How to get remote ip and fields name in signals ?
I have tried using def ModelChangeLogger(sender, request, **Kwargs): but it throws error message takes only one argument. The code:
signals.py
def ModelChangeLogger(sender, **Kwargs):
if str(sender._meta) == str(models.DBLogEntry._meta):
return
log_time = datetime.datetime.now()
log_table_name = sender._meta.object_name
log_instance = Kwargs['instance']
log_ip = '0.0.0.0' **####### Remote ip #########**
log_change_type = ''
if 'created' in Kwargs:
log_change_type = Kwargs['created'] and 'Creation' or 'Updating'
else:
log_change_type = 'Deleting'
models.DBLogEntry.objects.create(
log_time=log_time,
log_table_name=log_table_name,
log_instance=log_instance,
log_change_type=log_change_type
)
__init__.py
from django.db.models.signals import post_save
from django.db.models.signals import pre_save
from django.db.models.signals import post_delete
from myapp.tracker.signals import ModelChangeLogger
pre_save.connect(ModelChangeLogger)
post_save.connect(ModelChangeLogger)
post_delete.connect(ModelChangeLogger)
How to get remote_add and field names from there?
It is not recommendable to have a signal handler expecting a request object due to the fact that a model save might be triggered without having a request coming from a web browser (eg. if you simply do it through the shell) or call model.save() somewhere else in your code!
You could either make your own custom signal that gets send from the views that modifiy your model or call the logging method yourself in your views.
Related
I have done the below post_save signal in my project.
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")
The operation_by column, I want to get the user_id and store it. Any idea how can do that?
Can't be done. The current user is only available via the request, which is not available when using purely model functionality. Access the user in the view somehow.
I was able to do it by inspecting the stack and looking for the view then looking at the local variables for the view to get the request. It feels like a bit of a hack, but it worked.
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
Ignacio is right. Django's model signals are intended to notify other system components about events associated with instances and their respected data, so I guess it's valid that you cannot, say, access request data from a model post_save signal, unless that request data was stored on or associated with the instance.
I guess there are lots of ways to handle it, ranging from worse to better, but I'd say this is a prime example for creating class-based/function-based generic views that will automatically handle this for you.
Have your views that inherit from CreateView, UpdateView or DeleteView additionally inherit from your AuditMixin class if they handle verbs that operate on models that need to be audited. The AuditMixin can then hook into the views that successfully create\update\delete objects and create an entry in the database.
Makes perfect sense, very clean, easily pluggable and gives birth to happy ponies. Flipside? You'll either have to be on the soon-to-be-released Django 1.3 release or you'll have to spend some time fiddlebending the function-based generic views and providing new ones for each auditing operation.
You can do that with the help of middleware. Create get_request.py in your app. Then
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)
Then add this middleware to your settings:
MIDDLEWARE = [
....
'<your_app>.get_request.RequestMiddleware',
]
Then add import to your signals:
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")
Why not adding a middleware with something like this :
class RequestMiddleware(object):
thread_local = threading.local()
def process_request(self, request):
RequestMiddleware.thread_local.current_user = request.user
and later in your code (specially in a signal in that topic) :
thread_local = RequestMiddleware.thread_local
if hasattr(thread_local, 'current_user'):
user = thread_local.current_user
else:
user = None
For traceability add two attributes to your Model(created_by and updated_by), in "updated_by" save the last user who modified the record. Then in your signal you have the user:
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()
signals.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))
You could also use django-reversion for this purpose, e.g.
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())
Read more on their API https://django-reversion.readthedocs.io/en/stable/api.html#revision-api
You can do a small hack by overriding you model save() method and setting the user on the saved instance as additional parameter. To get the user I used get_current_authenticated_user() from django_currentuser.middleware.ThreadLocalUserMiddleware (see https://pypi.org/project/django-currentuser/).
In your 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)
In your signals.py:
#receiver(post_save, sender=YourModel)
def your_model_saved(sender, instance, **kwargs):
user = getattr(instance, 'current_authenticated_user', None)
PS: Don't forget to add 'django_currentuser.middleware.ThreadLocalUserMiddleware' to your MIDDLEWARE_CLASSES.
I imagine you would have figured this out, but I had the same problem and I realised that all the instances I create had a reference to the user that creates them (which is what you are looking for)
it's possible i guess.
in models.py
class _M(models.Model):
user = models.ForeignKey(...)
in views.py
def _f(request):
_M.objects.create(user=request.user)
in signals.py
#receiver(post_save, sender=_M)
def _p(sender, instance, created, **kwargs):
user = instance.user
No ?
Request object can be obtained from frame record by inspecting.
import inspect
request = [
frame_record[0].f_locals["request"]
for frame_record in inspect.stack()
if frame_record[3] == "get_response"
][0]
def get_requested_user():
import inspect
for frame_record in inspect.stack():
if frame_record[3] == 'get_response':
request = frame_record[0].f_locals['request']
return request.user
else:
return None
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',
)
I'm struggling with the following.
I'm trying to create a custom signal that will trigger when the current time will be equal to the value of my model's notify_on DateTimeField.
Something like this:
class Notification(models.Model):
...
notify_on = models.DateTimeField()
def send_email(*args, **kwargs):
# send email
signals.when_its_time.connect(send_email, sender=User)
After I've read through all docs and I found no information on how to implement such a signal.
Any ideas?
UPDATE:
Less naive approach with ability to discard irrelevant tasks: https://stackoverflow.com/a/55337663/9631956
Ok, thanks to comments by #SergeyPugach I've done the following:
Added a post_save signal that calls a function that adds a task to the celery. apply_async let's you pass eta - estimated time of arrival which can accept DateTimeField directly, that's very convenient.
# models.py
from django.db.models import signals
from django.db import models
from .tasks import send_notification
class Notification(models.Model):
...
notify_on = models.DateTimeField()
def notification_post_save(instance, *args, **kwargs):
send_notification.apply_async((instance,), eta=instance.notify_on)
signals.post_save.connect(notification_post_save, sender=Notification)
And the actual task in the tasks.py
import logging
from user_api.celery import app
from django.core.mail import send_mail
from django.template.loader import render_to_string
#app.task
def send_notification(self, instance):
try:
mail_subject = 'Your notification.'
message = render_to_string('notify.html', {
'title': instance.title,
'content': instance.content
})
send_mail(mail_subject, message, recipient_list=[instance.user.email], from_email=None)
except instance.DoesNotExist:
logging.warning("Notification does not exist anymore")
I will not get into details of setting up celery, there's plenty of information out there.
Now I will try to figure out how to update the task after it's notification instance was updated, but that's a completely different story.
In django's documentation there is two interesting signals that may help you on this task: pre_save and post_save.
It depends on your needs, but let's say you want to check if your model's notify_on is equal to the current date after saving your model (actually after calling the save() or create() method). If it's your case you can do:
from datetime import datetime
from django.contrib.auth.models import User
from django.db import models
from django.dispatch import receiver
from django.db.models.signals import post_save
class Notification(models.Model):
...
# Every notification is related to a user
# It depends on your model, but i guess you're doing something similar
user = models.ForeignKey(User, related_name='notify', on_delete=models.DO_NOTHING)
notify_on = models.DateTimeField()
...
def send_email(self, *args, **kwargs):
"""A model method to send email notification"""
...
#receiver(post_save, sender=User)
def create_notification(sender, instance, created, **kwargs):
# check if the user instance is created
if created:
obj = Notification.objects.create(user=instance, date=datetime.now().date())
if obj.notify_on == datetime.now().date():
obj.send_email()
And you should know, that django signals won't work by they own only if there is an action that triggers them. What this mean is that Django signals won't loop over your model's instances and perform an operation, but django signals will trigger when your application is performing an action on the model connected to a signal.
Bonus: To perform a loop over your instances and process an action regulary you may need an asyncworker with a Queue database (mostly, Celery with Redis or RabbitMQ).
Sitting over a day on it. Really can't understand why this signal is not triggered when a user is activated, no error log, no exception in the admin on activation. Can anybody help? The following code should result in a log message in the apache error.log when a user, right?
import logging
from django.dispatch import receiver
from registration.signals import user_activated
#receiver(user_activated)
def registered_callback(sender, **kwargs):
logger = logging.getLogger("user-activated")
logger.error("activated here")
same with user_registered
First of all im using django 1.8.3 .You should register your signal first. As far as i know, there are some methods to do that but this is what im doing;
Create signals.py in your app write your signal there;
from django.db.models.signals import post_save
from django.dispatch import receiver
#receiver(post_save, sender=your_model,dispatch_uid="yourmodel_save_receiver")
def post_save_yourmodel(sender, instance, **kwargs):
if instance.profile_status:
print "active"
else:
print "not active"
Then you should create apps.py. This file contains configuration information to your model.
from django.apps import AppConfig
class yourmodel_config(AppConfig):
name = 'yourmodel_config'
verbose_name = 'your_model config'
def ready(self):
import yourmodel.signals
With this whenever your app is ready, your signals will be imported
Finally open your __init__.py and add the following.
default_app_config = 'yourmodel.apps.yourmodel_config'
With this you are defining application configuration for your model.This example when ever yourmodel is saved, signal checks for profile_status attribute and prints output depending on the value(true or false) to your console. You can also add created parameter to your model to know that if instance of the model is created. created will return True if a new record was created. def post_save_yourmodel(sender, instance, created, **kwargs):. Otherwise this signal will be triggered whenever your model is saved with yourmodel.save().
Consider that is a post_save example.You can find list of the model signals from here.
I'm trying to setup a signal so that when a valid form is saved, a function is ran to carry out a related task.
My app structure is as follows;
- events
- helpers
- __init__.py
- status.py
- models
- signals
- __init__.py
- event.py
- __init__.py
- event.py
- status.py
- views
- __init__.py
- event.py
I believe signals need to be imported as early as possible, before models, so at the top of models/__init__.py I've got from .signals import *.
# views/event.py
class AddEventView(CreateView):
"""
View for adding an Event.
"""
model = Event
form_class = EventForm
success_url = reverse_lazy('events:all_events')
def form_valid(self, form):
self.object = form.save()
signals.event_status.send(
sender=None, request=self.request, event=self.object, status=None
) # Should the sender be self.object?
return super(AddEventView, self).form_valid(form)
# signals/event.py
from django.dispatch import Signal
event_status = Signal(providing_args=["request", "event", "status"])
# helpers/status.py
from ..models import Status, StatusHistory
from ..models.signals import event_status
def create_status(sender, **kwargs):
"""
Create a status for a given event.
"""
event = kwargs['event']
status = kwargs['status']
creator = User.objects.get(pk=event.creator)
try:
current_status = StatusHistory.objects.filter(
event=event).order_by('timestamp')[0]
except IndexError:
# Not sure what we're doing here yet.
pass
if not status:
status = Status.objects.get(description=_("Submitted"))
statushistory = StatusHistory.create(
event=event,
event_status=status,
user=creator
)
statushistory.save()
event_status.connect(create_status)
I'm running the debug server in Pycharm with a break point in the create_status() function & it's never getting hit.
Have I implemented this wrong?
I've used signals in some of my projects and I allways import the signals in the __init__.py of my Django APP (Same folder as settings.py, views.py, urls.py...)
__init__.py:
import signals
signals.py:
from django.db.models.signals import post_save, pre_delete
from django.dispatch import receiver
from my_project.models import *
#receiver(post_save, sender=Modelname) # Called after an object is saved
def create_modelname(sender, **kwargs):
obj = kwargs['instance'] # I get the object being saved here
# ... Here I do whatever I want
#receiver(pre_delete, sender=Modelname) # Called before an object is deleted
def delete_modelname(sender, **kwargs):
obj = kwargs['instance']
# ... Do whatever you need
Remember this 2 imports:
from django.db.models.signals import post_save, pre_delete
from django.dispatch import receiver
Remember to import the signals
To import the signals you need to add import signals in your __init__.py of your project
Using this code, this functions are called automatically by Django when an object of the class Modelname is created or deleted.
The receiver for created object is called after the object is created, and the receiver for deleted object is called before the object is deleted.
I think maybe you just need to import your helpers/status.py eg in models/__init__.py
otherwise your event_status signal gets defined ok but the signal handler create_status never gets connected by Django
if you only have one handler for that signal it might make sense to put it in the same module as the signal definition
I found one case that signal is not working.
Here are cases that signal(pre_save, post_save) won't happen.
Model.objects.filter(pk=pk).update(key=value)
Bulk model functions won't happen signals.
I'm using django-registration and I'm trying to connect to its signals to automatically create a UserProfile.
Signal definition:
from django.dispatch import Signal
# A new user has registered.
user_registered = Signal(providing_args=["user", "request"])
Signal send by django-registration:
def register(self, request, **kwargs):
"""
Create and immediately log in a new user.
"""
username, email, password = kwargs['username'], kwargs['email'], kwargs['password1']
User.objects.create_user(username, email, password)
# authenticate() always has to be called before login(), and
# will return the user we just created.
new_user = authenticate(username=username, password=password)
login(request, new_user)
signals.user_registered.send(sender=self.__class__,
user=new_user,
request=request)
return new_user
My signal connect:
from registration.signals import *
from core.models import UserProfile
from django.contrib.auth.models import User
def createUserProfile(sender, instance, **kwargs):
UserProfile.objects.get_or_create(user=instance)
user_registered.connect(createUserProfile, sender=User)
Needless to say no UserProfile is being created. What am I missing here?
Thanks a lot!
EDIT: I moved my connect() and its corresponding method to a model.py and still no luck.
New code:
from django.db import models
from django.contrib import auth
from django.contrib.auth import login
from core.forms import AuthForm
from registration.signals import *
from django.contrib.auth.models import User
# Create your models here.
class UserProfile(models.Model) :
user = models.ForeignKey(User, unique=True)
def __unicode__(self):
return self.user.username
def createUserProfile(sender, instance, **kwargs):
print "creating profile"
UserProfile.objects.get_or_create(user=instance)
user_registered.connect(createUserProfile, sender=User)
I'm using Pycharm to debug, and in the very beginning my breakpoint on user_registered.connect() is hit. So I assume that connect() is being registered correctly. However, I still don't see createUserProfile being run. Anything else I'm missing?
Thanks!
ANSWER: Doh. My connect and receiver code was wrong. Correct code:
def createUserProfile(sender, user, request, **kwargs):
UserProfile.objects.get_or_create(user=user)
user_registered.connect(createUserProfile)
Realized it after I read signals.py in django-registration
You need to register (connect) your signal in a module which is imported on server startup. Your file where user_registered.connect(createUserProfile, sender=User)lives is mot likely not imported on startup. From the django docs:
You can put signal handling and
registration code anywhere you like.
However, you'll need to make sure that
the module it's in gets imported early
on so that the signal handling gets
registered before any signals need to
be sent. This makes your app's
models.py a good place to put
registration of signal handlers.
http://docs.djangoproject.com/en/dev/topics/signals/#connecting-receiver-functions
So models.py of your custom app would be a good place (or any other module which is definitely imported on server startup).
Torsten is right: the alternative way is to use decorators as stated in documentation:
from registration.signals import user_registered
# ...
#receiver(user_registered)
def your_function_name_here(sender, user, request, **kwargs):
# your code here
pass
I like this way because it's compact and readable.