使用pre_save（）填充django字段？ [英] Populating django field with pre_save()?

问题描述

  class TodoList（models.Model）：
 title = models.CharField（maxlength = 100）
 slug = models.SlugField（maxlength = 100）
 def save（self）：
 self.slug = title 
 super（TodoList，self）.save（）
  

我假设上面是当标题插入到表TodoList中时如何创建和存储一个s，如果没有，请纠正我！

无论如何，我一直在寻找pre_save（）作为另一种方式做到这一点，但不能弄清楚它是如何工作的。如何使用pre_save（）？

就像

  def pre_save（self）：
 self.slug = title 
  

没有。

解决方案

很可能是指 django的 pre_save 信号。您可以设置如下：

 来自django.db.models.signals import pre_save 
 from django.dispatch import receiver 
 from django.template.defaultfilters import slugify 
 
 @receiver（pre_save）
 def my_callback（sender，instance，* args，** kwargs）：
 instance .slug = slugify（instance.title）
  

如果您不在装饰器中包含sender参数， @receiver（pre_save，sender = MyModel），将为所有模型调用回调。

在您的应用程序执行期间解析的任何文件中的代码， models.py 是一个很好的地方。

class TodoList(models.Model):
    title = models.CharField(maxlength=100)
    slug = models.SlugField(maxlength=100)
    def save(self):
        self.slug = title
        super(TodoList, self).save()

I'm assuming the above is how to create and store a slug when a title is inserted into the table TodoList, if not, please correct me!

Anyhow, I've been looking into pre_save() as another way to do this, but can't figure out how it works. How do you do it with pre_save()?

is it like

def pre_save(self):
     self.slug = title

I'm guessing no. What is the code to do this?

Thanks!

解决方案

Most likely you are referring to django's pre_save signal. You could setup something like this:

from django.db.models.signals import pre_save
from django.dispatch import receiver
from django.template.defaultfilters import slugify

@receiver(pre_save)
def my_callback(sender, instance, *args, **kwargs):
    instance.slug = slugify(instance.title)

If you dont include the sender argument in the decorator, like @receiver(pre_save, sender=MyModel), the callback will be called for all models.

You can put the code in any file that is parsed during the execution of your app, models.py is a good place for that.

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