python - Django 'File' 对象在管理中的更改表单上没有属性 '_size'

Question

我有这个模型，它有一个干净的方法来验证 django admin 中 mp3 文件的上传(注意 audio_file 字段):

class Cancion(models.Model):


    nombre = models.CharField(max_length=100
                              ,verbose_name=_("nombre"))
    audio_file = models.FileField(upload_to="audio"
                                  , verbose_name=_("audio"))
    album =  models.ManyToManyField("music_manager.Album"
                                    ,through="music_manager.CancionAlbum"
                                    ,through_fields=('cancion', 'album')
                                    ,verbose_name=_("canciones_albums")
                                    ,related_name="cancione_albums")
    reproducciones = models.IntegerField(verbose_name=_("reproducciones")
                                         ,default=0)

    playlist =  models.ManyToManyField("music_manager.Playlist"
                                    ,through="music_manager.CancionPlaylist"
                                    ,through_fields=('cancion', 'playlist')
                                    ,verbose_name=_("canciones_playlist")
                                    ,related_name="cancione_playlist")

    class Meta:


        verbose_name_plural= "Canciones"
        verbose_name = "Cancion"
    # Override the __unicode__() method to return out something meaningful!
    def __unicode__(self):


        return self.nombre

    def clean(self):
         file = self.audio_file.file
         print("Archivo: "+str(file))
         if file:
             if file._size > 20*1024*1024:
                   raise ValidationError(_("El archivo de audio es demasiado grande ( > 20mb )"))
             if not file.content_type in ["audio/mp3"]:
                   raise ValidationError(_("El archvivo no es MP3"))
             if not os.path.splitext(file.name)[1] in [".mp3",]:
                   raise ValidationError(_("El archivo no posee la extension apropiada"))
             # Here we need to now to read the file and see if it's actually
             # a valid audio file. I don't know what the best library is to
             # to do this

             return file
         else:
             raise ValidationError("Couldn't read uploaded file")

当创建新的模型对象时，clean 函数效果很好。但是，当更改管理更改表单上的对象属性时，我得到:

'File' object has no attribute '_size'

谁能告诉我我做错了什么？

Answer 1

_size 是一个内部 Django 属性，用于缓存文件大小 - 它并不总是被设置(例如，在管理中编辑现有对象时)。您不应该直接访问它。

尝试file.size .