CODEWITHSUNDEEP
djangodjango-rest-frameworkdjango-serializer
Muhammad Muaaz
Muhammad Muaaz

Reputation: 304

How to write and make correct POST request for nested serializers in DRF?

I have two simple models, and serializers for Course and Department as below: (A course belongs to a department, that is many to one relationship from Course to Department)

# models.py
# Department Model
class Department(models.Model):
  name = models.CharField(max_length=256)
  location = models.CharField(max_length=1024)

# Course Model
class Course(models.Model):
  code = models.CharField(max_length=15, unique=True)
  name = models.CharField(max_length=15, unique=True)
  department = models.ForeignKey(Department, on_delete=models.CASCADE, default=None,
                                   null=True, blank=True)

###################################
# serializers.py
# Department serializer
class DepartmentSerializer(serializers.ModelSerializer):
    class Meta:
        model = Department
        fields = ['id', 'name']

# Course serializer
class CourseSerializer(serializers.ModelSerializer):
    department = DepartmentSerializer()

    class Meta:
        model = Course
        fields = '__all__'

After adding some courses through SQL Queries, I made a GET request to the end point localhost:8000/courses/ which gives the expected result.

[
  {
    "id": 1,
    "code": "SS240",
    "name": "Sociology",
    "department": {
      "id": 1,
      "name": "Humanities"
    }
  },
  {
    "id": 2,
    "code": "CS310",
    "name": "Data Structures and Algorithms",
    "department": {
      "id": 5,
      "name": "Computer Sciences"
    }
  }
]

I want to make a POST request to the end point localhost:8000/courses/. Say, I have a department with name = Computer Sciences with id = 5. I want to add a course with code=CS330, name = Object Oriented Design, department = Computer Sciences. How should I write the body of the request?

The following gives the error because of nested representation of department

{
  "code": "CS330",
  "name": "Object Oriented Design",
  "department": 5
}

Should it be like this?

{
  "code": "CS330",
  "name": "Object Oriented Design",
  "department": {
    "id": 5,
    "name": "Computer Sciences"
  }
}

How should I overrride the .create() method?

Upvotes: 1

Views: 318

Answers (1)

JPG
JPG

Reputation: 88449

Override your to_representation(...) method of CourseSerializer class

class CourseSerializer(serializers.ModelSerializer):
    class Meta:
        model = Course
        fields = '__all__'

    def to_representation(self, instance):
        rep = super().to_representation(instance)
        rep['department'] = DepartmentSerializer(instance.department).data
        return rep

Reference:

Upvotes: 1

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