新增 查询sql生成工厂类 AdncMySqlQuerySqlGeneratorFactory.cs，为后面集成mycat实现读写分离做准备。

src/ServerApi/Adnc.Infr.EfCore/AdncMySqlQuerySqlGeneratorFactory.cs

@@ -0,0 +1,111 @@
+using System;
+using System.Linq.Expressions;
+using JetBrains.Annotations;
+using Microsoft.EntityFrameworkCore.Query;
+using Microsoft.EntityFrameworkCore.Storage;
+using Microsoft.EntityFrameworkCore.Query.SqlExpressions;
+using Pomelo.EntityFrameworkCore.MySql.Query.Internal;
+using Pomelo.EntityFrameworkCore.MySql.Infrastructure.Internal;
+
+namespace Pomelo.EntityFrameworkCore.MySql.Query.ExpressionVisitors.Internal
+{
+    /// <summary>
+    /// adnc sql生成工厂类
+    /// </summary>
+#pragma warning disable EF1001 // Internal EF Core API usage.
+    public class AdncMySqlQuerySqlGeneratorFactory : MySqlQuerySqlGeneratorFactory
+#pragma warning restore EF1001 // Internal EF Core API usage.
+    {
+        private readonly QuerySqlGeneratorDependencies _dependencies;
+        private readonly MySqlSqlExpressionFactory _sqlExpressionFactory;
+        private readonly IMySqlOptions _options;
+
+        public AdncMySqlQuerySqlGeneratorFactory(
+            [NotNull] QuerySqlGeneratorDependencies dependencies,
+            ISqlExpressionFactory sqlExpressionFactory,
+            IMySqlOptions options) : base(dependencies, sqlExpressionFactory, options)
+        {
+            _dependencies = dependencies;
+            _sqlExpressionFactory = (MySqlSqlExpressionFactory)sqlExpressionFactory;
+            _options = options;
+        }
+
+        /// <summary>
+        /// 重写QuerySqlGenerator
+        /// </summary>
+        /// <returns></returns>
+        public override QuerySqlGenerator Create()
+        {
+            var result = new AdncQuerySqlGenerator(_dependencies, _sqlExpressionFactory, _options);
+            return result;
+        }
+    }
+
+    /// <summary>
+    /// adnc sql 生成类
+    /// </summary>
+#pragma warning disable EF1001 // Internal EF Core API usage.
+    public class AdncQuerySqlGenerator : MySqlQuerySqlGenerator
+#pragma warning restore EF1001 // Internal EF Core API usage.
+    {
+        protected readonly Guid ContextId;
+        private bool _isQueryMaseter = false;
+
+        public AdncQuerySqlGenerator(
+            [NotNull] QuerySqlGeneratorDependencies dependencies,
+            [NotNull] MySqlSqlExpressionFactory sqlExpressionFactory,
+            [CanBeNull] IMySqlOptions options)
+            : base(dependencies, sqlExpressionFactory, options)
+        {
+            ContextId = Guid.NewGuid();
+        }
+
+        /// <summary>
+        /// 获取IQueryable的tags,并生成注解
+        /// </summary>
+        /// <param name="selectExpression"></param>
+        protected override void GenerateTagsHeaderComment(SelectExpression selectExpression)
+        {
+            var mycatTag = "db_type=master";
+            if(selectExpression.Tags.Contains(mycatTag))
+            {
+                _isQueryMaseter = true;
+                selectExpression.Tags.Remove(mycatTag);
+            }
+            base.GenerateTagsHeaderComment(selectExpression);
+        }
+
+        /// <summary>
+        /// pomelo最终生成的sql
+        /// 该方法主要是调试用
+        /// </summary>
+        /// <param name="selectExpression"></param>
+        /// <returns></returns>
+        public override IRelationalCommand GetCommand(SelectExpression selectExpression)
+        {
+            var command = base.GetCommand(selectExpression);
+            return command;
+        }
+
+        /// <summary>
+        /// 在pomelo生成查询sql前，插入mycat注解
+        /// 该注解的意思是从写库读取数据
+        /// </summary>
+        /// <param name="selectExpression"></param>
+        /// <returns></returns>
+        protected override Expression VisitSelect(SelectExpression selectExpression)
+        {
+            /*
+            /*#mycat:db_type=master*/
+            /*SELECT `s`.`Password`, `s`.`Salt`, `s`.`Name`, `s`.`Email`, `s`.`RoleId`, `s`.`Account`, `s`.`ID`, `s`.`Status`
+            FROM `SysUser` AS `s`
+            WHERE(`s`.`IsDeleted` = FALSE) AND(`s`.`Account` = 'alpha2008')
+            LIMIT 1
+            */
+            if (_isQueryMaseter)
+                Sql.Append("/*#mycat:db_type=master*/ ");
+
+            return base.VisitSelect(selectExpression);
+        }
+    }
+}

src/ServerApi/Adnc.WebApi.Shared/SharedServicesRegistration.cs

@@ -46,6 +46,8 @@
 using Adnc.Infr.Common.Helper;
 using Adnc.WebApi.Shared.Extensions;
 using ProblemDetails = Microsoft.AspNetCore.Mvc.ProblemDetails;
+using Microsoft.EntityFrameworkCore.Query;
+using Pomelo.EntityFrameworkCore.MySql.Query.ExpressionVisitors.Internal;
 
 namespace Adnc.WebApi.Shared
 {
@@ -247,7 +249,8 @@ public virtual void AddEfCoreContext()
                     mySqlOptions.MinBatchSize(2);
                     mySqlOptions.MigrationsAssembly(_serviceInfo.AssemblyName.Replace("WebApi", "Migrations"));
                 });
-                options.AddInterceptors(new CustomCommandInterceptor());
+                //替换默认查询sql生成器,为后面集成mycat实现读写分离做准备,
+                //options.ReplaceService<IQuerySqlGeneratorFactory, AdncMySqlQuerySqlGeneratorFactory>();
             });
         }