yahoo news video doesn't play on placeholder activation

[al_9x]

Fx 3.6.17 & 4.0.1, NS 2.1.0.3 & 2.1.0.4rc6, new profile, block flash on trusted

http://news.yahoo.com/video/

This is caused by the instantiation code keeping a reference to the temp dummy embed and then when the activated player fires a ready event (the player receives the event handler via the flashvars) the dummy is used to initiate playback, instead of the real object.

This type of problem could be solved by a new kind of page level activation surrogate that NS would invoke immediately after obtaining a reference to an activated object, somehow passing this reference to it, allowing it to connect the object to the page JS and initialize it if necessarily. In this case simply updating the reference should do the trick. This can probably also fix quicktime activation on apple.com. What do you think of this approach?

[Giorgio Maone]

It sounds good. Any code?

[Giorgio Maone]

Sorry, I made some attempts but didn't manage to make this work.
The main problem is that the object originally instantiated cannot be reused (it needs to be cloned in order to play correctly), so the instance grabbed by the code cannot be manipulated.
On the other hand, there's no way to change the instance itself.
Probably the only way to make this is modifying original instance to proxy every single call and forward it to the new instance: I'm trying, but so far with not much success because of native wrappers. Surely it won't make next stable.

If you've got other ideas, please feel free to share.

[Giorgio Maone]

OK, this is what I'm currently trying right before replacing the placeholder with the cloned embedded element:

Code: Select all

var obj = ctx.object.cloneNode(true);
let sb = new CU.Sandbox(ctx.window, { wantXrays: false });
sb.o = ctx.object;
sb.c = obj;
sb.w = ctx.window;
            CU.evalInSandbox("for (var p in o) if (typeof o[p] === 'function') (function(p) { c[p] = o[p]; o[p] = function() { w.alert(p); return c[p].apply(c, arguments); }})(p)", sb);

While the function proxying code seems to work correctly, I never see an alert with a function call.
It would seem no function gets called on the original object, unless I'm missing something.

[al_9x]

Sorry, I made some attempts but didn't manage to make this work.

The idea I had was to execute a per page customized piece of code (surrogate) on placeholder activation after the plugin is created, allowing this code to update the page's references to the plugin, that would otherwise continue pointing to the dead dummy node. From my debugging session, it looked possible, there is only a single reference to the plugin object and it's reachable and updatable from top level page code (surrogate)

You seem to be trying a generic approach by turning the dummy into a proxy to the real node? If that can work reliably, it would be better than a surrogate and ought to be sufficient in this case. Are there caveats, like property access or anything layout related? There are probably scenarios where extra initialization is needed after instantiation so an activation surrogate would still be necessary.

It would seem no function gets called on the original object

I debugged the page, before the first post, the player is definitely scripted after becoming ready, that's how it gets its playlist, which is not supplied through the flashvars

[Giorgio Maone]

The idea I had was to execute a per page customized piece of code (surrogate) on placeholder activation after the plugin is created, allowing this code to update the page's references to the plugin, that would otherwise continue pointing to the dead dummy node. From my debugging session, it looked possible, there is only a single reference to the plugin object and it's reachable and updatable from top level page code (surrogate)

So this should be an ad hoc per-site surrogate, right?
And how should it look like?
As far as I could see, the stored instance is a local var called "instance" which is visible only from inside some closures, and as such it's not updatable by my code.
Am I missing something obvious?

[al_9x]

So this should be an ad hoc per-site surrogate, right?

Yes, page level, invoked on plugin activation. Are you giving up on proxying?

And how should it look like?

It would need to receive the ref to the created plugin (player id and flashvars which could be useful can be obtained from it, right?). Not sure what is that best way to accomplish this, maybe have the surrogate define a function that NS would call? That could be done by a @ surrogate, so no need for a new type.

As far as I could see, the stored instance is a local var called "instance" which is visible only from inside some closures, and as such it's not updatable by my code.
Am I missing something obvious?

The ref to the player embed is "YAHOO.Media.Hub.Player.player._player" and should be updatable. Where did you see this "instance" var?

[Giorgio Maone]

So this should be an ad hoc per-site surrogate, right?

Yes, page level, invoked on plugin activation. Are you giving up on proxying?

Yes, because it doesn't work. It seems the player doesn't get called directly.

And how should it look like?

It would need to receive the ref to the created plugin (player id and flashvars which could be useful can be obtained from it, right?).

In fact, I changed all the code above with just

Code: Select all

ScriptSurrogate.execute(doc, ' YAHOO.Media.Hub.Player.player._player = document.getElementById("' + obj.id + '")')

called just after the node gets replaced. The replacement does work, but the movie does not autoplay anyway.

The ref to the player embed is "YAHOO.Media.Hub.Player.player._player" and should be updatable. Where did you see this "instance" var?

Calling "toSource()" on functions (e.g. accessibilityFunction()) called by the player's UI elements, such as

Code: Select all

<button id="player_access_controls_play_63299" accesskey="1" title="Play/Pause Video" value="Play/Pause Video" onclick="YEP63299.accessibilityFunction('togglePlayPause')">Play/Pause Video</button>

[al_9x]

So this should be an ad hoc per-site surrogate, right?

Yes, page level, invoked on plugin activation. Are you giving up on proxying?

Yes, because it doesn't work. It seems the player doesn't get called directly.

Their code sets innerhtml and then does getelementnyid on the same stack to get the player ref. Does it not retrieve the dummy node which forwards, this way? Then since they definitely call through that ref to load the playlist and start playback, why would forwarding not work?

And how should it look like?

It would need to receive the ref to the created plugin (player id and flashvars which could be useful can be obtained from it, right?).

In fact, I changed all the code above with just

Code: Select all

ScriptSurrogate.execute(doc, ' YAHOO.Media.Hub.Player.player._player = document.getElementById("' + obj.id + '")')

called just after the node gets replaced. The replacement does work, but the movie does not autoplay anyway.

The page polls for player readiness and then starts playback, so as long as the ref is updated before ready fires, it should work. Can you make a test build (or paste the code, so I can add it) where you invoke a content function (if present, to be set up by a surrogate) immediately after player creation (it has to be synchronous with no delays, otherwise ready will fire first). I'll play around with it, try to get it working.

The ref to the player embed is "YAHOO.Media.Hub.Player.player._player" and should be updatable. Where did you see this "instance" var?

Calling "toSource()" on functions (e.g. accessibilityFunction()) called by the player's UI elements, such as

Code: Select all

<button id="player_access_controls_play_63299" accesskey="1" title="Play/Pause Video" value="Play/Pause Video" onclick="YEP63299.accessibilityFunction('togglePlayPause')">Play/Pause Video</button>

What you're seeing there is a delegate function:

Code: Select all

        function _delegate(instance, method) {
            return function() {
                return method.apply(instance, arguments)
            }
        }

it forwards to the real accessibilityFunction which ends up calling the player via the sole reference to it, YAHOO.Media.Hub.Player.player._player.

[Giorgio Maone]

You don't need a custom build, you can just leverage DOM mutation events:

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document.getElementsByClassName("__noscriptPlaceholder__")[0].parentNode.addEventListener("DOMNodeInserted", function(ev) { 
  if (ev.target instanceof HTMLEmbedElement) alert(YAHOO.Media.Hub.Player.player._player = ev.target); 
}, false)

(of course run this after page's onload fires to ensure the placeholder is there)

[al_9x]

You don't need a custom build, you can just leverage DOM mutation events:

Code: Select all

document.getElementsByClassName("__noscriptPlaceholder__")[0].parentNode.addEventListener("DOMNodeInserted", function(ev) { 
  if (ev.target instanceof HTMLEmbedElement) alert(YAHOO.Media.Hub.Player.player._player = ev.target); 
}, false)

(of course run this after page's onload fires to ensure the placeholder is there)

ok, i'll try this, is it guaranteed to be called before the plugin can fire any events?

[Giorgio Maone]

You don't need a custom build, you can just leverage DOM mutation events:

Code: Select all

document.getElementsByClassName("__noscriptPlaceholder__")[0].parentNode.addEventListener("DOMNodeInserted", function(ev) { 
  if (ev.target instanceof HTMLEmbedElement) alert(YAHOO.Media.Hub.Player.player._player = ev.target); 
}, false)

(of course run this after page's onload fires to ensure the placeholder is there)

ok, i'll try this, is it guaranteed to be called before the plugin can fire any events?

Yes, it's called even before the next instruction in the same flow as the replaceChild() call which inserts the element.

[al_9x]

You don't need a custom build, you can just leverage DOM mutation events:

Code: Select all

document.getElementsByClassName("__noscriptPlaceholder__")[0].parentNode.addEventListener("DOMNodeInserted", function(ev) { 
  if (ev.target instanceof HTMLEmbedElement) alert(YAHOO.Media.Hub.Player.player._player = ev.target); 
}, false)

(of course run this after page's onload fires to ensure the placeholder is there)

This worked. I ran it as a bookmarklet, then the plugin started playing on activation. The placeholder is not yet there onload, so one would have poll for it, or perhaps attach to another node since I think the event bubbles. Regardless, it's cumbersome to set this up using current functionality, is it worth it making it easier?

About the proxying, the page saves the ref returned by getelementbyid, is it getting your proxy this way? If not that explains it, but if it is, then I don't see why it wouldn't work.

[Giorgio Maone]

Should be fixed in latest development build (by dynamically proxying both the placeholder and the original removed element, so that custom methods are intercepted no matter how the reference had been obtained).

[al_9x]

Should be fixed in latest development build (by dynamically proxying both the placeholder and the original removed element, so that custom methods are intercepted no matter how the reference had been obtained).

Ok in 4.0.1, but not working in 3.6.17, should it?