Make `UserFlashSaleResultCache` have an absolute expiration

plugins/FlashSales/src/EasyAbp.EShop.Plugins.FlashSales.Application/EasyAbp/EShop/Plugins/FlashSales/FlashSalePlans/FlashSalePlanAppService.cs

@@ -278,10 +278,10 @@ public class FlashSalePlanAppService :
             );
         });
 
-        await SetUserFlashSaleResultCacheAsync(plan.Id, result.Id);
-
         var createFlashSaleOrderEto = await PrepareCreateFlashSaleOrderEtoAsync(plan, result.Id, input, userId, now, preOrderCache.HashToken);
 
+        await SetUserFlashSaleResultCacheAsync(plan.Id, result.Id);
+
         await DistributedEventBus.PublishAsync(createFlashSaleOrderEto);
 
         return new FlashSaleOrderResultDto() { IsSuccess = true, FlashSaleResultId = result.Id };
@@ -348,7 +348,10 @@ public class FlashSalePlanAppService :
     protected virtual async Task SetUserFlashSaleResultCacheAsync(Guid planId, Guid resultId)
     {
         var userFlashSaleResultCacheKey = await GetUserFlashSaleResultCacheKeyAsync(planId);
-        await DistributedCache.SetStringAsync(userFlashSaleResultCacheKey, resultId.ToString());
+        await DistributedCache.SetStringAsync(userFlashSaleResultCacheKey, resultId.ToString(), new DistributedCacheEntryOptions()
+        {
+            AbsoluteExpiration = DateTimeOffset.Now.Add(Options.UserFlashSaleResultCacheExpires)
+        });
     }
 
     #endregion
@@ -423,9 +426,12 @@ public class FlashSalePlanAppService :
             HashToken = hashToken
         };
 
-        foreach (var item in input.ExtraProperties)
+        if (input.ExtraProperties != null)
         {
-            eto.ExtraProperties.Add(item.Key, item.Value);
+            foreach (var item in input.ExtraProperties)
+            {
+                eto.ExtraProperties.Add(item.Key, item.Value);
+            }
         }
 
         return Task.FromResult(eto);

plugins/FlashSales/src/EasyAbp.EShop.Plugins.FlashSales.Application/EasyAbp/EShop/Plugins/FlashSales/FlashSalePlans/FlashSalesOptions.cs

@@ -8,4 +8,9 @@ public class FlashSalesOptions
     /// Default: 3 minutes
     /// </summary>
     public TimeSpan PreOrderExpires { get; set; } = TimeSpan.FromMinutes(3);
+
+    /// <summary>
+    /// Default: 5 minutes
+    /// </summary>
+    public TimeSpan UserFlashSaleResultCacheExpires { get; set; } = TimeSpan.FromMinutes(5);
 }