Using popularimeter with mediafile

popm.py

import collections
import mutagen
import six
from mediafile import StorageStyle, MediaField, MediaFile

Popularimeter = collections.namedtuple('Popularimeter', ['rating', 'count'])


class PopmMediaField(MediaField):
    def __init__(self, *styles, **kwargs):
        kwargs['out_type'] = dict
        super().__init__(*styles, **kwargs)

    def __get__(self, mediafile, owner=None):
        return super().__get__(mediafile=mediafile, owner=owner)

    def __set__(self, mediafile, value):
        return super().__set__(mediafile=mediafile, value=value)

    def __delete__(self, mediafile):
        return super().__delete__(mediafile)


class MP3PopmStorageStyle(StorageStyle):
    """Store data in ID3 frames.
    """
    formats = ['MP3', 'AIFF', 'DSF']

    def __init__(self, key, **kwargs):
        super(MP3PopmStorageStyle, self).__init__(key, as_type=dict, **kwargs)

    def fetch(self, mutagen_file):
        ratings = mutagen_file.tags.getall('POPM')
        return {popm.email: Popularimeter(rating=popm.rating, count=popm.count)
                for popm in ratings}


popm_field = PopmMediaField(
    MP3PopmStorageStyle('POPM'),
)

MediaFile.add_field('popm', popm_field)
f = MediaFile('/tmp/popm.mp3')
print(f.popm['traktor@native-instruments.de'].rating)
print(f.popm['traktor@native-instruments.de'].count)