Is firewall blocking shiny websockets (wss)



Some of our client’s corporate networks seem to be tightly locked down and although they can log in to our shiny apps they are getting grayed out screens after logging into the app.

The javascript console shows an error "Websocket connection to ‘wss.//…’ Unexpected response code: 400

Since this only happens to a very small few of our clients I’m assuming it is a firewall and websockets issue on their end.

My questions are these:
Is this url with the “wss” something that Shiny is doing? Because we are not explicitly using websockets ourselves.

If so, what would be an appropriate firewall rule to allow websockets from Shiny?


Yes, it’s something that Shiny is doing–wss just uses port 443 like normal HTTPS, so if it’s failing it’s probably due to an HTTP proxy that doesn’t understand websockets. You can work around this by including the directive disable_websockets; in your shiny-server.conf, and Shiny Server will replace the websocket traffic with more conventional-looking HTTP requests.


Thanks Joe. I’ll try this out today.