Creating MessageChannel from framescript or bootstrap.js

Add-ons Development
#1

I couldn’t find a way to create a MessageChannel in framescript so what I’m doing is spawning a webworker, having it create the ports, then transfer them both to the framescript:

var portWorker = new Worker(core.addon.path.scripts + 'msgchanWorker.js');
    portWorker.onmessage = function(e) {
        portWorker.terminate();
        var port = e.data.port1;
        var port2 = e.data.port2;
        console.log('port:', port, 'port2:', port2);
    }

I terminate the worker there too.
Here is code in worker:

var msgchan = new MessageChannel();
self.postMessage({
    port1: msgchan.port1,
    port2: msgchan.port2
}, [msgchan.port1, msgchan.port2]);

This works, but spawining a worker, especially during startup of the browser is not ideal.

Does anyone have any other ways to create a MessageChannel in these scopes?

#2

Hi Noitidart Have you tried sending back the messages from the frame script to the main process using the messagemanager API and then handle it there ?

#3

Yep I’m brushing up a API I wrote for that right now. It works pretty great. I should be done touching it up in a couple days. I can help you drop in what I have right now though if your repo is on github.

#4

Thanks. I’m currently working on some frame script stuff now at the minute and cleaning up some code. I’ll see how I get on and If I can’t get it working I’ll message you in a few days. Thanks for the offer. I appreciate it. As for the repo I believe you are already familiar with it, random agent spoofer :wink:

#5

Oh super sweet! Just realized RAS stood for!! hahaha

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#6

Oh a note from sending message from framescript to bootstrap via messageManager API - communication between framescript and bootstrap is cross process, so transferring is not option. So getting messagechannel ports can’t be sent like that. :frowning: So my framescript-bootstrap comm part of the api, does the same thing, just no transferring of stuff.

The three communications layer are:

  • bootstrap-worker - transferring allowed
  • bootstrap-framescript
  • bootstrap-content / framescript-content - transferring allowed
#7

I have not used bootstrap so I’m not too familiar with it but what I meant was to use the main addon context scope to facilitate communication between the areas that can’t naturally communicate. so framescript <-> messagemanager <-> chrome context <-> any other part of of the addon via exports/require

So if you can access boostrap from anything in /lib/ you can get at it from a frame script.

Another thing you could try is lazily initialize the worker so it is only created on first use rather than startup.

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