Add-ons/dataDirectory

Addon Data Directory

Addons may want to store settings or other data on the local computer. In the past, add-ons would use preferences or an arbitrary location on the user's filesystem. Preferences are less than ideal, so each Addon object should provide built-in helpers to access a directory specific to it. Then the addon's internal code can refer to the filesystem in a common location.

Option 1: Direct access to a nsIFile object

  get dataDirectory() {
    try {
      return FileUtils.getFile(KEY_PROFILEDIR, ["extension-data", this.id], false);
    }
    catch(e) {
      return null;
    }
  },

We may just want to expose an Addon.dataDirectory property. This property points to a folder which is not initially guaranteed to exist. (Unless an add-on demands it, we don't need to create it.) Add-on developers can then either migrate existing files to this directory. They can also create SQLite databases, JSON files, and other settings there.

Option 2: Indirect access through friendly API's

We may create the data directory for an add-on, but expose a special Addon.localData API with various methods (.json, .getDBConnection(dbName), etc) for addon developers.