连接到 MySQL 8 时 C# 应用程序出现身份验证异常

我们编写了一个测试工具，因为我们的应用程序在连接到 MySQL 8 数据库时出现以下异常：

Unhandled Exception: System.Security.Authentication.AuthenticationException: 
    Authentication to host 'xxx.xxx.x.xx' faied.
        at MySql.Data.Common.Ssl.StartSSL(Stream& baseStream, 
            Encoding encoding, String connectionString)
        at MySql.Data.MySqlClient.NativeDriver.Open()
        at MySql.Data.MySqlClient.Driver.Open()
        at MySql.Data.MySqlClient.Driver.Create(MySqlConnectionStringBuilder settings)
        at MySql.Data.MySqlClient.MySqlPool.CreateNewPooledConnection()
        at MySql.Data.MySqlClient.MySqlPool.GetPooledConnection()
        at MySql.Data.MySqlClient.MySqlPool.TryToGetDriver()
        at MySql.Data.MySqlClient.MySqlPool.GetConnection()
        at MySql.Data.MySqlClient.MySqlConnection.Open()
        at DatabaseTestConnection.Program.Main(String[] args)

所以我编写了以下测试工具来尝试获取更多调试信息......

using MySql.Data.MySqlClient;
using System;

namespace DatabaseTestConnection
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("MySQL Database Connection Test");
            Console.WriteLine("Please enter database IP");
            string dbIP = Console.ReadLine();

            string connectionString = @$"
                SERVER={dbIP};
                DATABASE=test;
                UID=xxxxx;
                PASSWORD=xxxxxx;
                DEFAULT COMMAND TIMEOUT = 180;";

            MySqlConnection connection = new MySqlConnection(connectionString);

            try
            {
                Console.WriteLine("Connecting to the database....");
                connection.Open();
                Console.WriteLine("Succesfully Connected to the database....");
            }
            catch (MySqlException ex)
            {
                switch (ex.Number)
                {
                    case 0:
                        Console.WriteLine(
                            "{0} {1} : Cannot connect to server. Contact adminis",
                            DateTime.Now.ToLongDateString(),
                            DateTime.Now.ToLongTimeString());
                        break;
                    case 1045:
                        Console.WriteLine(
                            "{0} {1} : Invalid username/password, please try again",
                            DateTime.Now.ToLongDateString(),
                            DateTime.Now.ToLongTimeString());
                        break;
                    default:
                        Console.WriteLine(
                            "{0} {1} : Unable to open connection: {2}",
                            DateTime.Now.ToLongDateString(),
                            DateTime.Now.ToLongTimeString(),
                            ex.Message);
                        break;
                }
                Console.WriteLine("Press any key to continue....");
                Console.ReadLine();
                System.Environment.Exit(1);
            }

            Console.WriteLine("Counting users table....");
            int Count = 0;
            
            //Create Mysql Command
            using (MySqlCommand cmd = new MySqlCommand())
            {
                cmd.Connection = connection;
                cmd.CommandText = "SELECT COUNT(*) FROM users";                    

                try
                {
                    //ExecuteScalar will return one value
                    Count = int.Parse(cmd.ExecuteScalar() + "");
                    Console.WriteLine(
                        $"Counted {Count.ToString()} users in the users table");
                }
                catch (Exception ex)
                {
                    Console.WriteLine("{0} {1} : Database error on Select count: {2}",
                        DateTime.Now.ToLongDateString(),
                        DateTime.Now.ToLongTimeString(),
                        ex.Message);

                    Count = 0;
                    Console.WriteLine("Press any key to continue....");
                    Console.ReadLine();
                    System.Environment.Exit(1);
                }
            }

            try
            {
                Console.WriteLine("Closing the connection....");
                connection.Close();
                Console.WriteLine("Succesfully closed the connection");
                Console.WriteLine("Press any key to continue....");
                Console.ReadLine();
            }
            catch (MySqlException ex)
            {
                Console.WriteLine("{0} {1} : Unable to close connection: {2}",
                    DateTime.Now.ToLongDateString(),
                    DateTime.Now.ToLongTimeString(),
                    ex.Message);

                Console.WriteLine("Press any key to continue....");
                Console.ReadLine();
            }
        }
    }
}

测试工具在一台不在 AD 中的电脑上运行，但在 AD 中的电脑上失败并出现上述错误。

我是否在连接字符串中缺少一些附加配置？

我在 ModDbExport 模块中遇到了同样的问题快速SCADA。导出到 MSSQL 时我没有遇到任何问题，但导出到 MySQL 却并不简单。

1. 连接选项仅限于服务器、数据库和登录凭据。连接字符串是唯一的方法。

2. 有一个模糊的选项，SslMode，这显然默认为“首选”，并且连接不起作用。注意：连接“不”安全，因为安全性是由转发本地主机端口 3306 的 SSH 隧道提供的...导出模块认为它正在连接并向本地计算机发送数据，但相反，它通过以下方式将其发送到数据库服务器：安全通道）。

解决方案是明确声明SslMode=None在连接字符串中。数据导出工作完美无缺。