I'm working on building a tree-like hierarchical database system using Django Rest Framework and django-polymorphic-tree. I have two models- BaseTreeNode and DescriptionNode (the later one is derived from BaseTreeNode). Specifically, here's my models.py
:
class BaseTreeNode(PolymorphicMPTTModel):
parent = PolymorphicTreeForeignKey('self', blank=True, null=True, related_name='children', verbose_name=_('parent'))
title = models.CharField(_("Title"), max_length=200)
def __str__(self):
return "{}>{}".format(self.parent, self.title)
class Meta(PolymorphicMPTTModel.Meta):
verbose_name = _("Tree node")
verbose_name_plural = _("Tree nodes")
# Derived model for the tree node:
class DescriptionNode(BaseTreeNode):
description = models.CharField(_("Description"), max_length=200)
class Meta:
verbose_name = _("Description node")
verbose_name_plural = _("Description nodes")
So, each title
field (belonging to BaseTreeNode
) has an associated description
field (belonging to DescriptionNode) with it.
Now, all I want to have is a JSON that returns a nested representation of my entire tree. For now, I have only defined a simple serializer with a recursive field. My serializers.py
from rest_framework_recursive.fields import RecursiveField
class DescriptionNodeSerializer(serializers.ModelSerializer):
class Meta:
model = DescriptionNode
fields = ('description',)
class BaseTreeNodeSerializer(serializers.ModelSerializer):
subcategories = serializers.ListSerializer(source="children",child=RecursiveField())
class Meta:
model = BaseTreeNode
fields = ('id', 'title', 'subcategories')
Which gives me (for BaseTreeNodeSerializer only):
[
{
"id": 1,
"title": "Apple",
"subcategories": [
{
"id": 2,
"title": "Contact Person",
"subcategories": []
},
{
"id": 3,
"title": "Sales Stage",
"subcategories": [
{
"id": 4,
"title": "Suspecting",
"subcategories": [
{
"id": 5,
"title": "Contact verification",
"subcategories": []
}
]
},
{
"id": 6,
"title": "Prospecting",
"subcategories": [
{
"id": 7,
"title": "Client Detail",
"subcategories": []
}
]
}
]
},
{
"id": 9,
"title": "Medium",
"subcategories": [
{
"id": 10,
"title": "Status",
"subcategories": []
}
]
},
{
"id": 13,
"title": "Remainder",
"subcategories": []
}
]
}
]
My question is, how can I include the description
field (from the derived model) which is associated with every single title
field (from the BaseTreeNode model) in the hierarchy?
Something like:
... {
"id": 5,
"title": "Contact verification",
"description": "Verified"
"subcategories": []
} ...
The Corresponding Model would be as follows:
Serializer would be as follows: