16.5 Save data generated from user inputs

Modified from here https://stackoverflow.com/questions/63329561/r-shiny-load-data-in-to-form-fields-from-previously-persistent-stored-data. See also the links given in the answer to that question. There is a New button, which resets the user inputs. There is a Delete button, which I thought was supposed to delete entries but it doesn’t seem to work.

Code

library(shiny)

# Define the fields we want to save from the form
fields <- c("name", "used_shiny", "r_num_years")

outputDir <- "responses"

saveData <- function(data) {

  # Create a unique file name
  fileName <- sprintf("%s_%s.csv", as.integer(Sys.time()), digest::digest(data))
  
  # Write the file to the local system
  write.csv(
      x = data,
      file = file.path(outputDir, fileName), 
      row.names = FALSE, quote = TRUE
  )
}

loadData <- function() {
    
    # Read all the files into a list
    files <- list.files(outputDir, full.names = TRUE)
    data <- lapply(files, read.csv, stringsAsFactors = FALSE) 
    
    # Concatenate all data together into one data.frame
    data <- do.call(rbind, data)
    data
}

# Shiny app with 3 fields that the user can submit data for
shinyApp(
    ui = fluidPage(
        DT::dataTableOutput("responses", width = 300), tags$hr(),
        textInput("name", "Name", ""),
        checkboxInput("used_shiny", "I've built a Shiny app in R before", FALSE),
        sliderInput("r_num_years", "Number of years using R",
                    0, 25, 2, ticks = FALSE),
        actionButton("submit", "Submit")
    ),
    
    server = function(input, output, session) {

        # When the Submit button is clicked, save the form data
        observeEvent(input$submit, {
            df = data.frame(name=input$name, 
                            used_shiny = input$used_shiny, 
                            r_num_years = input$r_num_years)
            df
            saveData(df)
        })
        
        # Show the previous responses
        # (update with current response when Submit is clicked)
        output$responses <- DT::renderDataTable({
            input$submit
            loadData()
        })     
    }
)