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CloudBuilder/CloudBuilder.Core/DatabaseAccessor/UnitOfWorkAttribute.cs

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+using CloudBuilder.Core.Service;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Mvc.Filters;
+using Microsoft.EntityFrameworkCore;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using System.Transactions;
+
+namespace CloudBuilder.Core.DatabaseAccessor
+{
+    /*
+        事务范围：TransactionScopeOption.RequiresNew 管理的是分布式事务，
+                  TransactionScopeOption.Required但对于单个数据库连接，通常不需要分布式事务。
+        OnActionExecutionAsync 是 ASP.NET Core 中异步的 Action 过滤器执行方法。
+        // OnActionExecuting: Action 执行前
+        [开始事务]
+        ↓
+        [Action 方法执行]
+        ↓
+        // OnActionExecuted: Action 执行后（无论是否异常）
+        [检查异常]
+        //Controller对象不抛出异常，返回的是异常对象ValidatedException、ServiceErrorException（方便前端信息统一处理）
+        [提交或回滚事务]
+     */
+    [AttributeUsage(AttributeTargets.Method)]
+    public class UnitOfWorkAttribute : ActionFilterAttribute
+    {
+        private TransactionScope _transactionScope;
+
+        public override void OnActionExecuting(ActionExecutingContext context)
+        {
+            _transactionScope = new TransactionScope(TransactionScopeOption.RequiresNew,
+                new TransactionOptions
+                {
+                    IsolationLevel = IsolationLevel.ReadCommitted,
+                    Timeout = TransactionManager.MaximumTimeout
+                });
+
+            base.OnActionExecuting(context);
+        }
+
+        //public override void OnActionExecuting(ActionExecutingContext context)
+        //{
+        //    // 正确：单机数据库事务（不是分布式）
+        //    _transactionScope = new TransactionScope(
+        //        TransactionScopeOption.Required,
+        //        new TransactionOptions
+        //        {
+        //            IsolationLevel = IsolationLevel.ReadCommitted
+        //        },
+        //        TransactionScopeAsyncFlowOption.Enabled); // 必须加这个
+
+        //    base.OnActionExecuting(context);
+        //}
+
+        public override void OnActionExecuted(ActionExecutedContext context)
+        {
+            if (_transactionScope == null)
+            {
+                base.OnActionExecuted(context);
+                return;
+            }
+
+            bool needRollback = false;
+
+            try
+            {
+                // ==============================================
+                // 核心逻辑：判断返回值是不是异常对象
+                // ==============================================
+                if (context.Result is ObjectResult objectResult)
+                {
+                    var value = objectResult.Value;
+
+                    if (value != null)
+                    {
+                        // 只要是这两个异常 → 必须回滚
+                        if (value is ValidatedException || value is ServiceErrorException)
+                        {
+                            needRollback = true;
+                        }
+                    }
+                }
+
+                // 如果没有异常，才提交
+                if (!needRollback)
+                {
+                    //必须要有 SaveChanges() 调用，否则数据只会停留在内存中，不会真正保存到数据库。
+                    _transactionScope.Complete();
+                }
+            }
+            finally
+            {
+                // 不 Complete() 就是自动回滚
+                _transactionScope.Dispose();
+            }
+
+            base.OnActionExecuted(context);
+        }
+    }
+}