DRF(django-rest-framework) and TokenAuthentication, how to fill json field automatically based Token?

Question

settings.py

REST_FRAMEWORK = {
    'DEFAULT_AUTHENTICATION_CLASSES': (
        'rest_framework.authentication.TokenAuthentication',
    ),
    'DEFAULT_PERMISSION_CLASSES': (
        'rest_framework.permissions.AllowAny',
    ),
}

serializers.py

class UserSerializer(serializers.ModelSerializer):
    related_postwriter = serializers.PrimaryKeyRelatedField(many=True, read_only=True)
    class Meta:
        model = User
        fields = ('id', 'username', 'email', 'related_postwriter')

class PostSerializer(serializers.ModelSerializer):
    class Meta:
        model = Post
        fields = ('id', 'created_date', 'author', 'text', 'image')
    def create(self, validated_data):
        validated_data['author'] = self.context['request'].user
        return super(PostSerializer, self).create(validated_data)

models.py

class Post(models.Model):
    author = models.ForeignKey(User, related_name='related_postwriter')
    text = models.TextField(blank = False)
    image = models.ImageField(null = False, blank = False, upload_to='images')
    created_date = models.DateTimeField(
        default=timezone.now
        )

    def __str__(self):              # __unicode__ on Python 2
        return self.text

views.py

class PostViewSet(viewsets.ModelViewSet):
    serializer_class = PostSerializer
    permission_classes = [IsAuthenticated]
    queryset = Post.objects.all()

I had to make this RESTful api for json request and json response. When i use this RESTful api for Android application, I learned that i login and get Token from RESTful api, and then that Token is used to post data to RESTful api through Header.

As postman capture,

I must fill "author":"number" on Body. I think this number means that user's registering order on my RESTful api. From above capture, that author is first user of my RESTful api.

If i made author field empty, it returned

{
  "author": [
    "This field is required."
  ]
}

1. How can i fill "author" part automatically using Token (or other way not using Token)?

2. How can i get json response "author":"some alphabet name readable", not "author":"1 or 2 like number" as capture. I want form like "author":"stackoverflowman".

Answer 1

for you first question, you should add in PostViewSet this function:

def perform_create(self, serializer):
     serializer.save(author=self.request.user)

for your second question, you should call the UserSerializer from PostSerializer:

class PostSerializer(serializers.ModelSerializer):
    author = UserSerializer(read_only=True)

    class Meta:
        model = Post
        fields = ('id', 'created_date', 'author', 'text', 'image')

EDIT

if you only want one field, you can declare a field with source:

class PostSerializer(serializers.ModelSerializer):
    author = serializers.ReadOnlyField(source='author.username')

    class Meta:
        model = Post
        fields = ('id', 'created_date', 'author', 'text', 'image')