Download links and downloadHandlers do not work from inside a PivotItem about shiny.fluent HOT 3 OPEN

My suspicion on this is that the downloadButton is hidden inside the react_data structure which is rendered after the page has been downloaded after the server function is executed. When the server function executes, there is no button in the DOM for the id selector to catch it, and therefore the href is not updated to the correction value.

A fix for this would be some sort of callback to be executed after the data is rendered, but not sure how that would work.

A secondary deeper dirtier fix for this would be to have a hidden download button on the main page with reactive values for the filename and the data that can be updated by later nested modules. The reactive values would just need to be passed to each of the follow-on modules.

I am not sure if this is the issue, what are your thoughts?

from shiny.fluent.

I have a potential working solution which honors keeping all of the relevant code in the same file (for modularity) and it supports nested modules cleanly. The idea is to inject a static hidden download button from the server function right after the body tag which means that it completly circumvents the React system. Then, when the downloadHandler is called, the DOM contains the element.

library(shiny)
library(shiny.fluent)
library(shinyjs)

ui <- fluentPage(
  useShinyjs(),

  # This one is outside the Pivot and will likely work correctly
  div(
    downloadButton("download_outside", label = "")
  ),

  Pivot(
    PivotItem(id = 'pivot1', headerText = 'One', alwaysRender = TRUE, tagList(
      # This one is inside the Pivot and will not work correctly
      div(
        PrimaryButton.shinyInput('downloadButton', text = 'Download', iconProps = list(iconName = "Download"))      )
    ))
  )
)

server <- function(input, output, session) {
  insertUI('body', 'afterBegin', session = session, ui = tagList(
      div(
      style = 'visibility: hidden; display: none',
      downloadButton('download_inside', label = 'Download')
      )
  ))

  observeEvent(input$downloadButton, {
    click('download_inside')
  })

  output$download_inside <- downloadHandler(
    filename = function() {
      paste("data-", Sys.Date(), ".csv", sep="")
    },
    content = function(file) {
      write.csv(iris, file)
    }
  )

  output$download_outside <- downloadHandler(
    filename = function() {
      paste("data-", Sys.Date(), ".csv", sep="")
    },
    content = function(file) {
      write.csv(iris, file)
    }
  )

  outputOptions(output, 'download_inside', suspendWhenHidden = FALSE)

}

shiny::runApp(shinyApp(ui, server), launch.browser = FALSE)

from shiny.fluent.

Thanks @justacec for taking time to submit such a detailed description of the issue.

The issue boils down to downloadHandler not working in reactContext, we'll use this example as a starting point to fixing the issue:

library(shiny)
library(shiny.fluent)
library(shinyjs)

ui <- fluentPage(
  useShinyjs(),
  # This one is outside the Pivot and will likely work correctly
  downloadButton("download_outside", label = ""),
  shiny.react:::ReactContext(
    # This one is inside the Pivot and will not work correctly
    downloadButton("download_inside", label = "")
  )
)

server <- function(input, output, session) {  
  output$download_inside <- downloadHandler(
    filename = function() {
      paste("data-", Sys.Date(), ".csv", sep="")
    },
    content = function(file) {
      write.csv(iris, file)
    }
  )

  output$download_outside <- downloadHandler(
    filename = function() {
      paste("data-", Sys.Date(), ".csv", sep="")
    },
    content = function(file) {
      write.csv(iris, file)
    }
  )
}

shiny::runApp(shinyApp(ui, server))

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