Shiny App re-runs observeEvent when restoring a bookmarked state

Question

I'm building a data-driven Shiny App that requires the user to bookmark the App state sometimes so that she can save the processed data then reverting to it later to continue working on the App. I have used the bookmarking method in Shiny but I'm stuck with a problem that makes Shiny re-run the event whenever I restore the state, as if I hit the button again.

I attach herewith a sample code representing the problem. It is a simple interface with months and years dropdown menus. The user is expected to select a month and a year then hit the 'Set Billing Month' button to store the values. If the user elects to Bookmark the state, she hits the Bookmark button and receives the modal box with the URL. The user can then plug the URL into the browser and restores the state as she left it. All that works well except that when the App restores the state, it re-runs the observeEvent function of the Set Month button. This is evident by throwing the designed message "Billing Month has been set!" that appears when hitting the button.

I'm expecting Shiny to restore the bookmarked values without re-running the App to get them back. The bookmarking is done on 'server' as a store. This issue causes a problem to me especially for other functions that require loading big data and processing them.

I tried to replicate the problem with the sample code below.

Any assistance is highly appreciated!

`

library(shiny)
library(shinyjs)


enableBookmarking()

ui <- function(request) {
  
  fluidPage(
    useShinyjs(),
    bookmarkButton(),
    titlePanel("Billing App"),
    tabsetPanel(
      tabPanel("Invoicing Setup",
               selectInput("BillMo",label = "Month",choices = c(1,2,3,4,5,6,7,8,9,10,11,12)),
               selectInput("BillYr",label = "Year",choices = c(2022,2023,2024,2025,2026,2027,2028,2029,2030)),
               actionButton("btnSetInvMo",label = "Set Billing Month",icon = NULL)
      )
    )
  )
}




server <- function(input, output, session) {
  # Set up Reactive Values
  rVals <- reactiveValues(rBillMo=NULL,
                          rBillYr=NULL)
  

  observeEvent(input$btnSetInvMo,{
    BillMo <- as.integer(input$BillMo)
    BillYr <- as.integer(input$BillYr)
    
    # Assign reactive variables
    observe({rVals$rBillMo <- BillMo})
    observe({rVals$rPrvMo2 <- BillYr})
    
    shinyjs::disable("btnSetInvMo")
    
    showNotification("Billing Month has been set!", type = "message")
    
  })
  
  
  # BOOKMARKING
  onBookmark(function(state){
    state$values$billMo <- rVals$rBillMo
    state$values$billYr <- rVals$rBillYr
    
  })
  
  onRestore(function(state){
    rVals$rBillMo <- reactive(state$values$BillMo)
    rVals$rBillYr <- reactive(state$values$BillYr)
  })
}

shinyApp(ui, server,enableBookmarking = "server")

`

score 1 · Answer 1 · answered Dec 18 '22 at 12:24

Add ignoreInit = TRUE to your observer

observeEvent(input$btnSetInvMo,{
    BillMo <- as.integer(input$BillMo)
    BillYr <- as.integer(input$BillYr)
    
    # Assign reactive variables
    observe({rVals$rBillMo <- BillMo})
    observe({rVals$rPrvMo2 <- BillYr})
    
    shinyjs::disable("btnSetInvMo")
    print("doing")
    showNotification("Billing Month has been set!", type = "message")
    
  },ignoreInit = TRUE)

Shiny App re-runs observeEvent when restoring a bookmarked state

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