Django -无法为具有动态upload_to值的ImageField创建迁移
Django -无法为具有动态upload_to值的ImageField创建迁移
提问于 2014-09-10 22:17:07
我刚刚把我的应用升级到了1.7 (实际上还在尝试)。
这是我在models.py中所拥有的：
def path_and_rename(path):
def wrapper(instance, filename):
ext = filename.split('.')[-1]
# set filename as random string
filename = '{}.{}'.format(uuid4().hex, ext)
# return the whole path to the file
return os.path.join(path, filename)
return wrapper
class UserProfile(AbstractUser):
#...
avatar = models.ImageField(upload_to=path_and_rename("avatars/"),
null=True, blank=True,
default="avatars/none/default.png",
height_field="image_height",
width_field="image_width")当我尝试makemigrations时，它抛出：
ValueError: Could not find function wrapper in webapp.models.
Please note that due to Python 2 limitations, you cannot serialize unbound method functions (e.g. a method declared
and used in the same class body). Please move the function into the main module body to use migrations.回答 3
Stack Overflow用户
回答已采纳
发布于 2014-09-10 22:27:28
我不确定是否可以回答我自己的问题，但我只是想(我想)。
根据this bug report的说法，我编辑了我的代码：
from django.utils.deconstruct import deconstructible
@deconstructible
class PathAndRename(object):
def __init__(self, sub_path):
self.path = sub_path
def __call__(self, instance, filename):
ext = filename.split('.')[-1]
# set filename as random string
filename = '{}.{}'.format(uuid4().hex, ext)
# return the whole path to the file
return os.path.join(self.path, filename)
path_and_rename = PathAndRename("/avatars")然后，在字段定义中：
avatar = models.ImageField(upload_to=path_and_rename,
null=True, blank=True,
default="avatars/none/default.png",
height_field="image_height",
width_field="image_width")这对我很有效。
Stack Overflow用户
发布于 2018-10-17 19:35:37
您可以使用kwargs创建函数，如下所示：
def upload_image_location(instance, filename, thumbnail=False):
name, ext = os.path.splitext(filename)
path = f'news/{instance.slug}{f"_thumbnail" if thumbnail else ""}{ext}'
n = 1
while os.path.exists(path):
path = f'news/{instance.slug}-{n}{ext}'
n += 1
return path并将此方法与模型中的functools.partial一起使用：
image = models.ImageField(
upload_to=upload_image_location,
width_field='image_width',
height_field='image_height'
)
thumbnail_image = models.ImageField(upload_to=partial(upload_image_location, thumbnail=True), blank=True)您将获得如下的迁移：
class Migration(migrations.Migration):
dependencies = [
('news', '0001_initial'),
]
operations = [
migrations.AddField(
model_name='news',
name='thumbnail_image',
field=models.ImageField(blank=True, upload_to=functools.partial(news.models.upload_image_location, *(), **{'thumbnail': True})),
),
migrations.AlterField(
model_name='news',
name='image',
field=models.ImageField(height_field='image_height', upload_to=news.models.upload_image_location, width_field='image_width'),
),
]Stack Overflow用户
发布于 2022-02-08 07:37:41
field=models.ImageField(blank=True, upload_to="/smth", *(), **{'thumbnail': True})),而不是
field=models.ImageField(blank=True, upload_to=functools.partial(news.models.upload_image_location, *(), **{'thumbnail': True}))页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/25767787
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