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input-file.R
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input-file.R
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#' File Upload Control
#'
#' Create a file upload control that can be used to upload one or more files.
#'
#' Whenever a file upload completes, the corresponding input variable is set to
#' a dataframe. See the `Server value` section.
#'
#' Each time files are uploaded, they are written to a new random subdirectory
#' inside of R's process-level temporary directory. The Shiny user session keeps
#' track of all uploads in the session, and when the session ends, Shiny deletes
#' all of the subdirectories where files where uploaded to.
#'
#' @family input elements
#'
#' @inheritParams textInput
#' @param multiple Whether the user should be allowed to select and upload
#' multiple files at once. **Does not work on older browsers, including
#' Internet Explorer 9 and earlier.**
#' @param accept A character vector of "unique file type specifiers" which gives
#' the browser a hint as to the type of file the server expects. Many browsers
#' use this prevent the user from selecting an invalid file.
#'
#' A unique file type specifier can be:
#' * A case insensitive extension like `.csv` or `.rds`.
#' * A valid MIME type, like `text/plain` or `application/pdf`
#' * One of `audio/*`, `video/*`, or `image/*` meaning any audio, video,
#' or image type, respectively.
#' @param buttonLabel The label used on the button. Can be text or an HTML tag
#' object.
#' @param placeholder The text to show before a file has been uploaded.
#' @param capture What source to use for capturing image, audio or video data.
#' This attribute facilitates user access to a device's media capture
#' mechanism, such as a camera, or microphone, from within a file upload
#' control.
#'
#' A value of `user` indicates that the user-facing camera and/or microphone
#' should be used. A value of `environment` specifies that the outward-facing
#' camera and/or microphone should be used.
#'
#' By default on most phones, this will accept still photos or video. For
#' still photos only, also use `accept="image/*"`. For video only, use
#' `accept="video/*"`.
#' @examples
#' ## Only run examples in interactive R sessions
#' if (interactive()) {
#'
#' ui <- fluidPage(
#' sidebarLayout(
#' sidebarPanel(
#' fileInput("file1", "Choose CSV File", accept = ".csv"),
#' checkboxInput("header", "Header", TRUE)
#' ),
#' mainPanel(
#' tableOutput("contents")
#' )
#' )
#' )
#'
#' server <- function(input, output) {
#' output$contents <- renderTable({
#' file <- input$file1
#' ext <- tools::file_ext(file$datapath)
#'
#' req(file)
#' validate(need(ext == "csv", "Please upload a csv file"))
#'
#' read.csv(file$datapath, header = input$header)
#' })
#' }
#'
#' shinyApp(ui, server)
#' }
#'
#' @section Server value:
#'
#' A `data.frame` that contains one row for each selected file, and following
#' columns:
#' \describe{
#' \item{`name`}{The filename provided by the web browser. This is
#' **not** the path to read to get at the actual data that was uploaded
#' (see
#' `datapath` column).}
#' \item{`size`}{The size of the uploaded data, in
#' bytes.}
#' \item{`type`}{The MIME type reported by the browser (for example,
#' `text/plain`), or empty string if the browser didn't know.}
#' \item{`datapath`}{The path to a temp file that contains the data that was
#' uploaded. This file may be deleted if the user performs another upload
#' operation.}
#' }
#'
#' @export
fileInput <- function(inputId, label, multiple = FALSE, accept = NULL,
width = NULL, buttonLabel = "Browse...", placeholder = "No file selected",
capture = NULL) {
restoredValue <- restoreInput(id = inputId, default = NULL)
# Catch potential edge case - ensure that it's either NULL or a data frame.
if (!is.null(restoredValue) && !is.data.frame(restoredValue)) {
warning("Restored value for ", inputId, " has incorrect format.")
restoredValue <- NULL
}
if (!is.null(restoredValue)) {
restoredValue <- toJSON(restoredValue, strict_atomic = FALSE)
}
inputTag <- tags$input(
id = inputId,
class = "shiny-input-file",
name = inputId,
type = "file",
# Don't use "display: none;" style, which causes keyboard accessibility issue; instead use the following workaround: https://css-tricks.com/places-its-tempting-to-use-display-none-but-dont/
style = "position: absolute !important; top: -99999px !important; left: -99999px !important;",
`data-restore` = restoredValue
)
if (multiple)
inputTag$attribs$multiple <- "multiple"
if (length(accept) > 0)
inputTag$attribs$accept <- paste(accept, collapse=',')
if (!is.null(capture)) {
inputTag$attribs$capture <- capture
}
div(class = "form-group shiny-input-container",
style = css(width = validateCssUnit(width)),
shinyInputLabel(inputId, label),
div(class = "input-group",
# input-group-prepend is for bootstrap 4 compat
tags$label(class = "input-group-btn input-group-prepend",
span(class = "btn btn-default btn-file",
buttonLabel,
inputTag
)
),
tags$input(type = "text", class = "form-control",
placeholder = placeholder, readonly = "readonly"
)
),
tags$div(
id=paste(inputId, "_progress", sep=""),
class="progress active shiny-file-input-progress",
tags$div(class="progress-bar")
)
)
}