get; set; }
+            public int? Inventory { get; set; } = null;
         }
 
         public class CurrencyInfoData

BTCPayServer/Services/Apps/AppService.cs

@@ -17,14 +17,20 @@ using BTCPayServer.Services.Apps;
 using BTCPayServer.Services.Invoices;
 using BTCPayServer.Services.Rates;
 using BTCPayServer.Services.Stores;
+using ExchangeSharp;
 using Ganss.XSS;
 using Microsoft.AspNetCore.Cors;
 using Microsoft.AspNetCore.Http.Extensions;
 using Microsoft.AspNetCore.Identity;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.EntityFrameworkCore;
+using NBitcoin;
+using NBitcoin.DataEncoders;
 using NBitpayClient;
+using Newtonsoft.Json.Linq;
 using YamlDotNet.RepresentationModel;
+using YamlDotNet.Serialization;
+using YamlDotNet.Serialization.NamingConventions;
 using static BTCPayServer.Controllers.AppsController;
 using static BTCPayServer.Models.AppViewModels.ViewCrowdfundViewModel;
 
@@ -268,7 +274,33 @@ namespace BTCPayServer.Services.Apps
             return _storeRepository.FindStore(app.StoreDataId);
         }
 
+        public string SerializeTemplate(ViewPointOfSaleViewModel.Item[] items)
+        {
+            var mappingNode = new YamlMappingNode();
+            foreach (var item in items)
+            {
+                var itemNode = new YamlMappingNode();
+                itemNode.Add("title", new YamlScalarNode(item.Title));
+                itemNode.Add("price", new YamlScalarNode(item.Price.Value.ToStringInvariant()));
+                if (!string.IsNullOrEmpty(item.Description))
+                {
+                    itemNode.Add("description", new YamlScalarNode(item.Description));
+                }
+                if (!string.IsNullOrEmpty(item.Image))
+                {
+                    itemNode.Add("image", new YamlScalarNode(item.Image));
+                }
+                itemNode.Add("custom", new YamlScalarNode(item.Custom.ToStringLowerInvariant()));
+                if (item.Inventory.HasValue)
+                {
+                    itemNode.Add("inventory", new YamlScalarNode(item.Inventory.ToString()));
+                }
+                mappingNode.Add(item.Id, itemNode);
+            }
 
+            var serializer = new SerializerBuilder().Build();
+            return serializer.Serialize(mappingNode);
+        }
         public ViewPointOfSaleViewModel.Item[] Parse(string template, string currency)
         {
             if (string.IsNullOrWhiteSpace(template))
@@ -293,7 +325,8 @@ namespace BTCPayServer.Services.Apps
                                  Value = decimal.Parse(cc.Value.Value, CultureInfo.InvariantCulture),
                                  Formatted = Currencies.FormatCurrency(cc.Value.Value, currency)
                              }).Single(),
-                    Custom = c.GetDetailString("custom") == "true"
+                    Custom = c.GetDetailString("custom") == "true",
+                    Inventory = string.IsNullOrEmpty(c.GetDetailString("inventory")) ?(int?) null:  int.Parse(c.GetDetailString("inventory"), CultureInfo.InvariantCulture)
                 })
                 .ToArray();
         }
@@ -369,7 +402,6 @@ namespace BTCPayServer.Services.Apps
 
             public string GetDetailString(string field)
             {
-
                 return GetDetail(field).FirstOrDefault()?.Value?.Value;
             }
         }
@@ -396,5 +428,51 @@ namespace BTCPayServer.Services.Apps
                 return app;
             }
         }
+
+        public async Task UpdateOrCreateApp(AppData app)
+        {
+            using (var ctx = _ContextFactory.CreateContext())
+            {
+                if (string.IsNullOrEmpty(app.Id))
+                {
+                    app.Id = Encoders.Base58.EncodeData(RandomUtils.GetBytes(20));
+                    app.Created = DateTimeOffset.Now;
+                    await ctx.Apps.AddAsync(app);
+                }
+                else
+                {
+                    ctx.Apps.Update(app);
+                    ctx.Entry(app).Property(data => data.Created).IsModified = false;
+                    ctx.Entry(app).Property(data => data.Id).IsModified = false;
+                    ctx.Entry(app).Property(data => data.AppType).IsModified = false;
+                }
+                await ctx.SaveChangesAsync();
+            }
+        }
+        
+        private static bool TryParseJson(string json, out JObject result)
+        {
+            result = null;
+            try
+            {
+                result = JObject.Parse(json);
+                return true;
+            }
+            catch
+            {
+                return false;
+            }
+        }
+
+        public static bool TryParsePosCartItems(string posData, out Dictionary<string, int> cartItems)
+        {
+            cartItems = null;
+            if (!TryParseJson(posData, out var posDataObj) ||
+                !posDataObj.TryGetValue("cart", out var cartObject)) return false;
+            cartItems = cartObject.Select(token => (JObject)token)
+                .ToDictionary(o => o.GetValue("id", StringComparison.InvariantCulture).ToString(),
+                    o => int.Parse(o.GetValue("count", StringComparison.InvariantCulture).ToString(), CultureInfo.InvariantCulture ));
+            return true;
+        }
     }
 }

BTCPayServer/Views/Apps/UpdateCrowdfund.cshtml

@@ -273,6 +273,12 @@
                     <textarea rows="3" cols="40" class="js-product-description form-control mb-2">{description}</textarea>
                 </div>
             </div>
+            <div class="form-row">
+                <div class="col">
+                    <label>Inventory (leave to not use inventory feature)</label>
+                    <input type="number" step="1" class="js-product-inventory form-control mb-2" value="{inventory}"/>
+                </div>
+            </div>
         </div>
     </script>
 }

BTCPayServer/Views/Apps/UpdatePointOfSale.cshtml

@@ -277,6 +277,12 @@
                     <textarea rows="3" cols="40" class="js-product-description form-control mb-2">{description}</textarea>
                 </div>
             </div>
+            <div class="form-row">
+                <div class="col">
+                    <label>Inventory (leave blank to not use inventory feature)</label>
+                    <input type="number" step="1" class="js-product-inventory form-control mb-2" value="{inventory}"/>
+                </div>
+            </div>
         </div>
     </script>
 

BTCPayServer/Views/AppsPublic/Crowdfund/ContributeForm.cshtml

@@ -1,4 +1,5 @@
 @using Microsoft.EntityFrameworkCore.Internal
+@using Microsoft.EntityFrameworkCore.Storage
 @model BTCPayServer.Models.AppViewModels.ContributeToCrowdfund
 
 <form method="post">
@@ -43,11 +44,29 @@
                 <p class="card-text overflow-hidden">@Safe.Raw(item.Description)</p>
 
             </div>
-            @if (Model.ViewCrowdfundViewModel.PerkCount.ContainsKey(item.Id))
+            @if (Model.ViewCrowdfundViewModel.PerkCount.ContainsKey(item.Id) || item.Inventory.HasValue)
             {
                 <div class="card-footer d-flex justify-content-between">
-                    <span></span>
+                        @switch (item.Inventory)
-                    <span> @Model.ViewCrowdfundViewModel.PerkCount[item.Id] Contributors</span>
+                        {
+                            case null:
+                                <span></span>
+                                break;
+                            case int i when i <= 0:
+                                <span>Sold out</span>
+                                break;
+                            default:
+                                <span>@item.Inventory left</span>
+                                break;
+                        }
+                        @if (Model.ViewCrowdfundViewModel.PerkCount.ContainsKey(item.Id))
+                        {
+                            <span> @Model.ViewCrowdfundViewModel.PerkCount[item.Id] Contributors</span>
+                        }
+                        else
+                        {
+                            <span></span>
+                        }
                 </div>
             }
         </div> 

BTCPayServer/Views/AppsPublic/Crowdfund/VueCrowdfund.cshtml

@@ -300,9 +300,11 @@
                 </div>
             </div>
         </div>
-        <div class="card-footer d-flex justify-content-between" v-if="perk.sold">
+        <div class="card-footer d-flex justify-content-between" v-if="perk.sold || perk.inventory != null">
-           <span ></span>
+           
-           <span x >{{perk.sold}} Contributor{{perk.sold > 1? "s": ""}}</span>
+            <span v-if="perk.inventory != null && perk.inventory > 0" class="text-center text-muted">{{perk.inventory}} left</span>
+            <span v-if="perk.inventory != null && perk.inventory <= 0" class="text-center text-muted">Sold out</span>
+           <span v-if="perk.sold" >{{perk.sold}} Contributor{{perk.sold > 1? "s": ""}}</span>
         </div>
     </form>
 </div> 

BTCPayServer/Views/AppsPublic/ViewPointOfSale.cshtml

@@ -6,6 +6,7 @@
     ViewData["Title"] = Model.Title;
     Layout = null;
     int[] CustomTipPercentages = Model.CustomTipPercentages;
+    var anyInventoryItems = Model.Items.Any(item => item.Inventory.HasValue);
 }
 
 <!DOCTYPE html>
@@ -42,10 +43,19 @@
             grid-gap: .5rem;
         }
 
-        .card-deck .card:only-of-type {
+            .card-deck .card:only-of-type {
-            max-width: 320px;
+                max-width: 320px;
-            margin: auto;
+                margin: auto;
-        }
+            }
+            
+            .js-cart-item-count::-webkit-inner-spin-button, 
+            .js-cart-item-count::-webkit-outer-spin-button { 
+                -webkit-appearance: none;
+                -moz-appearance: none;
+                appearance: none;
+                margin: 0; 
+            }
+            
     </style>
     @if (!string.IsNullOrEmpty(Model.EmbeddedCSS))
     {
@@ -55,7 +65,7 @@
 </head>
 
 <body class="h-100">
-    <script id="template-cart-item" type="text/template">
+<script id="template-cart-item" type="text/template">
         <tr data-id="{id}">
             {image}
             <td class="align-middle pr-0 pl-2"><b>{title}</b></td>
@@ -67,7 +77,7 @@
                     <div class="input-group-prepend">
                         <a class="js-cart-item-minus btn btn-link px-2" href="#"><i class="fa fa-minus-circle fa-fw text-danger"></i></a>
                     </div>
-                    <input class="js-cart-item-count form-control form-control-sm pull-left" type="text" name="count" placeholder="Qty" value="{count}" data-prev="{count}">
+                    <input class="js-cart-item-count form-control form-control-sm pull-left" type="number" step="1" name="count" placeholder="Qty" max="{inventory}"  value="{count}" data-prev="{count}">
                     <div class="input-group-append">
                         <a class="js-cart-item-plus btn btn-link px-2" href="#">
                             <i class="fa fa-plus-circle fa-fw text-success"></i>
@@ -287,7 +297,7 @@
                             var image = item.Image;
                             var description = item.Description;
 
-                            <div class="js-add-cart card my-2 card-wrapper" data-id="@index">
+                            <div class="js-add-cart card my-2 card-wrapper" data-index="@index">
                                 @if (!String.IsNullOrWhiteSpace(image))
                                 {
                                     @:<img class="card-img-top" src="@image" alt="Card image cap">
@@ -302,6 +312,23 @@
                                 <div class="card-footer pt-0 bg-transparent border-0">
 
                                     <span class="text-muted small">@String.Format(Model.ButtonText, @item.Price.Formatted)</span>
+                                     @if (item.Inventory.HasValue)
+                                     {
+                                    
+                                         <div class="w-100 pt-2 text-center text-muted">
+                                             @if (item.Inventory > 0)
+                                             {
+                                                 <span>@item.Inventory left</span>
+                                             }
+                                             else
+                                             {
+                                                 <span>Sold out</span>
+                                             }
+                                         </div>
+                                     }else if (anyInventoryItems)
+                                     {
+                                         <div class="w-100 pt-2">&nbsp</div>
+                                     }
                                 </div>
                             </div>
                         }
@@ -378,29 +405,51 @@
 
                             </div>
                             <div class="card-footer bg-transparent border-0">
-                                @if (item.Custom)
+                                @if (!item.Inventory.HasValue || item.Inventory.Value > 0)
                                 {
-                                    <form method="post" asp-controller="AppsPublic" asp-action="ViewPointOfSale" asp-route-appId="@Model.AppId" asp-antiforgery="false" data-buy>
+                                    <div class="w-100">
-                                        <input type="hidden" name="choicekey" value="@item.Id" />
+                                        @if (item.Custom)
-                                        <div class="input-group">
+                                        {
-                                            <div class="input-group-prepend">
+                                            <form method="post" asp-controller="AppsPublic" asp-action="ViewPointOfSale" asp-route-appId="@Model.AppId" asp-antiforgery="false" data-buy>
-                                                <span class="input-group-text">@Model.CurrencySymbol</span>
+                                                <input type="hidden" name="choicekey" value="@item.Id"/>
-                                            </div>
+                                                <div class="input-group">
-                                            <input class="form-control" type="number" min="@item.Price.Value" step="@Model.Step" name="amount"
+                                                    <div class="input-group-prepend">
-                                                   value="@item.Price.Value" placeholder="Amount">
+                                                        <span class="input-group-text">@Model.CurrencySymbol</span>
-                                            <div class="input-group-append">
+                                                    </div>
-                                                <button class="btn btn-primary" type="submit">@Model.CustomButtonText</button>
+                                                    <input class="form-control" type="number" min="@item.Price.Value" step="@Model.Step" name="amount"
-                                            </div>
+                                                           value="@item.Price.Value" placeholder="Amount">
-                                        </div>
+                                                    <div class="input-group-append">
-                                    </form>
+                                                        <button class="btn btn-primary" type="submit">@Model.CustomButtonText</button>
+                                                    </div>
+                                                </div>
+                                            </form>
+                                        }
+                                        else
+                                        {
+                                            <form method="post" asp-controller="AppsPublic" asp-action="ViewPointOfSale" asp-route-appId="@Model.AppId" asp-antiforgery="false">
+                                                <button type="submit" name="choiceKey" class="js-add-cart btn btn-primary" value="@item.Id">
+                                                    @String.Format(Model.ButtonText, @item.Price.Formatted)
+                                                </button>
+                                            </form>
+                                        }
+                                    </div>
                                 }
-                                else
+                                @if (item.Inventory.HasValue)
                                 {
-                                    <form method="post" asp-controller="AppsPublic" asp-action="ViewPointOfSale" asp-route-appId="@Model.AppId" asp-antiforgery="false">
+
-                                        <button type="submit" name="choiceKey" class="js-add-cart btn btn-primary" value="@item.Id">
+                                    <div class="w-100 pt-2 text-center text-muted">
-                                            @String.Format(Model.ButtonText, @item.Price.Formatted)
+                                        @if (item.Inventory > 0)
-                                        </button>
+                                        {
-                                    </form>
+                                            <span>@item.Inventory left</span>
+                                        }
+                                        else
+                                        {
+                                            <span>Sold out</span>
+                                        }
+                                    </div>
+                                }else if (anyInventoryItems)
+                                {
+                                    <div class="w-100 pt-2">&nbsp</div> 
                                 }
                             </div>
                         </div>
@@ -425,6 +474,10 @@
                                         </div>
                                     </div>
                                 </form>
+                                @if (anyInventoryItems)
+                                {
+                                    <div class="w-100 pt-2">&nbsp</div>
+                                }
                             </div>
                         </div>
                     }

BTCPayServer/wwwroot/cart/js/cart.jquery.js

@@ -52,8 +52,8 @@ $(document).ready(function(){
 
         var $btn = $(event.target),
             self = this;
-            id = $btn.closest('.card').data('id'),
+            index = $btn.closest('.card').data('index'),
-            item = srvModel.items[id],
+            item = srvModel.items[index],
             items = cart.items;
 
         // Is event catching disabled?
@@ -68,10 +68,11 @@ $(document).ready(function(){
             });
 
             cart.addItem({
-                id: id,
+                id: item.id,
                 title: item.title,
                 price: item.price,
-                image: typeof item.image != 'underfined' ? item.image : null
+                image: typeof item.image != 'undefined' ? item.image : null,
+                inventory: item.inventory
             });
             cart.listItems();
         }

BTCPayServer/wwwroot/cart/js/cart.js

@@ -150,7 +150,7 @@ Cart.prototype.addItem = function(item) {
 
     // Add new item because it doesn't exist yet
     if (!result.length) {
-        this.content.push({id: id, title: item.title, price: item.price, count: 0, image: item.image});
+        this.content.push({id: id, title: item.title, price: item.price, count: 0, image: item.image, inventory: item.inventory});
         this.emptyCartToggle();
     }
 
@@ -159,21 +159,30 @@ Cart.prototype.addItem = function(item) {
 }
 
 Cart.prototype.incrementItem = function(id) {
-    var self = this;
+    var oldItemsCount = this.items;
     this.items = 0; // Calculate total # of items from scratch just to make sure
-
+    var result = true;
-    this.content.filter(function(obj){
+    for (var i = 0; i < this.content.length; i++) {
-        // Increment the item count
+        var obj = this.content[i];
         if (obj.id === id){
+            if(obj.inventory != null && obj.inventory <= obj.count){
+                result = false;
+                continue;
+            }
+
             obj.count++;
             delete(obj.disabled);
         }
 
         // Increment the total # of items
-        self.items += obj.count;
+        this.items += obj.count;
-    });
+    }
-
+    if(!result){
+        this.items = oldItemsCount;
+    }
+    
     this.updateAll();
+    return result;
 }
 
 // Disable cart item so it doesn't count towards total amount
@@ -425,6 +434,7 @@ Cart.prototype.listItems = function() {
                 }) : '',
                 'title': this.escape(item.title),
                 'count': this.escape(item.count),
+                'inventory': this.escape(item.inventory < 0? 99999: item.inventory),
                 'price': this.escape(item.price.formatted)
             });
             list.push($(tableTemplate));
@@ -499,14 +509,14 @@ Cart.prototype.listItems = function() {
         // Increment item
         $('.js-cart-item-plus').off().on('click', function(event){
             event.preventDefault();
-
+            if(self.incrementItem($(this).closest('tr').data('id'))){              
-            var $val = $(this).parents('.input-group').find('.js-cart-item-count'),
+                var $val = $(this).parents('.input-group').find('.js-cart-item-count'),
-                val = parseInt($val.val() || $val.data('prev')) + 1;
+                    val = parseInt($val.val() || $val.data('prev')) + 1;
-            
+                
-            $val.val(val);
+                $val.val(val);
-            $val.data('prev', val);
+                $val.data('prev', val);
-            self.resetTip();
+                self.resetTip();
-            self.incrementItem($(this).closest('tr').data('id'));
+            }
         });
 
         // Decrement item
@@ -625,15 +635,39 @@ Cart.prototype.saveLocalStorage = function() {
 
 Cart.prototype.loadLocalStorage = function() {
     this.content = $.parseJSON(localStorage.getItem(this.getStorageKey('cart'))) || [];
+    var self = this;
 
     // Get number of cart items
-    for (var key in this.content) {
+    for (var i = this.content.length-1; i >= 0; i--) {
-        if (this.content.hasOwnProperty(key) && typeof this.content[key] != 'undefined' && this.content[key] != null) {
+        if (!this.content[i]) {
-            this.items += this.content[key].count;
+            this.content.splice(i,1);
-
+            continue;
-            // Delete the disabled flag if any
-            delete(this.content[key].disabled);
         }
+
+        //check if the pos items still has the cached cart items 
+        var matchedItem = srvModel.items.find(function(item){
+            return item.id === self.content[i].id;
+        });
+        if(!matchedItem){
+            //remove if no longer available
+            this.content.splice(i,1);
+            continue;
+        }else{
+            
+            if(matchedItem.inventory != null && matchedItem.inventory <= 0){
+                //item is out of stock
+                this.content.splice(i,1);
+            }else if(matchedItem.inventory != null && matchedItem.inventory <  this.content[i].count){
+                //not enough stock for original cart amount, reduce to available stock
+                this.content[i].count = matchedItem.inventory;
+            }
+            //update its stock
+            this.content[i].inventory = matchedItem.inventory;
+            
+        }
+        this.items += this.content[i].count;
+            // Delete the disabled flag if any
+            delete(this.content[i].disabled);
     }
 
     this.discount = localStorage.getItem(this.getStorageKey('cartDiscount'));

BTCPayServer/wwwroot/crowdfund/app.js

@@ -38,7 +38,7 @@ addLoadEvent(function (ev) {
         },
         computed: {
             canExpand: function(){
-                return !this.expanded && this.active && (this.perk.price.value || this.perk.custom)
+                return !this.expanded && this.active && (this.perk.price.value || this.perk.custom) && (this.perk.inventory==null || this.perk.inventory > 0)
             }
         },
         methods: {

BTCPayServer/wwwroot/products/js/products.jquery.js

@@ -35,7 +35,8 @@ $(document).ready(function(){
         var index = $('.js-product-index').val(),
             description = $('.js-product-description').val(),
             image = $('.js-product-image').val(),
-            custom = $('.js-product-custom').val();
+            custom = $('.js-product-custom').val(),
+            inventory = parseInt($('.js-product-inventory').val(), 10);
             obj = {
                 id: products.escape($('.js-product-id').val()),
                 price: products.escape($('.js-product-price').val()),
@@ -58,7 +59,9 @@ $(document).ready(function(){
             if (!Boolean(index)) {
                 obj.id = products.escape(obj.title.toLowerCase() + ':');
             }
-    
+            if(inventory != null && !isNaN(inventory ))
+            obj.inventory = inventory;
+            
             products.saveItem(obj, index);
         }
     });
@@ -66,4 +69,4 @@ $(document).ready(function(){
     $('.js-product-add').click(function(){
         products.itemContent();
     });
-});
+});

BTCPayServer/wwwroot/products/js/products.js

@@ -9,8 +9,21 @@ function Products() {
 }
 
 Products.prototype.loadFromTemplate = function() {
-    var template = $('.js-product-template').val().trim(),
+    var template = $('.js-product-template').val().trim();
-        lines = template.split("\n\n");
+    
+    var lines = [];
+    var items = template.split("\n");
+    for (var i = 0; i < items.length; i++) {
+        if(items[i] === ""){
+            continue;
+        }
+        if(items[i].startsWith("  ")){
+            lines[lines.length-1]+=items[i] + "\n";
+        }else{
+           
+            lines.push(items[i] + "\n");
+        }
+    }
 
     this.products = [];
 
@@ -19,7 +32,7 @@ Products.prototype.loadFromTemplate = function() {
         var line = lines[kl],
             product = line.split("\n"),
             id, price, title, description, image = null,
-            custom;
+            custom, inventory=null;
 
         for (var kp in product) {
             var productProperty = product[kp].trim();
@@ -43,6 +56,9 @@ Products.prototype.loadFromTemplate = function() {
             if (productProperty.indexOf('custom:') !== -1) {
                 custom = productProperty.replace('custom:', '').trim();
             }
+            if (productProperty.indexOf('inventory:') !== -1) {
+                inventory = parseInt(productProperty.replace('inventory:', '').trim(),10);
+            }
         }
 
         if (price != null || title != null) {
@@ -53,12 +69,13 @@ Products.prototype.loadFromTemplate = function() {
                 'price': price,
                 'image': image || null,
                 'description': description || null,
-                'custom': Boolean(custom)
+                'custom': Boolean(custom),
+                'inventory': isNaN(inventory)? null: inventory
             });
         }
         
     }
-}
+};
 
 Products.prototype.saveTemplate = function() {
     var template = '';
@@ -69,9 +86,10 @@ Products.prototype.saveTemplate = function() {
             id = product.id,
             title = product.title,
             price = product.price? product.price : 0,
-            image = product.image
+            image = product.image,
             description = product.description,
-            custom = product.custom;
+            custom = product.custom,
+            inventory = product.inventory;
 
         template += id + '\n' +
         '  price: ' + parseFloat(price).noExponents() + '\n' +
@@ -86,11 +104,14 @@ Products.prototype.saveTemplate = function() {
         if (custom) {
             template += '  custom: true\n';
         }
+        if(inventory != null){
+            template+= '  inventory: ' + inventory + '\n';
+        }
         template += '\n';
     }
 
     $('.js-product-template').val(template);
-}
+};
 
 Products.prototype.showAll = function() {
     var list = [];
@@ -106,7 +127,7 @@ Products.prototype.showAll = function() {
     }
 
     $('.js-products').html(list);
-}
+};
 
 // Load the template
 Products.prototype.template = function($template, obj) {
@@ -118,7 +139,7 @@ Products.prototype.template = function($template, obj) {
     }
 
     return template;
-}
+};
 
 Products.prototype.saveItem = function(obj, index) {
     // Edit product
@@ -143,7 +164,7 @@ Products.prototype.removeItem = function(index) {
     }
 
     this.saveTemplate();
-}
+};
 
 Products.prototype.itemContent = function(index) {
     var product = null,
@@ -162,11 +183,12 @@ Products.prototype.itemContent = function(index) {
         'title': product != null ? this.escape(product.title) : '',
         'description': product != null ? this.escape(product.description) : '',
         'image': product != null ? this.escape(product.image) : '',
+        'inventory': product != null ? parseInt(this.escape(product.inventory),10) : '',
         'custom': '<option value="true"' + (custom ? ' selected' : '') + '>Yes</option><option value="false"' + (!custom ? ' selected' : '') + '>No</option>'
     });
 
     $('#product-modal').find('.modal-body').html(template);
-}
+};
 
 Products.prototype.modalEmpty = function() {
     var $modal = $('#product-modal');