884136 - messages should be queued until the first listener is attached

Status: RESOLVED WONTFIX

(Add-on SDK Graveyard :: General, defect)

Description

[Erik Vold [:erikvold] (please needinfo? me)]

If I have a Sidebar/Panel/Widget thing that adds a `addon` global to the associated window, then it will be impossible to listen to the following 'X' message using the `addon` global.

In Addon:

    thing.once('attach', function(worker) {
      worker.port.emit('X', 'Y');
    });


In Content:

    <script>
    addon.on('X', function doStuff() {})
    </script>

IE `doStuff` above is never called.

The only way this message passing is possible is to have the window use the `addon` to initiate the communication, or wait until the window is loaded before emit messages to the worker.

At the moment the best solution I can think of is to queue these messages and emit them when the first available listener is attached.

This doesn't seem ideal tho..

Comment 1

[Erik Vold [:erikvold] (please needinfo? me)]

The example on https://github.com/mozilla/addon-sdk/wiki/JEP-Sidebars is a good example of what does not work, the same is true for panels.

Comment 2

[Erik Vold [:erikvold] (please needinfo? me)]

I just want to see what you think Irakli, before I attempt to patch this.

Comment 3

[Irakli Gozalishvili [:irakli] [:gozala] [@gozala]]

Erik I'm not convinced that queuing up messages by default is a good idea, it may make sense for that specific cases, but there maybe be others when it wouldn't. I think it would make more sense to expose something like `thing.on("ready", function(port) { ... })` instead or make a helper function like `enqueue(thing, "X", "Y")` that will queue up messages.

Comment 4

[Erik Vold [:erikvold] (please needinfo? me)]

(In reply to Irakli Gozilalishvili [:irakli] [:gozala] [@gozala] from comment #3)
> `thing.on("ready", function(port) { ... })` instead or make a helper
> function like `enqueue(thing, "X", "Y")` that will queue up messages.

I like both of these ideas, for now I think I will former, by emitting the `show` event when the sidebar loads instead of when it starts showing.

Atm my ui-sidebar branch emits `attach` when the window is created, before `show` which emits when the window loads.

sidebar.on('attach', function(worker) {});

sidebar.on('show', function({worker}) {});

So I think we can close this for now.  No matter when show emits we should be able to pass a worker.

Comment 5

[Dave Townsend [:mossop]]

Closing per the last comment.