A recent suervey on The Register showed that Rush was the average developers favorite artist. I don’t consider myself as an “average developer”, at least not when it comes to musical tastes.
I use the Apple iTunes media player which has a nifty “hidden feature”, it stores the library as a XML file.
The XML document has a rather odd structure. It is not your typical XML tree but more of a serialized dictionary object. This means that the elements in the document are limited to keys and values. These key-value pairs a composed of sibling pairs, where the first element is the key and the next is the value.
I guess you can’t blame Apple for not using a more intuitive structure, after all the document is a representation of a in-memory data structure.
|
<plist version="1.0">
<dict>
<key>Major Version</key>
<integer>1</integer>
<key>Minor Version</key>
<integer>1</integer>
<key>Application Version</key>
<string>4.5</string>
<key>Music Folder</key>
<string>file://localhost/C:/Documents%20and%20Settings/anders.noras/My%20Documents/My%20Music/iTunes/iTunes%20Music/</string>
<key>Library Persistent ID</key>
<string>E4F5BED92B419441</string>
<key>Tracks</key>
<dict>
<key>35</key>
<dict>
<key>Track ID</key>
<integer>35</integer>
<key>Name</key>
<string>The Step</string>
<key>Artist</key>
<string>!!!</string>
<key>Album</key>
<string>!!!</string>
<key>Kind</key>
<string>MPEG audio file</string>
<key>Size</key>
<integer>8857518</integer>
<key>Total Time</key>
<integer>369005</integer>
<key>Track Number</key>
<integer>1</integer>
<key>Date Modified</key>
<date>2004-03-08T12:46:09Z</date>
<key>Date Added</key>
<date>2004-05-01T13:57:18Z</date>
<key>Bit Rate</key>
<integer>192</integer>
<key>Sample Rate</key>
<integer>44100</integer>
<key>Location</key>
<string>file://localhost/C:/Documents%20and%20Settings/anders.noras/My%20Documents/My%20Music/Complete/!!!/!!!%20-%20!!!/01-The%20Step.mp3/</string>
<key>File Folder Count</key>
<integer>-1</integer>
<key>Library Folder Count</key>
<integer>-1</integer>
</dict>
</dict>
</plist> |
As you can see, the structure is not the easiest to extract data from by using XPath expressions. However, since the document follows a strict key-value pair structure it is a simple task to write an XSLT script to make it easier to do queries against the node tree.
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<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes"/>
<xsl:template match="/">
<tracks>
<xsl:apply-templates select="plist/dict/dict/dict"/>
</tracks>
</xsl:template>
<xsl:template match="dict">
<track>
<xsl:apply-templates select="key"/>
</track>
</xsl:template>
<xsl:template match="key">
<xsl:element name="{translate(text(), ' ', '_')}">
<xsl:value-of select="following-sibling::node()[1]"/>
</xsl:element>
</xsl:template>
</xsl:stylesheet> |
Using the above XSLT script you can transform the document into the following structure:
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<?xml version="1.0" encoding="UTF-8"?>
<tracks>
<track>
<Track_ID>35</Track_ID>
<Name>The Step</Name>
<Artist>!!!</Artist>
<Album>!!!</Album>
<Kind>MPEG audio file</Kind>
<Size>8857518</Size>
<Total_Time>369005</Total_Time>
<Track_Number>1</Track_Number>
<Date_Modified>2004-03-08T12:46:09Z</Date_Modified>
<Date_Added>2004-05-01T13:57:18Z</Date_Added>
<Bit_Rate>192</Bit_Rate>
<Sample_Rate>44100</Sample_Rate>
<Location>file://localhost/C:/Documents%20and%20Settings/anders.noras/My%20Documents/My%20Music/Complete/!!!/!!!%20-%20!!!/01-The%20Step.mp3/</Location>
<File_Folder_Count>-1</File_Folder_Count>
<Library_Folder_Count>-1</Library_Folder_Count>
</track>
</tracks> |
This is a vanilla XML document. Using the “new and improved” iTunes library document you can perform all sorts of XPath queries on the document.
I have extracted the songs I’ve listened to the most from the start of August till today, and as the following “chart” shows I’m not your average Rush fan.
|
Artist |
Song title |
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Tubby Hayes & The Paul Gonsalves All Stars |
Don't Fall Off The Bridge |
|
Seiji |
Untitled |
|
Troublemakers |
Le Bocal |
|
Incognito |
The 25th Chapter |
|
Cowboy Junkies |
One Soul Now |
|
Whirlwind |
Full time thing (between dusk and dawn) |
|
Magic Number |
That day fest. Rachel Foster |
|
Radar One |
Don't run away |
|
Landspeed |
Got To Get Your Love (Special Kenny Dope Gonzales Edit) |
|
Anthony Hamilton |
I Tried |
|
The Divine Comedy |
My Imaginary Friend |
|
The Sound Providers |
Braggin’ Boasting Ft. Little Brother |
|
Bettye Swann |
The Dance Is Over |
|
Calexico |
Si Tu Disais |
|
Dublex Inc |
Mentiras |
|
General Levy |
Mad Them |
|
Talib Kweli |
Get By (Blackbeard Vocal) |
|
Vanessa Freeman |
Lifeline |
|
Edson Frederico |
Bobeira |
|
Anthony Hamilton |
Better Days |
|
Jackson 5 |
Ben (Hiroshi Fujiwara & K.U.D.O.'s HF Remix #2) |
|
Usher |
Can You Help Me (Bootleg Vocal House Mix) |
|
Johnny Copeland |
Sufferin' City |
|
Doris Monteiro |
A peteca |
|
Peven Everett |
See Saw |
|
Fertile Ground |
Homage (Yesterday) |
|
South |
Mend These Trends |
|
Louie Vega |
Brand New Day featuring Blaze |
|
The Roots |
Duck Down |
|
Nancy Wilson |
A Lot Of Livin' To Do |
|
Brandy |
Afrodisiac |
|
Quintessence |
1st Impressions |
|
Wande De Sah |
Só Danço Samba |
|
Nina Simone |
O-O-Child |
|
Vanessa Freeman |
Cover Me |
|
Blackalicious |
Rock The Spot |
|
Chiara Mastroianni & Benjamin Biolay |
L'Arizona |
|
Gilberto Gil |
Queremos guerra |
|
Chiara Mastroianni & Benjamin Biolay |
Tete à Claques |
|
Hot Chip |
The Beach Party |
|
I Beats & L'armonica Di Franco Di Gemini |
Ciao Dal Mur |
|
Bruno E |
Dado |
|
George Soul |
Get Involved |
I used Visual XPath to run a variety of expressions on the library.
To extract all songs play more than 2 times you can use this query:
songlist/song[Play_Count > 2]
To extract all songs played on a particular date you can use a query like this:
songs/song[starts-with(Play_Date_UTC,'2004-08-12')]