rstudio · jooyoungseo · Jun 8, 2020 · Jun 9, 2020 · Jun 9, 2020 · Jun 9, 2020
diff --git a/NEWS.md b/NEWS.md
@@ -2,6 +2,8 @@
 shiny 1.5.0.9000
 ================
 
+## Full changelog
+
 ### Accessibility
 
 * Added [bootstrap accessibility plugin](https://github.com/paypal/bootstrap-accessibility-plugin) under the hood to improve accessibility of shiny apps for screen-reader and keyboard users: the enhancements include better navigations for alert, tooltip, popover, modal dialog, dropdown, tab Panel, collapse, and carousel elements. (#2911)
@@ -14,6 +16,8 @@ shiny 1.5.0.9000
 
 * Closed #2847: `selectInput()` is reasonably accessible for screen readers even when `selectize` option is set to TRUE. To improve `selectize.js` accessibility, We have added [selectize-plugin-a11y](https://github.com/SLMNBJ/selectize-plugin-a11y) by default. (#2993)
 
+* Closed #2844: Added `lang` argument to ui `*Page()` functions (e.g., `fluidPage`, `bootstrapPage`) that specifies document-level language within the app for the accessibility of screen readers and search-engine parsers. By default, it is set to empty string which is commonly recognized as a browser's default locale. (#2920)
+
 ### Minor new features and improvements
 
 * When UI is specified as a function (e.g. `ui <- function(req) { ... }`), the response can now be an HTTP response as returned from the (newly exported) `httpResponse()` function. (#2970)
@@ -22,6 +26,8 @@ shiny 1.5.0.9000
 
 * Closed #2972: `runExample()` now supports the `shiny.port` option (thanks to @ColinFay). (#2982)
 
+* Added the `lang` argument to `shinyApp()` that specifies document-level language within the app for the accessibility of screen readers and search-engine parsers [#2844](https://github.com/rstudio/shiny/issues/2844).
+
 ### Bug fixes
 
 * Fixed #2859: `renderPlot()` wasn't correctly setting `showtext::showtext_opts()`'s `dpi` setting with the correct resolution on high resolution displays; which means, if the font was rendered by showtext, font sizes would look smaller than they should on such displays. (#2941)

diff --git a/R/bootstrap-layout.R b/R/bootstrap-layout.R
@@ -16,6 +16,7 @@
 #' @param theme Alternative Bootstrap stylesheet (normally a css file within the
 #'   www directory). For example, to use the theme located at
 #'   `www/bootstrap.css` you would use `theme = "bootstrap.css"`.
+#' @param lang ISO 639-1 language code used within the shiny app. Default is set to empty value.
 #'
 #' @return A UI defintion that can be passed to the [shinyUI] function.
 #'
@@ -87,11 +88,12 @@
 #' }
 #' @rdname fluidPage
 #' @export
-fluidPage <- function(..., title = NULL, responsive = NULL, theme = NULL) {
+fluidPage <- function(..., title = NULL, responsive = NULL, theme = NULL, lang = NULL) {
   bootstrapPage(div(class = "container-fluid", ...),
                 title = title,
                 responsive = responsive,
-                theme = theme)
+                theme = theme,
+                lang = lang)
 }
 
 
@@ -118,6 +120,7 @@ fluidRow <- function(...) {
 #' @param theme Alternative Bootstrap stylesheet (normally a css file within the
 #'   www directory). For example, to use the theme located at
 #'   `www/bootstrap.css` you would use `theme = "bootstrap.css"`.
+#' @param lang ISO 639-1 language code used within the shiny app. Default is set to empty value.
 #'
 #' @return A UI defintion that can be passed to the [shinyUI] function.
 #'
@@ -156,11 +159,12 @@ fluidRow <- function(...) {
 #'
 #' @rdname fixedPage
 #' @export
-fixedPage <- function(..., title = NULL, responsive = NULL, theme = NULL) {
+fixedPage <- function(..., title = NULL, responsive = NULL, theme = NULL, lang = NULL) {
   bootstrapPage(div(class = "container", ...),
                 title = title,
                 responsive = responsive,
-                theme = theme)
+                theme = theme,
+                lang = lang)
 }
 
 #' @rdname fixedPage

diff --git a/R/bootstrap.R b/R/bootstrap.R
@@ -18,6 +18,7 @@ NULL
 #'   Bootstrap 3.
 #' @param theme Alternative Bootstrap stylesheet (normally a css file within the
 #'   www directory, e.g. `www/bootstrap.css`)
+#' @param lang ISO 639-1 language code used within the shiny app. Default is set to empty value.
 #'
 #' @return A UI defintion that can be passed to the [shinyUI] function.
 #'
@@ -26,13 +27,13 @@ NULL
 #'
 #' @seealso [fluidPage()], [fixedPage()]
 #' @export
-bootstrapPage <- function(..., title = NULL, responsive = NULL, theme = NULL) {
+bootstrapPage <- function(..., title = NULL, responsive = NULL, theme = NULL, lang = NULL) {
 
   if (!is.null(responsive)) {
     shinyDeprecated("The 'responsive' argument is no longer used with Bootstrap 3.")
   }
 
-  attachDependencies(
+  ui <- attachDependencies(
     tagList(
       if (!is.null(title)) tags$head(tags$title(title)),
       if (!is.null(theme)) {
@@ -44,6 +45,19 @@ bootstrapPage <- function(..., title = NULL, responsive = NULL, theme = NULL) {
     ),
     bootstrapLib()
   )
+
+  # Also store `lang` to be passed for rendering processor.
+  if (!is.null(lang)) {
+    if (is.character(lang) && length(lang) == 1) {
+      # Append lang attribute to be passed to renderPage function
+      attributes(ui) <- c(attributes(ui), list(lang = lang))
+    } else {
+      warning("Invalid lang value: defaulting to empty string.")
+      attributes(ui) <- c(attributes(ui), list(lang = NULL))
+    }
+  }
+
+  return(ui)
 }
 
 #' Bootstrap libraries
@@ -132,6 +146,7 @@ basicPage <- function(...) {
 #'   shown in the document).
 #' @param bootstrap If `TRUE`, load the Bootstrap CSS library.
 #' @param theme URL to alternative Bootstrap stylesheet.
+#' @param lang ISO 639-1 language code used within the shiny app. Default is set to empty value.
 #'
 #' @family layout functions
 #'
@@ -159,22 +174,37 @@ basicPage <- function(...) {
 #' )
 #' @export
 fillPage <- function(..., padding = 0, title = NULL, bootstrap = TRUE,
-  theme = NULL) {
+  theme = NULL, lang = NULL) {
 
   fillCSS <- tags$head(tags$style(type = "text/css",
     "html, body { width: 100%; height: 100%; overflow: hidden; }",
     sprintf("body { padding: %s; margin: 0; }", collapseSizes(padding))
   ))
 
-  if (isTRUE(bootstrap)) {
-    bootstrapPage(title = title, theme = theme, fillCSS, ...)
+  ui <- if (isTRUE(bootstrap)) {
+    bootstrapPage(title = title, theme = theme, fillCSS, lang = lang, ...)
   } else {
     tagList(
       fillCSS,
       if (!is.null(title)) tags$head(tags$title(title)),
       ...
     )
   }
+
+  # Also store `lang` to be passed for rendering processor.
+  if (!isTRUE(bootstrap)) {
+    if (!is.null(lang)) {
+      if (is.character(lang) && length(lang) == 1) {
+        # Append lang attribute to be passed to renderPage function
+        attributes(ui) <- c(attributes(ui), list(lang = lang))
+      } else {
+        warning("Invalid lang value: defaulting to empty string.")
+        attributes(ui) <- c(attributes(ui), list(lang = NULL))
+      }
+    }
+  }
+
+  return(ui)
 }
 
 collapseSizes <- function(padding) {
@@ -226,6 +256,7 @@ collapseSizes <- function(padding) {
 #'   `www/bootstrap.css` you would use `theme = "bootstrap.css"`.
 #' @param windowTitle The title that should be displayed by the browser window.
 #'   Useful if `title` is not a string.
+#' @param lang ISO 639-1 language code used within the shiny app. Default is set to empty value.
 #' @param icon Optional icon to appear on a `navbarMenu` tab.
 #'
 #' @return A UI defintion that can be passed to the [shinyUI] function.
@@ -270,7 +301,8 @@ navbarPage <- function(title,
                        fluid = TRUE,
                        responsive = NULL,
                        theme = NULL,
-                       windowTitle = title) {
+                       windowTitle = title,
+                       lang = NULL) {
 
   if (!missing(collapsable)) {
     shinyDeprecated("`collapsable` is deprecated; use `collapsible` instead.")
@@ -341,6 +373,7 @@ navbarPage <- function(title,
     title = windowTitle,
     responsive = responsive,
     theme = theme,
+    lang = lang,
     tags$nav(class=navbarClass, role="navigation", containerDiv),
     contentDiv
   )

diff --git a/R/shinyui.R b/R/shinyui.R
@@ -25,6 +25,13 @@ withMathJax <- function(...) {
 }
 
 renderPage <- function(ui, showcase=0, testMode=FALSE) {
+  # Check if ui has lang attribute; otherwise, NULL
+  lang <- if ("lang" %in% names(attributes(ui))) {
+    attributes(ui)$lang
+  } else {
+    NULL
+  }
+
   # If the ui is a NOT complete document (created by htmlTemplate()), then do some
   # preprocessing and make sure it's a complete document.
   if (!inherits(ui, "html_document")) {
@@ -38,6 +45,7 @@ renderPage <- function(ui, showcase=0, testMode=FALSE) {
     # Put the body into the default template
     ui <- htmlTemplate(
       system.file("template", "default.html", package = "shiny"),
+      lang = lang,
       body = ui
     )
   }

diff --git a/inst/template/default.html b/inst/template/default.html
@@ -1,5 +1,5 @@
 <!DOCTYPE html>
-<html>
+<html lang = "{{ lang }}">
 <head>
 {{ headContent() }}
 </head>

diff --git a/inst/template/error.html b/inst/template/error.html
@@ -1,6 +1,6 @@
 <html>
 
-<head>
+<head lang = "en">
   <title>An error has occurred</title>
 </head>
 

diff --git a/man/bootstrapPage.Rd b/man/bootstrapPage.Rd
diff --git a/man/fillPage.Rd b/man/fillPage.Rd
diff --git a/man/fixedPage.Rd b/man/fixedPage.Rd
diff --git a/man/fluidPage.Rd b/man/fluidPage.Rd
diff --git a/man/navbarPage.Rd b/man/navbarPage.Rd