Send basic JS info in data- attributes.

This includes the page version, session id, and comet ids and
versions. The data- attributes are set and read on the body
element of the page.

web/webkit/src/main/resources/toserve/lift.js

@@ -342,24 +342,59 @@
     }
 
     // Call on page load
-    function registerComet(tw, sessId) {
+    function registerComet(cometGuid, cometVersion, startComet) {
+      if (typeof startComet == 'undefined') {
+        startComet = true;
+      }
+
       toWatch = tw;
       sessionId = sessId;
 
-      cometSuccessFunc();
+      if (startComet === true) {
+        cometSuccessFunc();
+      }
     }
 
     // public object
     return {
       init: function(options) {
         // override default settings
         this.extend(settings, options);
+
+        var lift = this;
+        $(document).ready(function() {
+          var gc = document.body.getAttribute('data-lift-gc');
+          if (gc) {
+            lift.startGc();
+          }
+
+          var attributes = document.body.attributes,
+              cometGuid, cometVersion;
+          for (var i = 0; i < attributes.length; ++i) {
+            if (attributes[i].name == 'data-lift-gc') {
+              pageId = attributes[i].value;
+              lift.startGc();
+            } else if (attributes[i].name.match(/^data-lift-comet-/)) {
+              cometGuid = attributes[i].name.substring('data-lift-comet-'.length);
+              cometVersion = parseInt(attributes[i].value)
+
+              registerComet(cometGuid, cometVersion, false);
+            } else if (attributes[i].name == 'data-lift-session-id') {
+              sessionId = attributes[i].value
+            }
+          }
+
+          if (typeof cometGuid != 'undefined') {
+            cometSuccessFunc(); // we saw a comet, so start the comet cycle
+          }
+        });
+
         // start the cycle
         doCycleIn200();
       },
       logError: settings.logError,
       ajax: appendToQueue,
-      register: successRegisterGC,
+      startGc: successRegisterGC,
       ajaxOnSessionLost: function() {
         settings.ajaxOnSessionLost();
       },

web/webkit/src/main/scala/net/liftweb/http/LiftMerge.scala

@@ -203,19 +203,6 @@ private[http] trait LiftMerge {
         S.appendJs(LiftJavaScript.initCmd(LiftRules.javascriptSettings.vend().apply(this)))
       }
 
-      if (!cometList.isEmpty && LiftRules.autoIncludeComet(this)) {
-        S.appendJs(LiftRules.renderCometPageContents(this, cometList))
-      }
-
-      if (LiftRules.enableLiftGC && stateful_?) {
-        import js.JsCmds._
-
-        S.appendJs(JE.Call("window.lift.setPageId", RenderVersion.get))
-
-        if (!cometList.isEmpty || hasFuncsForOwner(RenderVersion.get))
-          S.appendJs(JE.Call("window.lift.register"))
-      }
-
       S.jsToAppend match {
         case Nil =>
         case x :: Nil => addlTail += js.JsCmds.Script(x)
@@ -228,10 +215,34 @@ private[http] trait LiftMerge {
 
       bodyChildren += nl
 
+      val bodyAttributes: List[(String, Option[String])] =
+        ("data-lift-gc" ->
+          Some(RenderVersion.get).filter { _ =>
+            LiftRules.enableLiftGC && stateful_?
+          }
+        ) ::
+        (
+          if (LiftRules.autoIncludeComet(this)) {
+            ("data-lift-session-id" -> Some(S.session.map(_.uniqueId) openOr "xx")) ::
+            cometList.map {
+              case CometVersionPair(guid, version) =>
+                (s"data-lift-comet-$guid" -> Some(version.toString))
+            }
+          } else {
+            Nil
+          }
+        )
+
       htmlKids += nl
       htmlKids += Elem(headTag.prefix, headTag.label, headTag.attributes, headTag.scope, headTag.minimizeEmpty, headChildren.toList: _*)
       htmlKids += nl
-      htmlKids += Elem(bodyTag.prefix, bodyTag.label, bodyTag.attributes, bodyTag.scope, bodyTag.minimizeEmpty, bodyChildren.toList: _*)
+      htmlKids +=
+        bodyAttributes.foldLeft(bodyTag.copy(child = bodyChildren.toList)) { (element, attribute) =>
+          attribute match {
+            case (name, Some(value)) => element % (name -> value)
+            case _ => element
+          }
+        }
       htmlKids += nl
 
       val tmpRet = Elem(htmlTag.prefix, htmlTag.label, htmlTag.attributes, htmlTag.scope, htmlTag.minimizeEmpty, htmlKids.toList: _*)

web/webkit/src/main/scala/net/liftweb/http/LiftRules.scala

@@ -1684,14 +1684,6 @@ class LiftRules() extends Factory with FormVendor with LazyLoggable {
         Empty
     } ) {}
 
-  /**
-   * Renders that JavaScript that holds Comet identification information
-   */
-  @volatile var renderCometPageContents: (LiftSession, Seq[CometVersionPair]) => JsCmd =
-  (session, vp) => JsCmds.Run(
-    "window.lift.registerComet(" + vp.map(p => p.guid.encJs + ": " + p.version).mkString("{", " , ", "}") + ", '"+S.encodeURL(session.uniqueId)+"');"
-    )
-
   /**
    * Holds the last update time of the Ajax request. Based on this server may return HTTP 304 status
    * indicating the client to used the cached information.
@@ -2073,6 +2065,11 @@ trait CometVersionPair {
 
   def version: Long
 }
+object CometVersionPair {
+  def unapply(pair: CometVersionPair): Option[(String, Long)] = {
+    Some((pair.guid, pair.version))
+  }
+}
 
 case class CVP(guid: String, version: Long) extends CometVersionPair