Django Modelviewset Filtering - django

Question

I have two models Category & Post. In Post model there is foreign key of category. Based on category I want to filter the data to show the post category wise. Here's my code.
models.py
class Category(models.Model):
name = models.CharField(max_length=200)
slug = models.SlugField()
parent = models.ForeignKey('self',blank=True, null=True ,related_name='news', on_delete=models.CASCADE)
class Meta:
unique_together = ('slug', 'parent',)
verbose_name_plural = "Category"
def __str__(self):
full_path = [self.name]
k = self.parent
while k is not None:
full_path.append(k.name)
k = k.parent
return ' -> '.join(full_path[::-1])
class Post(models.Model):
NEWS_TYPE = (('Images','Images'),('Multi-Images','Multi-Images'),('Image-Text','Image-Text'),
('Audio-Video','Audio-Video'),('Audio-Video-Text','Audio-Video-Text'),('Audio','Audio'),
('Audio-Text','Audio-Text'))
POST_STATUS = (('Pending','Pending'),('Verified','Verified'),('Un-Verified','Un-Verified'),
('Published','Published'),('Mint','Mint'))
category = models.ForeignKey(Category, related_name='posts', on_delete=models.CASCADE)
post_type = models.CharField(max_length=100, verbose_name='Post Type', choices=NEWS_TYPE)
title = models.TextField(verbose_name='News Title')
content = models.TextField(verbose_name='News Content')
hash_tags = models.CharField(max_length=255, verbose_name='Hash Tags')
source = models.CharField(max_length=255, verbose_name='News Source')
author = models.ForeignKey(User, related_name='Post', on_delete=models.CASCADE)
views = models.ManyToManyField(User,related_name='Views', blank=True)
likes = models.ManyToManyField(User, related_name='Likes', blank=True)
dislikes = models.ManyToManyField(User, related_name='Dislikes', blank=True)
status = models.CharField(max_length=20, verbose_name='Status', choices=POST_STATUS, default='Pending')
created_at = models.DateTimeField(auto_now_add=True)
updated_at = models.DateTimeField(auto_now=True)
def __str__(self):
return (self.post_type)+ '-' +self.title
serializers.py
class CategorySerializer(serializers.ModelSerializer):
class Meta:
model = Category
fields = '__all__'
class PostSerializer(serializers.ModelSerializer):
category = CategorySerializer(many=True, read_only=True)
class Meta:
model = Post
fields = ('category','post_type','title','content','hash_tags','source','author','views',
'likes','dislikes','status')
views.py
class CategoryAPI(viewsets.ModelViewSet):
queryset = Category.objects.all()
serializer_class = CategorySerializer
class PostAPI(viewsets.ModelViewSet):
serializer_class = PostSerializer
def get_queryset(self):
news_post = Post.objects.all()
return news_post
def retrieve(self, request, *args, **kwargs):
params = kwargs
print(params['pk'])
category = Category.objects.filter(name=params['pk'])
serializer = CategorySerializer(category, many=True)
return Response(serializer.data)
urls.py
from django.urls import path, include
from rest_framework import routers
from rest_framework.routers import DefaultRouter
from news.views import PostAPI, CategoryAPI
from . import views
router = DefaultRouter()
router.register('posts', views.PostAPI, basename='posts'),
router.register('category', views.CategoryAPI, basename='category'),
urlpatterns = router.urls
I tried solving in these way but it tells 'PostSerializer' object has no attribute 'get_category'. Is there anything i'm doing wrong. Please your support would be helpful. Thank you

Answer 1

I think then your approach should be the other way round, meaning you should add the list of Posts to your Category:
serializers.py
class PostSerializer(serializers.ModelSerializer):
class Meta:
model = Post
fields = ('category','post_type','title','content','hash_tags','source','author','views',
'likes','dislikes','status')
class CategorySerializer(serializers.ModelSerializer):
posts = PostSerializer(many=True, read_only=True)
class Meta:
model = Category
fields = ['name', 'slug', 'parent', 'posts']
Attention: I changed the related name of your category field in the Post model to 'posts'
This should show you all Posts when retrieving a category. No need to override any method in your views:
class CategoryAPI(viewsets.ModelViewSet):
queryset = Category.objects.all()
serializer_class = CategorySerializer
class PostAPI(viewsets.ModelViewSet):
queryset = Post.obejcts.all()
serializer_class = PostSerializer
If do not want identify the category by id but by category name, e.g.:
http://127.0.0.1:8000/news/category/sports/
add a custom lookup field to your category view, e.g.
class CategoryAPI(viewsets.ModelViewSet):
queryset = Category.objects.all()
serializer_class = CategorySerializer
lookup_field = 'name'
but make sure the lookup_field is unique