Dealing with missing room structure (eg Nodes)

Question

Hi,
I'm sure most developers have seen this error pop up during development:
"Error - insufficient permissions to create a new CollectionNode. You must be an OWNER of the room to add new multi-user features to it. Log in with developer credentials in order to do so."
This error occurs when a non-owner subscribes to an object that doesn't exist (there's an implicit attempt to create it, which fails).  As far as I can tell, this condition cannot be detected cleanly by a client application -- you're just supposed to make sure it doesn't happen on a released application.
If that's correct so far, then the design seems to assume that a given collaborating application connects to a specific well-known room (or at least, the template for the room is known).  What if the Flex code providing collaboration support is part of a library, and it doesn't know for sure that the provided room has the proper structure?  The goal here is to detect this situation and handle it within the library, without the error above happening.
BTW CollectionNode.canUserSubscribe doesn't seem to help out here.  It seems to return false unless you're already subscribed!
DB

Answer 1

Hi DB,
Sorry I misunderstood.
I have attached a code sample to see how you could handle the issue. The key here is to subscribe to your collection after your room is synchronized. Check the buildmodel() method.
<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" x="0" width="400" height="400"
                    xmlns:rtc="AfcsNameSpace" creationComplete="init(event);" xmlns:session="com.adobe.rtc.session.*">
     <mx:Script>
          <![CDATA[
               import com.adobe.rtc.authentication.AdobeHSAuthenticator;
               import com.adobe.rtc.events.AuthenticationEvent;
               import com.adobe.rtc.events.ChatEvent;
               import com.adobe.rtc.events.SessionEvent;
               import com.adobe.rtc.session.ConnectSessionContainer;
               import com.adobe.rtc.sharedModel.SimpleChatModel;
               import com.adobe.rtc.sharedModel.descriptors.ChatMessageDescriptor;
               import flash.events.*;
               import flash.ui.Keyboard;
               import mx.controls.Alert;
               // this simple example just shows how this shared model can be made easily binable for MXML.
               // See SimpleChatModel for details
               [Bindable]
               public var _auth:AdobeHSAuthenticator = new AdobeHSAuthenticator();
               [Bindable]
               public var simpleChatModel:SimpleChatModel;
               [Bindable]
               private var _cmd:ChatMessageDescriptor;
               protected function init(p_evt:Event):void
                    _auth.userName = "Guest";
                    _auth.password = null;
                    _auth.addEventListener(AuthenticationEvent.AUTHENTICATION_FAILURE, onAuthenticationResponse);
                    _auth.addEventListener(AuthenticationEvent.AUTHENTICATION_SUCCESS, onAuthenticationResponse);
                    cSession.addEventListener(SessionEvent.SYNCHRONIZATION_CHANGE, onSessionEventResponse);
                    cSession.addEventListener(SessionEvent.ERROR, onSessionEventResponse);
                    cSession.login();
               public function onAuthenticationResponse(event:AuthenticationEvent):void {
                    if (event.type == AuthenticationEvent.AUTHENTICATION_SUCCESS) {
                         trace("Authentication Succeeded");
                         //buildModel();
                    else if (event.type == AuthenticationEvent.AUTHENTICATION_FAILURE) {
                         Alert.show("Authentication Error : " + event.toString());
               public function onSessionEventResponse(event:Event):void {
                    if (event.type == SessionEvent.SYNCHRONIZATION_CHANGE) {
                         if (cSession.isSynchronized) {
                              //Now we are connected and the Pods have synchronized themselves, so switch to main Screen
                              //Switch to Collaborative Pods i.e. ConnectSessionContainer
                              //vsMain.selectedIndex = 1;
                              buildModel();
                         else {
                              //We are disconnected now
                              cSession.roomURL = null;
                              //vsMain.selectedIndex = 0;
                    else if (event.type == SessionEvent.ERROR) {
                         var sError:SessionEvent = event as SessionEvent;
                         Alert.show(sError.error.name + " : " + sError.error.message);
               private function buildModel():void
                    // Create the model: just calling the constructor won't create the collection node or pass the messages.
                    // Call subscribe and five it a shared ID while creating the model.
                    // The shared ID becomes the name of the collection node.
                    try {
                         simpleChatModel = new SimpleChatModel(true);
                         simpleChatModel.sharedID = "simpleChatModel1";
                         simpleChatModel.subscribe();
                    } catch(e:Error) {
                         trace("Slow death :(");
                    simpleChatModel.addEventListener(ChatEvent.HISTORY_CHANGE, onChatMsg);
               private function submitChat(str:String):void
                    _cmd = new ChatMessageDescriptor();
                    _cmd.displayName = cSession.userManager.getUserDescriptor(cSession.userManager.myUserID).displayName;
                    trace(_cmd.displayName);
                    trace(str);
                    _cmd.msg = str;
                    simpleChatModel.sendMessage(_cmd);
                    chat_msg_input.text = "";
               private function clearChat():void
                    chat_msg_area.text = "";
                    simpleChatModel.clear();
               private function onChatMsg(evt:ChatEvent):void
                    if (evt.message != null && evt.message.msg != null && evt.message.displayName != null)
                         chat_msg_area.text +=  evt.message.displayName + ": " + evt.message.msg + "\r";
                    } else {
                         chat_msg_area.text = "";
          ]]>
     </mx:Script>
     <session:ConnectSessionContainer roomURL="https://connectnow.acrobat.com/USERNAME/ROOMNAME" authenticator="{_auth}"
                                         id="cSession"
                                         width="100%"
                                         height="100%"
                                         autoLogin="false" >
          <mx:VBox width="100%" height="100%">
               <mx:TextArea width="100%" height="100%" id="chat_msg_area" />
               <mx:ControlBar >
                    <mx:TextInput width="100%" id="chat_msg_input" />
                    <mx:Button label="Submit Chat" click="{ submitChat(chat_msg_input.text) }" />
                    <mx:Button label="Clear Chat" click="clearChat()" />
               </mx:ControlBar>
          </mx:VBox>
     </session:ConnectSessionContainer>
</mx:Application>