Rstudio Viewer window not closed on shiny::stopApp()

[vnijs]

@kevinushey A while back I posted an issue/question on Rstudio Community about Rstudio Viewer (and Rstudio Window) not (always) closing when closing a shiny app. I now have a minimal reproducible example (see code below). If you start the app and click the Stop button the app stops and the window closes. However, if you click the Refresh button first and then click on the Stop button the window does not close, even though the shiny app does stop. The error that pops-up from shinyapp.js is shown in the screen shot below.

It seems that the Rstudio browser tries to reset the port when the Refresh button is pressed and the code in shinyapp.js is not able to capture that.

I think this might be an issue in Rstudio because I don't see it in Chrome or other browsers. I'm posting here but cc-ing @kevinushey (and @jcheng5 and @bborgesr)

This is an important issue in all my apps (e.g., radiant.data). Being able to refresh the (Rstudio) browser from code is key to (fully) (re)setting the state of an app (i.e., data, inputs, etc.) based on a previous state loaded by the user.

[Error] Unable to post message to http://127.0.0.1:4535. Recipient has origin http://127.0.0.1:25108.

ui <- fluidPage(
  actionButton("refresh", "Refresh", icon = icon("refresh")),
  uiOutput("refresh_window"),
  actionButton("stop", "Stop", class = "btn-danger", onclick = "setTimeout(function(){window.close();}, 100);")
)

server <- function(input, output) {
  observeEvent(input$stop, {
    stopApp(message("App stopped"))
  })

  output$refresh_window <- renderUI({
    req(input$refresh)
    tags$script("window.location.reload();")
  })
}

shinyApp(ui = ui, server = server)

[jcheng5]

The problem appears to be this:

shiny/srcjs/shinyapp.js

Line 154 in 9c3a0c8

var parentUrl = (parent !== window) ? document.referrer : null;

document.referrer starts out as the URL for RStudio itself, but after reload, it becomes the URL for the Shiny app. So in the latter case we call postMessage with the wrong origin. I guess we need to rely on something other than document.referrer.

[jcheng5]

Alternatively, we could decide that the fact that the app is disconnected is not privileged information and postMessage('disconnected', '*').

[wch]

@jcheng5 I think using '*' is OK here.

[jcheng5]

@vnijs, my PR fixes it, but it's too late for Shiny v1.1--we'll merge it as soon as the master branch opens back up for Shiny v1.2. In the meantime, you can work around this issue by including the following JS snippet:

tags$script("$(document).on('shiny:disconnected', function() {window.parent.postMessage('disconnected', '*');});")

Thanks for another great bug report!

[vnijs]

Wonderful! The work around works great! Thanks so much @jcheng5