I am trying to download a zip file on my server by doing
WebClient.DownloadFileAsync(new Uri(DownloadLink),
Path.GetFileName(DownloadLink));
I have events linked to download completed and progress changed and when the download gets to 99%, it stops. So I give it a minute and then it gives me an exception:
System.Net.WebException: An exception occurred during a WebClient request. ---> System.IO.IOException: Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host. ---> System.Net.Sockets.SocketException: An existing connection was forcibly closed by the remote host
at System.Net.Sockets.NetworkStream.EndRead(IAsyncResult asyncResult)
--- End of inner exception stack trace ---
at System.Net.ConnectStream.EndRead(IAsyncResult asyncResult)
at System.Net.WebClient.DownloadBitsReadCallbackState(DownloadBitsState state, IAsyncResult result)
--- End of inner exception stack trace ---
I am stumped. I can download the file fine on my browser.
I don't have a direct answer to your question, but there are a few things I'd try in order to see if I could identify the problem.
First, get rid of the asynchronous call and just call DownloadFile. Does the error still occur?
Call DownloadData to get the data in a byte array, and then save the file.
If either or both of the above work, then I'd say there's something wrong with your DownloadDataCompleted event handler, although why that'd throw a WebException is beyond me.
Oh, one other thing: are you sure that Path.GetFileName(DownloadLink) is returning a valid file name, and that you have the necessary permissions to write the file in the current directory?
You will get a WebException if DownloadLink returns an error like 404. Put a breakpoint in and check the actual path going into the method.
Edit: If DownloadLink is a url string check if you are escaping '/'. Try #"..."
Related
I have a web API(service) whose target framework is .net core 2.0.
This service is calling a custom identity server 4 endpoint using HttpClient by using the 'using' statement. This call always works fine on the development/UAT server.
But on all production servers, it fails intermittently and throws the following exception:
One or more errors occurred. (An error occurred while sending the
request.) Exception: System.AggregateException: One or more errors
occurred. (An error occurred while sending the request.) --->
System.Net.Http.HttpRequestException: An error occurred while sending
the request. ---> System.Net.Http.WinHttpException: The operation
timed out at
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at
System.Threading.Tasks.RendezvousAwaitable`1.GetResult() at
System.Net.Http.WinHttpHandler.d__105.MoveNext() ---
End of inner exception stack trace --- at
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task
task) at
System.Runtime.CompilerServices.ConfiguredTaskAwaitable`1.ConfiguredTaskAwaiter.GetResult()
at
System.Net.Http.HttpClient.d__58.MoveNext()
--- End of inner exception stack trace --- at System.Threading.Tasks.Task`1.GetResultCore(Boolean
waitCompletionNotification) at Get(String a, String b)
I went through related stack-overflow posts, some suggested making HttpClient static as it might throw socket exhaustion error. But I am not getting that error either I am able to reproduce this issue on a development server. I created a console application and called this service 64k times, but still, it worked properly.
How to stop outbound HTTP connections from timing out
Asp.net Core HttpClient has many TIME_WAIT or CLOSE_WAIT connections
Can someone please tell me, what can be the reason for this intermittent error only on the production server or is there any way I can reproduce this issue on the dev server. I have tried by making many calls to service, but still unable to reproduce the error.
I am logging the connection status events with the wcf relay, and I'm seeing something like this in the logs.
1/26 06:47:12 ERROR Service Bus ConnectionStatus: 'Reconnecting' Event. [(null)][42]
LastError: System.ServiceModel.CommunicationException: Exception of type 'System.ServiceModel.CommunicationException' was thrown. ---> Microsoft.ServiceBus.Messaging.Amqp.AmqpException: An AMQP error occurred (condition='amqp:unauthorized-access').
--- End of inner exception stack trace ---
This exception doesn't show up in the list on this microsoft page, and the only other post I can find anywhere related to this error message is here. However, that post does not have any recent comments or a resolution or workaround for the issue. Also, the exception doesn't have any stacktrace, so how am I supposed to troubleshoot this error?
I guess as a follow-up, I would ask whether this is anything to actually worry about if the wcf connection is never faulting.
Apparently, the token that the relay keeps refreshing to stay active requires the time on the server to match the azure service that it is connecting with, and if not, this type of error will show up. We were able to fix it by correcting the server time.
Our WCF client normally invokes a web service. All deployments of the client invoke the same web service. In most deployments it makes the call without any issues, except in one instance it reports the following exception:
System.Net.Http.HttpRequestException: An error occurred while sending the request. ---> System.Net.WebException: The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel. ---> System.Security.Authentication.AuthenticationException: The remote certificate is invalid according to the validation procedure.
at System.Net.TlsStream.EndWrite(IAsyncResult asyncResult)
at System.Net.PooledStream.EndWrite(IAsyncResult asyncResult)
at System.Net.ConnectStream.WriteHeadersCallback(IAsyncResult ar)
--- End of inner exception stack trace ---
at System.Net.HttpWebRequest.EndGetResponse(IAsyncResult asyncResult)
at System.Net.Http.HttpClientHandler.GetResponseCallback(IAsyncResult ar)
--- End of inner exception stack trace ---
What could be different with this one installation?
We tested the URL that the client uses to make the call to the web service in the browser. The web service returns a response ok in Firefox but not in IE.
Have you seen this article yet? It contains fairly good tips for troubleshooting these issues: http://blogs.msdn.com/b/jpsanders/archive/2009/09/16/troubleshooting-asp-net-the-remote-certificate-is-invalid-according-to-the-validation-procedure.aspx?Redirected=true
For example, you'll need to check that the particular machine has all the root and intermediate certificates properly deployed.
I found the solution - there was a new web service server certificate installed with SHA256 and Windows 2003 Server requires a hotfix to support it:
http://support.microsoft.com/kb/938397
I am trying to run/debug locally my cloud project, but service bus connection keeps crashing with error:
<15:46:59> MessagingFactory successfully created
<15:47:39> Exception: The underlying connection was closed: An unexpected error occurred on a send..
....
System.IO.IOException: Unable to read data from the transport connection:
An existing connection was forcibly closed by the remote host. ---> System.Net.Sockets.SocketException: An existing connection was forcibly closed by the remote host
at System.Net.Sockets.Socket.EndReceive(IAsyncResult asyncResult)
at System.Net.Sockets.NetworkStream.EndRead(IAsyncResult asyncResult)
--- End of inner exception stack trace ---
at System.Net.TlsStream.EndWrite(IAsyncResult asyncResult)
at System.Net.PooledStream.EndWrite(IAsyncResult asyncResult)
at System.Net.ConnectStream.WriteHeadersCallback(IAsyncResult ar)}
Also I receive this error when using Service Bus Explorer tool.
When deploy to cloud everything works ok, service bus connection is ok.
Can anyone help me with this? what could be the reason?
Thank you in advance!
Maybe the problem is with the SSL certificate validation protocol. Try this to force the latest protocol type.
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
There are several reason leading to such error so you may check the following
You have configured the settings correctly.
Firewall in your system allows the connection (protocol, host & port)
DNS servers configured in your network are able to resolve the host.
Your ISP is not blocking your connection due to any reason
Since there is no fixed solution for your error, you may have to work a little hard to figure out the actual issue. You may also find some useful information from the log files if enabled.
Sorry if the Title is a little vague but the truth is I do not understand my problem, I have never come across this before and I havent done anything out of the Ordinary.
Right I have a basic Silverlight 4 Application using the Business Application Template. I have also created a WCF Service Application Project which is used to simply return an Observable collection for some entries in my Database,
I published this to my Local computer which I then referenced in my SL4 app and I get this exception
[System.ServiceModel.CommunicationException: The remote server returned an error: NotFound. ---> System.Net.WebException: The remote server returned an error: NotFound. ---> System.Net.WebException: The remote server returned an error: NotFound.
at System.Net.Browser.BrowserHttpWebRequest.InternalEndGetResponse(IAsyncResult asyncResult)
at System.Net.Browser.BrowserHttpWebRequest.<>c__DisplayClass5. <EndGetResponse>b__4(Object sendState)
at System.Net.Browser.AsyncHelper.<>c__DisplayClass4.<BeginOnUI>b__0(Object sendState)
--- End of inner exception stack trace ---
at System.Net.Browser.AsyncHelper.BeginOnUI(SendOrPostCallback beginMethod, Object state)
at System.Net.Browser.BrowserHttpWebRequest.EndGetResponse(IAsyncResult asyncResult)
at System.ServiceModel.Channels.HttpChannelFactory.HttpRequestChannel.HttpChannelAsyncRequest. CompleteGetResponse(IAsyncResult result)
--- End of inner exception stack trace ---
at System.ServiceModel.AsyncResult.End[TAsyncResult](IAsyncResult result)
at System.ServiceModel.Channels.ServiceChannel.EndCall(String action, Object[] outs, IAsyncResult result)
at System.ServiceModel.ClientBase`1.ChannelBase`1.EndInvoke(String methodName, Object[] args, IAsyncResult result)
at RMServiceRIA.rService.Service1Client.Service1ClientChannel.EndgetBuildings(IAsyncResult result)
at RMServiceRIA.rService.Service1Client.RMServiceRIA.rService.IService1.EndgetBuildings(IAsync Result result)
at RMServiceRIA.rService.Service1Client.OnEndgetBuildings(IAsyncResult result)
at System.ServiceModel.ClientBase`1.OnAsyncCallCompleted(IAsyncResult result)}
I have got a clientaccess policy and crossdomain policy which for the purpose of testing is set to allow anything access,
Client Access Policy
Cross Domain
any ideas on how to fix this problem, I debugged my WCF Service and it receives the call, the method executed reaches its return statement, yet my SL4 never even receives the result, as soon as my WCF service has the result I get an exception thrown within my SL4 app, to me it just seems that the connection gets closed but I dont know and I have tried to research but where do you start with something you dont fully understand? I found many people with the same sort of error message but WCF is so damn cryptic... I did try and enable the debugging information inside of my webconfig. I have also tried to host the WCF service on my Web server but no luck, I have several WCF Services running on that with a similar set up so I am unsure why this isnt working
Web Config for WCF Service
client config
Thanks for having a look, and if you need any more info just ask I'll be happy to provide you with it,
Your best bet is to turn on WCF Tracing so you can see what is going on.
http://software.intel.com/en-us/blogs/2010/02/03/adventures-with-silverlight-and-wcf-the-remote-server-returned-an-error-notfound/
Most likely there is an issue with serializing something. Not found is just the Silverlight version of a 500 error.