Save R Shiny bookmark into a table and retrieve it

Question

I am trying save the bookmark URL from the shiny app into a table so if the user clicks on a saved URL to retrieve the bookmarked state of the app. When you click on the bookmark button you get a URL how can that be inserted into a table. When saved in a table a view button with each saved bookmark will allow the user to view the saved bookmark state.

 ui <- function(request) {
  fluidPage(
    plotOutput("plot"),
    sliderInput("n", "Number of observations", 1, nrow(faithful), 100),
    bookmarkButton()
  )
}

server <- function(input, output, session) {
  output$plot <- renderPlot({
    hist(faithful$eruptions[seq_len(input$n)], breaks = 40)
  })
}

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

Answer 1

Here is how I would approach this:

Edit: Now using sqlite to persist the changes across different session, also duplicates are avoided.

2nd Edit: Added a description input for the bookmarks.

library(shiny)
library(RSQLite)
library(data.table)

ui <- function(request) {
  fluidPage(
    plotOutput("plot"),
    sliderInput("n", "Number of observations", 1, nrow(faithful), 100),
      fluidRow(column(2, textInput(inputId = "description", label = "Bookmark description", placeholder = "Data Summary")), column(2, bookmarkButton(id="bookmarkBtn"))),
      DT::dataTableOutput("urlTable", width = "100%"),
    tags$style(type='text/css', "#bookmarkBtn { width:100%; margin-top: 25px;}")
  )
}

server <- function(input, output, session) {

  con <- dbConnect(RSQLite::SQLite(), "bookmarks.db", overwrite = FALSE)
  myBookmarks <- reactiveValues(urlDF = NULL)

  observeEvent(input$bookmarkBtn, {
    session$doBookmark()
  })

  if(dbExistsTable(con, "Bookmarks")){
    tmpUrlDF <- data.table(dbReadTable(con, "Bookmarks"))
    myBookmarks$urlDF <- tmpUrlDF[, Timestamp := as.POSIXct(Timestamp, origin="1970-01-01 00:00")]
  } else {
    myBookmarks$urlDF <- NULL
  }

  session$onSessionEnded(function() {
    tmpUrlDF <- isolate({myBookmarks$urlDF})
    if(!is.null(tmpUrlDF)){
      dbWriteTable(con, "Bookmarks", tmpUrlDF, overwrite = TRUE)
    }
    dbDisconnect(con)
  })

  setBookmarkExclude(c("bookmarkBtn", "description", "urlTable_cell_clicked", "urlTable_rows_all", "urlTable_rows_current", "urlTable_rows_selected", "urlTable_search", "urlTable_state", "urlTable_row_last_clicked"))

  output$plot <- renderPlot({
    hist(faithful$eruptions[seq_len(input$n)], breaks = 40)
  })

  onBookmarked(fun=function(url){
    if(!url %in% myBookmarks$urlDF$URL){
      if(is.null(myBookmarks$urlDF)){
        myBookmarks$urlDF <- unique(data.table(Description = input$description, URL = paste0("<a href='", url, "'>", url,"</a>"), Timestamp = Sys.time(), Session = session$token), by="URL")
      } else {
        myBookmarks$urlDF <- unique(rbindlist(list(myBookmarks$urlDF, data.table(Description = input$description, URL = paste0("<a href='", url, "'>", url,"</a>"), Timestamp = Sys.time(), Session = session$token))), by="URL")
      }
    }
  })

  output$urlTable = DT::renderDataTable({
    myBookmarks$urlDF
  }, escape=FALSE)

}

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

You might want to think about saving the bookmark table to a file (e.g. using saveRDS()) and load it globally so its available for new sessions. For further information see this.