python - 使用 Django 的 post_save() 信号

Question

我有两张桌子：

class Advertisement(models.Model):
    created_at = models.DateTimeField(auto_now_add=True)
    author_email = models.EmailField()

class Verification(models.Model):
    advertisement = models.ForeignKeyField(Advertisement)
    key = models.CharField(max_length=32)

添加新广告后，我需要自动填充验证表。

def gen_key(sender, instance, created, **kwargs):
    if created:
        from hashlib import md5
        vkey = md5("%s%s" % (instance.author_email, instance.created_at))
        ver = Verification(advertisement=instance)
        ver.key = vkey
        ver.save()

post_save.connect(gen_key, sender=Advertisement)

当然是行不通的。Django 1.2 问：我该怎么做？

---

好的，解决了一半。
问题是父模型的 post_save() 不调用子模型。
因此，您可以通过直接提供子类来解决它。

class Advertisement(models.Model):
    created_at = models.DateTimeField(auto_now_add=True)
    author_email = models.EmailField()

class Sale(Advertisement):
    rooms = models.IntegerField(max_length=1)
    subway = models.ForeignKey(Subway)

class Verification(models.Model):
    advertisement = models.ForeignKeyField(Advertisement)
    key = models.CharField(max_length=32)

def gen_key(sender, instance, created, **kwargs):
    code goes here
post_save.connect(gen_key, sender=Sale, dispatch_uid="my_unique_identifier")

所以下一个问题是“我如何使用父类进行 post_save()？”

Answer 1

而不是连接到特定的发件人，通常只需连接到 post_save 并检查处理程序中已保存实例的类，例如

def gen_key(sender, **kwargs):
    if issubclass(sender, Advertisement):
        code goes here
post_save.connect(gen_key, dispatch_uid="my_unique_identifier")