CODEWITHSUNDEEP
djangodjango-rest-framework
Shoaib Ijaz
Shoaib Ijaz

Reputation: 5597

How to change field name in Django REST Framework

I am trying to change Model field name in DRF Serializer like alias in SQL. I have tried different methods but cannot succeed.

models.py

class Park(models.Model):
    name = models.CharField(max_length=256)
    alternate_name = models.CharField(max_length=256, blank=True)
    objects = models.GeoManager()

    class Meta:
        db_table = u'p_park'

    def __unicode__(self):
        return '%s' % self.name

    def alias_alternate_name(self):
        return self.alternate_name

serializers.py

class ParkSerializer(serializers.ModelSerializer):

    location = serializers.Field(source='alias_alternate_name')
    #location = serializers.SerializerMethodField(source='alias_alternate_name')

    #alternate_name as location


    class Meta:
        model = Park
        fields = ('id', 'name', 'location')

I have also tried to add alias in Django Queryset but cannot changed.

Updated

This is the exception that i am facing

AttributeError at /ViewName/ 'module' object has no attribute 'Field'

How can I do this?

Upvotes: 165

Views: 129851

Answers (5)

Sailist
Sailist

Reputation: 164

Another method

class UrlHyperlinkedModelSerializer(serializers.HyperlinkedModelSerializer):
    field_name_map = {}

    def to_representation(self, instance):
        res = super().to_representation(instance)
        nres = res.__class__()
        for k, v in res.items():
            nres[self.field_name_map.get(k, k)] = v
        return nres

class CommentSerializer(UrlHyperlinkedModelSerializer):
    field_name_map = {
        'a': 'a_url'
    }

    class Meta:
        model = models.Comment
        fields = ['a', 'url', 'body', 'created_at']

Upvotes: 1

iankit
iankit

Reputation: 9372

There is a very nice feature in serializer fields and serializers in general called 'source' where you can specify source of data from the model field.

class ParkSerializer(serializers.ModelSerializer):
    location = serializers.SomeSerializerField(source='alternate_name')

    class Meta:
        model = Park
        fields = ('other_fields', 'location')

Where serializers.SomeSerializerField can be serializers.CharField as your model suggests but can also be any of the other fields. Also, you can put relational fields and other serializers instead and this would still work like charm. ie even if alternate_name was a foreignkey field to another model.

class ParkSerializer(serializers.ModelSerializer):
    locations = AlternateNameSerializer(source='alternate_name', many=true)

    class Meta:
        model = Park
        fields = ('other_fields', 'locations')

class AlternateNameSerializer(serializers.ModelSerialzer):
    class Meta:
        model = SomeModel

This works with the creation, deletion, and modification requests too. It effectively creates one on one mapping of the field name in the serializer and field name in models.

Upvotes: 309

theQuestionMan
theQuestionMan

Reputation: 1562

I know this is nearly 2 years later, but thought it might be of help for any future devs...

The reason the code doesn't work is because of the following line in models.py
location = serializers.Field(source='alias_alternate_name')
That's what the exception is trying to tell us. That is:
AttributeError at /ViewName/ 'module' object has no attribute 'Field'
means that the serializers module has no item called Field.

I want to offer a different solution than the other answers:
Modify models.py to include the related_name field and then simply use this name in serializers.

The advantage of this approach is that you have one on one mapping of field name in the serializer and field name in models with less code and the disadvantage of this is that this approach may not work with complex foreign key relationships.

Here is a demo of my approach:

models.py

class Park(models.Model):
    name = models.CharField(max_length=256)
    alternate_name = models.CharField(max_length=256, blank=True, related_name='location')
    objects = models.GeoManager()

    class Meta:
        db_table = u'p_park'

serializers.py

class ParkSerializer(serializers.ModelSerializer):

    class Meta:
        model = Park
        fields = ('id', 'name', 'location')

Read more about this here: https://www.django-rest-framework.org/api-guide/relations/

Upvotes: -2

erthalion
erthalion

Reputation: 3244

You can use serializers.SerializerMethodField:

Here is the model Park, which has name and alternate_name fields. 

class Park(models.Model):
    name = models.CharField(max_length=256)
    alternate_name = models.CharField(max_length=256, blank=True)
    objects = models.GeoManager()

    class Meta:
        db_table = u'p_park'

    def __unicode__(self):
        return '%s' % self.name

Here is Serializer for Park Model, ParkSerializer. This changes the name of alternate_name to location. 

class ParkSerializer(serializers.ModelSerializer):
    location = serializers.SerializerMethodField('get_alternate_name')

    class Meta:
        model = Park
        fields = ('other_fields', 'location')

    def get_alternate_name(self, obj):
        return obj.alternate_name

Additionally, you can use serializers.CharField with source attribute:

class ParkSerializer(serializers.ModelSerializer):
    location = serializers.CharField(source='other_fields')

    class Meta:
        model = Park
        fields = ('other_fields', 'location')

Django's __ notation to traverse foreign key also works:

location = serializers.CharField(source='OtherModel__other_fields')

The same principle applies if you want to change the return type on the API, so you can do serializers.DecimalField(source=...) and other field types as well.

This would however work only for read only fields.

Upvotes: 100

vijay
vijay

Reputation: 886

This would work for write operations also

class ParkSerializer(serializers.ModelSerializer):
    location = serializers.CharField(source='alternate_name')

    class Meta:
        model = Park
        fields = ('id', 'name', 'location')

Upvotes: 23

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