[英]How to get pk of an instance of a django model before saving the instance
我正在嘗試使用models.ImageField(upload_to=upload_location)
上傳圖像
def upload_location(instance,filename):
print("%s/%s"%(instance.id,filename))
return "%s/%s" %(instance.id,filename)
但是它給出了"GET /media/None/image_qacfEsv.jpg HTTP/1.1"
我嘗試使用slug字段,它工作正常,但是id
和pk
都不起作用,我想使用obj ID來命名圖像的文件夾,但是none
給出在id屬性中這是我的文件
def upload_location(instance,filename):
print("%s/%s"%(instance.id,filename))
return "%s/%s"%(instance.id,filename)
class Post(models.Model):
draft = models.BooleanField(default=False)
publish = models.DateField(auto_now=False,auto_now_add=False)
user = models.ForeignKey(settings.AUTH_USER_MODEL,default=1)
slug = models.SlugField(unique=True)
title = models.CharField(max_length=120)
image = models.ImageField(upload_to=upload_location,
null=True,blank=True,
width_field="width_field",
height_field="height_field")
height_field = models.IntegerField(default=0)
width_field = models.IntegerField(default=0)
content = models.TextField()
updated = models.DateTimeField(auto_now=True, auto_now_add=False)
timestamp = models.DateTimeField(auto_now=False, auto_now_add=True)
保存對象之前無法獲取pk
實際上,檢查對象是否具有pk
是檢查其是否已保存的好方法。
因此,我建議您在模型上添加一個UUID字段。 就像是:
import uuid
class Post(models.Model):
uuid = models.UUIDField(default=uuid.uuid4, editable=False, unique=True)
...
uuid字段將是唯一的,並且在創建對象時將可用,因此可以在上載路徑中使用它。
我遇到了類似的問題,這就是我的做法。
def upload_location(instance, filename):
#return "%s/%s.%s" %(instance.id, instance.id, extension)
if not instance.id:
Model = instance.__class__
new_id=None
try:
new_id = Model.objects.order_by("id").last().id
if new_id:
new_id += 1
else:
pass
except:
new_id=1
else:
new_id = instance.id
return "%s/%s/%s" %(Model.__name__, new_id, filename)
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