How to write flat and read nested from ModelSerializer in Django Rest Framework?

Question

I need to implement a functionality where ID of an account needs to be submitted while writing post and read additional info of an account with reading the post. How do I write the data with depth one but read data with more depth?

ModelSerializers:

class PostSerializer(serializers.ModelSerializer):
    author = UserSerializer(required=False, allow_null=True)
    class Meta:
        model = Post
        fields = ('id', 'author', 'message', 'rating', 'create_date', 'close_date',)

class UserSerializer(serializers.ModelSerializer):
   class Meta:
       model = User
       fields = ('id', 'username', 'full_name',)

Could you post what you have tried? – bryanph Jan 17 '16 at 19:08 — bryanph, Jan 17 '16 at 19:08
I have updated the model serializers. – Puneet Jan 18 '16 at 04:03 — Puneet, Jan 18 '16 at 04:03

Serjik · Answer 1 · 2016-01-18T07:01:52.163

0

As I get you want some of your fields to be read-only for example you need 'create_date' to be read but cannot be written

This is my approach:

models.py

# This extra modification done as late comments 
class Post(models.Model):
  ...
  def username(self):
     return self.author.username

  def full_name(self):
     return self.author.full_name

Serializer.py

class PostSerializer(serializers.ModelSerializer):
    # author = UserSerializer(required=False, allow_null=True)  # Don't define this
    create_date_read_only = serializers.DateTimeField(required = False, read_only = True, source = 'create_date')
    class Meta:
        model = Post
        # username, full_name added to fileds tuple
        fields = ('id', 'author', 'username','full_name','message', 'rating', 'create_date_read_only', 'close_date',)

Do The same for other readonly fileds

edited Jan 18 '16 at 07:01

answered Jan 18 '16 at 06:29

Serjik

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I have later mentioned the read_only_fields array specifying create_date and other fields and it worked. I now need read only for full_name and username in UserSerializer used in PostSerializer and it's not working in nested serializer. – Puneet Jan 18 '16 at 06:38
Have you declared author as ForeignKey to the User on Post model? – Serjik Jan 18 '16 at 06:50
Yes..I have used author as foreign key to the user model – Puneet Jan 18 '16 at 06:52
See the latest modification on my answer – Serjik Jan 18 '16 at 07:35
I need user data to be returned nested inside my post data during read. – Puneet Jan 24 '16 at 03:35
Just test it, that's the desired result – Serjik Jan 24 '16 at 05:37

norbert.mate · Answer 2 · 2016-01-18T14:06:46.793

0

you an use SerializerMethodField for this.

You don't have to modify the model. Your serializer would look like this:

class PostSerializer(serializers.ModelSerializer):
    my_username = serializers.SerializerMethodField()

    class Meta:
        model = Post
        fields = ('id', 'author', 'my_field'...)

    def get_my_username(self, obj):
        return obj.user.author.username

edited Jan 18 '16 at 14:06

answered Jan 18 '16 at 12:53

norbert.mate

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This misses the "write flat" part of the question, this only reads the flat version. – Kevin Brown-Silva Jan 19 '16 at 01:52

How to write flat and read nested from ModelSerializer in Django Rest Framework?

2 Answers2