In aoles/shinyURL: Save and restore the state of Shiny apps

It is possible to embed Shiny components in an R Markdown document, resulting in interactive R Markdown documents. More information on how to use these documents is available on the Shiny and R Markdown websites.

Even though interactive documents don't explicitly specify an UI and a server, enabling shinyURL is still easy: simply call the function shinyURL.server anywhere in your document.

library("shinyURL")
url = shinyURL.server()

shinyURL.server returns the app's URL in form of an reactive expression. In the example above we store it under the name url. Rather than embedding the default UI widget provided by shinyURL, we will use this reactive expression to insert the link inline, as demonstrated in Share this document Additionally, with the help of the R package qrcode we generate a QR code containing the app's URL.

Sample Inputs and Outputs

inputPanel(
  selectInput("n_breaks", label = "Number of bins:",
              choices = c(10, 20, 35, 50), selected = 20),

  sliderInput("bw_adjust", label = "Bandwidth adjustment:",
              min = 0.2, max = 2, value = 1, step = 0.2)
)

renderPlot({
  hist(faithful$eruptions, probability = TRUE, breaks = as.numeric(input$n_breaks),
       xlab = "Duration (minutes)", main = "Geyser eruption duration")

  dens <- density(faithful$eruptions, adjust = input$bw_adjust)
  lines(dens, col = "blue")
})

Share this document {#share}

The current view state of this document can be accessed at r output$link = renderText( url() ); textOutput("link", container = a), or using the QR code below.

library(qrcode)

qrcode = reactive( t(qrcode_gen(url(), plotQRcode = FALSE, dataOutput = TRUE, softLimitFlag = FALSE)) )
nc = reactive( ncol(qrcode()) )
nr = reactive( nrow(qrcode()) )
scale = 4

renderPlot({
      opar = par(mar=c(0,0,0,0))
      on.exit( par(opar) )
      image(1L:nc(), 1L:nr(), qrcode(), xlim = 0.5 + c(0, nc()),
            ylim = 0.5 + c(nr(), 0), axes = FALSE, xlab = "", ylab = "",
            col = c("white", "black"), asp = 1)
      }, width = function() scale*nc(), height = function() scale*nr())