ASP.NET Core 3 Razor Components not working without WebSockets on IIS

[chrdlx]

I installed the latest runtime Runtime 3.0.0-preview3-27503-5, and when publishing the solution to an IIS without Websocket support, the interactivity doesn't work.

The published application is just the default Razor Components template, browsing the "Counter" page, the button "Click me" that increments the counter doesn't work.. I tried adding other buttons to the default template and publishing my own project and doesn't work either. It seems to be a problem with "long polling" as far as I understand how SignalR connects to a server without Websocket protocol available. See the attached screenshots.

I found this when trying to publish my own razor components app to a production server Windows 2008 R2 which doesn't have Websocket support.

[asterinex]

Is there a temporary fix for development in Visual Studio 2019 and IIS Express 10 ?

[springy76]

The same problem seems to happen when the server has web socket support but the clients can't use it because of firewalls or whatever other network reason.

The long polling alternative seems to be entirely broken, don't know whether by SignalR changes or Razor Component changes.
Does anyone have better insight what goes wrong and if there exists a work around?

[asterinex]

I just want to share following info.
I have deployed our new .NET Core 3 Prev3 App on our Windows 2012 Server R2 with IIS 8.5.9600.16384.
The app did start but did not respond to events.

I have then added the Websocket Role () and everything works fine now.

Seems the Websocket Support for IIS was introduced in IIS 8.0.

[springy76]

With the Websocket Role the app is only broken for the users which can't establish websockets due to their firewalls (or whatever), without the Websocket Role the app is broken for everyone: Fallback to long polling is initiated but fails in some way so no render messages get through.
But long polling fallback should work automatically: #6920 (comment)

[mkArtakMSFT]

Seems this is going to be resolved by #6920.

[vishnupv]

The counter does not work in IE. But Works in Chrome. Bizzare.

[chrdlx]

The counter does not work in IE. But Works in Chrome. Bizzare.

That's another issue, currently there's no IE support, this is not related with the websocket issue on discussion here.