Add show_undo_redo parameter to Dash for R

NAMESPACE

@@ -27,4 +27,4 @@ importFrom(routr,RouteStack)
 importFrom(routr,ressource_route)
 importFrom(stats,setNames)
 importFrom(tools,file_ext)
-importFrom(utils,getFromNamespace)
+importFrom(utils,getFromNamespace)

R/dash.R

@@ -18,7 +18,8 @@
 #'   requests_pathname_prefix = NULL,
 #'   external_scripts = NULL,
 #'   external_stylesheets = NULL,
-#'   suppress_callback_exceptions = FALSE
+#'   suppress_callback_exceptions = FALSE,
+#'   show_undo_redo = FALSE
 #' )
 #'
 #' @section Arguments:
@@ -53,7 +54,9 @@
 #'   `external_stylesheets` \tab \tab List. An optional list of valid URLs from which
 #'   to serve CSS for rendered pages.\cr
 #'   `suppress_callback_exceptions` \tab \tab Logical. Whether to relay warnings about
-#'   possible layout mis-specifications when registering a callback.
+#'   possible layout mis-specifications when registering a callback.\cr
+#'   `show_undo_redo` \tab \tab Logical. Set to `TRUE` to enable undo and redo buttons for
+#'   stepping through the history of the app state.
 #'  }
 #'
 #' @section Fields:
@@ -130,6 +133,7 @@
 #'     \describe{
 #'       \item{path}{Character. A path string prefixed with a leading `/` which directs at a path or asset directory.}
 #'       \item{requests_pathname_prefix}{Character. The pathname prefix for the app on a deployed application. Defaults to the environment variable set by the server, or `""` if run locally.}
+#'       }
 #'   }
 #'   \item{`strip_relative_path(path, requests_pathname_prefix)`}{
 #'     The `strip_relative_path` method simplifies the handling of URLs and pathnames for apps
@@ -140,7 +144,8 @@
 #'     \describe{
 #'       \item{path}{Character. A path string prefixed with a leading `/` and `requests_pathname_prefix` which directs at a path or asset directory.}
 #'       \item{requests_pathname_prefix}{Character. The pathname prefix for the app on a deployed application. Defaults to the environment variable set by the server, or `""` if run locally.}
-#'   }
+#'       }
+#'  }
 #'  \item{`index_string(string)`}{
 #'     The `index_string` method allows the specification of a custom index by changing
 #'     the default `HTML` template that is generated by the Dash UI. Meta tags, CSS, Javascript,
@@ -271,7 +276,8 @@ Dash <- R6::R6Class(
                           external_scripts = NULL,
                           external_stylesheets = NULL,
                           compress = TRUE,
-                          suppress_callback_exceptions = FALSE) {
+                          suppress_callback_exceptions = FALSE,
+                          show_undo_redo = FALSE) {
 
       # argument type checking
       assertthat::assert_that(inherits(server, "Fire"))
@@ -305,6 +311,7 @@ Dash <- R6::R6Class(
       self$config$requests_pathname_prefix <- resolvePrefix(requests_pathname_prefix, "DASH_REQUESTS_PATHNAME_PREFIX", url_base_pathname)
       self$config$external_scripts <- external_scripts
       self$config$external_stylesheets <- external_stylesheets
+      self$config$show_undo_redo <- show_undo_redo
 
       # ------------------------------------------------------------
       # Initialize a route stack and register a static resource route
@@ -352,8 +359,6 @@ Dash <- R6::R6Class(
         response$status <- 200L
         response$type <- 'json'
 
-
-
         TRUE
       })
 
@@ -560,27 +565,27 @@ Dash <- R6::R6Class(
           # if debug mode is not active
           dep_path <- system.file(dep_pkg$rpkg_path,
                                   package = dep_pkg$rpkg_name)
-          
+
           response$type <- get_mimetype(filename)
 
           if (grepl("text|javascript", response$type)) {
             response$body <- readLines(dep_path,
                                        warn = FALSE,
                                        encoding = "UTF-8")
-            
+
             if (private$compress && length(response$body) > 0) {
               response <- tryCompress(request, response)
             }
           } else {
             file_handle <- file(dep_path, "rb")
             file_size <- file.size(dep_path)
-            
+
             response$body <- readBin(dep_path,
                                      raw(),
                                      file_size)
             close(file_handle)
-          }          
-          
+          }
+
           if (!private$debug && has_fingerprint) {
             response$status <- 200L
             response$set_header('Cache-Control',

R/utils.R

@@ -506,7 +506,7 @@ get_package_mapping <- function(script_name, url_package, dependencies) {
       dep_path <- file.path(x$src$file, x$stylesheet)
     else if (!is.null(x$other))
       dep_path <- file.path(x$src$file, x$other)
-    
+
     # remove n>1 slashes and replace with / if present;
     # htmltools seems to permit // in pathnames, but
     # this complicates string matching unless they're
@@ -542,7 +542,7 @@ get_mimetype <- function(filename) {
   else if (filename_ext %in% c('js.map', 'map'))
     return('application/json')
   else
-    return(mime::guess_type(filename, 
+    return(mime::guess_type(filename,
                             empty = "application/octet-stream"))
 }
 

tests/integration/test_render.py

@@ -0,0 +1,62 @@
+def click_undo(self):
+    undo_selector = "._dash-undo-redo span:first-child div:last-child"
+    undo = self.wait_for_element_by_css_selector(undo_selector)
+    self.wait_for_text_to_equal(undo_selector, "undo")
+    undo.click()
+
+
+def click_redo(self):
+    redo_selector = "._dash-undo-redo span:last-child div:last-child"
+    self.wait_for_text_to_equal(redo_selector, "redo")
+    redo = self.wait_for_element_by_css_selector(redo_selector)
+    redo.click()
+
+
+app = ''' 
+library(dash)
+library(dashHtmlComponents)
+library(dashCoreComponents)
+app <- Dash$new(show_undo_redo=TRUE)
+
+app$layout(htmlDiv(list(dccInput(id="a"), htmlDiv(id="b"))))
+
+app$callback(
+  output("b", "children"),
+  list(input("a", "value")),
+  function(a) {
+    return(a)
+  }
+)
+
+app$run_server()
+'''
+
+
+def test_rstr001r_undo_redo(dashr):
+    dashr.start_server(app)
+    dashr.wait_for_element_by_css_selector(
+        "#a"
+    )   
+    input1 = dashr.find_element("#a")
+    input1.send_keys("xyz")
+    dashr.wait_for_text_to_equal(
+        "#b", "xyz", timeout=1
+    )
+    click_undo(dashr)
+    dashr.wait_for_text_to_equal(
+        "#b", "xy", timeout=1
+    )
+    click_undo(dashr)
+    dashr.wait_for_text_to_equal(
+        "#b", "x", timeout=1
+    )
+    click_redo(dashr)
+    dashr.wait_for_text_to_equal(
+        "#b", "xy", timeout=1
+    )
+    dashr.percy_snapshot(name="undo-redo")
+    click_undo(dashr)
+    click_undo(dashr)
+    dashr.wait_for_text_to_equal(
+        "#b", "", timeout=1
+    )