Exclude history fields from django simples history on to_representation method in django rest framework

Question

I'm using Django Rest Framework with django-simple-history and currently I would like to return the history modifications in my Board rest API, currently it is doing well but I would like to hide some fields. This is the currently output:

But, I don't need id, history_id, etc.

my implementation is the same of alexander answer in this post. this is my currently serializers, where I put history on my Board model

class HistoricalRecordField(serializers.ListField):
    child = serializers.DictField()

    def to_representation(self, data):
        representation = super().to_representation(data.values())
        # i've tried to do it by deleting, but does't work well.
        del representation[0]['history_id']
        return representation


class BoardSerializer(serializers.ModelSerializer):
    history = HistoricalRecordField(read_only=True)

    class Meta:
        model = Board
        fields = '__all__'

But it does not seem the best way to do it.

If you have some hint about how to do it the correct way I would like to know. Thanks in advance!

Could you share the entire code of your serializer please? – ThomasGth Jan 05 '22 at 14:21 — ThomasGth, Jan 05 '22 at 14:21

score 0 · Answer 1 · answered Jan 05 '22 at 14:46

You can try this for history_id at least:

def to_representation(self, data):
        representation = super().to_representation(data.values())
        for hist in representation['history']:
            hist.pop('history_id')
        return representation

ThomasGth · Answer 2 · 2022-01-06T09:16:54.730

I don't know django-simple-history, so they may be better solutions than mine.
However, you can do this with a more DRF-friendly approach by simply using a ModelSerializer instead of a ListSerializer:

class HistoricalRecordSerializer(serializers.ModelSerializer):

    class Meta:
        model = HistoricalRecords
        fields = ('name', 'description', 'share_with_company', [...]) # Only keep the fields you want to display here


class BoardSerializer(serializers.ModelSerializer):
    history = HistoricalRecordSerializer(read_only=True, many=True)

    class Meta:
        model = Board
        fields = ('name', 'description', 'history', [...]) # Only keep the fields you want to display here

If you want to only retrieve the latest update, you could use a SerializerMethodField (documentation here). Remember to declare it in Meta.fields instead of 'history' (or rename your SerializerMethodField "history" if you want to keep this name):

class HistoricalRecordSerializer(serializers.ModelSerializer):

    class Meta:
        model = HistoricalRecords
        fields = ('name', 'description', 'share_with_company', [...]) # Only keep the fields you want to display here


class BoardSerializer(serializers.ModelSerializer):
    latest_history = serializers.SerializerMethodField()

    def get_latest_history(self, instance):
        latest_history = instance.history.most_recent()  # Retrieve the record you want here
        return HistoricalRecordSerializer(latest_history).data

    class Meta:
        model = Board
        fields = ('name', 'description', 'latest_history', [...]) # Only keep the fields you want to display here

Keep in mind that I don't know much about this lib, so this should work but I cannot guarantee it's the best way to to it.

Your solution works very well, just one question before accept this answer: Using your approach, there is any way to show in the history field just the last update? history field show me all updates and it is what I need, but I'm just curious about the possibility to get just the last update (last object). — Leonardo Furtado, Jan 05 '22 at 18:46

Exclude history fields from django simples history on to_representation method in django rest framework

2 Answers2