python - Django 信号 : How to initialize bindings?

Question

我正在应用程序的 __init__.py 文件中导入信号文件。问题发生在我运行 manage.py runserver 时，我发现 __init__.py 被导入了两次，并且我的回调运行了两次。

但是，当我运行 manage.py shell 时，__init__.py 按预期工作(一次)

(Django 1.8.3)

app/__init__.py:

print 'Hello!'
import signals

应用程序/模型.py:

from django.db import models

class RemoteTask(models.Model):
    title = models.CharField(max_length=50)

class RemoteTaskStatus(models.Model):
    remote_task = models.IntegerField()
    status = models.IntegerField()

应用程序/信号.py:

print '------> app/signals.py'

from django.db.models.signals import post_save
from django.dispatch import receiver
from app.models import RemoteTask, RemoteTaskStatus

@receiver(post_save, sender=RemoteTask)
def status_new(sender, **kwargs):
    print '---------> Running callback'
    if kwargs.get('created', 'False') is True:
        instance = kwargs['instance']
        RemoteTaskStatus.objects.create(
            remote_task=instance,
            status=0
        )

示例输出:

$ ./manage.py runserver
Hello!
------> app/signals.py
Hello!
------> app/signals.py
Performing system checks...

System check identified no issues (0 silenced).
August 12, 2015 - 19:50:38
Django version 1.8.3, using settings 'signal_loca.settings'
Starting development server at http://127.0.0.1:8000/
Quit the server with CONTROL-C.

Angel Velasquez 的解决方案: app/__init__.py:

print 'Hello!'
import app.signals

Answer 1

在 AppConfig.ready 方法中导入您的 signals.py 以防止回调被注册两次。以下是执行此操作的推荐方法:

my_awesome_project/
|-- app/
|   |-- __init__.py   <-- set default_app_config here
|   |-- apps.py       <-- define your AppConfig subclass here
|   |-- models.py
|   |-- signals.py    <-- define your signal handling functions here
|-- other_app/
|-- my_awesome_project/
    |-- __init__.py
    |-- settings.py
    |-- wsgi.py

app/__init__.py

default_app_config = 'app.apps.MyAppConfig'

app/apps.py

from django.apps import AppConfig

class MyAppConfig(AppConfig):
    name="app"

    def ready(self):
        from . import signals

apps/models.py

from django.db import models

class RemoteTask(models.Model):
    title = models.CharField(max_length=50)

class RemoteTaskStatus(models.Model):
    remote_task = models.IntegerField()
    status = models.IntegerField()

app/signals.py

from django.db.models.signals import post_save
from django.dispatch import receiver
from app.models import RemoteTask, RemoteTaskStatus

@receiver(post_save, sender=RemoteTask, dispatch_uid="status_new_signal_on_RemoteTask_post_save")
def status_new(sender, **kwargs):
    print '---------> Running callback'
    if kwargs.get('created', 'False') is True:
        instance = kwargs['instance']
        RemoteTaskStatus.objects.create(
            remote_task=instance,
            status=0
        )

编辑:

添加 dispatch_uid 到 receiver 装饰器。