How to prevent a shiny app from being grayed out?

Question

we have a shiny app hosted in Heroku. After 55 secs of user inactivity, the app will be grayed out. This is applicable for Chrome and Safari. Edge is working fine. Heroku have a default timeout for that, and it looks like it cannot be modified using the R buildpack (https://github.com/virtualstaticvoid/heroku-shiny-app).



    function ping() {
        if (!window.Shiny.shinyapp.isConnected()) {
            window.Shiny.shinyapp.reconnect();
        }
    }
    setInterval(ping, 2000);

We embedded below JS code to reconnect using the WebSocket, but the session data is lost. Is there anything else we can try?

Here is more info about our app: R 3.4.4 Shiny 1.1.0

https://stackoverflow.com/questions/33839543/shiny-server-session-time-out-doesnt-work This might help. — Chabo, Feb 08 '19 at 15:26
@Chabo, thanks for the suggestion but this isn't an option in Heroku. It's applicable if you host a Shiny server. — stackoverflow2019, Feb 08 '19 at 16:19

score 18 · Accepted Answer · answered Feb 09 '19 at 08:47

18

After 55 secs of user inactivity, the app will be grayed out.

I had a similar problem, but the context was different (this was due to proxy settings and I didn't use Heroku) so I don't know whether the solution I used is an option for you (I post it here because my reply is too long for a comment).

I simply included these lines:

  autoInvalidate <- reactiveTimer(10000)
  observe({
    autoInvalidate()
    cat(".")
  })

In this way a dot is printed in the console by every passage of 10 secs and my app didn't gray out anymore (though this is not really a "user activity").

answered Feb 09 '19 at 08:47

Stéphane Laurent

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this is an awesome workaround :) Thanks for your help Stephane! – stackoverflow2019 Feb 11 '19 at 15:47
@stackoverflow2019 You mean this works? Nice. Please consider [accepting the answer](https://stackoverflow.com/help/someone-answers). Otherwise it is considered as non-answered by SO. – Stéphane Laurent Feb 11 '19 at 15:52
1

I'd suggest using `observe({ invalidateLater(10000) cat(".") })` – ismirsehregal Feb 05 '21 at 08:54
1

This was a nice idea but it didn't seem to prevent the app greying out for me – F. Lumley Dec 15 '21 at 15:09

How to prevent a shiny app from being grayed out?

1 Answers1

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