我如何在 django 中实现通知系统

Question

I created an app where user's can post a question and get answers from others users. Now I want to implement a notification system, so that when a user answer a question, the author of that question will receive notification. Like social media notifications.

The home templates:

<div class="container">
    <div class="row justify-content-center">
        <div class="row justify-content-center">
            <div class="col-md-6">
                <a href="{% url 'question' %}" class="btn btn-primary  m-1">Ask Question</a>
                <a href="{% url 'notification' %}" class="btn btn-primary  m-1">Notifications</a>
                <a href="{% url 'FeedBack' %}" class="btn btn-primary  m-1">FeedBack</a>
                <a href="{% url 'login' %}" class="btn btn-primary  m-1">Log Out</a>
            </div>
        </div>
    </div>
</div>

 <div class="container">
    <div class="row justify-content-center">
        {% for question in list_of_question reversed %}
        <div class="col-md-4">
            <div class="card my-3">
                <div class="card-header">
                    <p class="card-title">{{question.user.username.upper}}</p>
                </div>
                <div class="card-body">
                    <a href="{% url 'view-Question' question.id %}" style="text-decoration: none;">
                        <p class="card-title">{{question.title}}</p>
                    </a>
                    <p>Category: {{question.category}}</p>
                </div>
            </div>
        </div>
        {%endfor%}
    </div>
</div>

the models:

class Question(models.Model):
    user = models.ForeignKey(User, on_delete=models.CASCADE)
    title = models.CharField(max_length=100, blank=False, null=False)
    body = RichTextField(blank=False, null=False) 
    category = models.CharField(max_length=50, blank=False, null=False)

    def __str__(self):
        return str(self.title)

class Answer(models.Model):
    user = models.ForeignKey(User, blank=False, null=False, on_delete=models.CASCADE)
    answer = RichTextField(blank=False, null=False)
    post = models.ForeignKey(Question, blank=False, null=False, on_delete=models.CASCADE)

    def __str__(self):
        return str(self.user)

The views:

class My_Question(LoginRequiredMixin, CreateView):
    model = Question
    fields = ['title', 'body', 'category']
    template_name = 'question.html'
    success_url = reverse_lazy('index')

    def form_valid(self, form):
        form.instance.user = self.request.user
        return super (My_Question, self).form_valid(form)

class My_Answer(LoginRequiredMixin, CreateView):
    model = Answer
    fields = ['answer']
    template_name = 'answer.html'
    success_url = reverse_lazy('index')

    def form_valid(self, form):
        form.instance.user = self.request.user
        form.instance.post_id = self.kwargs['pk']
        return super (My_Answer, self).form_valid(form)

def viewQuestion(request, pk):
    question = Question.objects.get(id=pk)
    answers = Answer.objects.filter(post_id=question)
    context = {'question':question, 'answers':answers}
    return render(request, 'viewQuestion.html', context)

the home page view:

@login_required(login_url='login')
def index(request):
    query = request.GET.get('q', None)
    list_of_question = Question.objects.all()
    if query is not None:
        list_of_question = Question.objects.filter(
            Q(title__icontains=query) |
            Q(category__icontains=query)
        )
    context = {'list_of_question':list_of_question}
    return render(request, 'index.html', context)

the urls

path('index/', views.index, name='index'),
path('view/<int:pk>/', views.viewQuestion, name='view-Question'),
path('question/<int:pk>/answer/', views.My_Answer.as_view(), 
name='answer'),
path('question/', views.My_Question.as_view(), name='question'),

Answer 1

Here is an outline for a basic notification system in Django:

Model

You need a model to store notifications. Each notification belongs to a user and has content (ie a text message). You also need to store whether a message has been read and a timestamp:

class Notification(models.Model):
    is_read = models.BooleanField(default=False)
    message = models.TextField()
    timestamp = models.DateTimeField(auto_now_add=True)
    user = models.ForeignKey(User, on_delete=models.CASCADE)

Creating a notification

You can then create a new notification for a user when needed, eg when another user answers a question you can also create a notification for the question's owner in the view.

class My_Answer(LoginRequiredMixin, CreateView):
    ...
    def form_valid(self, form):
        ...
        form.instance.user = self.request.user
        question_author = form.instance.post.user
        Notification.objects.create(user=question_author, text="New answer!")
        ...
        return super().form_valid(form)

List of notifications

Then you need a page that lists all notifications for the current user. That can be implemented with a standard list view.

The query would look something like this:

class NotificationListView(ListView):
    model = Notification

    def get_queryset(self):
        return Notifications.objects.filter(user=self.request.user).order_by("-timestamp")

You of course also need to define a URL and a template for this new view. We will define the URL name as notifications .

Showing new notifications to users

Finally, you need to inform users about new notifications. This can be done by checking how many unread notifications the current user has and showing a badge on the web badge. This would be part of the index view.

@login_required(login_url='login')
def index(request):
    ...
    unread_notifications = Notification.objects.filter(user=request.user, is_read=False).count()
    context["unread_notifications"] = unread_notifications
    ...

Then on your home page you need a link to a page that shows all notifications and a badge that shows how many unread notifications the current user has. Something like this:

<a href="{% url "notifications" %}">
  Notifications
  {% if unread_notifications %}  
    <span class="badge bg-secondary">{{ unread_notifications }}</span>
  {% endif %}
</a>

Real life example

If you want to see how this is implemented in a real project, here is the link to an open source project called "Alliance Auth" that implements a portal web page and has a very similar notification architecture. The link is to the notification app within that portal: https://gitlab.com/allianceauth/allianceauth/-/tree/master/allianceauth/notifications