After SignalR disconnects due to connection error, the state is Disconnected and EnsureReconnecting() may be called to attempt to reconnect. If the reconnect is successful, will the previous proxies still be valid? Or do I need to recreate them using CreateHubProxy()?
I suspect the proxy will still be valid as EnsureReconnecting doesn't do much according to the code: https://github.com/SignalR/SignalR/blob/3a219c101587333d562f04f30903d50ad9773e1c/src/Microsoft.AspNet.SignalR.Client/ConnectionExtensions.cs
Related
I use WTelegramClient. The client does not reconnect after the Internet connection is restored.
Showing this:
Connecting to 149.154.167.91:443...
SocketException HostUnreachable (10065): A socket operation was attempted to an unreachable host.
Connecting to [2001:67c:4e8:f004::a]:443...
Connecting to 149.154.167.50:443...
After the connection has been established, transient connection losses should be detected and handled automatically by WTelegramClient:
A reconnection is attempted automatically after a few seconds and pending API calls are automatically resent.
After MaxAutoReconnect reconnection attempts, if the connection can still not be re-established, the client.OnUpdate event receives a ReactorError object, so you can decide what to do.
Now the log you provide doesn't give much context so I presume this happens at the very beginning of opening a session with WTelegramClient.
In this case there is no automatic retry, you should just catch the connection error using a try..catch around the ConnectAsync or LoginUserIfNeeded call, and decide what to do, when to retry the connection.
Is there a way to stop a remote connection?
In more detail if a WCF connection is created using the ChannelFactory
var aChannelFactory = new ChannelFactory<ISomeService>(aBinding, aEndpoint);
and the connection is used via GSM, it makes sense to enlarge timeouts so that
aChannelFactory.CreateChannel();
has the possibility to connect to the remote site.
Now the problem is that a user may have the wish to stop the creation of a connection (Abort a getting connencted window, only use offline part of a programm).
But how is this possible?
The CreateChannel-call is synchronous.
Even if it is wrapped in a thread, nowadays Thread.Abort should not be used.
Is there any way to stop the creation of a channel automatically?
Or must it be "faked" to a user, so that the connection still is running until its timeout (or success) even is user decided to work temporarely offline?
As Grant Thomas stated it is not necessary to abort the connection.
I face the following problem :
Connection Pool has reached the maximum number of connections
I followed all the recommendations. the problem is n't like before but it happens rarely !!
I use the Using statement with all my connections and Readers .
Lately i face the following error , and i had to reset the iis to fix my problem.
Connection Pool has reached the maximum number of connections. at IBM.Data.Informix.IfxConnectionPool.ReportOpenTimeOut()
at IBM.Data.Informix.IfxConnectionPool.Open(IfxConnection connection)
at IBM.Data.Informix.IfxConnPoolManager.Open(IfxConnection connection)
at IBM.Data.Informix.IfxConnection.Open()
at DB_Connection_s.DB_Connection.GetUserSystems(String emp_num)
Now I read about this method ClearAllPools() .but i don't know when to use this method .and if this considered as a good solution to prevent the have to reset the iis to fix the request time out problem ??
You can call ClearAllPools() when you dont have any active connection.
also check out http://www.codeproject.com/Articles/46267/Connection-Pooling-in-ASP-NET
Ensure that your application closes all database connections correctly and consistently.
Ensure that the database is online.
Increase the connection timeout.
The error pattern indicates that connections are "leaked" over a long period. To fix this problem, ensure that your application closes all database connections correctly and consistently.
The exception does not indicate that the database is offline. The exception indicates a connection pool problem.
On several occasions I have received the following error from a .Net (C#, 4.0) application out of the blue on sending a message thru a producer:
CWSMQ0082E: Failed to send to CompCode: 2, Reason: 2009. A problem was encountered whilst sending a message. See the linked exception for more information.
Of course, the LinkedException (why not use the InnerException IBM???) is null i.e. no more information available.
Code I'm using (pretty straightforward):
var m = _session.CreateBytesMessage();
m.WriteBytes(mybytearray);
m.JMSReplyTo = myreplytoqueue;
m.SetIntProperty(XMSC.JMS_IBM_MSGTYPE, MQC.MQMT_DATAGRAM);
m.SetIntProperty(XMSC.JMS_IBM_REPORT_COA, MQC.MQRO_COD);
m.SetIntProperty(XMSC.JMS_IBM_REPORT_COD, MQC.MQRO_COA);
myproducer.Send(m, DeliveryMode.Persistent, mypriority, myttl);
(Offtopic: I hate the SetIntProperty way of setting properties. Which <expletive deleted> came up with that idea? It takes ages to look up all sorts of constants all over the place and its allowed values.)
The exception is thrown on the .Send method. I'm using XMS.Net (IA9H / 2.0.0.7). The only Google result that turns up turns out to have a different reason code (and even if it were the same, it should be fixed in my version if I understand correctly). This occurs randomly (though it seems to happen more often when it's been a while since a message has been sent/received) and I have no way to reproduce this.
I have ab-so-lute-ly no idea how to troubleshoot this or even where to start looking. Is this something caused by the server-side? Is it caused by XMS.net or some underlying IBM WebSphere MQ infrastructure?
Some results that I found that seem similar are suggesting to set SHARECNV to any value higher than 0 or to "true" / "yes" but the documentation explicitly tells me the default is 10. Also; I have no idea if this is the cause so changing it to another value feels like a shotgun approach.
Anybody any idea on how to go about solving this? I could of course just catch the exception, tear everything (channels, sessions, whatever) down and restart but that's just plain ugly IMHO.
The 2009 return code means "Connection Broken." Basically, the underlying TCP socket is gone and the client finds out about it at the time of the API call. It is possible to tune the channels using heartbeat and keepalive so that WMQ tries harde to keep the socket alive. However if the socket is timed out by the underlying infrastructure, nothing WMQ can do will help. Examples we've seen are that firewalls and load balancers are often set to detect idle connections and sever them.
Modern versions of WMQ client will attempt to reconnect transparently. The application just blocks a bit longer when this occurs.
Short of using the automatic reconnect, the only solution is in fact to rebuild the connection. Since it will get a new connection handle, all the object handles must be rebuilt as well.
Many of the tuning functions described here are available through the client configuration file, available in v7.0 and greater clients. In particular, the TCP stanza of that file enables keepalive. (The TCP spec says that if keepalive is provided, it must be disabled by default.) The QMgr has a similar ini file with configuration stanzas, including one for keepalive. The latest WMQ client is available as SupportPac MQC71 if you need that.
In cases where the main exception is sufficient enough to indicate the error, the inner exception will be null. In your case it's MQ reason code 2009 which means a connection to queue manager has been broken. The socket through which your application and queue manager were communicating was closed for some reason. The reason for socket close could be a network blip.
Along with suggestions T.Rob noted above, You could also run a XMS and Queue manager trace to understand the problem further. Please see the Troubleshooting chapter in XMS InfoCenter.
HTH
I run my application on a network and in some cases the client lost connection to the server. After this time, when I wanted to send a message to the server I receive the following error: Operation not allowed on non-connected sockets (something like this).
I thought to create an event for object type TcpClient and when tcp_obj.Connected = false to call a function to discontinue execution of the current code. How could I do this?
Or giving me other suggestios.
Thanks.
I know at least from socket programming in Java that when a client loses connection to the server, the server does not and can not know about it. You need a heartbeat of some sort to detect the early disconnection.
We often use a heartbeat in our client/server applications to detect early disconnections and log them on the server. This way the server can close the associated socket and release the connection back to the pool.
Simply send a command to the client periodically and wait for a response. If no response is garnered within a timeout assume disconnect and close streams.
I would simply first check your connection object to ensure you are connected, prior to attempting to send the message. Also make sure that you are putting your send-logic inside of a try-catch, so that if you do happen to get disconnected mid transmission, you'll be able to resume without blowing your application apart.
Psuedo-Code:
private void SendMessage(string message, Socket socket)
{
if(socket.connectionState = States.Connected)
{
try{
// Attempt to Send
}
catch(SocketException Ex)
{
// Disconenct, Additional Cleanup Etc.
}
}
}
If you are in C#, prior to your connection state changing, you will have a socket disconnected event fire, prior to your connection state changing. Make sure you tie this event up as soon as your socket connects.
Can we know why you use TCP sockets? Is for calling a tcp device o server code?
I recommend you if is for calling a .net server app use Windows Communication Foudation. It is simple to expose services by net.tcp, http, etc.
Regards,
Actually this is a very old problem,
If I understand your question correctly you need a way to know whether you're application is still connected to the server or vice versa.
If so then a workaround is to have a UDP connection just to check the connectivity (overhead I know, but its much better then polling on Connected state), you could check just before you send you're data.
Since UDP is not Connection oriented you don't need to be connected when you send the data