Detecting Websocket Disconnect

Panel
1

I have found that when the websocket connection dies, Panel dashboards become unresponsive until the user refreses the page.

On cloud run, for example, the server will shut down after a few minutes of user inactivity.

Is there a way to have a front end component that could alert the user that the connection has been dropped and they need to refresh?

I did have one approach where there is a panel component that updates a front end variable every minute or so; and then I had front end code to regularly check that the variable was updated. But it felt super convoluted and didnt quite work.

Is there best practice here?

Thank you kindly

2

Hi @jay

This functionality was just added in Panel 1.2.1. Check out Add notifications on connect and disconnect — Panel v1.2.1

As this is brand new please provide feedback if this works for you. Request for improvements should be posted on GitHub. Thanks

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3

Hi @Marc, this is great - thank you very much. Looks really nice.

One note is that I was able to add HTML inside the message area; which allowed me to include a button users can click that refreshes

pn.extension(
    disconnect_notification="""Server Connected Closed <br /> <button class="btn btn-outline-light" onclick="location.reload();">Click To Reconnect</button> """
)

And it works nicely.

Greatly appreciate the effort to keep moving this project forward

3 Likes