feature(like/dislike articles): Like and dislike articles by users

- user can like article
- user can dislike article
- return liked/disliked article after like/dislike
- user can undo a like /dislike
- test the feature works

[Finishes #164047068]

authors/apps/article/models.py

@@ -1,7 +1,11 @@
+from cloudinary.models import CloudinaryField
 from django.db import models
-from django.utils.text import slugify
+from django.shortcuts import get_object_or_404
 from django.urls import reverse
-from cloudinary.models import CloudinaryField
+from django.utils.text import slugify
+from rest_framework import status
+from rest_framework.exceptions import APIException
+from rest_framework.response import Response
 
 from authors.apps.authentication.models import User
 
@@ -15,7 +19,8 @@ class Article(models.Model):
     created_at = models.DateTimeField(auto_now_add=True)
     updated_at = models.DateTimeField(auto_now=True)
     favourited = models.BooleanField(default=False)
-    author = models.ForeignKey(User, related_name="articles", on_delete=models.CASCADE)
+    author = models.ForeignKey(
+        User, related_name="articles", on_delete=models.CASCADE)
 
     def __str__(self):
         return self.title
@@ -46,14 +51,78 @@ class ArticleImage(models.Model):
         Article,
         related_name='article_images',
         on_delete=models.CASCADE,
-        verbose_name='Image associated with the article'
-    )
-    image = CloudinaryField('image', default="image/upload/v1551960935/books.png")
+        verbose_name='Image associated with the article')
+    image = CloudinaryField(
+        'image', default="image/upload/v1551960935/books.png")
     created = models.DateTimeField(
-        auto_now=True,
-        verbose_name='When was this image saved'
-    )
+        auto_now=True, verbose_name='When was this image saved')
     description = models.CharField(db_index=True, max_length=255)
 
     class Meta:
         ordering = ('created',)
+
+
+class ArticleLikes(models.Model):
+    """This class creates a model for Article likes and dislikes"""
+    user = models.ForeignKey(
+        User, related_name='liked_by', on_delete=models.CASCADE)
+    article = models.ForeignKey(
+        Article,
+        to_field='slug',
+        db_column='article',
+        on_delete=models.CASCADE,
+        related_name='liked')
+    likes = models.IntegerField(null=True)
+    dislikes = models.IntegerField(null=True)
+    created = models.DateTimeField(auto_now=True)
+
+    class Meta:
+        ordering = ('created',)
+
+    @staticmethod
+    def get_article(slug):
+        """ This method gets a sin gle Articel
+        :param slug: The Article's unique slug
+        :return: returns a serialized Article
+        """
+        article = get_object_or_404(Article, slug=slug)
+        return article
+
+    @staticmethod
+    def user_likes(user, slug, ArticleSerializer, value):
+        """This method creates an Article like or dislike.
+        :param user: The user liking or disliking an Article
+        :param slug: The Article unique slug
+        :param value: The value for like or dislike.
+                      Takes in a +1 for like or -1 for dislike.
+        :return: success message or fail
+        """
+        try:
+            likes = ArticleLikes.objects.filter(user=user, article=slug)
+            article = ArticleLikes.get_article(slug=slug)
+        except:
+            APIException.status_code = status.HTTP_404_NOT_FOUND
+            raise APIException(
+                {'article': {
+                    'message': 'Article requested does not exist'
+                }})
+        if not likes:
+            if value == 1:
+                ArticleLikes.objects.create(
+                    user=user, article=article, likes=value)
+                return Response(
+                    {'message': 'Successfully liked: {} article'.format(slug),
+                     'article': ArticleSerializer(article).data},
+                    status=status.HTTP_201_CREATED)
+            ArticleLikes.objects.create(
+                user=user, article=article, dislikes=value)
+            return Response(
+                {'message': 'Successfully disliked: {} article'.format(slug),
+                 'article': ArticleSerializer(article).data},
+                status=status.HTTP_201_CREATED)
+        likes.delete()
+        return Response({
+            'message':
+                'Successfully undid (dis)like on {} article'.format(slug),
+            'article': ArticleSerializer(article).data
+        }, status=status.HTTP_202_ACCEPTED)

authors/apps/article/serializers.py

@@ -1,25 +1,77 @@
 from rest_framework import serializers
-from .models import Article
 
 from authors.apps.authentication.serializers import UserSerializer
+from .models import Article, ArticleLikes
+
+
+class LikesSerializer(serializers.ModelSerializer):
+    """
+    This class serializes data from ArticleLikes model
+    """
+    user = UserSerializer()
+
+    class Meta:
+        model = ArticleLikes
+        fields = ('user', )
 
 
 class ArticleSerializer(serializers.ModelSerializer):
     """
     converts the model into JSON format
     """
-
-    title = serializers.CharField(required=True)
-    slug = serializers.SlugField(required=False)
-    description = serializers.CharField(required=True)
-    body = serializers.CharField(required=True)
-    created_at = serializers.DateTimeField(read_only=True)
-    updated_at = serializers.DateTimeField(read_only=True)
-    favourited = serializers.BooleanField(required=False)
     author = UserSerializer(read_only=True)
+    likes = serializers.SerializerMethodField()
+    dislikes = serializers.SerializerMethodField()
+    likes_count = serializers.SerializerMethodField()
+    dislikes_count = serializers.SerializerMethodField()
 
     class Meta:
         model = Article
-        fields = ['title', 'description',
-                  'body', 'created_at', 'updated_at', 'slug', 'favourited', 'author']
+        fields = [
+            'title',
+            'description',
+            'body',
+            'created_at',
+            'updated_at',
+            'slug',
+            'favourited',
+            'author',
+            'likes_count',
+            'dislikes_count',
+            'likes',
+            'dislikes',
+        ]
+
+    def get_likes(self, obj):
+        """
+        This method returns users who liked an Article
+        :param obj: This is the Article object
+        :return: users who liked an article
+        """
+        query = obj.liked.filter(likes=1)
+        return LikesSerializer(query, many=True).data
+
+    def get_dislikes(self, obj):
+        """
+        This method returns users who disliked an Article
+        :param obj: This is the Article object
+        :return: users who liked an article
+        """
+        query = obj.liked.filter(dislikes=-1)
+        return LikesSerializer(query, many=True).data
+
+    def get_likes_count(self, obj):
+        """
+        This method returns number of users who liked an Article
+        :param obj: This is the Article object
+        :return: count of users who liked an article
+        """
+        return obj.liked.filter(likes=1).count()
 
+    def get_dislikes_count(self, obj):
+        """
+        This method returns number of users who disliked an Article
+        :param obj: This is the Article object
+        :return: count of users who disliked an article
+        """
+        return obj.liked.filter(dislikes=-1).count()

authors/apps/article/tests/test_article.py

@@ -147,8 +147,8 @@ def test_same_slug(self):
                                     format='json')
         result = json.loads(response.content)
 
-        self.assertIn('the slug is already used', str(result))
-        self.assertEqual(response.status_code, status.HTTP_500_INTERNAL_SERVER_ERROR)
+        self.assertIn('article with this slug already exists.', str(result))
+        self.assertEqual(response.status_code, status.HTTP_400_BAD_REQUEST)
 
     def test_view_all_articles(self):
         """

authors/apps/article/tests/test_article_likes.py

@@ -0,0 +1,112 @@
+import json
+
+from rest_framework.test import APIClient, APITestCase
+from rest_framework.views import status
+
+
+class TestArticleLikes(APITestCase):
+    """ This class tests the Article like and dislike feature
+    """
+
+    client = APIClient()
+
+    def setUp(self):
+        """ This is the set-up method for all tests
+        """
+        self.user = {"user": {
+            "username": "kibet",
+            "email": "kibet@olympians.com",
+            "password": "qwerty12"
+        }}
+
+        self.profile = {
+            "bio": "am fantastic",
+            "interests": "football",
+            "favorite_quote": "Yes we can",
+            "mailing_address": "P.O BOX 1080",
+            "website": "http://www.web.com",
+            "active_profile": True
+        }
+
+        self.article = {
+            "title": "Andela",
+            "description": "sdsd",
+            "body": "dsd",
+            "images": ""
+        }
+
+        # create user
+        self.client.post(
+            '/api/users/', self.user, format='json')
+
+        response = self.client.post(
+            '/api/users/login/', self.user, format='json')
+
+        result = json.loads(response.content)
+
+        self.client.credentials(
+            HTTP_AUTHORIZATION='Token ' + result["user"]["token"])
+
+        profile = self.client.post(
+            '/api/profile/create_profile/', self.profile, format='json')
+        prof_result = json.loads(profile.content)
+
+        article = self.client.post('/api/articles/', self.article,
+                                   format='json')
+
+        article_result = json.loads(article.content)
+        self.slug = article_result["article"]["slug"]
+
+    def test_like_article(self):
+        """
+        Test like an article
+        """
+        #
+        response = self.client.post('/api/articles/' + self.slug + '/like',
+                                    format='json')
+        result = json.loads(response.content)
+
+        self.assertIn('Successfully liked: {} article'.format(self.slug),
+                      str(result))
+        self.assertEqual(response.status_code, status.HTTP_201_CREATED)
+
+    def test_dislike_article(self):
+        """
+        Test like an article
+        """
+        #
+        response = self.client.post('/api/articles/' + self.slug + '/dislike',
+                                    format='json')
+        result = json.loads(response.content)
+
+        self.assertIn('Successfully disliked: {} article'.format(self.slug),
+                      str(result))
+        self.assertEqual(response.status_code, status.HTTP_201_CREATED)
+
+    def test_like_non_existing_article(self):
+        """
+        Test like an article
+        """
+        #
+        response = self.client.post('/api/articles/random/like',
+                                    format='json')
+        result = json.loads(response.content)
+
+        self.assertIn('Article requested does not exist'.format(self.slug),
+                      str(result))
+        self.assertEqual(response.status_code, status.HTTP_404_NOT_FOUND)
+
+    def test_unlike_article(self):
+        """
+        Test like an article
+        """
+        #
+        self.client.post('/api/articles/' + self.slug + '/like',
+                         format='json')
+        response = self.client.post('/api/articles/' + self.slug + '/like',
+                                    format='json')
+        result = json.loads(response.content)
+
+        self.assertIn('Successfully undid (dis)like on {} article'.format(self.slug),
+                      str(result))
+        self.assertEqual(response.status_code, status.HTTP_202_ACCEPTED)

authors/apps/article/urls.py

@@ -1,10 +1,12 @@
 from django.urls import path
 
-from .views import (ArticlesAPIView, RetrieveArticleAPIView)
+from .views import (ArticlesAPIView, RetrieveArticleAPIView, LikeAPIView, DislikeAPIView)
 
 app_name = "articles"
 
 urlpatterns = [
     path('articles/', ArticlesAPIView.as_view()),
     path('articles/<slug>', RetrieveArticleAPIView.as_view()),
+    path('articles/<slug>/like', LikeAPIView.as_view()),
+    path('articles/<slug>/dislike', DislikeAPIView.as_view()),
 ]

authors/apps/article/views.py

@@ -1,13 +1,13 @@
 from django.db.utils import IntegrityError
+from rest_framework import status
+from rest_framework.exceptions import APIException
 from rest_framework.permissions import IsAuthenticated
 from rest_framework.response import Response
-from rest_framework import status, mixins, viewsets
-from rest_framework.exceptions import APIException
 from rest_framework.views import APIView
 
-from .models import Article, ArticleImage
-from .serializers import ArticleSerializer
+from .models import Article, ArticleImage, ArticleLikes
 from .renderer import ArticleJSONRenderer
+from .serializers import ArticleSerializer
 
 
 class ArticlesAPIView(APIView):
@@ -69,7 +69,7 @@ def get(self, request, slug):
         try:
             article = Article.objects.get(slug=slug)
             serializer = ArticleSerializer(article, many=False)
-            return Response(serializer.data, status=status.HTTP_200_OK)
+            return Response({'article': serializer.data}, status=status.HTTP_200_OK)
         except Article.DoesNotExist:
             return Response({"message": "The article requested does not exist"}, status=status.HTTP_404_NOT_FOUND)
 
@@ -106,3 +106,35 @@ def delete(self, request, slug):
             return Response(response, status=status.HTTP_401_UNAUTHORIZED)
         response = {"message": "article deleted"}
         return Response(response, status=status.HTTP_202_ACCEPTED)
+
+
+class LikeAPIView(APIView):
+    """ This class proviedes a view class to like and unlike an Article
+    :return: http Response mesage
+    """
+    permission_classes = (IsAuthenticated,)
+
+    def post(self, request, slug):
+        """This method provides a POST view to like an article.
+        :param request: http request object
+        :param slug: Article slug field
+        :return: http Response message
+        """
+        message = ArticleLikes.user_likes(request.user, slug, ArticleSerializer, 1)
+        return message
+
+
+class DislikeAPIView(APIView):
+    """ This class proviedes a view class to like and unlike an Article
+    :return: http Response mesage
+    """
+    permission_classes = (IsAuthenticated,)
+
+    def post(self, request, slug):
+        """This method provides a POST view to dislike an article.
+        :param request: http request object
+        :param slug: Article slug field
+        :return: http Response message
+        """
+        message = ArticleLikes.user_likes(request.user, slug, ArticleSerializer, -1)
+        return message