R/ui.R

In aoles/shinyURL: Save and restore the state of Shiny apps

#' @details The \code{shinyURL.ui} widget consists of a text field containing an
#'   URL to the app's current view state.  By default it also features the 
#'   convenience \sQuote{Copy} button for copying the URL to clipboard, and a 
#'   \sQuote{TinyURL} button for querying the URL shortening web service.  The 
#'   inclusion of these buttons is optional and can be controlled by the 
#'   \code{copyURL} and \code{tinyURL} arguments, respectively.
#'   
#'   The \sQuote{Copy} feature uses the ZeroClipboard library, which provides an
#'   easy way to copy text to the clipboard using an invisible Adobe Flash movie
#'   and JavaScript. shinyURL includes the JavaScript code to your app 
#'   automatically, but you also need to have the \dQuote{ZeroClipboard.swf} 
#'   available to the browser. By default shinyURL uses a local copy distributed
#'   with the package; you can override this by setting the
#'   \code{ZeroClipboard.swf} argument to \code{shinyURL.ui}, for example, use 
#'   "//cdnjs.cloudflare.com/ajax/libs/zeroclipboard/2.2.0/ZeroClipboard.swf"
#'   for a file hosted on jsDelivr CDN.
#' @param display logical, should the shinyURL widget be displayed
#' @param label Label for the URL field
#' @param width The width of the URL text field, e.g. \code{'100\%'}, or 
#'   \code{'400px'}; see \code{\link[shiny]{validateCssUnit}}.
#' @param copyURL Include a \sQuote{Copy} button for convenient copying to 
#'   clipboard
#' @param tinyURL Use the TinyURL web service for shortening the URL
#' @param ZeroClipboard.swf URL of the file ZeroClipboard.swf, as 
#'   passed to the \sQuote{swfPath} parameter of \sQuote{ZeroClipboard.config}; 
#'   if missing defaults to the local copy distributed with shinyURL
#' @rdname shinyURL
#' @export
shinyURL.ui = function(display = TRUE, label = "Share URL", width = "100%", copyURL = TRUE, tinyURL = TRUE, ZeroClipboard.swf) {
  if (missing(ZeroClipboard.swf)) {
    addResourcePath("shinyURL", system.file("zeroclipboard", package = "shinyURL"))
    ZeroClipboard.swf = "shinyURL/ZeroClipboard.swf"
  }
  
  tagList(
    ## hidden input which stores the URL query string
    tags$input(type="text", id=".shinyURL.queryString", style="display: none;"),
    tags$script(
      type="text/javascript",
      "$(\"input[id='.shinyURL.queryString']\").on('shiny:updateinput', function(event) {
          window.history.replaceState(null, document.title, '?' + event.message.value);
      })"),
    
    ## shinyURL widget
    if (isTRUE(display)) {
      div(
        class = "form-group shiny-input-container", # same as for textInput
        style = if (!is.null(width)) paste0("width: ", validateCssUnit(width), ";"),
        
        ## URL text field
        if (!is.null(label) && !is.na(label)) tags$label(label, `for` = inputId),
        tags$input(id = inputId, type="text", class="form-control", value="", style="margin-bottom: 5px;",
                   title = "URL of the current view state of the app"),
        
        ## Copy button
        if ( isTRUE(copyURL) )
          tagList(
            tags$button(id=".copyToClipboard", icon("clipboard"), "Copy", title="Copy to clipboard", type="button", class="btn btn-default", "data-clipboard-target"=inputId),
            includeScript(system.file("zeroclipboard", "ZeroClipboard.min.js", package="shinyURL"), type="text/javascript"),
            tags$script(
              type="text/javascript",
              sprintf("ZeroClipboard.config( { swfPath: '%s' } );", ZeroClipboard.swf),
              "var client = new ZeroClipboard( document.getElementById('.copyToClipboard') );"
            )
          ),
        
        ## TinyURL button
        if ( isTRUE(tinyURL) )
          actionButton(".getTinyURL", "TinyURL", icon=icon("compress"), title="Shorten URL")
      )
    }
  )
}