如何在 Django Rest 框架中序列化 ChoiceFields？

Question

First time Python user here, coming from Javascript world. I'm able to retrieve my Model serialized to JSON from Django API and display it on the frontend written in React. But now I just added one more field priority to the Model that has multiple choices and I struggle to get these choices to the frontend (I want to display them in a dropdown and update REST API). Migration was successful and I can select choices from the back end but on the frontend I just get the default value set from migrations. Here is my code right now:

models.py

class Todo(models.Model):
  title = models.CharField(max_length=120)
  description = models.TextField()
  completed = models.BooleanField(default=False)
  priority_choices = [
    ('High', 'High'),
    ('Medium', 'Medium'),
    ('Low', 'Low'),
  ]
  priority= models.CharField(max_length=6, choices=priority_choices, default='Low') #new field

  def __str__(self):
    return self.title

serializers.py

from rest_framework import serializers
from .models import Todo

      
class TodoSerializer(serializers.ModelSerializer):
  class Meta:
    model = Todo
    fields = ('id', 'title', 'description', 'completed', 'priority')

views.py

class TodoView(viewsets.ModelViewSet):     
  serializer_class = TodoSerializer          
  queryset = Todo.objects.all()   

I just want the simplest solution, preferably to just update TodoSerializer(serializers.ModelSerializer) class inside serializers.py so that it would all come from this one Model. Is that possible? Reading https://www.django-rest-framework.org/api-guide/fields/#choicefield is not clear for me whether I need to create a new class for the same Model just to retrieve ChoiceFields or if it's possible to do it all from one Class but whatever I try, I get syntax errors. Like I said, I'm very fresh to Python. Thanks.

Answer 1

You can accomplish this using a SerializerMethodField

class TodoSerializer(serializers.ModelSerializer):
    priority_choices = serializers.SerializerMethodField()

    def get_priority_choices(self, obj):
        return [choice[0] for choice in Todo.priority_choices]

    class Meta:
        model = Todo
        fields = ('id', 'title', 'description', 'completed', 'priority', 'priority_choices')