feat: Implement user can see readtime of an article (#35)

- write tests to calculate read time of an article
- add function tp calculate read time of an article in utils
- add readtime to article serializer
- move test data for readtime to test data file

[Starts #163383193]

authors/apps/articles/serializers.py

@@ -2,6 +2,7 @@
 
 from . import models
 from ..profiles import serializers as ProfileSerializers
+from .utils.utils import get_article_read_time
 
 
 class ArticleSerializer (serializers.ModelSerializer):
@@ -14,6 +15,7 @@ class ArticleSerializer (serializers.ModelSerializer):
     author = ProfileSerializers.ProfileSerializer(read_only=True)
     favorited = serializers.SerializerMethodField()
     average_ratings = serializers.IntegerField(required=False)
+    read_time = serializers.SerializerMethodField()
 
     class Meta:
         model = models.Article
@@ -32,15 +34,16 @@ class Meta:
             "favoritesCount",
             "favorited",
             "average_ratings",
-            "tag_list"
+            "tag_list",
+            "read_time",
         )
         read_only_fields = (
             'author',
             'slug',
             'created_at',
             'updated_at'
             'like_count',
-            'dislike_count'
+            'dislike_count',
         )
 
     def get_favorited(self, obj):
@@ -58,6 +61,9 @@ def get_favorited(self, obj):
             "slug": {"read_only": True}
         }
 
+    def get_read_time(self, obj):
+        return get_article_read_time(obj.body)
+
 
 class ArticleRatingSerializer(serializers.ModelSerializer):
     title = serializers.SerializerMethodField()

authors/apps/articles/tests/test_article_readtime.py

@@ -0,0 +1,20 @@
+from rest_framework import status
+from authors.apps.articles.tests import base_class
+from ..utils.utils import get_article_read_time
+from .test_data import test_article_data
+
+
+class TestArticleReadTime(base_class.BaseTest):
+    """Class tests calculation of read time of an article"""
+
+    def test_calculate_readtime(self):
+        read_time = get_article_read_time(
+            test_article_data.one_min_read_text
+        )
+        self.assertIn("1 min read", read_time)
+
+    def test_calculate_readtime_empty_body(self):
+        read_time = get_article_read_time(
+            test_article_data.zero_min_read_text
+        )
+        self.assertIn("0 min read", read_time)

authors/apps/articles/tests/test_data/test_article_data.py

@@ -23,3 +23,9 @@
     }
 }
 un_existing_slug = 'allInvalidHomie-jk23ll'
+
+one_min_read_text = "Hey there, how are you doing? \
+        Just wanted to let you know that Summer is almost here\
+        you should plan on getting your vacation in order. Thanks."
+
+zero_min_read_text = ""

authors/apps/articles/utils/utils.py

@@ -1,5 +1,6 @@
 import random
 import string
+import readtime
 
 from django.utils.text import slugify
 from django.db.models import Avg
@@ -22,3 +23,26 @@ def get_average_rate(**kwargs):
         return 0
     else:
         return int(average_ratings)
+
+
+def get_article_read_time(body):
+    """
+    Calculates the time some article takes the average human to read,
+    based on Medium’s read time formula.
+
+    Based on research, people are able to read English at 200 WPM
+    on paper, and 180 WPM on a monitor.
+    Read time is based on the average reading speed of an adult
+    (roughly 275 WPM). We take the total word count of a post
+    and translate it into minutes. Then, we add 12 seconds
+    for each inline image.
+
+    Parameters: Body of the article
+    Returns: average read time of an article
+
+    """
+    if body:
+        result = readtime.of_text(body)
+        return str(result)
+    else:
+        return "0 min read"

requirements.txt

@@ -36,3 +36,10 @@ six==1.12.0
 uritemplate==3.0.0
 urllib3==1.24.1
 whitenoise==4.1.2
+beautifulsoup4==4.7.1
+cssselect==1.0.3
+lxml==4.3.1
+markdown2==2.3.7
+pyquery==1.4.0
+readtime==1.0.6
+soupsieve==1.7.3