django - 在 django admin 上编辑实际对象之前保存相关对象

Question

是否可以在 django 管理表单上编辑实际对象之前保存相关对象？

例如：

在models.py

class Parent(model.Model):
    pass

class Child(model.Model):
    parent = models.ForeignKey(Parent)

@receiver(post_save,sender = Parent)
def notify_parent_save(sender, instance=None, **kwargs):
    print "Parent save"

@receiver(post_save,sender = Child)
def notify_child_save(sender, instance=None, **kwargs):
    print "Child saved"

在admin.py

class ChildInline(admin.TabularInline):
    model = Child
    extra = 1

class ParentsAdmin(admin.ModelAdmin):
    inlines = [ChildInline]

admin.site.register(Parent,ParentsAdmin)

现在，在 django admin 中，如果我保存父对象，它将在控制台上输出。

Parent save
Child save

我需要以相反的顺序发生这种情况：

Child save
Parent save

Answer 1

以下将首先拯救孩子：

class ParentAdmin(admin.ModelAdmin):
    inlines = [ChildInline]

    def save_model(self, request, obj, form, change):
        pass # don't actually save the parent instance

    def save_formset(self, request, form, formset, change):
        formset.save() # this will save the children
        form.instance.save() # form.instance is the parent

Answer 2

我对这篇文章中的答案有疑问，所以我想出了一个更简洁的答案。我遇到了一个问题，因为使用 django-fsm，这里的其他答案会尝试多次保存模型（每个表单集一次）而不是最后一次。

def save_model(self, request, obj, form, change):
    if not obj.pk: # call super method if object has no primary key 
        super(YourAdmin, self).save_model(request, obj, form, change)
    else:
        pass # don't actually save the parent instance

def save_related(self, request, form, formsets, change):
    form.save_m2m()
    for formset in formsets:
        self.save_formset(request, form, formset, change=change)
    super(YourAdmin, self).save_model(request, form.instance, form, change)

这基本只是翻转了Django ModelAdmin 源中调用的 save_model 和 save_related 的顺序

Answer 3

ccrisan 的回答让我走上了正轨，但我认为数据库中尚不存在的实例的保存行为存在缺陷。在这种情况下，不可能先保存相关对象，因为它们没有可以指向的外键。对我来说，以下扩展起到了作用：

class ParentAdmin(admin.ModelAdmin):
    inlines = [ChildInline]

    def save_model(self, request, obj, form, change):
        if not obj.pk: # call super method if object has no primary key 
            super(ParentAdmin, self).save_model(request, obj, form, change)
        else:
            pass # don't actually save the parent instance

    def save_formset(self, request, form, formset, change):
        formset.save() # this will save the children
        form.instance.save() # form.instance is the parent

Answer 4

根据您在信号中到底想做什么，您可以将子模型的 post_save 更改为 pre_save 吗？