Download multiple csv files with one button (downloadhandler) with R Shiny

Question

*Hi, I'm trying to download multiple csv file from a unique excel file. I want to download (using only one downloadbutton) the differents sheets from the excel file. I don't understand why a for() loop doesn't work, and I can't see how can I do? If anyone knows..

The point is to download differents csv files, which are in the "wb" list (wb[1],wb[2]...) Thanks. Here is my code who works with the third sheet for instance (and sorry for my bad english) : ui :

library(readxl)
library(shiny)
library(XLConnect)
fluidPage(
titlePanel("Export onglets en CSV"),
  sidebarLayout(
    sidebarPanel(
      fileInput('fichier1','Choisissez votre fichier excel :',
                accept = ".xlsx"),
      fluidPage(
    fluidRow(
      column(width = 12,
             numericInput("sheet","Indiquez l'onglet à afficher :",min = 1, value = 1),
             tags$hr(),
             textInput('text',"Indiquez le nom des fichiers :"),
             tags$hr(),
             h4("Pour télécharger les fichiers .csv :"),
             downloadButton("download","Télécharger")
             )

    )
  )),
mainPanel(
  tabsetPanel(
    tabPanel('Importation',
             h4("Fichier de base:"),
             dataTableOutput("contents"))
      )
    )
  )
)

Server :

function(input,output){

  #Création data :
  data <- reactive({
    inFile<- input$fichier1
    if (is.null(inFile)){
      return(NULL)
    }else{
      file.rename(inFile$datapath,
              paste(inFile$datapath,".xlsx", sep =""))
      wb = loadWorkbook(paste(inFile$datapath,".xlsx",sep=""))
      lst = readWorksheet(wb,sheet = getSheets(wb))
      list(wb = wb, lst = lst)
    }
  })



  #Sortie de la table :
  output$contents <- renderDataTable({
    data()$wb[input$sheet]
  },options = list(pageLength = 10))


  #Téléchargement :
  output$download <- downloadHandler(

    #for (i in 1:input$sheet){

    filename = function(){
      paste(input$text,"_0",3,".csv",sep = "")
    },
    content = function(file){
      write.table(data()$wb[3],file,
                  sep = ';', row.names = F, col.names = T)
    }
#}
  )
}

Answer 1

As @BigDataScientist pointed out, you could zip all of your csv file and download the zipped file. Your downloadHandler could look like:

output$download <- downloadHandler(
    filename = function(){
      paste0(input$text,".zip")

    },
    content = function(file){
      #go to a temp dir to avoid permission issues
      owd <- setwd(tempdir())
      on.exit(setwd(owd))
      files <- NULL;

      #loop through the sheets
      for (i in 1:input$sheet){
        #write each sheet to a csv file, save the name
        fileName <- paste(input$text,"_0",i,".csv",sep = "")
        write.table(data()$wb[i],fileName,sep = ';', row.names = F, col.names = T)
        files <- c(fileName,files)
      }
      #create the zip file
      zip(file,files)
    }
  )

This does not download all the sheets from the excel file but the sheets ranging from 1 to whatever the user has as input in input$sheet.

You could also disable the download button if the user has not added an excel file/name.