How to clear fileInput data and corresponding objects in R Shiny?

After looking at some exisiting solutions I still could not solve the problem.

I want to delete every data that was uploaded in my shiny app after pressing the sign_out button (which of course also logs out the users).

To upload data I am using the fileInput() command in Shiny.

        fileInput("file1", "Choose CSV File",
                  multiple = FALSE,
                  accept = c("text/csv",
                             "text/comma-separated-values,text/plain",
                             ".csv", "space"))

The corresponding data object based on this input is called df:

output$contents <- renderTable({
req(input$file1)

        df <- read.csv(input$file1$datapath,
                       header = input$header,
                       sep = input$sep,
                       quote = input$quote)
})

My current approach to remove this is the following:

  observeEvent(input$sign_out, {
    df <- NULL 
    reset(id = "") # from shinyjs package 
    f$sign_out()
    output$test <- renderTable({
      df()})
    
  })

The output$test object shows that after relogin the data of "df" is still there.

Hope you could help me and thank you in advance.

so I think I could solve the issue. Instead of setting any reactive Value to NULL I deleted the csv. file which is created when uploading data.

The key function for that is unlink.

  observeEvent(input$sign_out, {
    unlink(input$file1$datapath)
    reset(id = "") # from shinyjs package
  })

what you could do is, first, at the beginning of your code, just add this line of code:

values <- reactiveValues(uploadedData = NULL)

Secondly, you should modify the renderTable() function to use values$uploadedData instead of df :

renderTable({
req(input$file1)

        values$uploadedData <- read.csv(input$file1$datapath,
                             header = input$header,
                             sep = input$sep,
                             quote = input$quote)

And also,you must replace the line

output$test <- renderTable({ df() })

With this line of code:

output$test <- renderTable({ values$uploaded_data }) 

Lastly, when the user logs out, to empty the uploadedData, modify the observeEvent() by setting the values$uploadedData() to NULL :

observeEvent(input$sign_out, {
  values$uploadedData <- NULL 
  reset(id = "") # from shinyjs package 
  f$sign_out()
})

Try this, and let me know if this works for you.