Retrieving track information from the iTunes XML library file

In order to convert a playlist as described in the previous post, we need two pieces of information:

1. the tracks (represented by their IDs) in a playlist
2. the location of the file of a certain track

How to get this from the iTunes XML library file is described in the next sections.

Get Tracks in a playlist

Similar to the playlist member in the library, the trackIDs member of the playlist is built at the fist time it is accessed:

public List<String> getTrackIDs()
{   // lazy initialization
 if (_trackIDs == null)
 {
     _trackIDs = new List<String>();

     //Query XML for TrackIDs
     IEnumerable<XElement> tracks = (from element in _root.Descendants()
                                       where element.Value.Equals("Track ID")
                                       select element);
     foreach (XElement track in tracks)
     {
         _trackIDs.Add((track.NextNode as XElement).Value );
     }
 };
 return _trackIDs;
}

Again, the LinkToXML query retrieves the items with a certain value (“Track ID”) from the XML. The statement uses just the part representing the playlist (stored in the _root member). It then moves over to the NextNode to get the actual value and stores all of these in a member that the form can then iterate over.

Get filenames for a given TrackID

Once you know the IDs of all the tracks in the playlist, you can then retrieve the filename as follows:

internal string GetTrackLocation(string ptrackID)
{
 // get root of XML-Dictionary for this track
 XElement track = (from element in _root.Descendants().Elements("key")
                   where element.Value.Equals(ptrackID)
                   select element).First().NextNode as XElement;

 XElement location = (from element in track.Descendants()
                   where element.Value.Equals ("Location")
                   select element).First().NextNode as XElement;

 string fileName = HttpUtility.UrlDecode((string)(location  as XElement));

 return fileName;
}

This code is in the library class. I could have used a dedicated track class, but apart from this little piece of information, there wasn’t anything else needed – so that felt a little bit too small to actually build a class for that.

The code gets the location in these steps:

1. Get the dict for this specific track (lines 4 to 6)
2. Get the “Location” from within this specific dict (lines 8 to 10)
3. Get the ‘proper’ formatting by URL-Decoding the value from the XML.

I’m sure that there are easier or more compact ways to achieve this, but this code is working fine and seems quite clear to me. Let me know if you have better suggestions ….

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