How to get notification on template using django signals?

Question

I'm a beginner's level Django developer and I'm making a hospital system. In the hospital system, I want to add a notification system whenever any patient uploads a report against the doctor id I want to inform the doctor to the doctor notifications template that the report of patient(with name) has been submitted.

I was trying it to work for 2 days and used signals to create a message but I'm unable to show it on the doctor's side. Please anyone can tell me how can I make it easier or Should I use something else instead of signals.

The Previous Code that I tried.

from django.shortcuts import render, HttpResponse,request
from hospital.models import Patient ,Doctor,Report
from django.db.models.signals import post_save,pre_save

def save_report(sender,instance,**kwargs):
    instance = Patient.objects.get(id=1)
    dr_id= instance.assignedDoctorId
    patient=models.Patient.objects.get(user_id=request.user.id)
    doctor=models.Doctor.objects.get(id=dr_id)
    notifications=print("New report has been submitted")
    mydict={
    'doctor':doctor,
    'patient':patient,
    'notifications':notifications
    }
    return render(request,'temp/doctor_Notifications.html',context=mydict)

post_save.connect(save_report,sender=Report)

Answer 1

You should create model of Notification like:

class Notification(models.Model):
    person = models.ForeignKey(Mymodel, on_delete=models.CASCADE)
    is_read = models.BooleanField(default=False)
    message = models.TextField(max_length=100)

In your views simply create Notification whenever patient sends report:

def save_report(sender,instance,**kwargs):
    instance = Patient.objects.get(id=1)
    dr_id= instance.assignedDoctorId
    patient=models.Patient.objects.get(user_id=request.user.id)
    doctor=models.Doctor.objects.get(id=dr_id)
    Notification.objects.create(person=doctor, message=f'{instance} sent you a report!')
    mydict={
    'doctor':doctor,
    'patient':patient,
    }
    return render(request,'temp/doctor_Notifications.html',context=mydict)

Create view for displaying notifications, with switching to read when launched:

class NotificationListView(ListView):
    model = Notification
    template_name = 'users/notifications.html'

    def get_queryset(self):
        notifications = Notification.objects.filter(person=self.request.user).all()
        notifications.update(is_read=True)
        return notifications

template with notifications:

{% block content %}
    {% for notification in object_list %}
        <h6>{{ notification.message }}</h6>
    {% endfor %}
{% endblock %}

If you have navbar in your site you probably want to display number of unread notifications. You have to filter unread notifications first: In your app folder create new one called "templatetags" and inside create: init .py and notifilter.py for example.

-yourApp
 -templatetags
  -__init__.py
  -notifilter.py

notifilter.py

from django import template

register = template.Library()

@register.filter
def notifilter(args):
    filtered = []
    for i in args:
        if i.is_read == False:
            filtered.append(i)
    return filtered

load filter in template when you have navbar and add line like below:

{% load notifilter %}
<a class="nav-link" href="{% url 'notifications' %}">notifications({{ request.user.profile.notification_set.all|notifilter|length }})</a>