I have created a service which uses WCF for communication. Very basic. The server side is set up to listen like this where IEdWCF is my service contract which calls various methods on the server, ntb is a NetBinding with a ReceiveTimeout set to 60 minutes, and strHostURL is on localhost:
Host.AddServiceEndpoint(typeof(IEdWCF),
ntb,
new Uri(strHostURL));
The thing is that I have some items I want to send through but allow a longer processing time to (the client awaits a reply from the server and keeps getting dropped by the server)
I know on my client side I can extend the request by casting the channel as an IContextChannel and setting the OperationTimeout property.
I'd like to be able to do the same thing I'm doing with the client on the server.
Is this possible? Is there some way to dynamically change the setting on the server binding?
Related
Good time of day. I would like to know how to properly connect in a WCF application. In other words, it should be created when the app is launched and be active throughout the entire operation? Or do you need to create a connection every time a service function is called? Now I have the first option, but somewhere everything is fine, and sometimes for unknown reasons I get an error: it is Impossible to use the object for communication, since it is in the failed state. There are no visible reasons for this - the code runs without errors. NetTcpBinding is used as the binding
The wcf service needs to be hosted in the process so that the client can connect to the server. As long as you are using the wcf service, you need to enable it. Faulted state means there has been an unexpected exception on the server side, so you need to use a try…catch block. Another possibility is that the channel has expired. The default timeout period of the WCF service is 10 minutes. If the client does not communicate with the server within 10 minutes, the channel will be closed. You need to recreate the channel to call the service.
I am using Visual Studio 2012 to generate a web service to be used by a winforms client. I created the client side by using "add service reference". This winforms client is a .net c# replacement of an old VB 6 app. Previously, in the VB app there were external settings for timeout values including the following:
DNS timeout
Connect timeout
Request timeout
The DNS timeout would work when the endpoint host address is a FQDN forcing a DNS lookup. The timeout value here would place a limit on the amount of time to wait for DNS resolution.
The connect timeout would place a limit on the amount of time the winforms client would wait to establish an http connection to the server. DNS lookup would have been successful.
The request timeout would place a limit on the amount of time to wait for the request to return after an http connection was successful. This would come into play if a long running query took too long after the web service call was initiated.
Is there something similar to the above in .net 4.0. I would like to be able to configure this in the app.config. I do know about the below.
<bindings>
<basicHttpBinding>
<binding name="IncreasedTimeout"
openTimeout="12:00:00"
receiveTimeout="12:00:00" closeTimeout="12:00:00"
sendTimeout="12:00:00">
</binding>
</basicHttpBinding>
Could these map to the ones I need or does it really not matter?
thanks
The OpenTimeout setting for the WCF binding is for the length of time to wait when opening the channel, so I believe this will be analogous to your old Connect timeout. This should be fast so you normally would only want to specify a few seconds to wait (30 or less), not 12 hours.
The WCF CloseTimeout is for when a Close Channel message is sent, and this is how long to wait for an acknowledgement. This may not have an equivalent in your old architecture. Again, this should be fast and should only need a few seconds.
The WCF SendTimeout (for the client config) essentially covers the time for the Client to send the message to the service, and to receive back the response (if any). This would correspond to your old Request timeout. This may need to be for several minutes if your server takes a while to process things.
The WCF SendTimeout (for the server config) is for when you want callbacks, so that the Server knows how long to wait for acknowledgement that its callback was received.
The WCF ReceiveTimeout does not apply to client-side configuration. For Server-side config the ReceiveTimeout is used by ServiceFramework layer to initialize the session-idle timeout (to be honest I don't really know what that is)
This MSDN discussion may be helpful http://social.msdn.microsoft.com/Forums/vstudio/en-US/84551e45-19a2-4d0d-bcc0-516a4041943d/explaination-of-different-timeout-types?forum=wcf
As a final note, having really big timeout values isn't a good idea unless you definitely have long running requests. This is because you can run out of available resources on your server if the client isn't closing the connections properly.
I've started working on a client-server distributed application using WCF. The clients should also send requests to the server, therefore I chose to implement duplex operations using the NetTcpBinding since all the clients will b on the same intranet.
On the server side, for the service class that implements the server contract I use these settings
[ServiceBehavior(ConcurrencyMode = ConcurrencyMode.Single, InstanceContextMode = InstanceContextMode.Single, UseSynchronizationContext = false)]
Every time a client is initialized, I'm creating an instance of the proxy class generated by adding the service using 'Add service reference' option in Visual Studio. After the proxy is initialized, I send a Connect message to the server:
_proxy.InnerChannel.Faulted += new EventHandler(InnerChannel_Faulted);
_proxy.InnerChannel.Closing += new EventHandler(InnerChannel_Closing);
//send a connect message to the server
_proxy.ClientConnected(ClientHostName, Version, ClientID, ClientIP);
Now the server has a reference to the connected client, by using
OperationContext.Current.GetCallbackChannel<IClientEvents>()
This is pretty straight forward, nothing fancy. However, I'm having a bit of trouble with making the client reconnecting to the server after the server went online. In my scenario, I will have up to 50-100 clients connected to the server and they will rarely communicate with the server, let's say in average, 1 request per hour.
What I want to achieve is to have the client "hanging" while the is offline, for this I try to reinitialize the communication channel on the client side every time the channel ends up in Faulted state, which works ok. But when I try to close the server, I get the following message
This could be because a client failed to close a sessionful channel within the required time.
I'm now struggling to find the most appropriate implementation for my scenario:
Not closing the channel after the service call. This way the client will always try to recreate the channel once the connection with the server is down (e.g. interval of 1 min). Doesn't make much sense to keep the channel opened all this time though, so I'm not that sure about this approach.
Closing the channel after each call and recreate when making a new call to the server. This works fine when making service calls, but what happens if the server wants to send a notification the client? The callback reference on the server side will not be valid anymore, I'd have to wait for the client to send a new connect message to get the new callback reference, right? In this case, should I regularly have a different call similar to a Ping() to the server in order to ensure that the server can always contact the client?
I'm still reading materials on WCF duplex operations, just can't decide which approach is better so that I don't run into problems later on.
Thanks for your advice!
I am using netTcpBinding in WCF and I would like to know, on the client side, when it disconnects or when its channel state goes to faulted, so that I can reconnect with the server.
The idea is creating a keep alive using channel events. I know it is possible to know that the client disconnected/went into faulted state in the server side using Channel.Faulted event. That way I can remove any subscriptions the client had on the server. However, I cannot reconnect the client on the server side. And that's exactly what I would like to do.
I have 2 wcf services, 1 which polls the other service at regular interval.The service2 is hosted in no. of machines with the same configuration.
My problem is that whenever the poller service gets restarted, even though the service2 on other machines runs fine, i am not getting the response from those services (basically it gets timed out - getting SYSTEM.TimeOutException ). If I try to access the same service (service2) from some temp application (without restarting the service2) it gives response.
If I restart the service2, than it works fine, the service1 (poller service) gets the responses from all hosted services (Service2).
Dont know what is causing problem.
Regards,
Chirag
Attach VS to your wcf service which hangs. And find out if your connection is successful.
Do it with both services, so that you can debug the services at runtime.
If you're using a sessionful binding (netTcpBinding, wsHttpBinding), it's more than likely that you're not explicitly closing your client channel when you're done with it. This would cause the behavior you see, because the session takes a minute or so to time out if you don't explicitly close it, and the default max number of sessions is low (10)- the server will let new sessions stack up until old ones close. You can also adjust the service throttle on the server side binding to increase the max number of open sessions allowed, but you really should make sure your clients are getting cleaned up properly first.