c# – 尝试catch异步等待https异常

2019年8月4日 345次阅读

我有一个看似非常奇怪的情况.我有一些async / await代码,它使用RestSharp从一些目录服务返回的几个其他API(托管在不同URL上的相同API)中获取一些数据.

现在问题是：所述目录服务返回的API之一以某种方式“私有”,并且启动与它的SSL连接失败. Fiddler捕获以下响应：

HTTP/1.1 200 Connection Established
FiddlerGateway: Direct
StartTime: 19:13:11.117
Connection: close

fiddler.network.https> HTTPS handshake to foo.bar.com failed. System.IO.IOException The handshake failed due to an unexpected packet format.

理想情况下,如果发生这种情况,我希望跳过从此API获取数据并继续前进.然而,事实证明try / catch没有帮助！抛出NullReferenceException,但即使是通用的try / catch也无法捕获它.

代码非常简单：

try
{
   await GetDataAsync(url);
}
catch 
{
   // never gets called
}

和

private async Task<List<Data>> GetDataAsync(string url)
{
   var request = new RestRequest("/foo");
   var restClient = new RestClient(url);

   var response = await restClient.ExecuteTaskAsync<List<Data>>(request); // <-- this throws 
   return response.Data;
}

我已经在一个库中提取了代码,并在Console应用程序和WPF应用程序中尝试了它,同样的结果,catch块永远不会被输入.

有任何想法吗？

l.e.：根据要求,这是完整的异常堆栈跟踪

Unhandled Exception: System.NullReferenceException: Object reference not set to
an instance of an object.
at RestSharp.RestClient.<>c__DisplayClass15`1.<ExecuteTaskAsync>b__12(IRestResponse`1 response, RestRequestAsyncHandle _)
at RestSharp.RestClient.DeserializeResponse[T](IRestRequest request, Action`2 callback, IRestResponse response, RestRequestAsyncHandle asyncHandle)
at RestSharp.RestClient.<>c__DisplayClassa`1.<ExecuteAsync>b__9(IRestResponse response, RestRequestAsyncHandle asyncHandle)
at RestSharp.RestClient.ProcessResponse(IRestRequest request, HttpResponse httpResponse, RestRequestAsyncHandle asyncHandle, Action`2 callback)
at RestSharp.RestClient.<>c__DisplayClass3.<ExecuteAsync>b__0(HttpResponse r)
at RestSharp.Http.ExecuteCallback(HttpResponse response, Action`1 callback)
at RestSharp.Http.ResponseCallback(IAsyncResult result, Action`1 callback)
at RestSharp.Http.<>c__DisplayClass3.<GetStyleMethodInternalAsync>b__1(IAsyncResult result)
at System.Net.LazyAsyncResult.Complete(IntPtr userToken)
at System.Net.ContextAwareResult.CompleteCallback(Object state)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Net.ContextAwareResult.Complete(IntPtr userToken)
at System.Net.LazyAsyncResult.ProtectedInvokeCallback(Object result, IntPtr userToken)
at System.Net.HttpWebRequest.SetResponse(Exception E)
at System.Net.HttpWebRequest.CheckWriteSideResponseProcessing()
at System.Net.ConnectStream.ProcessWriteCallDone(ConnectionReturnResult returnResult)
at System.Net.HttpWebRequest.WriteCallDone(ConnectStream stream, ConnectionReturnResult returnResult)
at System.Net.ConnectStream.CallDone(ConnectionReturnResult returnResult)
at System.Net.ConnectStream.IOError(Exception exception, Boolean willThrow)
at System.Net.ConnectStream.HandleWriteHeadersException(Exception e, WebExceptionStatus error)
at System.Net.ConnectStream.WriteHeadersCallback(IAsyncResult ar)
at System.Net.LazyAsyncResult.Complete(IntPtr userToken)
at System.Net.LazyAsyncResult.ProtectedInvokeCallback(Object result, IntPtr userToken)
at System.Net.TlsStream.ResumeIOWorker(Object result)
at System.Net.TlsStream.WakeupPendingIO(IAsyncResult ar)
at System.Net.LazyAsyncResult.Complete(IntPtr userToken)
at System.Net.LazyAsyncResult.ProtectedInvokeCallback(Object result, IntPtr userToken)
at System.Net.Security.SslState.FinishHandshake(Exception e, AsyncProtocolRequest asyncRequest)
at System.Net.Security.SslState.PartialFrameCallback(AsyncProtocolRequest asyncRequest)
at System.Net.AsyncProtocolRequest.CompleteRequest(Int32 result)
at System.Net.FixedSizeReader.CheckCompletionBeforeNextRead(Int32 bytes)
at System.Net.FixedSizeReader.ReadCallback(IAsyncResult transportResult)
at System.Net.LazyAsyncResult.Complete(IntPtr userToken)
at System.Net.ContextAwareResult.CompleteCallback(Object state)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Net.ContextAwareResult.Complete(IntPtr userToken)
at System.Net.LazyAsyncResult.ProtectedInvokeCallback(Object result, IntPtr userToken)
at System.Net.Sockets.BaseOverlappedAsyncResult.CompletionPortCallback(UInt32 errorCode, UInt32 numBytes, NativeOverlapped* nativeOverlapped)
at System.Threading._IOCompletionCallback.PerformIOCompletionCallback(UInt32errorCode, UInt32 numBytes, NativeOverlapped* pOVERLAP)

最佳答案 这似乎是
a bug in RestSharp.如果不修改RestSharp的来源,我不确定你能做些什么.

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