LegacyHelper

Objective

This API is a temporary helper while converting legacy extensions to modern WebExtensions. It allows to register resource:// URLs, which are needed to load custom system modules (*.sys.mjs), and chrome:// URLs, which are needed to open legacy XUL dialogs.

Usage

Add the LegacyHelper API to your add-on. Your manifest.json needs an entry like this:

  "experiment_apis": {
    "LegacyHelper": {
      "schema": "api/LegacyHelper/schema.json",
      "parent": {
        "scopes": ["addon_parent"],
        "paths": [["LegacyHelper"]],
        "script": "api/LegacyHelper/implementation.js"
      }
    }
  },

API Functions

This API provides the following functions:

async registerGlobalUrls(data)

Register chrome://*/content/ and resource://*/ URLs. The function accepts a data parameter, which is an array of URL definition items. For example:

await browser.LegacyHelper.registerGlobalUrls([
  ["content", "myaddon", "chrome/content/"],
  ["resource", "myaddon", "modules/"],
]);

This registers the following URLs:

• chrome://myaddon/content/ pointing to the /chrome/content/ folder (the /content/ part in the URL is fix and does not depend on the name of the folder it is pointing to)
• resource://myaddon/ pointing to the /modules/ folder. To register a resource:// URL which points to the root folder, use . instead".

async openDialog(name, path)

Open a XUL dialog. The name parameter is a unique name identifying the dialog. If the dialog with that name is already open, it will be focused instead of being re-opened. The path parameter is a chrome://*/content/ URL pointing to the XUL dialog file (*.xul or *.xhtml).

browser.LegacyHelper.openDialog(
  "XulAddonOptions",
  "chrome://myaddon/content/options.xhtml"
);