What is the best way to directly send a message from a panel to a page-mod's content script?

Question

What is the best way to directly send a message from a panel to a page-mod's content script?

When working with a code snippet in a Firefox addon like the one below:

var pagemod = PageMod({
    include: ['*'],
    contentScriptFile: [data.url('content.js')]
});

panel = require("sdk/panel").Panel({
  width: 322,
  height: 427,
  contentURL: data.url("main.html"),
  include:["http://*/*","https://*/*"],
  contentScriptFile: [data.url('panel.js')]  
});

I recently came across some example code in a Chrome extension where they utilize

window.parent.postMessage(message, "*")

to send messages and

window.addEventListener("message",function (e) {//do something}

to receive them. How can I establish direct communication for message passing from "panel.js" to "content.js" within a Firefox addon?

javascript firefox-addon-sdk

Answer 1

Answer №1

The solution concept closely resembles the approach outlined in this particular answer:

Keep track of message ports for each tab.
When sending a message, dispatch it to all recorded ports.

In order to manage a list of ports effectively, the following code snippet is implemented:

var ports = [];
var pagemod = PageMod({
    include: ['*'],
    contentScriptFile: [data.url('content.js')],
    onAttach: function(worker) {
        ports.push(worker.port);
        worker.on('detach', function() {
            var index = ports.indexOf(worker.port);
            if (index !== -1) ports.splice(index, 1);
        });
    }
});

Now, to send a message from panel.js, simply utilize:

// panel.js
self.port.emit('message-to-tabs', 'example message');

The handling of this message must occur in the main script post creation of the panel:

panel = require('sdk/panel').Panel({
    width: 322,
    height: 427,
    contentURL: data.url('main.html'),
    include: ['http://*/*', 'https://*/*'],
    contentScriptFile: [data.url('panel.js')]  
});
panel.port.on('message-to-tabs', function(message) {
    for (var i=0; i<ports.length; i++) {
        ports[i].emit('message-to-tab', message);
    }
});

Within the content script of the tab (content.js), you can listen for this event and process it accordingly:

self.port.on('message-to-tab', function(message) {
    // Handle message appropriately
});

Answer 2

The solution concept closely resembles the approach outlined in this particular answer:

Keep track of message ports for each tab.
When sending a message, dispatch it to all recorded ports.

In order to manage a list of ports effectively, the following code snippet is implemented:

var ports = [];
var pagemod = PageMod({
    include: ['*'],
    contentScriptFile: [data.url('content.js')],
    onAttach: function(worker) {
        ports.push(worker.port);
        worker.on('detach', function() {
            var index = ports.indexOf(worker.port);
            if (index !== -1) ports.splice(index, 1);
        });
    }
});

Now, to send a message from panel.js, simply utilize:

// panel.js
self.port.emit('message-to-tabs', 'example message');

The handling of this message must occur in the main script post creation of the panel:

panel = require('sdk/panel').Panel({
    width: 322,
    height: 427,
    contentURL: data.url('main.html'),
    include: ['http://*/*', 'https://*/*'],
    contentScriptFile: [data.url('panel.js')]  
});
panel.port.on('message-to-tabs', function(message) {
    for (var i=0; i<ports.length; i++) {
        ports[i].emit('message-to-tab', message);
    }
});

Within the content script of the tab (content.js), you can listen for this event and process it accordingly:

self.port.on('message-to-tab', function(message) {
    // Handle message appropriately
});

What is the best way to directly send a message from a panel to a page-mod's content script?

Answer №1

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