R/file-browser.R

In blockr.core: Graphical Web-Framework for Data Manipulation and Visualization

#' @section File browser block:
#' In order to make user data available to blockr, this block provides file-
#' upload functionality via [shiny::fileInput()]. Given that data provided in
#' this way are only available for the life-time of the shiny session, exported
#' code is not self-contained and a script containing code from an upload block
#' is cannot be run in a new session. Also, serialization of upload blocks is
#' currently not allowed as the full data would have to be included during
#' serialization.
#'
#' @param file_path File path
#' @param volumes Parent namespace
#'
#' @rdname new_file_block
#' @export
new_filebrowser_block <- function(file_path = character(),
                                  volumes = c(home = path.expand("~")), ...) {
  new_file_block(
    function(id) {
      moduleServer(
        id,
        function(input, output, session) {

          path <- reactiveVal(file_path)
          file <- reactive(
            shinyFiles::parseFilePaths(volumes, input$file)$datapath
          )

          shinyFiles::shinyFileChoose(input, "file", roots = volumes)

          observeEvent(
            file(),
            {
              req(file())
              path(unname(file()))
            }
          )

          list(
            expr = reactive(
              bquote(.(file), list(file = path()))
            ),
            state = list(
              file_path = path,
              volumes = volumes
            )
          )
        }
      )
    },
    function(id) {
      shinyFiles::shinyFilesButton(
        NS(id, "file"),
        label = "File select",
        title = "Please select a file",
        multiple = FALSE
      )
    },
    class = "filebrowser_block",
    ...
  )
}

#' @export
as.list.filebrowser_block <- function(x, ...) {
  stop("Cannot serialize upload blocks.")
}