Customization of Shiny Bookmarkable State

Enhance the bookmarkable state feature of 'shiny' with additional customization such as storage location and storage repositories leveraging the 'pins' package.

shinystate

shinystate is an R package that provides additional customization on top of the standard Shiny bookmarkable state capabilities.

Installation

# Install the released version from CRAN
install.packages("shinystate")

# Or the development version from GitHub:
remotes::install_github("rpodcast/shinystate")

Why shinystate?

If your Shiny application leverages bookmarkable state and the default feature set is working for your use case, then shinystate is likely not value-added.

However, as applications grow in complexity and are used in high-stakes situations, you may wish your application could support the following features:

• Flexible configuration of where bookmarkable state files are stored, whether on the same file system as the server running the application, or in a separate repository such as cloud storage.
• Allow users to save multiple bookmarkable state sessions, tailored to situations such as multiple "projects" inside the same application.
• Augment the bookmarkable state artifacts with metadata of your choosing. Possible metadata could include custom names and timestamps.

The shinystate package offers an intuitive class system built upon the R6 package with methods tailored to the common operations with managing bookmarkable state.

How to use it?

To enable saving bookmarkable state with shinystate, you need to:

1. Load the package: library(shinystate)
2. Create an instance of the StorageClass class outside of the application user interface and server functions: StorageClass$new()
3. Include use_shinystate() in your UI definition
4. Call the register_metadata() method from your instance of the StorageClass class at the beginning of the application server function
5. Enable the save-to-server bookmarking method by adding enableBookmarking = 'server' in the call to shinyApp()
6. Call the snapshot() method from your instance of the StorageClass class to save the state of the Shiny app session
7. Call the restore() method from your instance of the StorageClass class to restore a saved session based on the session URL, available in the data frame returned from the get_sessions() method.

Below is an example application illustrating the default usage of shinystate. Visit the Getting Started for additional details.

library(shiny)
library(bslib)
library(shinystate)

storage <- StorageClass$new()

ui <- function(request) {
  page_sidebar(
    title = "Basic App",
    sidebar = sidebar(
      accordion(
        open = TRUE,
        accordion_panel(
          id = "user_inputs",
          "User Inputs",
          textInput(
            "txt",
            label = "Enter Title",
            placeholder = "change this"
          ),
          checkboxInput("caps", "Capitalize"),
          sliderInput(
            "bins",
            label = "Number of bins",
            min = 1,
            max = 50,
            value = 30
          )
        ),
        accordion_panel(
          id = "state",
          "Bookmark State",
          actionButton("bookmark", "Bookmark"),
          actionButton("restore", "Restore Last Bookmark")
        )
      )
    ),
    use_shinystate(),
    card(
      card_header("App Output"),
      plotOutput("distPlot")
    )
  )
}

server <- function(input, output, session) {
  storage$register_metadata()

  plot_title <- reactive({
    if (!shiny::isTruthy(input$txt)) {
      value <- "Default Title"
    } else {
      value <- input$txt
    }

    if (input$caps) {
      value <- toupper(value)
    }

    return(value)
  })

  output$distPlot <- renderPlot({
    req(plot_title())
    x <- faithful$waiting
    bins <- seq(min(x), max(x), length.out = input$bins + 1)
    hist(
      x,
      breaks = bins,
      col = "#007bc2",
      border = "white",
      xlab = "Waiting time to next eruption (in mins)",
      main = plot_title()
    )
  })

  observeEvent(input$bookmark, {
    storage$snapshot()
    showNotification("Session successfully saved")
  })

  observeEvent(input$restore, {
    session_df <- storage$get_sessions()
    storage$restore(tail(session_df$url, n = 1))
  })

  setBookmarkExclude(c("add", "bookmark", "restore"))
}

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

Code of Conduct

Please note that the shinystate project is released with a Contributor Code of Conduct. By contributing to this project, you agree to abide by its terms.