Django rest framework - Assesment

articles/admin.py

@@ -1,5 +1,6 @@
 from django.contrib import admin
 
-from articles.models import Article
+from articles.models import Article, Tag
 
 admin.site.register(Article)
+admin.site.register(Tag)

articles/apps.py

@@ -4,3 +4,6 @@
 class ArticlesConfig(AppConfig):
     default_auto_field = "django.db.models.BigAutoField"
     name = "articles"
+
+    def ready(self):
+        import articles.signals

articles/migrations/0002_auto_20210510_0638.py

@@ -0,0 +1,49 @@
+# Generated by Django 3.2.2 on 2021-05-10 06:38
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("articles", "0001_initial"),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name="Tag",
+            fields=[
+                (
+                    "id",
+                    models.BigAutoField(
+                        auto_created=True,
+                        primary_key=True,
+                        serialize=False,
+                        verbose_name="ID",
+                    ),
+                ),
+                ("slug", models.SlugField()),
+                ("name", models.CharField(max_length=25)),
+                (
+                    "parent",
+                    models.ForeignKey(
+                        blank=True,
+                        null=True,
+                        on_delete=django.db.models.deletion.CASCADE,
+                        to="articles.tag",
+                    ),
+                ),
+            ],
+        ),
+        migrations.AddField(
+            model_name="article",
+            name="tag",
+            field=models.ForeignKey(
+                blank=True,
+                null=True,
+                on_delete=django.db.models.deletion.CASCADE,
+                to="articles.tag",
+            ),
+        ),
+    ]

articles/models.py

@@ -7,9 +7,19 @@ class Article(models.Model):
     title = models.CharField(max_length=32)
     slug = models.CharField(max_length=32, unique=True)
     content = models.TextField()
+    tag = models.ForeignKey("Tag", on_delete=models.CASCADE, blank=True, null=True)
 
     class Meta:
         ordering = ["id"]
 
     def __str__(self):
         return self.title
+
+
+class Tag(models.Model):
+    parent = models.ForeignKey("Tag", on_delete=models.CASCADE, blank=True, null=True)
+    slug = models.SlugField()
+    name = models.CharField(max_length=25)
+
+    def __str__(self):
+        return f"name:<{self.name}>-slug<{self.slug}>"

articles/serializers.py

@@ -1,9 +1,22 @@
 from rest_framework import serializers
 
-from articles.models import Article
+from articles.models import Article, Tag
 
 
 class ArticleSerializer(serializers.ModelSerializer):
     class Meta:
         model = Article
         fields = "__all__"
+        depth = 2
+
+    def perform_delete_on_tag(self):
+        tag = self.instance.tag
+        if tag:
+            self.instance.tag = None
+            self.instance.save()
+
+
+class TagSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = Tag
+        fields = "__all__"

articles/signals.py

@@ -0,0 +1,26 @@
+from rest_framework.exceptions import NotAcceptable
+
+from django.db.models.signals import pre_delete, pre_save
+from django.dispatch import receiver
+
+from articles.models import Article, Tag
+
+
+@receiver(pre_delete, sender=Tag)
+def check_tag_before_del(sender, instance, using, **kwargs):
+    tag_present = Article.objects.filter(tag_id=instance.id)
+    if tag_present:
+        raise NotAcceptable(detail="This tag is used by article", code=400)
+
+
+@receiver(pre_save, sender=Tag)
+def check_tag_before_del(sender, instance, using, update_fields, **kwargs):
+    tag_present = Article.objects.filter(tag_id=instance.id)
+    if tag_present:
+        updated_slug = instance.slug
+        previous_slug = tag_present[0].slug
+        if updated_slug != previous_slug:
+            raise NotAcceptable(
+                detail="This tag is used by article and 'slug' cannot be updated",
+                code=400,
+            )

articles/tests/factories.py

@@ -6,6 +6,7 @@
 class ArticleFactory(factory.django.DjangoModelFactory):
     title = factory.Sequence(lambda n: f"Article {n}")
     slug = factory.Sequence(lambda n: f"article-{n}")
+    content = factory.Sequence(lambda n: f"content-{n}")
 
     class Meta:
         model = Article

articles/tests/test_views.py

@@ -28,6 +28,49 @@ def test_create(self):
         article = Article.objects.get(id=response.data["id"])  # newly-created
         self.assertEqual(article.slug, "test-article")
 
+    def test_not_found_title_filter(self):
+        article1, article2 = ArticleFactory.create_batch(2)
+        response = self.client.get(f'{reverse("article_list")}?title=xyz')
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+        self.assertEqual(len(response.data), 0)
+
+    def test_not_found_content_filter(self):
+        article1, article2 = ArticleFactory.create_batch(2)
+        response = self.client.get(f'{reverse("article_list")}?content=xyz')
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+        self.assertEqual(len(response.data), 0)
+
+    def test_title_filter(self):
+        article1, article2 = ArticleFactory.create_batch(2)
+        response = self.client.get(f'{reverse("article_list")}?title={article1.title}')
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+        self.assertEqual(len(response.data), 1)
+        self.assertEqual(response.data[0].get("title"), article1.title)
+
+    def test_content_filter(self):
+        article1, article2 = ArticleFactory.create_batch(2)
+        response = self.client.get(
+            f'{reverse("article_list")}?content={article1.content}'
+        )
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+        self.assertEqual(len(response.data), 1)
+        self.assertEqual(response.data[0].get("content"), article1.content)
+
+    def test_not_found_content_and_title_filter(self):
+        article1, article2 = ArticleFactory.create_batch(2)
+        response = self.client.get(f'{reverse("article_list")}?content=xyz&title=xyz')
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+        self.assertEqual(len(response.data), 0)
+
+    def test_content_and_title_filter(self):
+        article1, article2 = ArticleFactory.create_batch(2)
+        response = self.client.get(
+            f'{reverse("article_list")}?content={article1.content}&title={article1.title}'
+        )
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+        self.assertEqual(len(response.data), 1)
+        self.assertEqual(response.data[0].get("content"), article1.content)
+
 
 class ArticleDetailAPIViewTest(APITestCase):
     def test_update(self):

articles/views.py

@@ -1,14 +1,77 @@
-from rest_framework import generics
+from rest_framework import generics, status
+from rest_framework.response import Response
 
-from articles.models import Article
-from articles.serializers import ArticleSerializer
+from django.db.models import Q
+
+from articles.models import Article, Tag
+from articles.serializers import ArticleSerializer, TagSerializer
 
 
 class ArticleListCreateAPIView(generics.ListCreateAPIView):
     queryset = Article.objects.all()
     serializer_class = ArticleSerializer
+    ordering_fields = ["title", "created_at"]
+
+    def get_queryset(self):
+        """
+        added params filter for 'title' and 'content'
+        """
+        title = self.request.query_params.get("title")
+        content = self.request.query_params.get("content")
+
+        if title is not None and content is None:
+            queryset = self.queryset.filter(title__exact=title)
+            return queryset
+        elif content is not None and title is None:
+            queryset = self.queryset.filter(content__exact=content)
+            return queryset
+        elif content and title:
+            queryset = self.queryset.filter(
+                Q(content__exact=content) & Q(title__exact=title)
+            )
+            return queryset
+
+        return self.queryset.all()
 
 
 class ArticleDetailAPIView(generics.RetrieveUpdateDestroyAPIView):
     queryset = Article.objects.all()
     serializer_class = ArticleSerializer
+
+    def destroy(self, request, pk):
+        # Note the use of `get_queryset()` instead of `self.queryset`
+        remove_tag = request.query_params.get("removeTag")
+        instance = self.get_object()
+
+        try:
+            if remove_tag and self.validate_remove_tag(remove_tag=remove_tag):
+                self.serializer_class(instance=instance).perform_delete_on_tag()
+                return Response(status=status.HTTP_204_NO_CONTENT)
+        except ValueError as error:
+            return Response(
+                data=dict(error=str(error)), status=status.HTTP_400_BAD_REQUEST
+            )
+        self.perform_destroy(instance)
+        return Response(status=status.HTTP_204_NO_CONTENT)
+
+    def validate_remove_tag(self, remove_tag):
+        if remove_tag.lower() != "true":
+            raise ValueError("specify 'removeTag' to be true")
+        return True
+
+
+class TagListCreateAPIView(generics.ListCreateAPIView):
+    queryset = Tag.objects.all()
+    serializer_class = TagSerializer
+
+
+class ArticleTagRetrieveAPIView(generics.RetrieveAPIView):
+    queryset = Article.objects.all()
+    serializer_class = ArticleSerializer
+    lookup_url_kwarg = "tag"
+
+    def get(self, request, *args, **kwargs):
+        key = self.kwargs[self.lookup_url_kwarg]
+        article = Article.objects.filter(tag_id=key)
+        serializer = self.serializer_class(article, many=True)
+        return Response(serializer.data)

project/urls.py

@@ -16,12 +16,23 @@
 from django.contrib import admin
 from django.urls import path
 
-from articles.views import ArticleDetailAPIView, ArticleListCreateAPIView
+from articles.views import (
+    ArticleDetailAPIView,
+    ArticleListCreateAPIView,
+    ArticleTagRetrieveAPIView,
+    TagListCreateAPIView,
+)
 
 urlpatterns = [
     path("admin/", admin.site.urls),
     path("api/articles/", ArticleListCreateAPIView.as_view(), name="article_list"),
     path(
         "api/articles/<int:pk>/", ArticleDetailAPIView.as_view(), name="article_detail"
     ),
+    path("api/tag/", TagListCreateAPIView.as_view(), name="article_list_create"),
+    path(
+        "api/articles/tag/<int:tag>/",
+        ArticleTagRetrieveAPIView.as_view(),
+        name="article_tag_retrieve",
+    ),
 ]