Django Rest Framework - How to make extra query before serializer.save

Question

I'm new to Django Rest Framework and I'm trying to do this simple thing, but I'm not sure how to do it.

So, this is my models.py

class Category(models.Model):

    name = models.CharField(max_length=250)
    slug = models.SlugField(max_length=250, unique=True) 
    email = models.EmailField(_('email address'), blank=True, null=True)

    class Meta:
        ordering = ('name',)

    def __str__(self):
        return self.name


class Report(models.Model):

    category = models.ForeignKey(Category, on_delete=models.PROTECT)
    description = models.TextField()
    address = models.CharField(max_length=500)
    reporter_first_name = models.CharField(max_length=250)
    reporter_last_name = models.CharField(max_length=250)
    reporter_email = models.CharField(max_length=250)
    reporter_phone = models.CharField(max_length=250)
    report_image_1 = models.ImageField(_("Image"), upload_to=upload_to, null=True, blank=True)
    report_image_2 = models.ImageField(_("Image"), upload_to=upload_to, null=True, blank=True)
    report_image_3 = models.ImageField(_("Image"), upload_to=upload_to, null=True, blank=True)
    date = models.DateTimeField(default=timezone.now)

    class Meta:
        ordering = ('-date',)

    def __str__(self):
        return self.description

I have a form in React that submits, among other values, the category ID. What I need to do, before saving the report to the DB, is send a mail to the email address of that category ID.

This is my views.py

class ManageCategories(viewsets.ModelViewSet):
    serializer_class = CategorySerializer

    def get_object(self, queryset=None, **kwargs):
        item = self.kwargs.get('pk')
        return get_object_or_404(Category, slug=item)

    def get_queryset(self):        
        return Category.objects.all()


class ManageReports(viewsets.ModelViewSet):
    serializer_class = ReportSerializer
    parser_classes = [MultiPartParser, FormParser]

    def get_permissions(self):
        if self.action == 'create':
            self.permission_classes = [permissions.AllowAny]
        else:
            self.permission_classes = [permissions.IsAuthenticated]
        return super(self.__class__, self).get_permissions()


    def create(self, request, *args, **kwargs):
        serializer = ReportSerializer(data=request.data)
        
        if serializer.is_valid():
            data = serializer.validated_data         

            try:
                serializer.save()
                return Response({"success": "Sent"})
            except Exception as ex:
                return Response({'success': f'{ex}'})
            
        return Response({"success": serializer.errors})


    def get_object(self, queryset=None, **kwargs):
        id = self.kwargs.get('pk')
        return get_object_or_404(Report, id=id)


    def get_queryset(self):        
        return Report.objects.all()

How do I get the email value starting from the submited category ID?

Answer 1

We can get all validated data from serializer, like as below:

serializer.validated_data["category"].email