Introducing shinystate

Launching Shiny collaboration to new heights

Eric Nantz

Statistician / Developer / Podcaster

Eli Lilly & Company

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eric-nantz

High-stakes Collaboration

• Need the answer quickly, but with all of these voices it can be overwhelming
• Get to the answer quickly, frantically toggling the settings

Complex Applications

• Radar app (Christian Luz)
• Complex apps with many inputs, toggles, that take more than one session to complete

• Capture state of application and restore at later point
• Not quite everything I needed …

• Feature landed in version 0.14 in 2016
• Two methods: URL bookmarking and server-side bookmarking
• For smaller applications, this may be good enough

URL Method

myapp.com/?_inputs_&_n=200&text=abc&....

Server-side Method

Store as files in hosting server

• Joe Cheng - keynote at R/Pharma 2018 (Using interactivity responsibly in pharma)
• https://rinpharma.com/publication/rinpharma_32/
• Very slight customizatoins to bookmarkable state that got my creative juices flowing

Enter {shinystate}

Supercharge Shiny’s Bookmarkable-state capability with key enhancements

• Granular control over storage location
• Capability to add optional metadata
• Object-oriented methods with {R6}

Enable shinystate

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

storage <- StorageClass$new()

ui <- function(request) {
  page_sidebar(
    use_shinystate(),
    # additional UI code
  )
}

server <- function(input, output, session) {
  storage$register_metadata()
  # additonal server logic
}

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

• StorageClass$new() initializes the R6 class for your shinystate bookmark sessions
• By default, a temporary directory is used to store bookmarkable state files
• use_shinystate() injects required JavaScript bindings
• storage$register_metadata() handles registering custom shiny::onBookmarked callback

Saving Bookmarkable State 💾

storage$snapshot(
  metadata = list(
    save_name = "exploring",
    timestamp = Sys.time()
  )
)

url	save_name	timestamp
?state_id=7c61d102e8b68a61	exploring	2025-09-16 13:14:07
?state_id=92af5e9aeae226c7	refine	2025-09-16 13:26:05
?state_id=2b0a78b6da5f2f65	finalize	2025-09-16 13:41:12

• url: Mapping to unique ID of session
• Optional: list of metadata values

• storage$snapshot() performs the bookmarking snapshot, wrapping session$doBookmark(). But you get to include optional metadata as a named list!

Restoring Bookmarkable State 📂

session_df <- storage$get_sessions()
url <- session_df |>
  dplyr::filter(save_name == "exploring") |>
  dplyr::pull(url)

storage$restore(url)

• storage$restore() loads the supplied bookmark state session by the custom url

Storage with {pins}

• Control where you store bookmarkable state files
• Leverages custom format capability

board <- pins::board_s3("awesome-bucket")
storage <- StorageClass$new(board_sessions = board)

Example pins board providers: * Posit Connect * S3 Object Storage (S3, Azure) * Google Drive / Dropbox / OneDrive * Online site (GitHub repo)

Power-up: Sharing Sessions

Dr. Light

Dr. Wily

Additional Benefits 🤔

• Custom processing of session state artifacts
• Traceability within and across user sessions
• Inputs to automated reporting

Current and Future Work

✅ Example applications from basic usage to Shiny modules

✅ Package website with interactive apps powered by WebAssembly!

⏳ CRAN submission (in queue)

🛠 Compatability with {golem} and {rhino}

Relief in Sight

Thank You!

📦 Documentation:

rpodcast.github.io/shinystate

📦 GitHub Repository:

github.com/rpodcast/shinystate

🏡 Slides:

rpodcast.github.io/shinystate-positconf2025

Let’s Connect!

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Shiny Developer Series

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