Download Data and graphs

Ottavia M. Epifania

The specific action button for the download

downloadButton("download", "Download this thing")

Download this thing

The button can be used to download almost anything. By default (if nothing is specified through the download handler, it downloads the source file)

The download action activated by the button is handled by a download handler

downloadHandler("filename", file)

An example

Choose a dataset:

rock pressure cars

Download plot

Dowload summary

• UI
• Server
• Together

ui = fluidPage(
  sidebarLayout(
    sidebarPanel(
      selectInput(inputId = "dataset",
                  label = "Choose a dataset:",
                  choices = c("rock", 
                                 "pressure",
                                 "cars")),
      actionButton("load", "Select dataset"),
    ), 
    mainPanel(plotOutput("graph"),
              downloadButton("downloadPlot", "Download plot"),
              verbatimTextOutput("summary"), 
              downloadButton("downloadSummary", "Dowload summary"))
  )
)

1

Dowload button for the plot

2

Download button for the dataset

server = function(input, output){
 dataInput = eventReactive(input$load, {
    switch(input$dataset,
           rock = rock,
           pressure = pressure,
           cars = cars)
  })
  output$graph <- renderPlot({
    df = dataInput()
    plot(df[, c(1:2)])
  })
ddata = reactive({
    df = dataInput()
    descript_data= df %>%
      summarise( m_1 = mean(df[,1]), sd_1 = sd(df[,1]),
                 m_2 = mean(df[,2]), sd_2 = sd(df[,2]))
    colnames(descript_data) <- gsub("1", colnames(df)[1],  colnames(descript_data))
    colnames(descript_data) = gsub("2", colnames(df)[2], colnames(descript_data))
    descript_data
  })  
  output$summary <- renderPrint({
    ddata()
  })
output$downloadSummary <- downloadHandler(
    filename = function() {
      paste("descriptive-",input$dataset, ".csv", sep = "")
    },
    content = function(file) {
      write.table(ddata(), file, sep = ",",
                  row.names = FALSE)
    }
  )
output$downloadPlot <- downloadHandler(
    filename = function() {
      paste0("plot-", input$dataset, ".png")
    },
    content = function(file) {
      png(file, width = 800, height = 600)
      df <- dataInput()
      plot(df[, 1:2])
      dev.off()
    }
  )
}

1

Create a reactive object containing the summary of the data, more suitable for the download

2

Actual download handler, where both the filename and content are defined as functions. The filename includes a brief description and the number of the dataset

3

Same thing, but the dowload handler is designed to handle the download of the plot. The format can be changed

shinyApp(ui, server)