how to check if a post status was changed from live to cancel in django?

Using Django Forms & APIs
1

i want to write a condition that would show a warning message when a user try to change the status of a post to cancel , if the post already have a participant in it. The conditional statement seems not to be working.

It sets the post to cancel even if there is already a participant. what i want is this, provided there is already at least 1 participant in the object, i want to show a warning message that they cannot cancel the post and then i redirect them back to the dashboard.

class PredictionUpdate(ProductInline, UpdateView):
    def form_valid(self, form):
        instance = form.instance
        if instance.participants.exists() and instance.status == 'cancelled':
            messages.warning(self.request, "You cannot cancel a bet that already have participants")
            return redirect("core:dashboard")
        else:
            form.save()
            return HttpResponseRedirect(self.get_success_url())

complete code

class PredictionUpdate(LoginRequiredMixin, ProductInline, UpdateView):

    def get_context_data(self, **kwargs):
        ctx = super(PredictionUpdate, self).get_context_data(**kwargs)
        ctx['named_formsets'] = self.get_named_formsets()
        return ctx
    
    def get_named_formsets(self):
        return {
            'variants': PredictionDataFormSet(self.request.POST or None, self.request.FILES or None, instance=self.object, prefix='variants'),
        }

    def dispatch(self, request ,*args, **kwargs):
        obj = self.get_object()
        if obj.user != self.request.user:
            messages.warning(self.request, "You are not allowed to edit this bet!")
            return redirect("core:dashboard")
        
        if obj.status == "finished":
            messages.warning(self.request, "You cannot edit this bet again, send an update request to continue.")
            return redirect("core:dashboard")
            # raise Http404("You are not allowed to edit this Post")
        return super(PredictionUpdate, self).dispatch(request, *args, **kwargs)
    
    def get_success_url(self):
        return reverse("core:dashboard")

    
    def form_valid(self, form):
        instance = form.instance
        if instance.participants.exists() and instance.status == 'cancelled':
            messages.warning(self.request, "You cannot cancel a bet that already have participants")
            return redirect("core:dashboard")
        else:
            form.save()
            return HttpResponseRedirect(self.get_success_url())
2

It’s not clear from this post what form or model is being worked on here. We’ll need to see those to understand what’s going on.

3

This is the model that is been worked on


class Predictions(models.Model):
    prediction_topic = models.ForeignKey(PredictionTopic, on_delete=models.SET_NULL, null=True, blank=True, related_name="prediction_topic")
    user = models.ForeignKey(User, on_delete=models.SET_NULL, null=True)
    status = models.CharField(choices=STATUS, max_length=100, default="in_review")
    participants = models.ManyToManyField(User, related_name="participants", blank=True)

This is the form


class PredictionForm(forms.ModelForm):
    image = ImageField(widget=FileInput)
    class Meta:
        model = Predictions
        fields = [
            'prediction_topic',
            'status',
        ]
4

What are the STATUS choices?

5

These are the STATUS

STATUS = (
    ("live", "Live"),
    ("in_review", "In review"),
    ("pending", "Pending"),
    ("cancelled", "Cancelled"),
    ("finished", "Finished"),
)
6

I’m not seeing anything obviously wrong with what you’ve posted. You might want to try to debug this by adding some print statements within your form_valid function before the if statement to show what the current values are of instance.participants and instance.status.

1 Like
7

This guided me to fix the problem, thanks alot.