Can't recieve port message from main.js in content script - firefox-addon

Question

I am trying to send a message via port from my main.js to my content script for my panel. I've tried many things without luck, however sending a message from the content script to main.js works perfectly.
Here is what my main.js looks like:
var data = require("self").data;
var setting = require("panel").Panel({
width: 250,
height: 130,
contentURL: data.url("www.google.com"),
contentScriptFile: data.url("script.js")
});
require("widget").Widget({
id: "sorter1",
label: "Search Result Sorting",
contentURL: data.url("icon.ico"),
panel: setting
});
setting.port.emit("message");
And here is my content script:
self.on("message", function(addonMessage) {
document.innerHTML = "Got Message"
});

Answer 1

I had this figured out a few days ago, just haven't had the time to post here.
A few things to keep in mind when using panels:
Pannel page is loaded when extension is loaded, not when it is shown.
Content script of the panel page is injected into the panel page when the page is shown.(when contentScriptWhen property is default)
Content scripts dont have access to add-on SDK resources.
This is how I implemented it
In main.js
panel.on("show", function() {
panel.port.emit("message");
});
In panel content script
self.port.on("message", function() {
//doThings
});
port.emit() doesn't need a second argument, though second argument is what will be passed to the content script for
function(secondArg) {
}

Answer 2

[Update] Sorry, I didn't fully read the code.
First off, you actually need to send the panel a message, eg
setting.port.emit('message', someData);
For the second part: I think you want:
self.port.on("message", function(addonMessage) {
document.innerHTML = "Got Message"
});
The relevant docs are here:
https://addons.mozilla.org/en-US/developers/docs/sdk/latest/dev-guide/guides/content-scripts/using-port.html