Include intermediary (through model) in responses in Django Rest Framework

How about.....

On your MemberSerializer, define a field on it like:

groups = MembershipSerializer(source='membership_set', many=True)

and then on your membership serializer you can create this:

class MembershipSerializer(serializers.HyperlinkedModelSerializer):    id = serializers.Field(source='group.id')    name = serializers.Field(source='group.name')    class Meta:        model = Membership        fields = ('id', 'name', 'join_date', )

That has the overall effect of creating a serialized value, groups, that has as its source the membership you want, and then it uses a custom serializer to pull out the bits you want to display.

EDIT: as commented by @bryanph, serializers.field was renamed to serializers.ReadOnlyField in DRF 3.0, so this should read:

class MembershipSerializer(serializers.HyperlinkedModelSerializer):    id = serializers.ReadOnlyField(source='group.id')    name = serializers.ReadOnlyField(source='group.name')    class Meta:        model = Membership        fields = ('id', 'name', 'join_date', )

for any modern implementations

I was facing this problem and my solution (using DRF 3.6) was to use SerializerMethodField on the object and explicitly query the Membership table like so:

class MembershipSerializer(serializers.ModelSerializer):    """Used as a nested serializer by MemberSerializer"""    class Meta:        model = Membership        fields = ('id','group','join_date')class MemberSerializer(serializers.ModelSerializer):    groups = serializers.SerializerMethodField()    class Meta:        model = Member        fields = ('id','name','groups')    def get_groups(self, obj):        "obj is a Member instance. Returns list of dicts"""        qset = Membership.objects.filter(member=obj)        return [MembershipSerializer(m).data for m in qset]

This will return a list of dicts for the groups key where each dict is serialized from the MembershipSerializer. To make it writable, you can define your own create/update method inside the MemberSerializer where you iterate over the input data and explicitly create or update Membership model instances.

NOTE: As a Software Engineer, I love to use Architectures and I have deeply worked on Layered Approach for Development so I am gonna be Answering it with Respect to Tiers.

As i understood the Issue, Here's the Solutionmodels.py

class Member(models.Model):    member_id = models.AutoField(primary_key=True)    member_name = models.CharField(max_length = class Group(models.Model):    group_id = models.AutoField(primary_key=True)    group_name = models.CharField(max_length = 20)    fk_member_id = models.ForeignKey('Member', models.DO_NOTHING,                              db_column='fk_member_id', blank=True, null=True)class Membership(models.Model):    membershipid = models.AutoField(primary_key=True)    fk_group_id = models.ForeignKey('Group', models.DO_NOTHING,                              db_column='fk_member_id', blank=True, null=True)    join_date = models.DateTimeField()

serializers.py

import serializerclass AllSerializer(serializer.Serializer):    group_id = serializer.IntegerField()    group_name = serializer.CharField(max_length = 20)    join_date = serializer.DateTimeField()

CustomModels.py

imports...    class AllDataModel():        group_id = ""        group_name = ""        join_date = ""

BusinessLogic.py

imports ....class getdata(memberid):    alldataDict = {}    dto = []    Member = models.Members.objects.get(member_id=memberid) #or use filter for Name    alldataDict["MemberId"] = Member.member_id    alldataDict["MemberName"] = Member.member_name    Groups = models.Group.objects.filter(fk_member_id=Member)    for item in Groups:        Custommodel = CustomModels.AllDataModel()        Custommodel.group_id = item.group_id        Custommodel.group_name = item.group_name        Membership = models.Membership.objects.get(fk_group_id=item.group_id)        Custommodel.join_date = Membership.join_date        dto.append(Custommodel)    serializer = AllSerializer(dto,many=True)    alldataDict.update(serializer.data)    return alldataDict

You would technically, have to pass the Request to DataAccessLayer which would return the Filtered Objects from Data Access Layer but as I have to Answer the Question in a Fast Manner so i adjusted the Code in Business Logic Layer!