feat(stats): implement user can view read stats

 - implement read count is logged when authenticated users read an article
 - implement authenticated users can view read count
 - implement article owners can view people who have read their articles
 - read count and readers returned when getting an article
[Delivers #165305284]

authors/apps/articles/migrations/0030_readstatsmodel.py

@@ -0,0 +1,24 @@
+# Generated by Django 2.2 on 2019-05-15 12:10
+
+from django.conf import settings
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+        ('articles', '0029_auto_20190513_1142'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='ReadStatsModel',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('article', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='read_article', to='articles.ArticleModel')),
+                ('user', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='read_user', to=settings.AUTH_USER_MODEL)),
+            ],
+        ),
+    ]

authors/apps/articles/models.py

@@ -75,3 +75,12 @@ class BookmarkArticleModel(models.Model):
                                 to_field='slug')
     bookmarked_at = models.DateTimeField(
         auto_created=True, auto_now=False, default=timezone.now)
+
+
+class ReadStatsModel(models.Model):
+    """Reading statistics model"""
+    user = models.ForeignKey(
+        User, related_name="read_user", on_delete=models.CASCADE)
+
+    article = models.ForeignKey(
+        ArticleModel, related_name="read_article", on_delete=models.CASCADE)

authors/apps/articles/serializers.py

@@ -1,7 +1,7 @@
 from rest_framework import serializers
 from django.apps import apps
 from .models import (ArticleModel, FavoriteArticleModel,
-                     BookmarkArticleModel, TagModel)
+                     BookmarkArticleModel, TagModel, ReadStatsModel)
 from fluent_comments.models import FluentComment
 from .utils import user_object, configure_response, TagField
 from django.contrib.auth.models import AnonymousUser
@@ -51,6 +51,8 @@ class ArticleSerializer(serializers.ModelSerializer):
         many=True,
         required=False
     )
+    read_count = serializers.SerializerMethodField()
+    article_readers = serializers.SerializerMethodField()
 
     class Meta:
         model = TABLE
@@ -78,6 +80,8 @@ class Meta:
             'mail',
             'readtime',
             'highlights',
+            'read_count',
+            'article_readers',
         )
         lookup_field = 'slug'
         extra_kwargs = {'url': {'lookup_field': 'slug'}}
@@ -143,6 +147,37 @@ def get_highlights(self, obj):
 
         return None
 
+    def get_read_count(self, obj):
+        """
+        Return the number of people who have read an article
+        This is visible to all logged in users
+        """
+        if not self.check_anonymous():
+            read = ReadStatsModel.objects.filter(article=obj).count()
+
+            if read:
+                return read
+            return 0
+        return None
+
+    def get_article_readers(self, obj):
+        """
+        Get the usernames of people who have read an article
+        This is only visible to the author of the article
+        """
+        if self.check_anonymous():
+            return None
+
+        request = self.context.get('request')
+
+        if request.user != obj.author:
+            return None
+
+        read = ReadStatsModel.objects.filter(article=obj)
+        users = [x.user.username for x in read]
+
+        return users
+
 
 class FavoriteArticleSerializer(serializers.ModelSerializer):
     """Favorite article serializer"""
@@ -193,3 +228,11 @@ class Meta:
 
     def to_representation(self, instance):
         return instance.tagname
+
+
+class ReadStatsSerializer(serializers.ModelSerializer):
+    """Article read statistics serializer"""
+
+    class Meta:
+        Model = ReadStatsModel
+        fields = '__all__'

authors/apps/articles/utils.py

@@ -9,8 +9,7 @@
 from django.db.models import Q
 from rest_framework import serializers
 from rest_framework.exceptions import ValidationError
-from .models import User
-from .models import ArticleModel, TagModel
+from .models import (User, ArticleModel, TagModel, ReadStatsModel)
 
 
 def ImageUploader(image):
@@ -103,6 +102,18 @@ def add_social_share(request):
     return request
 
 
+def save_read_stat(request, article):
+    """ Save a read statitic to db if it does not exist"""
+    if not request.user.is_anonymous:
+        existing_read = ReadStatsModel.objects.all().filter(
+            user=request.user, article=article
+        )
+
+        if not existing_read:
+            ReadStatsModel.objects.create(
+                user=request.user, article=article)
+
+
 class ArticleFilter(FilterSet):
     """
     Custom filter class for articles
@@ -145,14 +156,14 @@ def to_representation(self, value):
         """
         Return the representation that should be used to serialize the field
         """
-
         return value.tagname
 
     def to_internal_value(self, data):
         """
         Validate data and restore it back into its internal
         python representation
         """
+
         if data:
             if not re.match(r'^[a-zA-Z0-9][ A-Za-z0-9_-]*$', data):
                 raise ValidationError(

authors/apps/articles/views.py

@@ -18,9 +18,9 @@
                           CommentSerializer, FavoriteArticleSerializer,
                           BookmarkArticleSerializer, TagSerializer)
 from .models import (ArticleModel, FavoriteArticleModel,
-                     BookmarkArticleModel, TagModel)
+                     BookmarkArticleModel, TagModel, ReadStatsModel)
 from .utils import (ImageUploader, user_object,
-                    configure_response, add_social_share, ArticleFilter)
+                    configure_response, add_social_share, ArticleFilter, save_read_stat)
 
 
 class ArticleView(viewsets.ModelViewSet):
@@ -111,6 +111,9 @@ def retrieve(self, request, slug=None):
             return JsonResponse({"status": 404,
                                  "error": "Article with slug {} not found".format(slug)},
                                 status=404)
+
+        save_read_stat(request, article)
+
         serializer = ArticleSerializer(article,
                                        context={'request': request})
         response = Response(serializer.data)

authors/tests/data/test_read_stats.py

@@ -0,0 +1,92 @@
+"""
+Reader statistics tests
+"""
+import json
+from .base_test import BaseTest
+from .data import Data
+
+
+class HighlightArticleTestcase(BaseTest):
+    """
+    This class defines the test suite for like and dislike
+    cases.
+    """
+
+    def setUp(self):
+        """ Define the test client and required test variables. """
+
+        BaseTest.setUp(self)
+        data = self.base_data.user_data2
+        signup = self.signup_user()
+        signup2 = self.signup_user(data)
+
+        uid = signup.data.get('data')['id']
+        token = signup.data.get('data')['token']
+        uid_2 = signup2.data.get('data')['id']
+        token_2 = signup2.data.get('data')['token']
+
+        self.activate_user(uid=uid, token=token)
+        self.activate_user(uid=uid_2, token=token_2)
+        self.base_data = Data()
+
+        login = self.login_user()
+        self.token = login.data['token']
+        self.control_token = self.login_user_and_get_token(data)
+
+    def test_can_add_article_read_count_if_user_authenticated(self):
+        """
+        Test that a reading count is added after getting
+        an article by an authenticated user
+        """
+        article = self.create_article()
+        slug = article.data['data']['slug']
+
+        response = self.client.get('/api/articles/{}/'.format(slug),
+                                   HTTP_AUTHORIZATION='Bearer ' +
+                                   self.token)
+        res = json.loads(response.content.decode('utf-8'))
+
+        self.assertEqual(res['data']['read_count'], 1)
+
+    def test_cannot_add_article_read_count_if_user_not_authenticated(self):
+        """
+        Test that a reading count is not added after getting
+        an article by an unauthenticated user
+        """
+        article = self.create_article()
+        slug = article.data['data']['slug']
+
+        response = self.client.get('/api/articles/{}/'.format(slug))
+        res = json.loads(response.content.decode('utf-8'))
+
+        self.assertEqual(res['data']['read_count'], None)
+
+    def test_can_get_article_readers_if_owner(self):
+        """
+        Test that the author can view the people who have
+        read the article
+        """
+        article = self.create_article()
+        slug = article.data['data']['slug']
+
+        response = self.client.get('/api/articles/{}/'.format(slug),
+                                   HTTP_AUTHORIZATION='Bearer ' +
+                                   self.token)
+        res = json.loads(response.content.decode('utf-8'))
+
+        self.assertEqual(res['data']['article_readers'][0], 'Alpha')
+
+    def test_canot_get_article_readers_if_not_owner(self):
+        """
+        Test that one cannot view the people who have
+        read an article if they are not the author
+        """
+        article = self.create_article()
+        slug = article.data['data']['slug']
+
+        response = self.client.get('/api/articles/{}/'.format(slug),
+                                   HTTP_AUTHORIZATION='Bearer ' +
+                                   self.control_token)
+        res = json.loads(response.content.decode('utf-8'))
+
+        self.assertEqual(res['data']['article_readers'], None)