Using The Reserved Word "class" As Field Name In Django And Django Rest Framework

Description of the problem Taxonomy is the science of defining and naming groups of biological organisms on the basis of shared characteristics. Organisms are grouped together into

Solution 1:

You can rename field in the overloaded version of get_fields() method

classMySerializer(serializers.Serializer):
    class_ = serializers.ReadOnlyField()

    defget_fields(self):
        result = super().get_fields()
        # Rename `class_` to `class`
        class_ = result.pop('class_')
        result['class'] = class_
        return result

Solution 2:

You can do it like below

classSpeciesSerializer(serializers.HyperlinkedModelSerializer):
    classMeta:
        model = Speciesfields= (
            'url', 'id', 'canonical_name', 'slug',  'species', 'genus',
            'subfamily', 'family', 'order','class', 'phylum',
            'ncbi_id', 'ncbi_taxonomy',
        )
        read_only_fields = ('slug',)
        extra_kwargs = {
            'url': {'lookup_field': 'slug'}
        }

SpeciesSerializer._declared_fields["class"] = serializers.CharField(source="class_name")

As explained in below answer

https://stackoverflow.com/a/47717441/2830850

Solution 3:

Other software developers in the field of Bioinformatics might be interested in a solution of this problem, so I post here my approach as suggested by Alasdair.

The goal is to create a model for a living species, for the sake of simplicity let's say an animal, and create an endpoint with Django REST Framework representing the correct taxonomic ranks.

models.py

from django.db import models

classAnimal(models.Model):
    canonical_name = models.CharField(max_length=100, unique=True)
    species = models.CharField(max_length=60, unique=True)
    genus = models.CharField(max_length=30)
    family = models.CharField(max_length=30)
    order = models.CharField(max_length=30)
    # we can't use class as field name
    class_name = models.CharField('Class', db_column='class', max_length=30)
    phylum = models.CharField(max_length=30)
    # we don't need to define kingdom and domain# it's clear that it is an animal and eukaryotedef__str__(self):
        return'{} ({})'.format(self.canonical_name, self.species)

serializers.py

from collections import OrderedDict

from rest_framework import serializers

from .models import Species

classSpeciesSerializer(serializers.HyperlinkedModelSerializer):
    classMeta:
        model = Animal
        fields = ('url', 'id', 'canonical_name', 'species', 'genus',
            'subfamily', 'family', 'order', 'class_name', 'phylum')

    defto_representation(self, obj):
        # call the parent method and get an OrderedDict
        data = super(SpeciesSerializer, self).to_representation(obj)
        # generate a list of the keys and replace the key 'class_name'
        keys = list(data.keys())
        keys.insert(keys.index('class_name'), 'class')
        keys.remove('class_name')
        # remove 'class_name' and assign its value to a new key 'class'
        class_name = data.pop('class_name')
        data.update({'class': class_name})
        # create new OrderedDict with the order given by the keys
        response = OrderedDict((k, data[k]) for k in keys)
        return response

The method to_representation helps us to manipulate the output. I have put some extra work here to get the taxonomic ranks in the desired order.

Thus for the red fox the output looks like this:

Red fox (Vulpes vulpes)

{"url":"http://localhost:8000/animal/1","id":1,"canonical_name":"Red fox","species":"Vulpes vulpes","genus":"Vulpes","family":"Canidae","order":"Carnivora","class":"Mammalia","phylum":"Chordata"}

It is a simplified example and in reality you'd have many more fields or possibly a model for every taxonomic rank, but somewhere you might come across the conflict between the reserved word class and the taxonomic rank class. I hope this can help other people too.

Solution 4:

You can set the property of a class via strings as such:

classSpeciesSerializer(serializers.Serializer):
    species = serializers.CharField()
    genus = serializers.CharField()
    family = serializers.CharField()
    vars()['class'] = serializers.CharField()