Retrieving a Foreign Key value with django-rest-framework serializers

Question

I m using the django rest framework to create an API   I have the following models   class Category models Model       name   models CharField max length 100       def   unicode   self           return self name   class Item models Model       name   models CharField max length 100      category   models ForeignKey Category  related name  items        def   unicode   self           return self name   To create a serializer for the categories I d do   class CategorySerializer serializers ModelSerializer       items   serializers RelatedField many True       class Meta          model   Category       and this would provide me with      items    u Item 1   u Item 2   u Item 3    u id   1   name   u Cat 1       items    u Item 4   u Item 5   u Item 6    u id   2   name   u Cat 2       items    u Item 7   u Item 8   u Item 9    u id   3   name   u Cat 3      How would I go about getting the reverse from an Item serializer  ie     u id   1   name    Item 1    category name   u Cat 1     u id   2   name    Item 2    category name   u Cat 1     u id   3   name    Item 3    category name   u Cat 1     u id   4   name    Item 4    category name   u Cat 2     u id   5   name    Item 5    category name   u Cat 2     u id   6   name    Item 6    category name   u Cat 2     u id   7   name    Item 7    category name   u Cat 3     u id   8   name    Item 8    category name   u Cat 3     u id   9   name    Item 9    category name   u Cat 3      I ve read through the docs on reverse relationships for the rest framework but that appears to be the same result as the non-reverse fields   Am I missing something obvious

User · Accepted Answer

Just use a related field without setting many=True.

Note that also because you want the output named category_name, but the actual field is category, you need to use the source argument on the serializer field.

The following should give you the output you need...

class ItemSerializer(serializers.ModelSerializer):
    category_name = serializers.RelatedField(source='category', read_only=True)

    class Meta:
        model = Item
        fields = ('id', 'name', 'category_name')

User · Answer

Simple solution source  category name  where category is foreign key and  name it s attribute  from rest framework serializers import ModelSerializer  ReadOnlyField from my app models import Item  class ItemSerializer ModelSerializer       category name   ReadOnlyField source  category name        class Meta          model   Item         fields    quot   all   quot

User · Answer

this worked fine for me   class ItemSerializer serializers ModelSerializer       category name   serializers ReadOnlyField source  category name       class Meta          model   Item         fields      all

User · Answer

This solution is better because of no need to define the source model  But the name of the serializer field should be the same as the foreign key field name class ItemSerializer serializers ModelSerializer       category   serializers SlugRelatedField read only True  slug field  title        class Meta          model   Item         fields     id    name    category

User · Answer

In the DRF version 3 6 3  this worked for me  class ItemSerializer serializers ModelSerializer       category name   serializers CharField source  category name        class Meta          model   Item         fields     id    name    category name     More info can be found here  Serializer Fields core arguments

User · Answer

Another thing you can do is to    create a property in your Item model that returns the category name and  expose it as a ReadOnlyField    Your model would look like this   class Item models Model       name   models CharField max length 100      category   models ForeignKey Category  related name  items        def   unicode   self           return self name       property     def category name self           return self category name   Your serializer would look like this  Note that the serializer will automatically get the value of the category name model property by naming the field with the same name   class ItemSerializer serializers ModelSerializer       category name   serializers ReadOnlyField        class Meta          model   Item

User · Answer

Worked on 08 08 2018 and on DRF version 3 8 2   class ItemSerializer serializers ModelSerializer       category name   serializers ReadOnlyField source  category name        class Meta          model   Item         read only fields     id    category name           fields     id    category name    name      Using the Meta read only fields we can declare exactly which fields should be read only  Then we need to declare the foreign field on the Meta fields  better be explicit as the mantra goes  zen of python

[python] Retrieving a Foreign Key value with django-rest-framework serializers

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