models.py 文件源码

def validate_scene_name(value):
    """Validator for the scene_name field of PastSceneDownload Model."""
    try:
        Scene.objects.get(name=value)
        raise ValidationError(
            _('The scene you want is already on our database.')
            )
    except Scene.DoesNotExist:
        if len(value) != 21:
            raise ValidationError(
                _('The scene name needs to have 21 characters.')
            )
        elif not value.startswith('L') or value[2] not in ['5', '7', '8']:
            raise ValidationError(
                _('Wrong scene name. Please check it.')
            )