FileSystem

Objective

Use this API to read from and write to files in the user profile folder. Until Mozilla has made a final decision about including the Chrome FileSystem API, this API can be used as an interim solution.

Note: Currently does not work with TB78.

Usage

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

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

The API is using the following folder for file access:

<profile-folder>/FileSystemAPI/<add-on-id>/

The API provides two simple functions to read/write UTF-8 encoded text files:

async readFile(filename)

Returns a Promise for the file content. Throws if the file does not exist.

async writeFile(filename, data)

Returns a Promise which will resolve when the provided data has been written.