Parsing id3 data from a local audio file within firefox addon

Question

I'm developing a Firefox addon using the SDK, which lists audio files on your computer using require("sdk/io/file").list().
I build an array of file paths using the method above and pass this array to a contentScript attached to a Panel.
The Panel then loops through the array and displays all the files found.

Now I'm trying to use JavaScript-ID3-Reader so I can read ID3 data from each file and display this data alongside each file.
I've been trying this (read local files), from inside the contentScript e.g ..

var f = new File([""], "file:///home/user/audio.mp3");
ID3.loadTags("audio.mp3", function () {
        var tags = ID3.getAllTags("audio.mp3");
        console.log(tags.comment + " - " + tags.track + ", " + tags.lyrics);
}, {
        dataReader: FileAPIReader(f)
}); 

But the output I get is ..

undefined - undefined, undefined

/home/user/audio.mp3 contains the following ID3 data, found with http://web.ist.utl.pt/antonio.afonso/www.aadsm.net/libraries/id3/ ..

Artist
    A Perfect Circle
Title
    Annihilation
Album
    eMOTIVe
Year
    2004
Comment
Genre
    Pop/Rock
Track
    1/12
Lyrics

Here is another test I was trying ..

function getID3 (file) {
        var url = file.name;
        console.log(url); // console.log: addon: /home/user/audio.mp3
        ID3.loadTags(url, function () {
                var tags = ID3.getAllTags(url);
                console.log(tags); // console.log: addon: {}
                console.log(tags.artist); // console.log: addon: null
        }, {
                dataReader: new FileAPIReader(file)
        });
}

var f = new File([""], "file:///home/rob/audio.mp3", {type : "audio/mpeg"});
getID3(f);

Anyone know what might be wrong with this? /home/user/audio.mp3 does exist on file system.

Answer 1

This JavaScript-ID3-Reader library is meant to run in the context of a website, only for files available via http and https afaict.

You might want to find a library which will work on the add-on side.