在 post_save 信号中访问用户的请求

Question

我在我的项目中完成了以下 post_save 信号。

from django.db.models.signals import post_save
from django.contrib.auth.models import User

# CORE - SIGNALS
# Core Signals will operate based on post

def after_save_handler_attr_audit_obj(sender, **kwargs):
    print User.get_profile()

    if hasattr(kwargs['instance'], 'audit_obj'):
        if kwargs['created']:
            kwargs['instance'].audit_obj.create(operation="INSERT", operation_by=**USER.ID**).save()
        else:
            kwargs['instance'].audit_obj.create(operation="UPDATE").save()


# Connect the handler with the post save signal - Django 1.2
post_save.connect(after_save_handler_attr_audit_obj, dispatch_uid="core.models.audit.new")

operation_by 列，我想获取 user_id 并存储它。知道怎么做吗？

Answer 1

做不到。当前用户只能通过请求获得，这在使用纯模型功能时不可用。以某种方式访问​​视图中的用户。

Answer 2

我能够通过检查堆栈并查找视图然后查看视图的局部变量来获取请求来做到这一点。感觉有点像 hack，但确实有效。

import inspect, os

@receiver(post_save, sender=MyModel)
def get_user_in_signal(sender, **kwargs):
    for entry in reversed(inspect.stack()):
        if os.path.dirname(__file__) + '/views.py' == entry[1]:
            try:
                user = entry[0].f_locals['request'].user
            except:
                user = None
            break
    if user:
        # do stuff with the user variable

Answer 3

伊格纳西奥是对的。 Django 的模型信号旨在通知其他系统组件有关与实例关联的事件及其尊重的数据，所以我猜你不能从模型post_save 信号访问请求数据是有效的，除非该请求数据存储在或与实例相关联。

我想有很多方法可以处理它，从更差到更好，但我想说这是创建基于类/基于函数的通用视图的主要示例，它将自动为您处理。

如果从 CreateView、UpdateView 或 DeleteView 继承的视图处理在需要审核的模型上运行的动词，则它们还从您的 AuditMixin 类继承。然后AuditMixin 可以挂钩到成功创建\更新\删除对象的视图并在数据库中创建一个条目。

非常有意义，非常干净，易于插拔，并且可以生出快乐的小马。反面？您要么必须使用即将发布的 Django 1.3 版本，要么必须花一些时间来修改基于函数的通用视图并为每个审计操作提供新视图。

Answer 4

为什么不添加这样的中间件：

class RequestMiddleware(object):

    thread_local = threading.local()

    def process_request(self, request):
        RequestMiddleware.thread_local.current_user = request.user

以及稍后在您的代码中（特别是在该主题的信号中）：

thread_local = RequestMiddleware.thread_local
if hasattr(thread_local, 'current_user'):
    user = thread_local.current_user
else:
    user = None

Answer 5

为了可追溯性，为您的模型添加两个属性（created_by 和updated_by），在“updated_by”中保存最后修改记录的用户。然后在你的信号中你有用户：

models.py：

class Question(models.Model):
    question_text = models.CharField(max_length=200)
    pub_date = models.DateTimeField('date published')
    created_by = models. (max_length=100)
    updated_by = models. (max_length=100)

views.py

    p = Question.objects.get(pk=1)
    p.question_text = 'some new text'
    p.updated_by = request.user
    p.save()

信号.py

@receiver(pre_save, sender=Question)
def do_something(sender, instance, **kwargs):
    try:
        obj = Question.objects.get(pk=instance.pk)
    except sender.DoesNotExist:
        pass
    else:
        if not obj.user == instance.user: # Field has changed
            # do something
            print('change: user, old=%s new=%s' % (obj.user, instance.user))

Answer 6

您也可以为此目的使用 django-reversion，例如

from reversion.signals import post_revision_commit
import reversion

@receiver(post_save)
def post_revision_commit(sender, **kwargs):
    if reversion.is_active():
        print(reversion.get_user())

详细了解他们的 API https://django-reversion.readthedocs.io/en/stable/api.html#revision-api

Answer 7

您可以通过覆盖您的模型save() 方法并将保存的实例上的用户设置为附加参数来做一个小技巧。为了从django_currentuser.middleware.ThreadLocalUserMiddleware 获取我使用get_current_authenticated_user() 的用户（参见https://pypi.org/project/django-currentuser/）。

在你的models.py：

from django_currentuser.middleware import get_current_authenticated_user

class YourModel(models.Model):
    ...
    ...

    def save(self, *args, **kwargs):
        # Hack to pass the user to post save signal.
        self.current_authenticated_user = get_current_authenticated_user()
        super(YourModel, self).save(*args, **kwargs)

在你的signals.py：

@receiver(post_save, sender=YourModel)
def your_model_saved(sender, instance, **kwargs):
    user = getattr(instance, 'current_authenticated_user', None)

PS：不要忘记将'django_currentuser.middleware.ThreadLocalUserMiddleware' 添加到您的MIDDLEWARE_CLASSES。

Answer 8

您可以在中间件的帮助下做到这一点。在您的应用程序中创建get_request.py。那么

from threading import current_thread

from django.utils.deprecation import MiddlewareMixin


_requests = {}


def current_request():
    return _requests.get(current_thread().ident, None)


class RequestMiddleware(MiddlewareMixin):

    def process_request(self, request):
        _requests[current_thread().ident] = request

    def process_response(self, request, response):
        # when response is ready, request should be flushed
        _requests.pop(current_thread().ident, None)
        return response


    def process_exception(self, request, exception):
        # if an exception has happened, request should be flushed too
         _requests.pop(current_thread().ident, None)

然后将此中间件添加到您的设置中：

MIDDLEWARE = [
    ....
    '<your_app>.get_request.RequestMiddleware',
]

然后将导入添加到您的信号中：

from django.db.models.signals import post_save
from django.contrib.auth.models import User
from <your_app>.get_request import current_request

# CORE - SIGNALS
# Core Signals will operate based on post

def after_save_handler_attr_audit_obj(sender, **kwargs):
    print(Current User, current_request().user)
    print User.get_profile()

    if hasattr(kwargs['instance'], 'audit_obj'):
        if kwargs['created']:
            kwargs['instance'].audit_obj.create(operation="INSERT", operation_by=**USER.ID**).save()
        else:
            kwargs['instance'].audit_obj.create(operation="UPDATE").save()


# Connect the handler with the post save signal - Django 1.2
post_save.connect(after_save_handler_attr_audit_obj, dispatch_uid="core.models.audit.new")

Answer 9

我想你会想出来的，但是我遇到了同样的问题，我意识到 我创建的所有实例都引用了创建它们的用户（这就是你正在寻找的为）

Answer 10

context_processors.py

from django.core.cache import cache

def global_variables(request):
    cache.set('user', request.user)

----------------------------------
in you model

from django.db.models.signals import pre_delete
from django.dispatch import receiver
from django.core.cache import cache
from news.models import News

@receiver(pre_delete, sender=News)
def news_delete(sender, instance, **kwargs):
    user = cache.get('user')

in settings.py

TEMPLATE_CONTEXT_PROCESSORS = (
    'web.context_processors.global_variables',
)