Bug 779011 - Attach id's to all requests to prevent Marionette from getting out-of-sync, r=mdas, a=NPOTB

testing/marionette/components/marionettecomponent.js

@@ -19,7 +19,7 @@ function MarionetteComponent() {
   this._loaded = false;
   // set up the logger
   this.logger = Log4Moz.repository.getLogger("Marionette");
-  this.logger.level = Log4Moz.Level["All"];
+  this.logger.level = Log4Moz.Level["INFO"];
   let logf = FileUtils.getFile('ProfD', ['marionette.log']);
   
   let formatter = new Log4Moz.BasicFormatter();

testing/marionette/marionette-actors.js

@@ -123,6 +123,7 @@ function MarionetteRemoteFrame(windowId, frameId) {
   this.frameId = frameId;
   this.targetFrameId = null;
   this.messageManager = null;
+  this.command_id = null;
 }
 // persistent list of remote frames that Marionette has loaded a frame script in
 let remoteFrames = [];
@@ -239,6 +240,10 @@ MarionetteDriverActor.prototype = {
     messageManager.removeMessageListener("Marionette:switchToFrame", this);
   },
 
+  logRequest: function MDA_logRequest(type, data) {
+    logger.debug("Got request: " + type + ", data: " + JSON.stringify(data) + ", id: " + this.command_id);
+  },
+
   /**
    * Generic method to pass a response to the client
    *
@@ -250,9 +255,12 @@ MarionetteDriverActor.prototype = {
    */
   sendToClient: function MDA_sendToClient(msg, command_id) {
     logger.info("sendToClient: " + JSON.stringify(msg) + ", " + command_id + ", " + this.command_id);
-    if (this.command_id != null &&
+    if (!command_id) {
-        command_id != null &&
+      logger.warn("got a response with no command_id");
+    }
+    else if (this.command_id &&
         this.command_id != command_id) {
+      logger.warn("ignoring out-of-sync response");
       return;
     }
     this.conn.send(msg);
@@ -432,8 +440,20 @@ MarionetteDriverActor.prototype = {
     }
   },
 
+  getCommandId: function MDA_getCommandId() {
+    return this.uuidGen.generateUUID().toString();
+  },
+
   /**
    * Marionette API:
+   *
+   * All methods implementing a command from the client should create a
+   * command_id, and then use this command_id in all messages exchanged with
+   * the frame scripts and with responses sent to the client.  This prevents
+   * commands and responses from getting out-of-sync, which can happen in
+   * the case of execute_async calls that timeout and then later send a
+   * response, and other situations.  See bug 779011. See setScriptTimeout()
+   * for a basic example.
    */
 
   /**
@@ -444,6 +464,8 @@ MarionetteDriverActor.prototype = {
    *
    */
   newSession: function MDA_newSession() {
+    this.command_id = this.getCommandId();
+
     this.scriptTimeout = 10000;
 
     function waitForWindow() {
@@ -471,11 +493,13 @@ MarionetteDriverActor.prototype = {
       this.messageManager.broadcastAsyncMessage("Marionette:restart", {});
     }
     else {
-      this.sendError("Session already running", 500, null);
+      this.sendError("Session already running", 500, null, this.command_id);
     }
   },
 
   getSessionCapabilities: function MDA_getSessionCapabilities(){
+    this.command_id = this.getCommandId();
+
     let rotatable = appName == "B2G" ? true : false;
 
     let value = {
@@ -492,10 +516,12 @@ MarionetteDriverActor.prototype = {
           'version': Services.appinfo.version
     };
 
-    this.sendResponse(value);
+    this.sendResponse(value, this.command_id);
   },
 
   getStatus: function MDA_getStatus(){
+    this.command_id = this.getCommandId();
+
     let arch;
     try {
       arch = (Services.appinfo.XPCOMABI || 'unknown').split('-')[0]
@@ -517,7 +543,7 @@ MarionetteDriverActor.prototype = {
           }
     };
 
-    this.sendResponse(value);
+    this.sendResponse(value, this.command_id);
   },
 
   /**
@@ -528,30 +554,34 @@ MarionetteDriverActor.prototype = {
    *        'level' member hold log level
    */
   log: function MDA_log(aRequest) {
+    this.command_id = this.getCommandId();
     this.marionetteLog.log(aRequest.value, aRequest.level);
-    this.sendOk();
+    this.sendOk(this.command_id);
   },
 
   /**
    * Return all logged messages.
    */
   getLogs: function MDA_getLogs() {
-    this.sendResponse(this.marionetteLog.getLogs());
+    this.command_id = this.getCommandId();
+    this.sendResponse(this.marionetteLog.getLogs(), this.command_id);
   },
   
   /**
    * Log some performance data
    */
   addPerfData: function MDA_addPerfData(aRequest) {
+    this.command_id = this.getCommandId();
     this.marionettePerf.addPerfData(aRequest.suite, aRequest.name, aRequest.value);
-    this.sendOk();
+    this.sendOk(this.command_id);
   },
 
   /**
    * Retrieve the performance data
    */
   getPerfData: function MDA_getPerfData() {
-    this.sendResponse(this.marionettePerf.getPerfData());
+    this.command_id = this.getCommandId();
+    this.sendResponse(this.marionettePerf.getPerfData(), this.command_id);
   },
 
   /**
@@ -561,13 +591,15 @@ MarionetteDriverActor.prototype = {
    *        'value' member holds the name of the context to be switched to
    */
   setContext: function MDA_setContext(aRequest) {
+    this.command_id = this.getCommandId();
+    this.logRequest("setContext", aRequest);
     let context = aRequest.value;
     if (context != "content" && context != "chrome") {
-      this.sendError("invalid context", 500, null);
+      this.sendError("invalid context", 500, null, this.command_id);
     }
     else {
       this.context = context;
-      this.sendOk();
+      this.sendOk(this.command_id);
     }
   },
 
@@ -637,11 +669,11 @@ MarionetteDriverActor.prototype = {
    *        True if the script is asynchronous
    */
   executeScriptInSandbox: function MDA_executeScriptInSandbox(sandbox, script,
-     directInject, async) {
+     directInject, async, command_id) {
 
     if (directInject && async &&
         (this.scriptTimeout == null || this.scriptTimeout == 0)) {
-      this.sendError("Please set a timeout", 21, null);
+      this.sendError("Please set a timeout", 21, null, command_id);
       return;
     }
 
@@ -657,12 +689,13 @@ MarionetteDriverActor.prototype = {
 
     if (directInject && !async &&
         (res == undefined || res.passed == undefined)) {
-      this.sendError("finish() not called", 500, null);
+      this.sendError("finish() not called", 500, null, command_id);
       return;
     }
 
     if (!async) {
-      this.sendResponse(this.curBrowser.elementManager.wrapValue(res));
+      this.sendResponse(this.curBrowser.elementManager.wrapValue(res),
+                        command_id);
     }
   },
 
@@ -678,6 +711,8 @@ MarionetteDriverActor.prototype = {
    *        function body
    */
   execute: function MDA_execute(aRequest, directInject) {
+    let command_id = this.command_id = this.getCommandId();
+    this.logRequest("execute", aRequest);
     if (aRequest.newSandbox == undefined) {
       //if client does not send a value in newSandbox, 
       //then they expect the same behaviour as webdriver
@@ -687,7 +722,8 @@ MarionetteDriverActor.prototype = {
       this.sendAsync("executeScript", {value: aRequest.value,
                                        args: aRequest.args,
                                        newSandbox: aRequest.newSandbox,
-                                       timeout: this.scriptTimeout});
+                                       timeout: this.scriptTimeout,
+                                       command_id: command_id});
       return;
     }
 
@@ -695,7 +731,10 @@ MarionetteDriverActor.prototype = {
     let marionette = new Marionette(this, curWindow, "chrome",
                                     this.marionetteLog, this.marionettePerf,
                                     this.scriptTimeout, this.testName);
-    let _chromeSandbox = this.createExecuteSandbox(curWindow, marionette, aRequest.args, aRequest.specialPowers);
+    let _chromeSandbox = this.createExecuteSandbox(curWindow,
+                                                   marionette,
+                                                   aRequest.args,
+                                                   aRequest.specialPowers);
     if (!_chromeSandbox)
       return;
 
@@ -714,10 +753,11 @@ MarionetteDriverActor.prototype = {
                      "};" +
                      "func.apply(null, __marionetteParams);";
       }
-      this.executeScriptInSandbox(_chromeSandbox, script, directInject, false);
+      this.executeScriptInSandbox(_chromeSandbox, script, directInject,
+                                  false, command_id);
     }
     catch (e) {
-      this.sendError(e.name + ': ' + e.message, 17, e.stack);
+      this.sendError(e.name + ': ' + e.message, 17, e.stack, command_id);
     }
   },
 
@@ -728,13 +768,14 @@ MarionetteDriverActor.prototype = {
    *        'value' member is time in milliseconds to set timeout
    */
   setScriptTimeout: function MDA_setScriptTimeout(aRequest) {
+    this.command_id = this.getCommandId();
     let timeout = parseInt(aRequest.value);
     if(isNaN(timeout)){
-      this.sendError("Not a Number", 500, null);
+      this.sendError("Not a Number", 500, null, this.command_id);
     }
     else {
       this.scriptTimeout = timeout;
-      this.sendOk();
+      this.sendOk(this.command_id);
     }
   },
 
@@ -747,6 +788,7 @@ MarionetteDriverActor.prototype = {
    *        'timeout' member will be used as the script timeout if it is given
    */
   executeJSScript: function MDA_executeJSScript(aRequest) {
+    let command_id = this.command_id = this.getCommandId();
     //all pure JS scripts will need to call Marionette.finish() to complete the test.
     if (aRequest.newSandbox == undefined) {
       //if client does not send a value in newSandbox, 
@@ -766,7 +808,8 @@ MarionetteDriverActor.prototype = {
                                           args: aRequest.args,
                                           newSandbox: aRequest.newSandbox,
                                           async: aRequest.async,
-                                          timeout: this.scriptTimeout });
+                                          timeout: this.scriptTimeout,
+                                          command_id: command_id });
    }
   },
 
@@ -786,19 +829,20 @@ MarionetteDriverActor.prototype = {
    *        function body
    */
   executeWithCallback: function MDA_executeWithCallback(aRequest, directInject) {
+    let command_id = this.command_id = this.getCommandId();
     if (aRequest.newSandbox == undefined) {
       //if client does not send a value in newSandbox, 
       //then they expect the same behaviour as webdriver
       aRequest.newSandbox = true;
     }
-    this.command_id = this.uuidGen.generateUUID().toString();
 
     if (this.context == "content") {
       this.sendAsync("executeAsyncScript", {value: aRequest.value,
                                             args: aRequest.args,
                                             id: this.command_id,
                                             newSandbox: aRequest.newSandbox,
-                                            timeout: this.scriptTimeout});
+                                            timeout: this.scriptTimeout,
+                                            command_id: command_id});
       return;
     }
 
@@ -875,7 +919,8 @@ MarionetteDriverActor.prototype = {
                 + '__marionetteFunc.apply(null, __marionetteParams);';
       }
 
-      this.executeScriptInSandbox(_chromeSandbox, script, directInject, true);
+      this.executeScriptInSandbox(_chromeSandbox, script, directInject,
+                                  true, command_id);
     } catch (e) {
       chromeAsyncReturnFunc(e.name + ": " + e.message, 17);
     }
@@ -888,7 +933,9 @@ MarionetteDriverActor.prototype = {
    *        'value' member holds the url to navigate to
    */
   goUrl: function MDA_goUrl(aRequest) {
+    let command_id = this.command_id = this.getCommandId();
     if (this.context != "chrome") {
+      aRequest.command_id = command_id;
       this.sendAsync("goUrl", aRequest);
       return;
     }
@@ -897,7 +944,7 @@ MarionetteDriverActor.prototype = {
     let checkTimer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
     function checkLoad() { 
       if (curWindow.document.readyState == "complete") { 
-        sendOk();
+        sendOk(command_id);
         return;
       } 
       checkTimer.initWithCallback(checkLoad, 100, Ci.nsITimer.TYPE_ONE_SHOT);
@@ -909,11 +956,12 @@ MarionetteDriverActor.prototype = {
    * Gets current url
    */
   getUrl: function MDA_getUrl() {
+    this.command_id = this.getCommandId();
     if (this.context == "chrome") {
-      this.sendResponse(this.getCurrentWindow().location.href);
+      this.sendResponse(this.getCurrentWindow().location.href, this.command_id);
     }
     else {
-      this.sendAsync("getUrl", {});
+      this.sendAsync("getUrl", {command_id: this.command_id});
     }
   },
 
@@ -921,21 +969,23 @@ MarionetteDriverActor.prototype = {
    * Gets the current title of the window
    */
   getTitle: function MDA_getTitle() {
-    this.sendAsync("getTitle", {});
+    this.command_id = this.getCommandId();
+    this.sendAsync("getTitle", {command_id: this.command_id});
   },
 
   /**
    * Gets the page source of the content document
    */
   getPageSource: function MDA_getPageSource(){
+    this.command_id = this.getCommandId();
     if (this.context == "chrome"){
       var curWindow = this.getCurrentWindow();
       var XMLSerializer = curWindow.XMLSerializer; 
       var pageSource = new XMLSerializer().serializeToString(curWindow.document);
-      this.sendResponse(pageSource);
+      this.sendResponse(pageSource, this.command_id);
     }
     else {
-      this.sendAsync("getPageSource", {});
+      this.sendAsync("getPageSource", {command_id: this.command_id});
     }
   },
 
@@ -943,30 +993,34 @@ MarionetteDriverActor.prototype = {
    * Go back in history
    */
   goBack: function MDA_goBack() {
-    this.sendAsync("goBack", {});
+    this.command_id = this.getCommandId();
+    this.sendAsync("goBack", {command_id: this.command_id});
   },
 
   /**
    * Go forward in history
    */
   goForward: function MDA_goForward() {
-    this.sendAsync("goForward", {});
+    this.command_id = this.getCommandId();
+    this.sendAsync("goForward", {command_id: this.command_id});
   },
 
   /**
    * Refresh the page
    */
   refresh: function MDA_refresh() {
-    this.sendAsync("refresh", {});
+    this.command_id = this.getCommandId();
+    this.sendAsync("refresh", {command_id: this.command_id});
   },
 
   /**
    * Get the current window's server-assigned ID
    */
   getWindow: function MDA_getWindow() {
+    this.command_id = this.getCommandId();
     for (let i in this.browsers) {
       if (this.curBrowser == this.browsers[i]) {
-        this.sendResponse(i);
+        this.sendResponse(i, this.command_id);
       }
     }
   },
@@ -975,6 +1029,7 @@ MarionetteDriverActor.prototype = {
    * Get the server-assigned IDs of all available windows
    */
   getWindows: function MDA_getWindows() {
+    this.command_id = this.getCommandId();
     let res = [];
     let winEn = this.getWinEnumerator(); 
     while(winEn.hasMoreElements()) {
@@ -983,7 +1038,7 @@ MarionetteDriverActor.prototype = {
       winId = winId + ((appName == "B2G") ? '-b2g' : '');
       res.push(winId)
     }
-    this.sendResponse(res);
+    this.sendResponse(res, this.command_id);
   },
 
   /**
@@ -994,6 +1049,7 @@ MarionetteDriverActor.prototype = {
    *        'value' member holds the name or id of the window to switch to
    */
   switchToWindow: function MDA_switchToWindow(aRequest) {
+    let command_id = this.command_id = this.getCommandId();
     let winEn = this.getWinEnumerator(); 
     while(winEn.hasMoreElements()) {
       let foundWin = winEn.getNext();
@@ -1010,11 +1066,12 @@ MarionetteDriverActor.prototype = {
           utils.window = foundWin;
           this.curBrowser = this.browsers[winId];
         }
-        this.sendOk();
+        this.sendOk(command_id);
         return;
       }
     }
-    this.sendError("Unable to locate window " + aRequest.value, 23, null);
+    this.sendError("Unable to locate window " + aRequest.value, 23, null,
+                   command_id);
   },
  
   /**
@@ -1027,15 +1084,17 @@ MarionetteDriverActor.prototype = {
    *                of the frame to switch to
    */
   switchToFrame: function MDA_switchToFrame(aRequest) {
+    let command_id = this.command_id = this.getCommandId();
+    this.logRequest("switchToFrame", aRequest);
     let checkTimer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
     let checkLoad = function() { 
       let errorRegex = /about:.+(error)|(blocked)\?/;
       if (curWindow.document.readyState == "complete") { 
-        this.sendOk();
+        this.sendOk(command_id);
         return;
       } 
       else if (curWindow.document.readyState == "interactive" && errorRegex.exec(curWindow.document.baseURI)) {
-        this.sendError("Error loading page", 13, null);
+        this.sendError("Error loading page", 13, null, command_id);
         return;
       }
       
@@ -1096,7 +1155,8 @@ MarionetteDriverActor.prototype = {
         this.curFrame.focus();
         checkTimer.initWithCallback(checkLoad.bind(this), 100, Ci.nsITimer.TYPE_ONE_SHOT);
       } else {
-        this.sendError("Unable to locate frame: " + aRequest.value, 8, null);
+        this.sendError("Unable to locate frame: " + aRequest.value, 8, null,
+                       command_id);
       }
     }
     else {
@@ -1108,6 +1168,7 @@ MarionetteDriverActor.prototype = {
         // we send the message to the right listener.
         this.switchToGlobalMessageManager();
       }
+      aRequest.command_id = command_id;
       this.sendAsync("switchToFrame", aRequest);
     }
   },
@@ -1119,17 +1180,19 @@ MarionetteDriverActor.prototype = {
    *        'value' holds the search timeout in milliseconds
    */
   setSearchTimeout: function MDA_setSearchTimeout(aRequest) {
+    this.command_id = this.getCommandId();
     if (this.context == "chrome") {
       try {
         this.curBrowser.elementManager.setSearchTimeout(aRequest.value);
-        this.sendOk();
+        this.sendOk(this.command_id);
       }
       catch (e) {
-        this.sendError(e.message, e.code, e.stack);
+        this.sendError(e.message, e.code, e.stack, this.command_id);
       }
     }
     else {
-      this.sendAsync("setSearchTimeout", {value: aRequest.value});
+      this.sendAsync("setSearchTimeout", {value: aRequest.value,
+                                          command_id: this.command_id});
     }
   },
 
@@ -1141,20 +1204,30 @@ MarionetteDriverActor.prototype = {
    *        'value' member is the value the client is looking for
    */
   findElement: function MDA_findElement(aRequest) {
+    let command_id = this.command_id = this.getCommandId();
     if (this.context == "chrome") {
       let id;
       try {
         let on_success = this.sendResponse.bind(this);
         let on_error = this.sendError.bind(this);
-        id = this.curBrowser.elementManager.find(this.getCurrentWindow(),aRequest, on_success, on_error, false);
+        id = this.curBrowser.elementManager.find(
+                              this.getCurrentWindow(),
+                              aRequest,
+                              on_success,
+                              on_error,
+                              false,
+                              command_id);
       }
       catch (e) {
-        this.sendError(e.message, e.code, e.stack);
+        this.sendError(e.message, e.code, e.stack, command_id);
         return;
       }
     }
     else {
-      this.sendAsync("findElementContent", {value: aRequest.value, using: aRequest.using, element: aRequest.element});
+      this.sendAsync("findElementContent", {value: aRequest.value,
+                                            using: aRequest.using,
+                                            element: aRequest.element,
+                                            command_id: command_id});
     }
   },
 
@@ -1166,20 +1239,29 @@ MarionetteDriverActor.prototype = {
    *        'value' member is the value the client is looking for
    */
   findElements: function MDA_findElements(aRequest) {
+    let command_id = this.command_id = this.getCommandId();
     if (this.context == "chrome") {
       let id;
       try {
         let on_success = this.sendResponse.bind(this);
         let on_error = this.sendError.bind(this);
-        id = this.curBrowser.elementManager.find(this.getCurrentWindow(), aRequest, on_success, on_error, true);
+        id = this.curBrowser.elementManager.find(this.getCurrentWindow(),
+                                                 aRequest,
+                                                 on_success,
+                                                 on_error,
+                                                 true,
+                                                 command_id);
       }
       catch (e) {
-        this.sendError(e.message, e.code, e.stack);
+        this.sendError(e.message, e.code, e.stack, command_id);
         return;
       }
     }
     else {
-      this.sendAsync("findElementsContent", {value: aRequest.value, using: aRequest.using, element: aRequest.element});
+      this.sendAsync("findElementsContent", {value: aRequest.value,
+                                             using: aRequest.using,
+                                             element: aRequest.element,
+                                             command_id: command_id});
     }
   },
 
@@ -1191,19 +1273,22 @@ MarionetteDriverActor.prototype = {
    *        the element that will be clicked
    */
   clickElement: function MDA_clickElement(aRequest) {
+    let command_id = this.command_id = this.getCommandId();
     if (this.context == "chrome") {
       try {
         //NOTE: click atom fails, fall back to click() action
-        let el = this.curBrowser.elementManager.getKnownElement(aRequest.element, this.getCurrentWindow());
+        let el = this.curBrowser.elementManager.getKnownElement(
+            aRequest.element, this.getCurrentWindow());
         el.click();
-        this.sendOk();
+        this.sendOk(command_id);
       }
       catch (e) {
-        this.sendError(e.message, e.code, e.stack);
+        this.sendError(e.message, e.code, e.stack, command_id);
       }
     }
     else {
-      this.sendAsync("clickElement", {element: aRequest.element});
+      this.sendAsync("clickElement", {element: aRequest.element,
+                                      command_id: command_id});
     }
   },
 
@@ -1216,17 +1301,22 @@ MarionetteDriverActor.prototype = {
    *        'name' member holds the name of the attribute to retrieve
    */
   getElementAttribute: function MDA_getElementAttribute(aRequest) {
+    let command_id = this.command_id = this.getCommandId();
     if (this.context == "chrome") {
       try {
-        let el = this.curBrowser.elementManager.getKnownElement(aRequest.element, this.getCurrentWindow());
+        let el = this.curBrowser.elementManager.getKnownElement(
-        this.sendResponse(utils.getElementAttribute(el, aRequest.name));
+            aRequest.element, this.getCurrentWindow());
+        this.sendResponse(utils.getElementAttribute(el, aRequest.name),
+                          command_id);
       }
       catch (e) {
-        this.sendError(e.message, e.code, e.stack);
+        this.sendError(e.message, e.code, e.stack, command_id);
       }
     }
     else {
-      this.sendAsync("getElementAttribute", {element: aRequest.element, name: aRequest.name});
+      this.sendAsync("getElementAttribute", {element: aRequest.element,
+                                             name: aRequest.name,
+                                             command_id: command_id});
     }
   },
 
@@ -1238,21 +1328,24 @@ MarionetteDriverActor.prototype = {
    *        the element that will be inspected 
    */
   getElementText: function MDA_getElementText(aRequest) {
+    let command_id = this.command_id = this.getCommandId();
     if (this.context == "chrome") {
       //Note: for chrome, we look at text nodes, and any node with a "label" field
       try {
-        let el = this.curBrowser.elementManager.getKnownElement(aRequest.element, this.getCurrentWindow());
+        let el = this.curBrowser.elementManager.getKnownElement(
+            aRequest.element, this.getCurrentWindow());
         let lines = [];
         this.getVisibleText(el, lines);
         lines = lines.join("\n");
-        this.sendResponse(lines);
+        this.sendResponse(lines, command_id);
       }
       catch (e) {
-        this.sendError(e.message, e.code, e.stack);
+        this.sendError(e.message, e.code, e.stack, command_id);
       }
     }
     else {
-      this.sendAsync("getElementText", {element: aRequest.element});
+      this.sendAsync("getElementText", {element: aRequest.element,
+                                        command_id: command_id});
     }
   },
 
@@ -1264,17 +1357,20 @@ MarionetteDriverActor.prototype = {
    *        the element that will be inspected 
    */
   getElementTagName: function MDA_getElementTagName(aRequest) {
+    let command_id = this.command_id = this.getCommandId();
     if (this.context == "chrome") {
       try {
-        let el = this.curBrowser.elementManager.getKnownElement(aRequest.element, this.getCurrentWindow());
+        let el = this.curBrowser.elementManager.getKnownElement(
-        this.sendResponse(el.tagName.toLowerCase());
+            aRequest.element, this.getCurrentWindow());
+        this.sendResponse(el.tagName.toLowerCase(), command_id);
       }
       catch (e) {
-        this.sendError(e.message, e.code, e.stack);
+        this.sendError(e.message, e.code, e.stack, command_id);
       }
     }
     else {
-      this.sendAsync("getElementTagName", {element: aRequest.element});
+      this.sendAsync("getElementTagName", {element: aRequest.element,
+                                           command_id: command_id});
     }
   },
 
@@ -1286,17 +1382,20 @@ MarionetteDriverActor.prototype = {
    *        the element that will be checked 
    */
   isElementDisplayed: function MDA_isElementDisplayed(aRequest) {
+    let command_id = this.command_id = this.getCommandId();
     if (this.context == "chrome") {
       try {
-        let el = this.curBrowser.elementManager.getKnownElement(aRequest.element, this.getCurrentWindow());
+        let el = this.curBrowser.elementManager.getKnownElement(
-        this.sendResponse(utils.isElementDisplayed(el));
+            aRequest.element, this.getCurrentWindow());
+        this.sendResponse(utils.isElementDisplayed(el), command_id);
       }
       catch (e) {
-        this.sendError(e.message, e.code, e.stack);
+        this.sendError(e.message, e.code, e.stack, command_id);
       }
     }
     else {
-      this.sendAsync("isElementDisplayed", {element:aRequest.element});
+      this.sendAsync("isElementDisplayed", {element:aRequest.element,
+                                            command_id: command_id});
     }
   },
 
@@ -1308,23 +1407,26 @@ MarionetteDriverActor.prototype = {
    *        the element that will be checked
    */
   isElementEnabled: function MDA_isElementEnabled(aRequest) {
+    let command_id = this.command_id = this.getCommandId();
     if (this.context == "chrome") {
       try {
         //Selenium atom doesn't quite work here
-        let el = this.curBrowser.elementManager.getKnownElement(aRequest.element, this.getCurrentWindow());
+        let el = this.curBrowser.elementManager.getKnownElement(
+            aRequest.element, this.getCurrentWindow());
         if (el.disabled != undefined) {
-          this.sendResponse(!!!el.disabled);
+          this.sendResponse(!!!el.disabled, command_id);
         }
         else {
-        this.sendResponse(true);
+        this.sendResponse(true, command_id);
         }
       }
       catch (e) {
-        this.sendError(e.message, e.code, e.stack);
+        this.sendError(e.message, e.code, e.stack, command_id);
       }
     }
     else {
-      this.sendAsync("isElementEnabled", {element:aRequest.element});
+      this.sendAsync("isElementEnabled", {element:aRequest.element,
+                                          command_id: command_id});
     }
   },
 
@@ -1336,42 +1438,49 @@ MarionetteDriverActor.prototype = {
    *        the element that will be checked
    */
   isElementSelected: function MDA_isElementSelected(aRequest) {
+    let command_id = this.command_id = this.getCommandId();
     if (this.context == "chrome") {
       try {
         //Selenium atom doesn't quite work here
-        let el = this.curBrowser.elementManager.getKnownElement(aRequest.element, this.getCurrentWindow());
+        let el = this.curBrowser.elementManager.getKnownElement(
+            aRequest.element, this.getCurrentWindow());
         if (el.checked != undefined) {
-          this.sendResponse(!!el.checked);
+          this.sendResponse(!!el.checked, command_id);
         }
         else if (el.selected != undefined) {
-          this.sendResponse(!!el.selected);
+          this.sendResponse(!!el.selected, command_id);
         }
         else {
-          this.sendResponse(true);
+          this.sendResponse(true, command_id);
         }
       }
       catch (e) {
-        this.sendError(e.message, e.code, e.stack);
+        this.sendError(e.message, e.code, e.stack, command_id);
       }
     }
     else {
-      this.sendAsync("isElementSelected", {element:aRequest.element});
+      this.sendAsync("isElementSelected", {element:aRequest.element,
+                                           command_id: command_id});
     }
   },
 
   getElementSize: function MDA_getElementSize(aRequest) {
+    let command_id = this.command_id = this.getCommandId();
     if (this.context == "chrome") {
       try {
-        let el = this.curBrowser.elementManager.getKnownElement(aRequest.element, this.getCurrentWindow());
+        let el = this.curBrowser.elementManager.getKnownElement(
+            aRequest.element, this.getCurrentWindow());
         let clientRect = el.getBoundingClientRect();  
-        this.sendResponse({width: clientRect.width, height: clientRect.height});
+        this.sendResponse({width: clientRect.width, height: clientRect.height},
+                          command_id);
       }
       catch (e) {
-        this.sendError(e.message, e.code, e.stack);
+        this.sendError(e.message, e.code, e.stack, command_id);
       }
     }
     else {
-      this.sendAsync("getElementSize", {element:aRequest.element});
+      this.sendAsync("getElementSize", {element:aRequest.element,
+                                        command_id: command_id});
     }
   },
 
@@ -1384,19 +1493,23 @@ MarionetteDriverActor.prototype = {
    *        'value' member holds the value to send to the element
    */
   sendKeysToElement: function MDA_sendKeysToElement(aRequest) {
+    let command_id = this.command_id = this.getCommandId();
     if (this.context == "chrome") {
       try {
-        let el = this.curBrowser.elementManager.getKnownElement(aRequest.element, this.getCurrentWindow());
+        let el = this.curBrowser.elementManager.getKnownElement(
+            aRequest.element, this.getCurrentWindow());
         el.focus();
         utils.sendString(aRequest.value.join(""), utils.window);
-        this.sendOk();
+        this.sendOk(command_id);
       }
       catch (e) {
-        this.sendError(e.message, e.code, e.stack);
+        this.sendError(e.message, e.code, e.stack, command_id);
       }
     }
     else {
-      this.sendAsync("sendKeysToElement", {element:aRequest.element, value: aRequest.value});
+      this.sendAsync("sendKeysToElement", {element:aRequest.element,
+                                           value: aRequest.value,
+                                           command_id: command_id});
     }
   },
 
@@ -1406,8 +1519,11 @@ MarionetteDriverActor.prototype = {
    * The test name is used in logging messages.
    */
   setTestName: function MDA_setTestName(aRequest) {
+    this.command_id = this.getCommandId();
+    this.logRequest("setTestName", aRequest);
     this.testName = aRequest.value;
-    this.sendAsync("setTestName", {value: aRequest.value});
+    this.sendAsync("setTestName", {value: aRequest.value,
+                                   command_id: this.command_id});
   },
 
   /**
@@ -1418,29 +1534,34 @@ MarionetteDriverActor.prototype = {
    *        the element that will be cleared 
    */
   clearElement: function MDA_clearElement(aRequest) {
+    let command_id = this.command_id = this.getCommandId();
     if (this.context == "chrome") {
       //the selenium atom doesn't work here
       try {
-        let el = this.curBrowser.elementManager.getKnownElement(aRequest.element, this.getCurrentWindow());
+        let el = this.curBrowser.elementManager.getKnownElement(
+            aRequest.element, this.getCurrentWindow());
         if (el.nodeName == "textbox") {
           el.value = "";
         }
         else if (el.nodeName == "checkbox") {
           el.checked = false;
         }
-        this.sendOk();
+        this.sendOk(command_id);
       }
       catch (e) {
-        this.sendError(e.message, e.code, e.stack);
+        this.sendError(e.message, e.code, e.stack, command_id);
       }
     }
     else {
-      this.sendAsync("clearElement", {element:aRequest.element});
+      this.sendAsync("clearElement", {element:aRequest.element,
+                                      command_id: command_id});
     }
   },
 
   getElementPosition: function MDA_getElementPosition(aRequest) {
-      this.sendAsync("getElementPosition", {element:aRequest.element});
+    this.command_id = this.getCommandId();
+    this.sendAsync("getElementPosition", {element:aRequest.element,
+                                          command_id: this.command_id});
   },
 
   /**
@@ -1452,9 +1573,10 @@ MarionetteDriverActor.prototype = {
    * 1 then it deletes the session otherwise it closes the window
    */
   closeWindow: function MDA_closeWindow() {
+    let command_id = this.command_id = this.getCommandId();
     if (appName == "B2G") {
       // We can't close windows so just return
-      this.sendOk();
+      this.sendOk(command_id);
     }
     else {
       // Get the total number of windows
@@ -1474,10 +1596,11 @@ MarionetteDriverActor.prototype = {
       try{
         this.messageManager.removeDelayedFrameScript(FRAME_SCRIPT); 
         this.getCurrentWindow().close();
-        this.sendOk();
+        this.sendOk(command_id);
       }
       catch (e) {
-        this.sendError("Could not close window: " + e.message, 13, e.stack);
+        this.sendError("Could not close window: " + e.message, 13, e.stack,
+                       command_id);
       }
     }
   }, 
@@ -1492,10 +1615,13 @@ MarionetteDriverActor.prototype = {
    * and can safely be reused.
    */
   deleteSession: function MDA_deleteSession() {
+    let command_id = this.command_id = this.getCommandId();
     if (this.curBrowser != null) {
       if (appName == "B2G") {
-        this.globalMessageManager.broadcastAsyncMessage("Marionette:sleepSession" + this.curBrowser.mainContentId, {});
+        this.globalMessageManager.broadcastAsyncMessage(
-        this.curBrowser.knownFrames.splice(this.curBrowser.knownFrames.indexOf(this.curBrowser.mainContentId), 1);
+            "Marionette:sleepSession" + this.curBrowser.mainContentId, {});
+        this.curBrowser.knownFrames.splice(
+            this.curBrowser.knownFrames.indexOf(this.curBrowser.mainContentId), 1);
       }
       else {
         //don't set this pref for B2G since the framescript can be safely reused
@@ -1513,7 +1639,7 @@ MarionetteDriverActor.prototype = {
         winEnum.getNext().messageManager.removeDelayedFrameScript(FRAME_SCRIPT); 
       }
     }
-    this.sendOk();
+    this.sendOk(command_id);
     this.removeMessageManagerListeners(this.globalMessageManager);
     this.switchToGlobalMessageManager();
     // reset frame to the top-most frame
@@ -1533,7 +1659,8 @@ MarionetteDriverActor.prototype = {
    * Returns the current status of the Application Cache
    */
   getAppCacheStatus: function MDA_getAppCacheStatus(aRequest) {
-    this.sendAsync("getAppCacheStatus");
+    this.command_id = this.getCommandId();
+    this.sendAsync("getAppCacheStatus", {command_id: this.command_id});
   },
 
   _emu_cb_id: 0,
@@ -1574,23 +1701,28 @@ MarionetteDriverActor.prototype = {
   },
   
   importScript: function MDA_importScript(aRequest) {
+    let command_id = this.command_id = this.getCommandId();
     if (this.context == "chrome") {
       let file;
       if (this.importedScripts.exists()) {
-        file = FileUtils.openFileOutputStream(this.importedScripts, FileUtils.MODE_APPEND | FileUtils.MODE_WRONLY);
+        file = FileUtils.openFileOutputStream(this.importedScripts,
+            FileUtils.MODE_APPEND | FileUtils.MODE_WRONLY);
       }
       else {
         //Note: The permission bits here don't actually get set (bug 804563)
-        this.importedScripts.createUnique(Components.interfaces.nsIFile.NORMAL_FILE_TYPE, parseInt("0666", 8));
+        this.importedScripts.createUnique(
-        file = FileUtils.openFileOutputStream(this.importedScripts, FileUtils.MODE_WRONLY | FileUtils.MODE_CREATE);
+            Components.interfaces.nsIFile.NORMAL_FILE_TYPE, parseInt("0666", 8));
+        file = FileUtils.openFileOutputStream(this.importedScripts,
+            FileUtils.MODE_WRONLY | FileUtils.MODE_CREATE);
         this.importedScripts.permissions = parseInt("0666", 8); //actually set permissions
       }
       file.write(aRequest.script, aRequest.script.length);
       file.close();
-      this.sendOk();
+      this.sendOk(command_id);
     }
     else {
-      this.sendAsync("importScript", {script: aRequest.script});
+      this.sendAsync("importScript", {script: aRequest.script,
+                                      command_id: command_id});
     }
   },
 
@@ -1661,6 +1793,7 @@ MarionetteDriverActor.prototype = {
           let frame = remoteFrames[i];
           if ((frame.messageManager == mm)) {
             this.currentRemoteFrame = frame;
+            this.currentRemoteFrame.command_id = message.json.command_id;
             this.messageManager = frame.messageManager;
             this.addMessageManagerListeners(this.messageManager);
             this.messageManager.sendAsyncMessage("Marionette:restart", {});
@@ -1675,6 +1808,7 @@ MarionetteDriverActor.prototype = {
         this.messageManager = mm;
         let aFrame = new MarionetteRemoteFrame(message.json.win, message.json.frame);
         aFrame.messageManager = this.messageManager;
+        aFrame.command_id = message.json.command_id;
         remoteFrames.push(aFrame);
         this.currentRemoteFrame = aFrame;
         break;
@@ -1702,7 +1836,8 @@ MarionetteDriverActor.prototype = {
           this.sendAsync(
               "setState",
               {scriptTimeout: this.scriptTimeout,
-               searchTimeout: this.curBrowser.elementManager.searchTimeout});
+               searchTimeout: this.curBrowser.elementManager.searchTimeout,
+               command_id: this.currentRemoteFrame.command_id});
         }
 
         let browserType;

testing/marionette/marionette-elements.js

@@ -256,7 +256,7 @@ ElementManager.prototype = {
    * @return nsIDOMElement or list of nsIDOMElements
    *        Returns the element(s) by calling the on_success function.
    */
-  find: function EM_find(win, values, on_success, on_error, all) {
+  find: function EM_find(win, values, on_success, on_error, all, command_id) {
     let startTime = values.time ? values.time : new Date().getTime();
     let startNode = (values.element != undefined) ? this.getKnownElement(values.element, win) : win.document;
     if (this.elementStrategies.indexOf(values.using) < 0) {
@@ -270,19 +270,23 @@ ElementManager.prototype = {
         for (let i = 0 ; i < found.length ; i++) {
           ids.push(this.addToKnownElements(found[i]));
         }
-        on_success(ids);
+        on_success(ids, command_id);
       }
       else {
         let id = this.addToKnownElements(found);
-        on_success(id);
+        on_success(id, command_id);
       }
       return;
     } else {
       if (this.searchTimeout == 0 || new Date().getTime() - startTime > this.searchTimeout) {
-        on_error("Unable to locate element: " + values.value, 7, null);
+        on_error("Unable to locate element: " + values.value, 7, null, command_id);
       } else {
         values.time = startTime;
-        this.timer.initWithCallback(this.find.bind(this, win, values, on_success, on_error, all), 100, Components.interfaces.nsITimer.TYPE_ONE_SHOT);
+        this.timer.initWithCallback(this.find.bind(this, win, values,
+                                                   on_success, on_error, all,
+                                                   command_id),
+                                    100,
+                                    Components.interfaces.nsITimer.TYPE_ONE_SHOT);
       }
     }
   },

testing/marionette/marionette-listener.js

@@ -61,8 +61,9 @@ let checkTimer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
 function registerSelf() {
   Services.io.manageOfflineStatus = false;
   Services.io.offline = false;
-  let register = sendSyncMessage("Marionette:register", {value: winUtil.outerWindowID, href: content.location.href});
+  let msg = {value: winUtil.outerWindowID, href: content.location.href};
-  
+  let register = sendSyncMessage("Marionette:register", msg);
+
   if (register[0]) {
     listenerId = register[0];
     startListeners();
@@ -151,16 +152,16 @@ function setState(msg) {
     elementManager.setSearchTimeout(msg.json.searchTimeout);
   }
   catch (e) {
-    sendError(e.message, e.code, e.stack);
+    sendError(e.message, e.code, e.stack, msg.json.command_id);
     return;
   }
-  sendOk();
+  sendOk(msg.json.command_id);
 }
 
 /**
  * Restarts all our listeners after this listener was put to sleep
  */
-function restart() {
+function restart(msg) {
   removeMessageListener("Marionette:restart", restart);
   registerSelf();
 }
@@ -322,7 +323,8 @@ function createExecuteContentSandbox(aWindow, timeout) {
                   500, null, asyncTestCommandId);
       }
       else {
-        sendResponse({value: elementManager.wrapValue(value), status: status}, asyncTestCommandId);
+        sendResponse({value: elementManager.wrapValue(value), status: status},
+                     asyncTestCommandId);
       }
     }
     else {
@@ -352,12 +354,13 @@ function createExecuteContentSandbox(aWindow, timeout) {
  * or directly (for 'mochitest' like JS Marionette tests)
  */
 function executeScript(msg, directInject) {
+  let asyncTestCommandId = msg.json.command_id;
   let script = msg.json.value;
 
   if (msg.json.newSandbox || !sandbox) {
     sandbox = createExecuteContentSandbox(curWindow, msg.json.timeout);
     if (!sandbox) {
-      sendError("Could not create sandbox!");
+      sendError("Could not create sandbox!", asyncTestCommandId);
       return;
     }
   }
@@ -377,10 +380,10 @@ function executeScript(msg, directInject) {
       marionetteLogObj.clearLogs();
       marionettePerf.clearPerfData();
       if (res == undefined || res.passed == undefined) {
-        sendError("Marionette.finish() not called", 17, null);
+        sendError("Marionette.finish() not called", 17, null, asyncTestCommandId);
       }
       else {
-        sendResponse({value: elementManager.wrapValue(res)});
+        sendResponse({value: elementManager.wrapValue(res)}, asyncTestCommandId);
       }
     }
     else {
@@ -389,7 +392,7 @@ function executeScript(msg, directInject) {
           msg.json.args, curWindow);
       }
       catch(e) {
-        sendError(e.message, e.code, e.stack);
+        sendError(e.message, e.code, e.stack, asyncTestCommandId);
         return;
       }
 
@@ -407,12 +410,12 @@ function executeScript(msg, directInject) {
                                                perf: elementManager.wrapValue(marionettePerf.getPerfData())});
       marionetteLogObj.clearLogs();
       marionettePerf.clearPerfData();
-      sendResponse({value: elementManager.wrapValue(res)});
+      sendResponse({value: elementManager.wrapValue(res)}, asyncTestCommandId);
     }
   }
   catch (e) {
     // 17 = JavascriptException
-    sendError(e.name + ': ' + e.message, 17, e.stack);
+    sendError(e.name + ': ' + e.message, 17, e.stack, asyncTestCommandId);
   }
 }
 
@@ -421,7 +424,7 @@ function executeScript(msg, directInject) {
  */
 function setTestName(msg) {
   marionetteTestName = msg.json.value;
-  sendOk();
+  sendOk(msg.json.command_id);
 }
 
 /**
@@ -454,7 +457,7 @@ function executeJSScript(msg) {
 function executeWithCallback(msg, useFinish) {
   curWindow.addEventListener("unload", errUnload, false);
   let script = msg.json.value;
-  asyncTestCommandId = msg.json.id;
+  let asyncTestCommandId = msg.json.command_id;
 
   if (msg.json.newSandbox || !sandbox) {
     sandbox = createExecuteContentSandbox(curWindow, msg.json.timeout);
@@ -463,6 +466,7 @@ function executeWithCallback(msg, useFinish) {
       return;
     }
   }
+  sandbox.tag = script;
 
   // Error code 28 is scriptTimeout, but spec says execute_async should return 21 (Timeout),
   // see http://code.google.com/p/selenium/wiki/JsonWireProtocol#/session/:sessionId/execute_async.
@@ -482,7 +486,7 @@ function executeWithCallback(msg, useFinish) {
   let scriptSrc;
   if (useFinish) {
     if (msg.json.timeout == null || msg.json.timeout == 0) {
-      sendError("Please set a timeout", 21, null);
+      sendError("Please set a timeout", 21, null, asyncTestCommandId);
     }
     scriptSrc = script;
   }
@@ -492,7 +496,7 @@ function executeWithCallback(msg, useFinish) {
         msg.json.args, curWindow);
     }
     catch(e) {
-      sendError(e.message, e.code, e.stack);
+      sendError(e.message, e.code, e.stack, asyncTestCommandId);
       return;
     }
 
@@ -525,10 +529,10 @@ function setSearchTimeout(msg) {
     elementManager.setSearchTimeout(msg.json.value);
   }
   catch (e) {
-    sendError(e.message, e.code, e.stack);
+    sendError(e.message, e.code, e.stack, msg.json.command_id);
     return;
   }
-  sendOk();
+  sendOk(msg.json.command_id);
 }
 
 /**
@@ -536,6 +540,7 @@ function setSearchTimeout(msg) {
  * All other navigation is handled by the server (in chrome space).
  */
 function goUrl(msg) {
+  let command_id = msg.json.command_id;
   addEventListener("DOMContentLoaded", function onDOMContentLoaded(event) {
     // Prevent DOMContentLoaded events from frames from invoking this code,
     // unless the event is coming from the frame associated with the current
@@ -546,11 +551,11 @@ function goUrl(msg) {
 
       let errorRegex = /about:.+(error)|(blocked)\?/;
       if (curWindow.document.readyState == "interactive" && errorRegex.exec(curWindow.document.baseURI)) {
-        sendError("Error loading page", 13, null);
+        sendError("Error loading page", 13, null, command_id);
         return;
       }
 
-      sendOk();
+      sendOk(command_id);
     }
   }, false);
   curWindow.location = msg.json.value;
@@ -560,14 +565,14 @@ function goUrl(msg) {
  * Get the current URI
  */
 function getUrl(msg) {
-  sendResponse({value: curWindow.location.href});
+  sendResponse({value: curWindow.location.href}, msg.json.command_id);
 }
 
 /**
  * Get the current Title of the window
  */
 function getTitle(msg) {
-  sendResponse({value: curWindow.top.document.title});
+  sendResponse({value: curWindow.top.document.title}, msg.json.command_id);
 }
 
 /**
@@ -576,7 +581,7 @@ function getTitle(msg) {
 function getPageSource(msg) {
   var XMLSerializer = curWindow.XMLSerializer;
   var pageSource = new XMLSerializer().serializeToString(curWindow.document);
-  sendResponse({value: pageSource });
+  sendResponse({value: pageSource}, msg.json.command_id);
 }
 
 /**
@@ -584,7 +589,7 @@ function getPageSource(msg) {
  */
 function goBack(msg) {
   curWindow.history.back();
-  sendOk();
+  sendOk(msg.json.command_id);
 }
 
 /**
@@ -592,15 +597,19 @@ function goBack(msg) {
  */
 function goForward(msg) {
   curWindow.history.forward();
-  sendOk();
+  sendOk(msg.json.command_id);
 }
 
 /**
  * Refresh the page
  */
 function refresh(msg) {
+  let command_id = msg.json.command_id;
   curWindow.location.reload(true);
-  let listen = function() { removeEventListener("DOMContentLoaded", arguments.callee, false); sendOk() } ;
+  let listen = function() {
+    removeEventListener("DOMContentLoaded", arguments.callee, false);
+    sendOk(command_id);
+  };
   addEventListener("DOMContentLoaded", listen, false);
 }
 
@@ -608,13 +617,14 @@ function refresh(msg) {
  * Find an element in the document using requested search strategy 
  */
 function findElementContent(msg) {
+  let command_id = msg.json.command_id;
   try {
-    let on_success = function(id) { sendResponse({value:id}); };
+    let on_success = function(id, cmd_id) { sendResponse({value:id}, cmd_id); };
     let on_error = sendError;
-    elementManager.find(curWindow, msg.json, on_success, on_error, false);
+    elementManager.find(curWindow, msg.json, on_success, on_error, false, command_id);
   }
   catch (e) {
-    sendError(e.message, e.code, e.stack);
+    sendError(e.message, e.code, e.stack, command_id);
   }
 }
 
@@ -622,13 +632,14 @@ function findElementContent(msg) {
  * Find elements in the document using requested search strategy 
  */
 function findElementsContent(msg) {
+  let command_id = msg.json.command_id;
   try {
-    let on_success = function(id) { sendResponse({value:id}); };
+    let on_success = function(id, cmd_id) { sendResponse({value:id}, cmd_id); };
     let on_error = sendError;
-    elementManager.find(curWindow, msg.json, on_success, on_error, true);
+    elementManager.find(curWindow, msg.json, on_success, on_error, true, command_id);
   }
   catch (e) {
-    sendError(e.message, e.code, e.stack);
+    sendError(e.message, e.code, e.stack, command_id);
   }
 }
 
@@ -636,14 +647,15 @@ function findElementsContent(msg) {
  * Send click event to element
  */
 function clickElement(msg) {
+  let command_id = msg.json.command_id;
   let el;
   try {
     el = elementManager.getKnownElement(msg.json.element, curWindow);
     utils.click(el);
-    sendOk();
+    sendOk(command_id);
   }
   catch (e) {
-    sendError(e.message, e.code, e.stack);
+    sendError(e.message, e.code, e.stack, command_id);
   }
 }
 
@@ -651,12 +663,14 @@ function clickElement(msg) {
  * Get a given attribute of an element
  */
 function getElementAttribute(msg) {
+  let command_id = msg.json.command_id;
   try {
     let el = elementManager.getKnownElement(msg.json.element, curWindow);
-    sendResponse({value: utils.getElementAttribute(el, msg.json.name)});
+    sendResponse({value: utils.getElementAttribute(el, msg.json.name)},
+                 command_id);
   }
   catch (e) {
-    sendError(e.message, e.code, e.stack);
+    sendError(e.message, e.code, e.stack, command_id);
   }
 }
 
@@ -664,12 +678,13 @@ function getElementAttribute(msg) {
  * Get the text of this element. This includes text from child elements.
  */
 function getElementText(msg) {
+  let command_id = msg.json.command_id;
   try {
     let el = elementManager.getKnownElement(msg.json.element, curWindow);
-    sendResponse({value: utils.getElementText(el)});
+    sendResponse({value: utils.getElementText(el)}, command_id);
   }
   catch (e) {
-    sendError(e.message, e.code, e.stack);
+    sendError(e.message, e.code, e.stack, command_id);
   }
 }
 
@@ -677,12 +692,13 @@ function getElementText(msg) {
  * Get the tag name of an element.
  */
 function getElementTagName(msg) {
+  let command_id = msg.json.command_id;
   try {
     let el = elementManager.getKnownElement(msg.json.element, curWindow);
-    sendResponse({value: el.tagName.toLowerCase()});
+    sendResponse({value: el.tagName.toLowerCase()}, command_id);
   }
   catch (e) {
-    sendError(e.message, e.code, e.stack);
+    sendError(e.message, e.code, e.stack, command_id);
   }
 }
 
@@ -690,12 +706,13 @@ function getElementTagName(msg) {
  * Check if element is displayed
  */
 function isElementDisplayed(msg) {
+  let command_id = msg.json.command_id;
   try {
     let el = elementManager.getKnownElement(msg.json.element, curWindow);
-    sendResponse({value: utils.isElementDisplayed(el)});
+    sendResponse({value: utils.isElementDisplayed(el)}, command_id);
   }
   catch (e) {
-    sendError(e.message, e.code, e.stack);
+    sendError(e.message, e.code, e.stack, command_id);
   }
 }
 
@@ -703,13 +720,15 @@ function isElementDisplayed(msg) {
  * Get the size of the element and return it
  */
 function getElementSize(msg){
+  let command_id = msg.json.command_id;
   try {
     let el = elementManager.getKnownElement(msg.json.element, curWindow);
     let clientRect = el.getBoundingClientRect();  
-    sendResponse({value: {width: clientRect.width, height: clientRect.height}});
+    sendResponse({value: {width: clientRect.width, height: clientRect.height}},
+                 command_id);
   }
   catch (e) {
-    sendError(e.message, e.code, e.stack);
+    sendError(e.message, e.code, e.stack, command_id);
   }
 }
 
@@ -717,12 +736,13 @@ function getElementSize(msg){
  * Check if element is enabled
  */
 function isElementEnabled(msg) {
+  let command_id = msg.json.command_id;
   try {
     let el = elementManager.getKnownElement(msg.json.element, curWindow);
-    sendResponse({value: utils.isElementEnabled(el)});
+    sendResponse({value: utils.isElementEnabled(el)}, command_id);
   }
   catch (e) {
-    sendError(e.message, e.code, e.stack);
+    sendError(e.message, e.code, e.stack, command_id);
   }
 }
 
@@ -730,12 +750,13 @@ function isElementEnabled(msg) {
  * Check if element is selected
  */
 function isElementSelected(msg) {
+  let command_id = msg.json.command_id;
   try {
     let el = elementManager.getKnownElement(msg.json.element, curWindow);
-    sendResponse({value: utils.isElementSelected(el)});
+    sendResponse({value: utils.isElementSelected(el)}, command_id);
   }
   catch (e) {
-    sendError(e.message, e.code, e.stack);
+    sendError(e.message, e.code, e.stack, command_id);
   }
 }
 
@@ -743,13 +764,14 @@ function isElementSelected(msg) {
  * Send keys to element
  */
 function sendKeysToElement(msg) {
+  let command_id = msg.json.command_id;
   try {
     let el = elementManager.getKnownElement(msg.json.element, curWindow);
     utils.type(curWindow.document, el, msg.json.value.join(""), true);
-    sendOk();
+    sendOk(command_id);
   }
   catch (e) {
-    sendError(e.message, e.code, e.stack);
+    sendError(e.message, e.code, e.stack, command_id);
   }
 }
 
@@ -757,6 +779,7 @@ function sendKeysToElement(msg) {
  * Get the position of an element
  */
 function getElementPosition(msg) {
+  let command_id = msg.json.command_id;
   try{
     let el = elementManager.getKnownElement(msg.json.element, curWindow);
     var x = el.offsetLeft;
@@ -785,10 +808,10 @@ function getElementPosition(msg) {
     location.x = x;
     location.y = y;
 
-    sendResponse({value: location});
+    sendResponse({value: location}, command_id);
   }
   catch (e) {
-    sendError(e.message, e.code, e.stack);
+    sendError(e.message, e.code, e.stack, command_id);
   }
 }
 
@@ -796,13 +819,14 @@ function getElementPosition(msg) {
  * Clear the text of an element
  */
 function clearElement(msg) {
+  let command_id = msg.json.command_id;
   try {
     let el = elementManager.getKnownElement(msg.json.element, curWindow);
     utils.clearElement(el);
-    sendOk();
+    sendOk(command_id);
   }
   catch (e) {
-    sendError(e.message, e.code, e.stack);
+    sendError(e.message, e.code, e.stack, command_id);
   }
 }
 
@@ -811,14 +835,15 @@ function clearElement(msg) {
  * its index in window.frames, or the iframe's name or id.
  */
 function switchToFrame(msg) {
+  let command_id = msg.json.command_id;
   function checkLoad() { 
     let errorRegex = /about:.+(error)|(blocked)\?/;
     if (curWindow.document.readyState == "complete") {
-      sendOk();
+      sendOk(command_id);
       return;
     } 
     else if (curWindow.document.readyState == "interactive" && errorRegex.exec(curWindow.document.baseURI)) {
-      sendError("Error loading page", 13, null);
+      sendError("Error loading page", 13, null, command_id);
       return;
     }
     checkTimer.initWithCallback(checkLoad, 100, Ci.nsITimer.TYPE_ONE_SHOT);
@@ -876,7 +901,7 @@ function switchToFrame(msg) {
     }
   }
   if (foundFrame == null) {
-    sendError("Unable to locate frame: " + msg.json.value, 8, null);
+    sendError("Unable to locate frame: " + msg.json.value, 8, null, command_id);
     return;
   }
 
@@ -886,7 +911,9 @@ function switchToFrame(msg) {
     // The frame we want to switch to is a remote frame; notify our parent to handle
     // the switch.
     curWindow = content;
-    sendToServer('Marionette:switchToFrame', {frame: foundFrame, win: parWindow});
+    sendToServer('Marionette:switchToFrame', {frame: foundFrame,
+                                              win: parWindow,
+                                              command_id: command_id});
   }
   else {
     curWindow = curWindow.contentWindow;
@@ -895,8 +922,9 @@ function switchToFrame(msg) {
   }
 }
 
-function getAppCacheStatus() {
+function getAppCacheStatus(msg) {
-  sendResponse({ value: curWindow.applicationCache.status });
+  sendResponse({ value: curWindow.applicationCache.status },
+               msg.json.command_id);
 }
 
 // emulator callbacks
@@ -931,19 +959,23 @@ function emulatorCmdResult(msg) {
 }
 
 function importScript(msg) {
+  let command_id = msg.json.command_id;
   let file;
   if (importedScripts.exists()) {
-    file = FileUtils.openFileOutputStream(importedScripts, FileUtils.MODE_APPEND | FileUtils.MODE_WRONLY);
+    file = FileUtils.openFileOutputStream(importedScripts,
+        FileUtils.MODE_APPEND | FileUtils.MODE_WRONLY);
   }
   else {
     //Note: The permission bits here don't actually get set (bug 804563)
-    importedScripts.createUnique(Components.interfaces.nsIFile.NORMAL_FILE_TYPE, parseInt("0666", 8));
+    importedScripts.createUnique(Components.interfaces.nsIFile.NORMAL_FILE_TYPE,
-    file = FileUtils.openFileOutputStream(importedScripts, FileUtils.MODE_WRONLY | FileUtils.MODE_CREATE);
+                                 parseInt("0666", 8));
+    file = FileUtils.openFileOutputStream(importedScripts,
+                                          FileUtils.MODE_WRONLY | FileUtils.MODE_CREATE);
     importedScripts.permissions = parseInt("0666", 8); //actually set permissions
   }
   file.write(msg.json.script, msg.json.script.length);
   file.close();
-  sendOk();
+  sendOk(command_id);
 }
 
 /**