How to Download a file

I realize that this code works to download an R data set, but it does not work to download a file.
In order to download a file instead of an R dataset, I have written file <- read.table("/home/user/0.tsv", sep = '\t') and therefore instead of cars in selectInput() and in datasetInput() functions I use "file". What this does is to offer as choice in the dropdown selection the entire file content, but it saves an empty file. Is there any way I can display the parameter "file" in the drop down selection? and can save the file contents to a file?

# Define UI for data download app ----
ui <- fluidPage(
  # App title ----
  titlePanel("Downloading Data"),
  # Sidebar layout with input and output definitions ----
    # Sidebar panel for inputs ----
      #file <- read.table("/home/giuseppa/0.tsv", sep = '\t'),
      # Input: Choose dataset ----
      selectInput("dataset", "Choose a dataset:",
                  choices = c("cars")),
      # Button
      downloadButton("downloadData", "Download")
    # Main panel for displaying outputs ----

# Define server logic to display and download selected file ----
server <- function(input, output) {
  # Reactive value for selected dataset ----
  datasetInput <- reactive({
           "cars" = cars)
  # Table of selected dataset ----
  output$table <- renderTable({ 
  # Downloadable csv of selected dataset ----
  output$downloadData <- downloadHandler(
    filename = function() {
      paste(input$dataset, ".csv", sep = "")
    content = function(file) {
      write.table(datasetInput(), file, row.names = FALSE)

# Create Shiny app ----
shinyApp(ui = ui, server = server)

May be the points is converting the file to a dataset? if so, how can I do that?

I solved the problem by using params <- read.table("glycoPipe_PARAMS_TEMPLATE.tsv", sep = '\t') instead file <- read.table("glycoPipe_PARAMS_TEMPLATE.tsv", sep = '\t'). File conflicts with the content = function(file){