django - 反向关系 ToManyField Tastypie

Question

我有两个资源 (Tastypie)，其中一个具有 ToManyField 字段:

class SongResource(ModelResource):

    class Meta:
        queryset = Song.objects.all()
        resource_name = 'song'
        authorization = Authorization()



class AlbumResource(ModelResource):
    songs = fields.ToManyField('core.api.SongResource', 'songs', full=True)
    class Meta:
        queryset = Album.objects.all()
        resource_name = 'album'
        authorization = Authorization()

因此，当我访问 PlaylistResource 时，我会看到如下内容:

http://127.0.0.1:8000/api/v1/playlist/1/?format=json 这是我得到的响应:

{
"created_in": "2012-06-24T22:57:01+00:00",
"id": "1",
"number_of_plays": 0,
"playlist_slug": "my-first-playlist",
"playlist_title": "my first playlist",
"resource_uri": "/api/v1/playlist/1/",
"songs": [{
    "genre": "Progressive metal",
    "id": "2",
    "length": "04:19",
    "number_of_plays": 0,
    "price": 0.0,
    "resource_uri": "/api/v1/song/2/",
    "song_slug": "leyla-2008",
    "song_title": "Leyla",
    "song_url": "http://www.amazon.s3.com/prologue",
    "thumbnail": "http://almacosta.files.wordpress.com/2011/05/bob_marley.jpg?w=250",
    "year": 2008
}, {
    "genre": "Progressive metal",
    "id": "3",
    "length": "3.26",
    "number_of_plays": 0,
    "price": 0.0,
    "resource_uri": "/api/v1/song/3/",
    "song_slug": "yazamadim-2008",
    "song_title": "Yazamadim",
    "song_url": "http://www.amazon.s3.com/prologue",
    "thumbnail": "http://img72.imageshack.us/img72/3215/14so8.jpg",
    "year": 2008
}]

}

现在我想访问每首歌的专辑或艺术家，所以我添加了

album = fields.ForeignKey('core.api.AlbumResource','album')  

到我的SongResource，但我收到此错误

{
"error_message": "'Song' object has no attribute 'album'",
"traceback": "Traceback (most recent call last):\n\n  File \"/usr/local/lib/python2.7/dist-packages/tastypie/resources.py\", line 192, in wrapper\n    response = callback(request, *args, **kwargs)\n\n  File \"/usr/local/lib/python2.7/dist-packages/tastypie/resources.py\", line 406, in dispatch_detail\n    return self.dispatch('detail', request, **kwargs)\n\n  File \"/usr/local/lib/python2.7/dist-packages/tastypie/resources.py\", line 427, in dispatch\n    response = method(request, **kwargs)\n\n  File \"/usr/local/lib/python2.7/dist-packages/tastypie/resources.py\", line 1058, in get_detail\n    bundle = self.full_dehydrate(bundle)\n\n  File \"/usr/local/lib/python2.7/dist-packages/tastypie/resources.py\", line 654, in full_dehydrate\n    bundle.data[field_name] = field_object.dehydrate(bundle)\n\n  File \"/usr/local/lib/python2.7/dist-packages/tastypie/fields.py\", line 709, in dehydrate\n    m2m_dehydrated.append(self.dehydrate_related(m2m_bundle, m2m_resource))\n\n  File \"/usr/local/lib/python2.7/dist-packages/tastypie/fields.py\", line 514, in dehydrate_related\n    return related_resource.full_dehydrate(bundle)\n\n  File \"/usr/local/lib/python2.7/dist-packages/tastypie/resources.py\", line 654, in full_dehydrate\n    bundle.data[field_name] = field_object.dehydrate(bundle)\n\n  File \"/usr/local/lib/python2.7/dist-packages/tastypie/fields.py\", line 621, in dehydrate\n    foreign_obj = getattr(bundle.obj, self.attribute)\n\nAttributeError: 'Song' object has no attribute 'album'\n"

}

有什么技巧可以让我获取反向数据吗？

编辑这是我的歌曲和专辑模型(与 models.py 文件中的顺序相同)

class Song(models.Model):

    song_title = models.CharField(max_length=140)
    length = models.CharField(max_length=5, blank=True, null = True)
    genre = models.CharField(max_length=100, blank = True, null = True)
    year = models.IntegerField(blank = True, null = True)
    thumbnail = models.URLField(default = '/media/thumbnail.png')
    song_url = models.URLField()
    number_of_plays = models.IntegerField(verbose_name='Number of plays')
    price = models.FloatField(default = 0.0)
    song_slug = models.SlugField(unique=True, max_length=200)

    def __unicode__(self):
        return self.song_title

class Album(models.Model):

    album_title = models.CharField(max_length=140)
    release_year = models.IntegerField('Release Year')
    price = models.FloatField(default=0.0)
    album_slug = models.SlugField(unique=True)
    songs = models.ManyToManyField(Song)

    def __unicode__(self):
        return self.album_title

    def get_absolute_url(self):
        return '/album/%s' % self.album_slug

Answer 1

使用ToManyField而不是ForeignKey并告诉它属性是album_set。要获取要包含的完整资源，请指定 full=True。