added multiplex support via a few additional options

ox-reveal.el

@@ -137,6 +137,28 @@ can be include."
   :group 'org-export-reveal
   :type 'string)
 
+
+(defcustom org-reveal-multiplex-id ""
+  "The ID to use for multiplexing."
+  :group 'org-export-reveal
+  :type 'string)
+
+(defcustom org-reveal-multiplex-secret ""
+  "The secret to use for master slide."
+  :group 'org-export-reveal
+  :type 'string)
+
+(defcustom org-reveal-multiplex-url ""
+  "The url of the socketio server."
+  :group 'org-export-reveal
+  :type 'string)
+
+(defcustom org-reveal-multiplex-socketio-url
+  ""
+  "the url of the socketio.js library"
+  :group 'org-export-reveal
+  :type 'string)
+
 (defcustom org-reveal-control t
   "Reveal control applet."
   :group 'org-export-reveal
@@ -239,7 +261,8 @@ can be include."
           (const zoom)
           (const notes)
           (const search)
-          (const remotes)))
+          (const remotes)
+          (const multiplex)))
 
 (defun if-format (fmt val)
   (if val (format fmt val) ""))
@@ -461,6 +484,21 @@ transition: Reveal.getQueryHash().transition || '%s', // default/cube/page/conca
 transitionSpeed: '%s',\n"
              (plist-get info :reveal-trans)
              (plist-get info :reveal-speed))
+
+     ;; multiplexing - depends on defvar 'client-multiplex'
+     (when (plist-get info :reveal-multiplex-id)
+       (format
+"multiplex: {
+    secret: %s, // null if client
+    id: '%s', // id, obtained from socket.io server
+    url: '%s' // Location of socket.io server
+},\n"
+             (if (eq client-multiplex nil)
+                 (format "'%s'" (plist-get info :reveal-multiplex-secret))
+               (format "null"))
+             (plist-get info :reveal-multiplex-id)
+             (plist-get info :reveal-multiplex-url)))
+
      ;; optional JS library heading
      "
 // Optional libraries used to extend on reveal.js
@@ -475,7 +513,17 @@ dependencies: [
                zoom (format " { src: '%splugin/zoom-js/zoom.js', async: true, condition: function() { return !!document.body.classList; } }" root-path)
                notes (format " { src: '%splugin/notes/notes.js', async: true, condition: function() { return !!document.body.classList; } }" root-path)
                search (format " { src: '%splugin/search/search.js', async: true, condition: function() { return !!document.body.classList; } }" root-path)
-               remotes (format " { src: '%splugin/remotes/remotes.js', async: true, condition: function() { return !!document.body.classList; } }" root-path)))
+               remotes (format " { src: '%splugin/remotes/remotes.js', async: true, condition: function() { return !!document.body.classList; } }" root-path)
+               multiplex (format " { src: '%s', async: true },\n%s"
+                                 (plist-get info :reveal-multiplex-socketio-url)
+                                 ; following ensures that either client.js or master.js is included depending on defva client-multiplex value state
+                                 (if (not client-multiplex)
+                                     (progn
+                                       (if (plist-get info :reveal-multiplex-secret)
+                                          (setq client-multiplex t))
+                                       (format " { src: '%splugin/multiplex/master.js', async: true }" root-path))
+
+                                   (format " { src: '%splugin/multiplex/client.js', async: true }" root-path)))))
             (builtin-codes
              (mapcar
                (lambda (p)
@@ -744,15 +792,28 @@ info is a plist holding export options."
 </html>\n"))
 
 
+(defvar client-multiplex nil
+  "used to cause generation of client html file for multiplex")
 
 (defun org-reveal-export-to-html
   (&optional async subtreep visible-only body-only ext-plist)
   "Export current buffer to a reveal.js HTML file."
   (interactive)
   (let* ((extension (concat "." org-html-extension))
-         (file (org-export-output-file-name extension subtreep)))
-    (org-export-to-file 'reveal file
-      async subtreep visible-only body-only ext-plist)))
+         (file (org-export-output-file-name extension subtreep))
+         (clientfile (org-export-output-file-name (concat "_client" extension) subtreep)))
+
+    ; export filename_client HTML file if multiplexing
+    (setq client-multiplex nil)
+    (setq retfile (org-export-to-file 'reveal file
+                    async subtreep visible-only body-only ext-plist))
+
+    ; export the client HTML file if client-multiplex is set true
+    ; by previous call to org-export-to-file
+    (if (eq client-multiplex t)
+        (org-export-to-file 'reveal clientfile
+          async subtreep visible-only body-only ext-plist))
+    (cond (t retfile))))
 
 (defun org-reveal-export-to-html-and-browse
   (&optional async subtreep visible-only body-only ext-plist)