Catching SocketExceptions from BinaryClientFormatterSink

Question

Hi,

I'm trying to implement a way of "failing over" remoting to a different server if I encounter SocketExceptions, etc when Remoting.

Rather than trying to change every place I make a remote call, I have attempted to implement a ClientChannelSink, as follows:

Public Class FailoverClientChannelSink
    Inherits BaseChannelSinkWithProperties
    Implements IClientChannelSink
    Implements IMessageSink

I can configure this to be "in front of" the BinaryClientFormatter, however in SyncProcessMessage

 Public Function SyncProcessMessage(ByVal msg As System.Runtime.Remoting.Messaging.IMessage) As System.Runtime.Remoting.Messaging.IMessage Implements System.Runtime.Remoting.Messaging.IMessageSink.SyncProcessMessage
        Dim retmsg As IMessage = Nothing
        Dim MessageSend As Boolean = False

        While Not MessageSend
            Try
                Debug.WriteLine("In Syncprocess for FailoverMessageSink")
                retmsg = _nextMsgSink.SyncProcessMessage(msg)
                MessageSend = True
            Catch ex As Exception
                If TypeOf ex Is System.Runtime.Remoting.RemotingException Or TypeOf ex Is System.Net.Sockets.SocketException Then
                    SwitchRemoting(msg)
                    SyncProcessMessage(msg)
                Else
                    Throw
                End If
            End Try
        End While
        Return retmsg
    End Function

_nextMsgSink throws a SocketException which I can't catch (it bubbles straight up to the calling code).  Therefore I don't get a chance to change the msg.Properties("__Uri").

Any ideas what I'm doing wrong?  I've tried ContextAttributes, RealProxies, IMessageSinks and ClientMessageSinks and don't seem to be able to catch and deal with the exception in the correct place to be able to reconfigure the remoting URI.


Thanks,

Richard.

Answer 1

anyone?