如何从其他信号发送django信号

TL;DR:
I need a way to trigger a custom signal after the post_save signal, automatically, is there any way of doing it?

TL; DR：我需要一种方法在post_save信号之后自动触发自定义信号，有没有办法做到这一点？

I'm currently developing a library for django that requires a lot of comes and goes with the post_save signal in django and I was wondering if it's possible to trigger another signal after the post_save so I could implement my own and not intervene the post_save in case a project that uses the library needs to do it.

我正在开发一个django的库，它需要很多来自django中的post_save信号，我想知道是否有可能在post_save之后触发另一个信号所以我可以实现自己的而不是干预post_save以防万一使用库的项目需要这样做。

So far I know that signals are expected to receive a class as a sender argument, and if I trigger manually the signal from the post_save I would be doing nothing (I'd still be intervening it). Is there any workaround for this? Am I missing something in the docs?

到目前为止，我知道信号预计将接收一个类作为发送者参数，如果我手动触发post_save中的信号，我将无所事事（我仍然会干预它）。这有什么解决方法吗？我在文档中遗漏了什么吗？

1 个解决方案

#1

Although this may be possible by calling a signal manually from inside another signal like this:

虽然这可以通过从另一个信号中手动调用信号来实现，如下所示：

post_save.send(MyModel, instance=a_mymodel_instance)

There are easier ways to do something like that:

有更简单的方法来做这样的事情：

Let us assume that you follow the file organization that I use in this answer: Django Create and Save Many instances of model when another object are created

让我们假设您遵循我在此答案中使用的文件组织：Django创建并保存创建另一个对象时的许多模型实例

Suggestion 1:

建议1：

Let us assume that your first post_save does something to MyModel1 and another post_save signal does something to MyModel2 after some processing on the instance that triggered the first signal.
让我们假设您的第一个post_save对MyModel1做了一些事情，而另一个post_save信号在触发第一个信号的实例上进行一些处理之后对MyModel2做了一些事情。
post_save is always send at the end of a save() method.
post_save总是在save（）方法的末尾发送。

Organize your signals as follows:

按如下方式组织您的信号：

@receiver(post_save, sender=MyModel1)
def mymodel1_signal (sender, instance, **kwargs):
    Do stuff on MyModel1 instance...
    Do also stuff on MyModel2 and then call MyModel2.save()


@receiver(post_save, sender=MyModel2)
def mymodel2_signal (sender, instance, **kwargs):
    Do stuff on MyModel2 instance...

This way the mymodel2_signal signal will get triggered after the call to MyModel2.save() from mymodel1_signal.

这样，mymodel2_signal信号将在从mymodel1_signal调用MyModel2.save（）之后被触发。

Suggestion 2:

建议2：

Use a mix of signals to achieve the correct "timing".
使用混合信号来实现正确的“定时”。
Let us assume that you want to start a process on MyModel2 before a MyModel1 get's saved
让我们假设你想在MyModel1 get的保存之前在MyModel2上启动一个进程

Use a pre_save and a post_save signal:

使用pre_save和post_save信号：

@receiver(pre_save, sender=MyModel1)
def mymodel1_signal (sender, instance, **kwargs):
    Do stuff on MyModel1 instance...
    Do also stuff on MyModel2 and then call MyModel2.save()


@receiver(post_save, sender=MyModel2)
def mymodel2_signal (sender, instance, **kwargs):
    Do stuff on MyModel2 instance...

Suggestion 3:

建议3：

Use a MyModel2 method directly inside a MyModel1 post_save signal.

直接在MyModel1 post_save信号中使用MyModel2方法。

#1