SignalR websocket or ServerEvent protocol is hanging IIS

ISAPI_Rewrite is Apache mod_rewrite compatible URL rewriter for Microsoft IIS
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Joined: 09 Dec 2016, 09:00

SignalR websocket or ServerEvent protocol is hanging IIS

09 Dec 2016, 11:38

Hi All,

I have an issue where we have Proxy rule getting the page from subdomain which has SignalR code to start connection, SignalR tries websocket first, then ServerSent events and last long polling. I am experiencing that Helicon Proxy is not marshalling the response sent for WebSocket and ServerSent event protocols to javascript client, which initiated this call. When we have a lot of failure of this type of requests, IIS becomes unresponsive.

I have attached a Wireshark trace of the request to show subdomain is sending the responses correctly. I can see in IIS->worker processes -> Uncompleted Requests.

If anyone knows is it something Helicon does not support currently and we should only be using long polling with reverse proxy.

I can provide details steps with code to reproduce it, if someone can help me.

Many Thanks
Mo
Attachments
IISWorkerProcessRequestsNotCompleted.PNG
Screenshot of long running IIS requests
IISWorkerProcessRequestsNotCompleted.PNG (114.68 KiB) Viewed 7618 times
WiresharkTCPStreamTrace.txt
Wireshark trace for ServerSent Event request by client
(13.8 KiB) Downloaded 1595 times

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Posts: 402
Joined: 06 Mar 2012, 11:59

Re: SignalR websocket or ServerEvent protocol is hanging IIS

20 Dec 2016, 10:51

Hello.

Unfortunately you a recorrect, WebSockets proxy is not supported in the current version, i.e. you cannot use ISAPI_Rewrite to proxy WebSockets requests to another server.

Return to ISAPI_Rewrite 3.0

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