如何解决如何处理WCF异常与代码合并的列表
|| 我正在尝试在SO上扩展此答案，以使WCF客户端在出现瞬态网络故障时重试，并处理其他需要重试的情况，例如身份验证到期。 题： 需要处理哪些WCF异常，正确的处理方式是什么？ 除了[ѭ0]之外，我还是希望看到以下一些示例技术： 重试前延迟X秒 关闭并重新创建New（）WCF客户端。处置旧的。 不要重试并重新抛出此错误 重试N次，然后抛出 由于不可能由一个人知道所有异常或解决异常的方法，因此请分享您所知道的。我将在下面的代码示例中汇总答案和方法。 // USAGE SAMPLE
//int newOrderId = 0; // need a value for definite assignment
//Service<IOrderService>.Use(orderService=>
//{
// newOrderId = orderService.PlaceOrder(request);
//}
/// <summary>
/// A safe WCF Proxy suitable when sessionmode=false
/// </summary>
/// <param name=\"codeBlock\"></param>
public static void Use(UseServiceDelegateVoid<T> codeBlock)
{
IClientChannel proxy = (IClientChannel)_channelFactory.CreateChannel();
bool success = false;
try
{
codeBlock((T)proxy);
proxy.Close();
success = true;
}
catch (CommunicationObjectAbortedException e)
{
// Object should be discarded if this is reached.
// Debugging discovered the following exception here:
// \"Connection can not be established because it has been aborted\"
throw e;
}
catch (CommunicationObjectFaultedException e)
{
throw e;
}
catch (MessageSecurityException e)
{
throw e;
}
catch (ChannelTerminatedException)
{
proxy.Abort(); // Possibly retry?
}
catch (ServerTooBusyException)
{
proxy.Abort(); // Possibly retry?
}
catch (EndpointNotFoundException)
{
proxy.Abort(); // Possibly retry?
}
catch (FaultException)
{
proxy.Abort();
}
catch (CommunicationException)
{
proxy.Abort();
}
catch (TimeoutException)
{
// Sample error found during debug:
// The message Could not be transferred within the allotted timeout of
// 00:01:00. There was no space available in the reliable channel\'s
// transfer window. The time allotted to this operation may have been a
// portion of a longer timeout.
proxy.Abort();
}
catch (ObjectdisposedException )
{
//todo: handle this duplex callback exception. Occurs when client disappears.
// Source: https://stackoverflow.com/questions/1427926/detecting-client-death-in-wcf-duplex-contracts/1428238#1428238
}
finally
{
if (!success)
{
proxy.Abort();
}
}
}
解决方法
编辑：多次关闭并重新打开客户端似乎有些效率低下。我在这里探索解决方案，如果找到了，将更新和扩展此代码。 （或者，如果David Khaykin发布了答案，我会将其标记为已接受）
经过几年的修改，下面的代码是我首选的处理WCF重试和处理异常的策略（在从Wayback机器上看到此博客发布之后）。
我调查了每个异常，以及该异常的处理方法，并注意到了一个共同特征。每个需要从通用基类继承的“重试”的异常。我还注意到，使客户端进入无效状态的每个permFail异常也来自共享基类。
下面的示例捕获客户端可以通过的每个WCF异常，并且可以针对您自己的自定义通道错误进行扩展。
WCF客户端使用示例
生成客户端代理后，就可以实现它。
Service<IOrderService>.Use(orderService=>
{
orderService.PlaceOrder(request);
}
public delegate void UseServiceDelegate<T>(T proxy);
public static class Service<T>
{
public static ChannelFactory<T> _channelFactory = new ChannelFactory<T>(\"\");
public static void Use(UseServiceDelegate<T> codeBlock)
{
IClientChannel proxy = null;
bool success = false;
Exception mostRecentEx = null;
int millsecondsToSleep = 1000;
for(int i=0; i<5; i++) // Attempt a maximum of 5 times
{
// Proxy cann\'t be reused
proxy = (IClientChannel)_channelFactory.CreateChannel();
try
{
codeBlock((T)proxy);
proxy.Close();
success = true;
break;
}
catch (FaultException customFaultEx)
{
mostRecentEx = customFaultEx;
proxy.Abort();
// Custom resolution for this app-level exception
Thread.Sleep(millsecondsToSleep * (i + 1));
}
// The following is typically thrown on the client when a channel is terminated due to the server closing the connection.
catch (ChannelTerminatedException cte)
{
mostRecentEx = cte;
proxy.Abort();
// delay (backoff) and retry
Thread.Sleep(millsecondsToSleep * (i + 1));
}
// The following is thrown when a remote endpoint could not be found or reached. The endpoint may not be found or
// reachable because the remote endpoint is down,the remote endpoint is unreachable,or because the remote network is unreachable.
catch (EndpointNotFoundException enfe)
{
mostRecentEx = enfe;
proxy.Abort();
// delay (backoff) and retry
Thread.Sleep(millsecondsToSleep * (i + 1));
}
// The following exception that is thrown when a server is too busy to accept a message.
catch (ServerTooBusyException stbe)
{
mostRecentEx = stbe;
proxy.Abort();
// delay (backoff) and retry
Thread.Sleep(millsecondsToSleep * (i + 1));
}
catch (TimeoutException timeoutEx)
{
mostRecentEx = timeoutEx;
proxy.Abort();
// delay (backoff) and retry
Thread.Sleep(millsecondsToSleep * (i + 1));
}
catch (CommunicationException comException)
{
mostRecentEx = comException;
proxy.Abort();
// delay (backoff) and retry
Thread.Sleep(millsecondsToSleep * (i + 1));
}
catch(Exception e)
{
// rethrow any other exception not defined here
// You may want to define a custom Exception class to pass information such as failure count,and failure type
proxy.Abort();
throw e;
}
}
if (success == false && mostRecentEx != null)
{
proxy.Abort();
throw new Exception(\"WCF call failed after 5 retries.\",mostRecentEx );
}
}
}
var reusableSW = new LC.Utils.WCF.ServiceWrapper<IProcessDataDuplex>(channelFactory);
reusableSW.Reuse(client =>
{
client.CheckIn(count.ToString());
});
reusableSW.Dispose();
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