Firefox Extension Development - Data Storage - is Firefox Preferences a good place?

Question

I have developed a Firefox add-on that needs to save some user-data in the local machine. Right now, I use the filesystem functionality that Firefox provides to create some

Answer 1

It is possible to locate the profile or extensions directory of firefox via code. You can even locate the directory of your own extension. Portability shouldn't be a problem using this approach.

You can find instructions at the MDC (File I/O).

I wouldn't advice saving data in the preferences. Anyway, instead of using bare file i/o you may look into sqlite-databases - ubiquity uses those as well.

Cheers.

Answer 2

With newer versions of Firefox you can use SQLite to store data. The SQLite API in JavaScript isn't terribly good, but from Firefox 3.6 it's starting to get pretty solid (asynch fetching of data, binding multiple sets of data, etc).

You can open/create a file in the profile directory using the following code. It works on all platforms Firefox runs on:

var file = Components.classes["@mozilla.org/file/directory_service;1"]
                     .getService(Components.interfaces.nsIProperties)
                     .get("ProfD", Components.interfaces.nsIFile);
file.append("my_db_file_name.sqlite");