如何重用code，它重新打开连接？ [英] How to reuse code that reopens connection?

问题描述

我们的生产服务器杀死活动的连接，所以我们的API需要在需要的时候恢复。下面code的作品，但它是非常重复的：

 私人const int的MaxRetryCount = 3;

    公共静态SqlDataReader的RestoreConnectionAndExecuteReader（SqlCommand的命令）
    {
        INT retryCount = 0;

        而（retryCount ++＆LT; MaxRetryCount）
        {
            尝试
            {
                如果（command.Connection.State == ConnectionState.Closed）
                    command.Connection.Open（）;
                返回Command.ExecuteReader却（）;
            }
            赶上（例外五）
            {
                如果（！e.Message.ToLower（）。包含（发生传输级错误））
                {
                    扔;
                }
            }
        }
        抛出新的异常（无法还原命令连接：+ command.CommandText）;
    }

    公共静态无效RestoreConnectionAndExecuteNonQuery（SqlCommand的命令）
    {
        变种retryCount = 0;
        而（retryCount ++＆LT; MaxRetryCount）
        {
            尝试
            {
                如果（command.Connection.State == ConnectionState.Closed）
                    command.Connection.Open（）;
                command.ExecuteNonQuery（）;
                返回;
            }
            赶上（例外五）
            {
                如果（！e.Message.ToLower（）。包含（发生传输级错误））
                {
                    扔;
                }
            }
        }
        抛出新的异常（无法还原命令连接：+ command.CommandText）;
    }
 

我怎么能重构我的code和消除重复？我需要保持这些方法的签名，因为它们都用遍了该系统。

解决方案

 私人const int的MaxRetryCount = 3;

公共静态牛逼RestoreConnectionAndExecute＆LT; T＆GT;（SqlCommand的命令，函数功能：LT; SqlCommand的，T＆GT; FUNC）
{
    INT retryCount = 0;

    而（retryCount ++＆LT; MaxRetryCount）
    {
        尝试
        {
            如果（command.Connection.State == ConnectionState.Closed）
                command.Connection.Open（）;
            返回FUNC（命令）;
        }
        赶上（例外五）
        {
            如果（！e.Message.ToLower（）。包含（发生传输级错误））
            {
                扔;
            }
        }
    }
    抛出新的异常（无法还原命令连接：+ command.CommandText）;

}

公共静态SqlDataReader的RestoreConnectionAndExecuteReader（SqlCommand的命令）
{
    返回RestoreConnectionAndExecute（命令，C =＆GT; c.ExecuteReader（））;
}

公共静态INT RestoreConnectionAndExecuteNonQuery（SqlCommand的命令）
{
    返回RestoreConnectionAndExecute（命令，C =＆GT; c.ExecuteNonQuery（））;
}
 

Our production server kills inactive connections, so our API needs to restore them when they are needed. The following code works, but it is very repetitive:

   private const int MaxRetryCount = 3;

    public static SqlDataReader RestoreConnectionAndExecuteReader(SqlCommand command)
    {
        int retryCount = 0;

        while (retryCount++ < MaxRetryCount)
        {
            try
            {
                if (command.Connection.State == ConnectionState.Closed)
                    command.Connection.Open();
                return command.ExecuteReader();
            }
            catch(Exception e)
            {
                if(!e.Message.ToLower().Contains("transport-level error has occurred"))
                {
                    throw;
                }
            }
        }
        throw new Exception("Failed to restore connection for command:"+command.CommandText);
    }

    public static void RestoreConnectionAndExecuteNonQuery(SqlCommand command)
    {
        var retryCount = 0;
        while(retryCount++ < MaxRetryCount)
        {
            try
            {
                if (command.Connection.State == ConnectionState.Closed)
                    command.Connection.Open();
                command.ExecuteNonQuery();
                return;
            }
            catch(Exception e)
            {
                if (!e.Message.ToLower().Contains("transport-level error has occurred"))
                {
                    throw;
                }
            }
        }
        throw new Exception("Failed to restore connection for command:" + command.CommandText);
    }

How could I refactor my code and eliminate duplication? I need to keep the signatures of these methods, as they are used all over the system.

解决方案

private const int MaxRetryCount = 3;

public static T RestoreConnectionAndExecute<T>(SqlCommand command, Func<SqlCommand, T> func)
{
    int retryCount = 0;

    while (retryCount++ < MaxRetryCount)
    {
        try
        {
            if (command.Connection.State == ConnectionState.Closed)
                command.Connection.Open();
            return func(command);
        }
        catch(Exception e)
        {
            if(!e.Message.ToLower().Contains("transport-level error has occurred"))
            {
                throw;
            }
        }
    }
    throw new Exception("Failed to restore connection for command:"+command.CommandText);

} 

public static SqlDataReader RestoreConnectionAndExecuteReader(SqlCommand command)
{
    return RestoreConnectionAndExecute(command, c => c.ExecuteReader());
}

public static int RestoreConnectionAndExecuteNonQuery(SqlCommand command)
{
    return RestoreConnectionAndExecute(command, c => c.ExecuteNonQuery());
}

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