Download multiple csv files in a zipped folder in Shiny

Question

Can someone please point out how I can make this download zip function work in server.R? When I run this, I get the following error:

• [1] "/var/folders/00/1dk1r000h01000cxqpysvccm005p87/T//Rtmps3T6Ua"
• Warning in write.csv(datasetInput()$rock, file = "rock.csv", sep = ",") : attempt to set 'sep' ignored
• Warning in write.csv(datasetInput()$pressure, file = "pressure.csv", sep = ",") : attempt to set 'sep' ignored
• Warning in write.csv(datasetInput()$cars, file = "cars.csv", sep = ",") : attempt to set 'sep' ignored
• [1] "rock.csv" "pressure.csv" "cars.csv"
  
  • adding: rock.csv (deflated 54%)
  • adding: pressure.csv (deflated 42%)
  • adding: cars.csv (deflated 57%)
• Error opening file: 2

• Error reading: 9

  library(shiny)
  
  # server.R
  server <- function(input, output) {
  
    datasetInput <- reactive({
      return(list(rock=rock, pressure=pressure, cars=cars))
    })
  
    output$downloadData <- downloadHandler(
      filename = 'pdfs.zip',
      content = function(fname) {
        tmpdir <- tempdir()
        setwd(tempdir())
        print(tempdir())
  
        fs <- c("rock.csv", "pressure.csv", "cars.csv")
        write.csv(datasetInput()$rock, file = "rock.csv", sep =",")
        write.csv(datasetInput()$pressure, file = "pressure.csv", sep =",")
        write.csv(datasetInput()$cars, file = "cars.csv", sep =",")
        print (fs)
  
        zip(zipfile=fname, files=fs)
      },
      contentType = "application/zip"
    )
  
  }
  
  # ui.R
  ui <- shinyUI(fluidPage(
    titlePanel('Downloading Data'),
    sidebarLayout(
      sidebarPanel(
        downloadButton('downloadData', 'Download')
      ),
      mainPanel()
      )
    )
    )
  
  shinyApp(ui = ui, server = server)
  

Answer 1

Solution: Include if(file.exists(paste0(fname, ".zip"))) {file.rename(paste0(fname, ".zip"), fname)} after zip() call.

Answer 2

The top solution still wasn't working for me. I was working in RStudio Server on a Linux server. The problem was that RStudio couldn't automatically locate the path to the zip executable. I had to manually specify it. In the command line, which zip revealed to me /usr/bin/zip.

So, I just had to set the R_ZIPCMD environment variable at the top of my code.

Sys.setenv(R_ZIPCMD="/usr/bin/zip")

Source: The help file for zip() mentions R_ZIPCMD.