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pythonxmlpython-2.7unicodeitunes

Python 2.7.2: plistlib with itunes xml


I'm reading an itunes generated xml playlist with plistib. The xml has a utf8 header.

When I read the xml with plistib, I get both unicode (e.g., 'Name': u'Don\u2019t You Remember') and byte strings (e.g., 'Name': 'Where Eagles Dare').

Standard advice is to decode what you read with the correct encoding as soon as possible and use unicode within the program. However,

unicode_string.decode('utf8') 

fails (as it should) with

UnicodeEncodeError: 'ascii' codec can't encode character u'\u2019' in position 3: ordinal not in range(128)

The solution would seem to be:

for name in names:
    if isinstance(name, str):
        name = name.decode('utf8')
    # etc.

Is this the correct way of dealing with the problem? Is there a better way?

I'm on windows 7.

EDIT:

xml read with:

import plistlib
xml = plistlb.readPlist(fn)
for track in xml['Tracks']:
    info = xml['Tracks'][track]
    info['Name']

Produces in idle:

u'Don\u2019t You Remember'
'Where Eagles Dare'

Here's the xml file:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>Major Version</key><integer>1</integer>
    <key>Minor Version</key><integer>1</integer>
    <key>Date</key><date>2013-08-14T15:04:27Z</date>
    <key>Application Version</key><string>10.6.3</string>
    <key>Features</key><integer>5</integer>
    <key>Show Content Ratings</key><true/>
    <key>Music Folder</key><string>file://localhost/C:/Users/rdp/Music/iTunes/iTunes%20Media/</string>
    <key>Library Persistent ID</key><string>FE28CCACD9A36C34</string>
    <key>Tracks</key>
    <dict>
        <key>1019</key>
        <dict>
            <key>Track ID</key><integer>1019</integer>
            <key>Name</key><string>Where Eagles Dare</string>
            <key>Artist</key><string>Iron Maiden</string>
            <key>Album</key><string>Piece Of Mind</string>
            <key>Genre</key><string>Rock</string>
            <key>Kind</key><string>MPEG audio file</string>
            <key>Size</key><integer>7372755</integer>
            <key>Total Time</key><integer>370128</integer>
            <key>Track Number</key><integer>1</integer>
            <key>Year</key><integer>1983</integer>
            <key>Date Modified</key><date>2009-10-07T21:11:31Z</date>
            <key>Date Added</key><date>2008-02-07T16:04:15Z</date>
            <key>Bit Rate</key><integer>153</integer>
            <key>Sample Rate</key><integer>44100</integer>
            <key>Play Count</key><integer>4</integer>
            <key>Play Date</key><integer>3414416760</integer>
            <key>Play Date UTC</key><date>2012-03-12T21:06:00Z</date>
            <key>Artwork Count</key><integer>1</integer>
            <key>Persistent ID</key><string>FE28CCACD9A383E5</string>
            <key>Track Type</key><string>File</string>
            <key>Location</key><string>file://localhost/D:/music/Iron%20Maiden/Piece%20Of%20Mind/01%20Where%20Eagles%20Dare.mp3</string>
            <key>File Folder Count</key><integer>-1</integer>
            <key>Library Folder Count</key><integer>-1</integer>
        </dict>
        <key>11559</key>
        <dict>
            <key>Track ID</key><integer>11559</integer>
            <key>Name</key><string>Don’t You Remember</string>
            <key>Artist</key><string>Adele</string>
            <key>Album</key><string>21</string>
            <key>Genre</key><string>Pop</string>
            <key>Kind</key><string>MPEG audio file</string>
            <key>Size</key><integer>6120028</integer>
            <key>Total Time</key><integer>229511</integer>
            <key>Track Number</key><integer>4</integer>
            <key>Track Count</key><integer>11</integer>
            <key>Year</key><integer>2011</integer>
            <key>Date Modified</key><date>2012-11-17T10:50:31Z</date>
            <key>Date Added</key><date>2012-12-19T16:03:46Z</date>
            <key>Bit Rate</key><integer>199</integer>
            <key>Sample Rate</key><integer>44100</integer>
            <key>Artwork Count</key><integer>1</integer>
            <key>Persistent ID</key><string>7130C888606FB153</string>
            <key>Track Type</key><string>File</string>
            <key>Location</key><string>file://localhost/D:/music/Adele/21/04%20-%20Don%E2%80%99t%20You%20Remember.mp3</string>
            <key>File Folder Count</key><integer>-1</integer>
            <key>Library Folder Count</key><integer>-1</integer>
        </dict>
    </dict>
    <key>Playlists</key>
    <array>
        <dict>
            <key>Name</key><string>short</string>
            <key>Playlist ID</key><integer>30888</integer>
            <key>Playlist Persistent ID</key><string>166746C6572B0005</string>
            <key>All Items</key><true/>
            <key>Playlist Items</key>
            <array>
                <dict>
                    <key>Track ID</key><integer>11559</integer>
                </dict>
                <dict>
                    <key>Track ID</key><integer>1019</integer>
                </dict>
            </array>
        </dict>
    </array>
</dict>
</plist>

Solution

  • Wow this is a really weird behaviour. I would even say that this non-uniform behaviour is a bug in the 2.X implementation of the plistlib. The plistlib in Python 3 always returns unicode strings which is much better.

    But you have to live with it :) So the answer to your question is yes. You should protect yourself always when reading a string from a plist

    def safe_unicode(s):
        if isinstance(s, unicode):
            return s
        return s.decode('utf-8', errors='replace')
    
    value = safe_unicode(info['Name'])
    

    I added the errors='replace' just in case the string is not utf-8 encoded. You'll get a bunch of \ufffd characters if it cannot be decoded. If you rather get an exception just leave it out and use e.decode('utf-8').

    Update:

    When I tried with ElementTree:

    from xml.etree import ElementTree as et
    tree = et.parse('test.plist')
    map(lambda x: x.text, tree.findall('dict/dict/dict')[1].findall('string'))
    

    Which gave me:

    [u'Don\u2019t You Remember',
     'Adele',
     '21',
     'Pop',
     'MPEG audio file',
     '7130C888606FB153',
     'File',
     'file://localhost/D:/music/Adele/21/04%20-%20Don%E2%80%99t%20You%20Remember.mp3']
    

    So there are unicode and byte string mixed :-/