Off topic:Inconsistency in shinyFiles output.

Question

[Shaurya Jauhari]

Hi there.

My objective is to record a folder path that contains BED files. The user is required to browse to the folder and choose any BED file. On doing that the absolute path to that folder gets recorded. I have a working code below.

 ui <- shinyUI(bootstrapPage(
shinyFilesButton('files','Folder select','Please select a BED file', FALSE),
                            verbatimTextOutput('filepaths')))


server <- shinyServer(function(input, output) {
  roots = getVolumes()
  shinyFileChoose(input,'files', roots=roots, filetypes=c('','bed'))
  output$filepaths <- renderText({paste0(dirname(parseFilePaths(roots, input$files)$datapath), "/")})})

runApp(list(ui=ui,server=server))

Although, when I try to incorporate it into my actual script, an error is returned.

Warning: Error in list.files: invalid 'path' argument

The excerpts from the ui.R and server.R are as under, respectively.

ui.R

shinyUI(fluidPage(theme = shinytheme("united"),
...
sidebarLayout("", fluid = TRUE,
                                sidebarPanel(
                                  shinyFilesButton('files','Folder select','Please select a BED file', FALSE),
                                  verbatimTextOutput('filepaths', placeholder = TRUE),
...
))

server.R

    shinyServer(function(input, output, session){
...
dataFolder <- NULL
    ## Validating path and confirming upload

      roots <- getVolumes()
      shinyFileChoose(input,'files', roots=roots, filetypes=c('','bed'))  
      dataFolder <<- reactive({paste0(dirname(parseFilePaths(roots, input$files)$datapath), "/")}) ## Store folder location
      output$filepaths <- renderText({dataFolder})
...
    })

Any suggestions? Thanks.