Using Django signals to identify a present user session - python

i want to use django signals to identify if a user is logged-in twice and if so, revoke his first session so that only one user session can be present at once.
i used the following example but it seems that my signals.py does not even gets reconcnized and i dont know why.
Example:
How to prevent multiple login in Django
accounts/signals.py
from django.contrib.auth import user_logged_in
from django.dispatch.dispatcher import receiver
from django.contrib.sessions.models import Session
from .models import UserSession
#receiver(user_logged_in)
def remove_other_sessions(sender, user, request, **kwargs):
# remove other sessions
Session.objects.filter(usersession__user=user).delete()
# save current session
request.session.save()
# create a link from the user to the current session (for later removal)
UserSession.objects.get_or_create(
user=user,
session=Session.objects.get(pk=request.session.session_key)
)
accounts/models.py
# Model to store the list of logged in users
class UserSession(models.Model):
user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
session = models.OneToOneField(Session, on_delete=models.CASCADE)
accounts/apps.py
from django.apps import AppConfig
class AccountsConfig(AppConfig):
name = 'Accounts'
def ready(self):
import Accounts.signals
but for some reason nothing gets written onto the database for that table.
do i maybe miss something here, this is the very first time i get in touch with signals so i might missed something at the configuration.

Try this,
default_app_config = 'Accounts.apps.AccountsConfig'
Add this line in __init__.py file of your apps.py file directory.

Related

Django signals duplicate with unique dispatch id

I have a problem with duplicate signals. I have looked-up the relevant part of Django docs and a similar question on Stackoverflow but I still can't get it working right - i.e. the action that I have planned (creation on an ActivityLog entry) is actually happening 4 times :/
I have added the dispatch_uid and the problem still persists, so I guess I'm doing something wrong. Can you please hint me to the error?
Here's my code:
signals.py
from patient.models import Patient
from .models import ActivityLog
#receiver(pre_save, sender=Patient)
def create_new_patient(sender, instance, **kwargs):
ActivityLog.objects.create(
user=instance.created_by_user,
event='created a new patient',
patient_id=instance.patient_id
)
and this is it's usage in the patient.apps module:
from django.apps import AppConfig
from django.db.models.signals import pre_save
app_name = "patient"
class PatientConfig(AppConfig):
name = 'patient'
verbose_name = "Patients"
def ready(self):
from activity_logger.signals import create_new_patient
print('Patient APP is ready!')
pre_save.connect(create_new_patient, sender='patient.Patient', dispatch_uid='patient')
The print Patient APP is ready! does appear twice, and the object gets created 4 times, despite setting the dispatch_uid. What have I misunderstood?
The #receiver(Signal,...) decorator is a shortcut for Signal.connect(...), so you indeed register your create_new_patient handler twice (once thru #receiver when importing your signals module, the second time with pre_save.connect().
Solution : in your App.ready() method, you should just import your app's signal.py module. This will trigger the registration of the handlers decorated with #receiver.

How to add the last_login_ip, when the user login if using `rest-auth`?

How to add the last_login_ip, when the user login if using rest-auth?
Befor ask the post I searched one post bellow:
How can I do my logic in `http://127.0.0.1:8000/rest-auth/login/` of `django-rest-auth`?
The answer is perfect for custom verify the login params.
But, how about after login, then add attribute to the User?
I mean, the answer is just for verify the data, I want to after user login success, I want to add the last_login_ip to the user instance.
EDIT
Please be attention, I know how to get the remote IP who visit my site. I mean I use the rest-auth to login, and customized LoginSerializer like the link. The link is for verify the login data, I can not to change the last_login_ip data in the LoginSerializer, I want when the user login success, then change the user's last_login_ip. but where to write my change last_login_ip code?
EDIT-2
I follow the #at14's advice, in the init.py (as the same level as apps.py):
default_app_config = '管理员后台.用户管理.qiyun_admin_usermanage.apps.QiyunAdminUsermanageConfig'
and in the apps.py:
from django.apps import AppConfig
class QiyunAdminUsermanageConfig(AppConfig):
name = 'qiyun_admin_usermanage'
def ready(self):
import 管理员后台.用户管理.qiyun_admin_usermanage.api.signals
There will get bellow error:
django.core.exceptions.ImproperlyConfigured: Cannot import 'qiyun_admin_usermanage'. Check that '管理员后台.用户管理.qiyun_admin_usermanage.apps.QiyunAdminUsermanageConfig.name' is correct.
and I also tried to comment the default_app_config = '管理员后台.用户管理.qiyun_admin_usermanage.apps.QiyunAdminUsermanageConfig' in the init.py, but still not work.
Use django's user logged in signal to save this information into the database.
In signals.py,
from django.contrib.auth.signals import user_logged_in
from django.dispatch import receiver
#receiver(user_logged_in)
def user_logged_in_callback(sender, user, request, **kwargs):
// Get the IP Address and save it
Read more about signals here.
Do pay attention on how to import signals in your app ready method
Make an apps.py (it might already exist) in your app directory,
from django.apps import AppConfig
class YourAppConfig(AppConfig):
name = '管理员后台.用户管理.qiyun_admin_usermanage'
def ready(self):
import 管理员后台.用户管理.qiyun_admin_usermanage.api.signals # noqa
In your apps init.py file,
default_app_config = '管理员后台.用户管理.qiyun_admin_usermanage.apps.QiyunAdminUsermanageConfig'

How to avoid dependency injection in Django?

I'm trying to figure out how to avoid dependency injection in my project. There is a file notifications.py in app directory.
File notifications.py contains methods for sending emails to admin and users. To get admins email, I need to check object of SystemData model. But in models, I use notifications.
models
class SystemData(models.Model):
admin_alerts_email = models.EmailField(verbose_name=u'Emailová adresa admina')
contact_us_email = models.EmailField(verbose_name=u'Adresa kontaktujte nás')
waiting_threshold = models.PositiveSmallIntegerField(verbose_name=u'Maximálny počet minút čakania')
class SomeModel(models.Model):
....
def save(...):
notifications.send_message_to_admin('message')
notifications.py
from django.core.mail import EmailMessage
from models import SystemData
def send_message_to_admin(message):
mail = EmailMessage(subject, message, to=[SystemData.objects.all().first().admin_email])
mail.send()
Django returns that it can't import SystemData.
Do you know what to do?
EDIT:
stacktrace
You can solve circular dependencies in functions by using inline imports:
class SomeModel(models.Model):
....
def save(...):
from .notifications import send_message_to_admin
send_message_to_admin('message')
This will delay the import statement until the function is actually executed, so the models module has already been loaded. The notifications module can then safely import the models module.
Apart from using circular imports you can either do it like that:
from django.core.mail import EmailMessage
from django.db.models.signals import post_save
from django.dispatch import receiver
from .models import SystemData, SomeModel
#receiver(post_save, sender=SomeModel)
def send_message_to_admin(sender, instance, created, **kwargs):
message = 'message'
mail = EmailMessage(
subject,
message,
to=[SystemData.objects.all().first().admin_email]
)
mail.send()
and at the end of models.py put
from .notifications import *
or use newest approach with AppConfig to register signals (that's what your notifications actually do)
see: https://chriskief.com/2014/02/28/django-1-7-signals-appconfig/
that way it will load when app registry is ready and you'll avoid circular imports, so that line:
from .notifications import *
can be dropped from models.py
AppConfig can be used in a more generic way as well allowing you to import models like that:
from django.apps import apps
Model = apps.get_model('app_name', 'Model')

How to create multiple objects with django transactions?

I have to retrieve M objects from a list of Q objects and then maps the M objects to an User. To achieve this, I need to run the code inside a transaction and roll back the DB in the case 1 of M objects are not created:
def polls(request, template_name='polls/polls.html'):
question_list = random.sample(list(Question.objects.all()), 3)
try:
with transaction.atomic():
for question in question_list:
UserToQuestion.objects.create(
user=request.user.id,
question=question.id
)
except IntegrityError:
handle_exception()
How I can achieve this? How the exception should be handled? The django documentation doesn't show a real example.
Is also possible perform this task during the user registration overriding the save method in way each registered user is mapped to N questions?
You need to use django signals while doing user registration.
Also you do not need with transaction.atomic(): part. You need to use
bulk create
First of all, we create a signal, in order to map the related questions to an user when the user is registered. The signal is triggered from post_save() and the call-back function retrieve N random questions and map it to the user. The signal must be connected, to do it, we use the decorator #receiver. We also need to use a transaction, cause of bulk_create() method.
signals.py
import random
from django.dispatch import receiver
from django.contrib.auth.models import User
from django.db import transaction
from django.db.models.signals import post_save
from polls.models import Question, UserToQuestion
#transaction.atomic
#receiver(post_save, sender=User)
def sig_user_registered(instance, **kwargs):
question_list = random.sample(list(Question.objects.all()), 3)
UserToQuestion.objects.bulk_create([
UserToQuestion(user=instance, question=question) for question in question_list
])
The signal must be imported. To do it, we use the method ready().
apps.py
from django.apps import AppConfig
class AccountConfig(AppConfig):
name = 'account'
def ready(self):
import account.signals
Finally, we load the application
settings.py
INSTALLED_APPS = [
# Django apps
# ...
# Third-party apps
# ...
# Your apps
'account.apps.AccountConfig',
# ...
]

Django 1.8: Function not called on Signal

I'm picking up on a code which should send a signal every time a user logs in. Thats not happening though. The function get_create_stripe() isnt getting called when the user logs in.
Anyone can tell whats wrong?
I'm working in Django 1.8 and the whole code is here.
Gist about the code: This code is part of an e-commerce site which users stripe as its payment gateway. Intent is, every time user logs in, we create a new stripe id or return an existing one.
Is it because this function is not in models.py? This is written to a file 'signals.py' and I'm not quite sure how Django should understand to call get_create_stripe() from a signal call in this file. Is it so?
import stripe
from django.conf import settings
from django.contrib.auth.signals import user_logged_in
from .models import UserStripe
stripe.api_key = settings.STRIPE_SECRET_KEY
def get_create_stripe(sender, user, *args, **kwargs):
new_user_stripe, created = UserStripe.objects.get_or_create(user=user)
print "hello"
if created:
customer = stripe.Customer.create(
email = str(user.email)
)
print customer
new_user_stripe.stripe_id = customer.id
new_user_stripe.save()
user_logged_in(get_create_stripe)
You need to connect your signal method to the signal.
Something like
from django.dispatch import receiver
from django.contrib.auth.signals import user_logged_in
#receiver(user_logged_in, sender=UserStripe)
def get_create_stripe(sender, user, *args, **kwargs):
EDIT: Also, what is this:
user_logged_in(get_create_stripe)
That is not how signals work. Either you do what I wrote above, or do this:
user_logged_in.connect(get_create_stripe)

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