My application is using WebSocket protocol and all the connection and communication proccess is working well. However, after a long time with the user away, the ws connection is broken, occurs a new call to /signalr/negotiate? but there is none call to ws://localhost/signalr/connect. Inspecting the response from negotiate, it´s all ok.
The applications was running with an old client script version. I´ve updated it with version 1.1.2 and it´s all fine now.
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I have a Spring mvc application, and I'm using websockets to communicate a phisical device that sends data with an angular 2 front end.
the architecture is like this
device ----> Spring Mvc <-----angular 2 front end
I have a datasource listener that publish to a websocket topic everytime a new message appears and I consume that topic from angular.
My problem is that this is working properly in my local tomcat install but when I upload it to a faster server it doesn't.
The main problem I'm having is that is buffering the messages and is reaching the limit and closing the websocket session.
What I noticed checking the logs is that in my local server messages come 20 milliseconds after last one is finished but in the other server sometimes are coming at the same time and they are being buffered throwing the session limit exception.
I tried setting a higher buffer size.
Also tried a thread.sleep but it doesn't worked.
Do you have some ideas what can I do ? should I implement some kind of message queue ?
Thanks in advance
I am running an ASP classic website on a new dedicated server with SQL Server 2012 on it. All is running nicely but the database connection takes about 5.1 seconds to establish when a page is loaded. If the page is refreshed the connection is instant (presumably due to connection pooling?) but if the page is reloaded a few minutes later the connection takes 5.1 seconds to establish again.
Are there any settings that I can change to speed things up?
Have you tried pinning your tables to memory on the SQL side?
Check in chrome, most likely under the network tab, you will find your timeout is due to what Chrome Networking Tools defines as "waiting" - which means the browser is waiting for a response.
http://www.mcobject.com/in_memory_database
and you could try the DBCC PINTABLE function, so that the query doesn't have to fire from a non-cached engine each time.
I created a web application, here is the architecture :
Tomcat7 deploy on Amazon EC2
Granite DS
nginx to redirect HTTPS throught the tomct7 port 8181
Flex application that uses RemoteObject on a secure Channel.
Occasionaly, maybye when a request takes to long time, the execution of a RemoteObject in Flex triggers this error :
faultCode:Channel.Call.Failed faultString:'error' faultDetail:'NetConnection.Call.Failed: HTTP: Status 504'
But in the most time, the response of the Remote object is correct.
Could you tell me if Nginx could block something? Or if BlazeDs has a tomeout?Any clues?
Thank you very much
We've had this issue for a long time...problem is we haven't been able to find a repeatable way to force it to disconnect.
Here the most comprehensive list of things to try that i've been able to find:
http://www.bopit.in.th/2009/10/14/flex-channel-connect-failed-error-netconnection-call-failed-http-status-200/
We've tried a couple of those solutions and it seems like we're getting less client disconnects.
There also may be a problem with AVG's linkscanner hijacking the request as it leaves the browser, and then losing it somewhere. We had one machine in our shop that would disconnect when using IE, and since uninstalling AVG, it's never happened on that machine again.
another thing you could check is the socket timeout:
NetConnection.Call.Failed happening sporadically in Flex3/Tomcat/BlazeDS/Spring
and here is a thread on adobe forum about the issue:
http://forums.adobe.com/thread/552133
My understanding of the (JavaScript) hub client is that if a connection is lost, it enters a 'Reconnecting...' phase which attempts to reconnect. If it can't do so, it will enter a 'Disconnected' state which is where it'll stay until asked to start again.
How long is the 'Reconnecting...' phase meant to last before it gives up? I've read 40 seconds before, but my client seems to take much less time - about 10, maybe less. [EDIT: Nevermind this part, I had configured a 10 disconnect on the server as a test... and forgot. I understand this is set by the server during the negotiate. Makes sense!] ... I'd prefer to have the client continually retry until it is told to abort - can this be done, and would it cause issues?
Another question; during the Reconnecting... phase, if I attempt to call a hub method (again, in JS) it never seems to complete. I'm using the returned Deferred to check for 'done' and 'fail' events, but neither seems to get called. Is this by design?
Thanks.
You can definitely have it continually reconnect.
Handle the disconnected event on the client and call connection.start:
$.connection.hub.disconnected(function() {
setTimeout(function() {
$.connection.hub.start();
}, 5000); // Re-start connection after 5 seconds
});
The only issues this would cause is that you could potentially be triggering infinite requests to a server that isn't there for client machines. This becomes even more troublesome when you introduce the mobile market into the situation (drains battery like crazy).
When you attempt to call a hub method while reconnecting SignalR will try to send your command. Since there are 2 channels, one for receiving data and one for sending, (for all transports except web sockets) in some cases it can still be possible to send requests while your offline. Therefore SignalR does not know if a request fails until the browser tells it that it could not successfully make the request.
Hope this helps!
I might have a clue... Touching the Web.config produces an appPool Recycle, meaning that a new worker process will be created for new requests while the existing process will continue for a while until the remaining requests end or the timeout is reached. Request that do not end in the timeout period are terminated.
Signalr client reconnects to the new process while the long running task is running in the old process, so when on the long running task you do
GlobalHost.ConnectionManager.GetHubContext<ForceHub>();
you actually get a reference for "old" hub while the client is connected to the "new" hub.
That's why the test preformed by Wasp worked: he was making a new request to publish on the signalr hub that was processed in the newly created worker process.
You could try to configure a singalr backplane (https://www.asp.net/signalr/overview/performance/scaleout-in-signalr), it’s really easy to configure it using Sql Server (https://www.asp.net/signalr/overview/performance/scaleout-with-sql-server). The backplane should be capable of connect the two worker processes and hopefully you will get the notification on the client.
If this is the problem, notifications generated by new requests will work even without the backplane. Notice that the real purpose of the backplane is to scale out signalr, this is, to connect a farm of WebServers between them.
Also keep in mind that running long-running task inside IIS is as task hard to achieve as, among other things, IIS does regular appPool recycles and has timeout limits for the requests to execute. I recommend that you read the following post: http://www.hanselman.com/blog/HowToRunBackgroundTasksInASPNET.aspx
“If you think you can just write a background task yourself, it's likely you'll get it wrong. I'm not impugning your skills, I'm just saying it's subtle. Plus, why should you have to?”
Hope this helps
How do I detect when a client is failing to connect (or re-connect) to a Signalr hub?
Is there an event that fires on the js client?
Responding to your second comment:
Currently in 0.5.3 SignalR does not handle the case when the server goes away. However, this will be/is handled in the next release 1.0alpha.
For the interim I'd recommend pinging the server every 5 seconds and seeing if the request fails. If it fails say 2 times then chances are the server is down and you can handle the logic from there.
If you'd like to see how we do it in the next release here's the link to the github feature: https://github.com/SignalR/SignalR/issues/469