Fastest way to check if WCF endpoint is listening
Often, if a WCF endpoint is unavailable (in my case, usually because the service host is not running), I'll get an EndpointNotFoundException after a timeout. I'd like to have a fast way to query the service to see if it's available without having to rely on the normal timeout. In other words, I want to keep a normal timeout for normal circumstances, but for a quick "ping" of the endpoint, I want it to fail fast if it's not available right away.
How could this be accomplished?
You will have to wait for a TimeOut exception. You can set (override) the TimeOut when creating the Proxy object. They're cheap so make a temp proxy for the Ping.
On the server side, you could make sure there is a lightweight function to call (like GetVersion).
To check availability, you can try connecting to host thru Socket Connection like this (its vb.net 2.0 code should work in WCF too)
Dim sckTemp As Socket = New Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp) sckTemp.ReceiveTimeout = 500 : sckTemp.SendTimeout = 500 Try '' Connect using a timeout (1/2 second) Dim result As IAsyncResult = sckTemp.BeginConnect("Host_ADDRESS", YOUR_SERVER_PORT_HERE, Nothing, Nothing) Dim success As Boolean = result.AsyncWaitHandle.WaitOne(500, True) If (Not success) Then sckTemp.Close() : Return False Else Return True End If Catch ex As Exception Return False End Try
It will give you Server status in 1/2 second
It's the SendTimeout you want to change. In my particular case it's a FedEx package rating service which incidentally always seems to be down Friday night. You will probably have to carefully consider the timeout value depending upon how important false negatives (so the service being down) are.
rateService.Endpoint.Binding.SendTimeout = TimeSpan.FromSeconds(.5);
This value will just affect the WCF client and won't permanently change the timeout for that service.