Django Rest Framework - URL With Query Parameters in Serializer - django

Question

I have a Story and Post models, where a Post belongs to a Story. I want a URL to get all Posts associated with a given Story.
I was able to override the get_queryset of my PostViewSet in order to filter posts by story with URLs like http://localhost:8000/posts/?story=1/. This works beautifully if I type in the URL directly. Now I want to return this kind of url in my StorySerializer. I would like to be able to get Story responses that look like this
[
{
"url": "http://localhost:8000/stories/1/",
"title": "Hero's Journey",
"openings": 0,
"date_created": "2020-06-28T16:53:35.150630Z",
"posts": "http://localhost:8000/posts/?story=1/"
},
{
"url": "http://localhost:8000/stories/2/",
"title": "Halo 3",
"openings": 0,
"date_created": "2020-06-28T18:17:12.973586Z",
"posts": "http://localhost:8000/posts/?story=2/"
}
]
Is there DRF support for this kind of thing? I was trying to use a HyperlinkedIdentityField with 'post-list' View in my StorySerializer, but I couldn't find a combination of parameters that would work. The current exception I get is
AttributeError: 'Story' object has no attribute 'posts'
Serializers
class StorySerializer(serializers.HyperlinkedModelSerializer):
posts = serializers.HyperlinkedIdentityField(
view_name = 'post-list',
many=True,
lookup_field = 'pk',
lookup_url_kwarg = 'story',
)
class Meta:
model = models.Story
fields = ['url', 'title', 'openings', 'date_created', 'posts']
class PostSerializer(serializers.HyperlinkedModelSerializer):
class Meta:
model = models.Post
fields = ['url', 'story', 'user', 'text', 'date_created']
Views
class StoryViewSet(viewsets.ModelViewSet):
queryset = models.Story.objects.all()
serializer_class = serializers.StorySerializer
class PostViewSet(viewsets.ModelViewSet):
queryset = models.Post.objects.all()
serializer_class = serializers.PostSerializer
def get_queryset(self):
queryset = self.queryset
story_id = self.request.query_params.get('story', None)
if story_id is not None:
queryset = queryset.filter(story=story_id)
return queryset
Models
class Story(models.Model):
title = models.CharField(max_length=100)
date_created = models.DateTimeField(default=timezone.now)
openings = models.PositiveSmallIntegerField(default=0)
participant = models.ManyToManyField(User)
class Post(models.Model):
text = models.CharField(max_length=300)
user = models.ForeignKey(
User,
on_delete=models.PROTECT)
story = models.ForeignKey(
Story,
on_delete=models.PROTECT)
date_created = models.DateTimeField(default=timezone.now)

Answer 1

I was able to find a great solution here, overriding the get_url method to map 'pk' value to 'story' directly.
https://stackoverflow.com/a/27584761/7308261
from rest_framework.reverse import reverse
import urllib
class StoryPostsHyperlinkedIdentityField(serializers.HyperlinkedIdentityField):
def get_url(self, obj, view_name, request, format):
lookup_field_value = getattr(obj, self.lookup_field, None)
result = '{}?{}'.format(
reverse(view_name, kwargs={}, request=request, format=format),
urllib.parse.urlencode({'story': lookup_field_value})
)
return result
class StorySerializer(serializers.HyperlinkedModelSerializer):
posts = StoryPostsHyperlinkedIdentityField(
view_name='post-list',
)
class Meta:
model = models.Story
fields = ['url', 'title', 'openings', 'date_created', 'posts']