I'm trying to find an elegant way to retry an operation when a WCF channel is in faulted state. I've tried using the Policy Injection AB to reconnect and retry the operation when a faulted state exception occurs on first call, but the PolicyInjection.Wrap method doesn't seem to like wrapping the TransparentProxy objects (proxy returned from ChannelFactory.CreateChannel).
Is there any other mechanism I could try or how could I try get the PIAB solution working correctly开发者_开发百科 - any links, examples, etc. would be greatly appreciated.
Here is the code I was using that was failing:
var channelFactory = new ChannelFactory(endpointConfigurationName);
var proxy = channelFactory.CreateChannel(...);
proxy = PolicyInjection.Wrap<IService>(proxy);
Thank you.
I would rather use callback functions, something like this:
private SomeServiceClient proxy;
//This method invokes a service method and recreates the proxy if it's in a faulted state
private void TryInvoke(Action<SomeServiceClient> action)
{
try
{
action(this.proxy);
}
catch (FaultException fe)
{
if (proxy.State == CommunicationState.Faulted)
{
this.proxy.Abort();
this.proxy = new SomeServiceClient();
//Probably, there is a better way than recursion
TryInvoke(action);
}
}
}
//Any real method
private void Connect(Action<UserModel> callback)
{
TryInvoke(sc => callback(sc.Connect()));
}
And in your code you should call
ServiceProxy.Instance.Connect(user => MessageBox.Show(user.Name));
instead of
var user = ServiceProxy.Instance.Connect();
MessageBox.Show(user.Name);
Although my code uses proxy-class approach, you can write a similar code with Channels.
Thank you so much for your reply. What I ended up doing was creating a decorator type class that implemented the interface of my service, which then just wrapped the transparent proxy generated by the ChannelFactory. I was then able to use the Policy Injection Application Block to create a layer on top of this that would inject code into each operation call that would try the operation, and if a CommunicationObjectFaultedException occurred, would abort the channel, recreate it and retry the operation. It's working great now - although it works great, the only downside though is the wrapper class mentioned having to implement every service operation, but this was the only way I could use the PIAB as this made sense for me for in case I did find a way in future, it was easy enough to change just using interfaces.
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