List Posts by Rating

.travis.yml

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+language: python
+python:
+  - "2.7"
+services:
+  - sqlite3
+install:
+- pip install -q Django==1.11.15
+before_script:
+  - python manage.py migrate
+script:
+  - python manage.py test list_posts
+

README.md

@@ -1,2 +1,57 @@
-# ListPostsByRating
-App developed in Python, using the Django library
+[![Build Status](https://travis-ci.com/Ivopires/ListPostsByRating.svg?branch=challenge)](https://travis-ci.com/Ivopires/ListPostsByRating)
+
+# List Posts By Rating
+App developed in Python(2.7), using the Django(1.11.15) framework.
+
+## How to run
+
+### Setup Django (version 1.11.15):
+  1. Install pip (if you have not installed already): [Guide](https://packaging.python.org/tutorials/installing-packages/)
+  2. Install Django (version 1.11.15):
+    ```
+      pip install Django==1.11.15
+    ```
+
+### Load db scheme
+```
+python manage.py migrate
+```
+
+### Populate db with Posts
+
+```
+python manage.py shell
+
+>>>from list_posts.models import Posts
+>>>post = Post(post_text='Example text')
+>>>post.save()
+```
+
+### Run tests
+
+```
+python manage.py test list_posts
+```
+
+### Run the project
+To run project you must follow the following steps:
+
+  1. Start the server: 
+
+  ```
+    python manage.py runserver
+  ```
+
+  2. Go to the following link - [127.0.0.1:8000](http://127.0.0.1:8000)
+
+There are four available endpoints:
+```
+/
+/upvote/:post_id
+/downvote/:post_id
+/posts/
+```
+
+The first endpoint is responsible to list the latest 10 posts, ordered by posting date, if by accident 'future' posts are added to the database, these will not show on the page. The second and third endpoints are responsible to give the up/down votes, respectively, to the post with the <post_id>. Finally, the last endpoint, will show all the available posts, ordered by 'score', being the top-scored posts on the top and the less-scored posts on the bottom.
+
+To achieve a post score that would allow to order different posts with the same up/down votes ratio, as mentioned on the challenge's README, a Wilson-score Interval metric was used, which value depends solely on the number of up/down votes, total number of votes of the post and on the __z__ value used by the normal distribution (which depends on the degree of confidence used).

challenge/settings.py

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+"""
+Django settings for challenge project.
+
+Generated by 'django-admin startproject' using Django 1.11.15.
+
+For more information on this file, see
+https://docs.djangoproject.com/en/1.11/topics/settings/
+
+For the full list of settings and their values, see
+https://docs.djangoproject.com/en/1.11/ref/settings/
+"""
+
+import os
+
+# Build paths inside the project like this: os.path.join(BASE_DIR, ...)
+BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+
+# Quick-start development settings - unsuitable for production
+# See https://docs.djangoproject.com/en/1.11/howto/deployment/checklist/
+
+# SECURITY WARNING: keep the secret key used in production secret!
+SECRET_KEY = 'hj&%tr8llp&+n*nrq_c!8p7$#f=ocd3w86iq=eh88@kv0-^1=r'
+
+# SECURITY WARNING: don't run with debug turned on in production!
+DEBUG = True
+
+ALLOWED_HOSTS = []
+
+# Application definition
+
+INSTALLED_APPS = [
+    'list_posts.apps.ListPostsConfig',
+    'django.contrib.admin',
+    'django.contrib.auth',
+    'django.contrib.contenttypes',
+    'django.contrib.sessions',
+    'django.contrib.messages',
+    'django.contrib.staticfiles',
+]
+
+MIDDLEWARE = [
+    'django.middleware.security.SecurityMiddleware',
+    'django.contrib.sessions.middleware.SessionMiddleware',
+    'django.middleware.common.CommonMiddleware',
+    'django.middleware.csrf.CsrfViewMiddleware',
+    'django.contrib.auth.middleware.AuthenticationMiddleware',
+    'django.contrib.messages.middleware.MessageMiddleware',
+    'django.middleware.clickjacking.XFrameOptionsMiddleware',
+]
+
+ROOT_URLCONF = 'challenge.urls'
+
+TEMPLATES = [
+    {
+        'BACKEND': 'django.template.backends.django.DjangoTemplates',
+        'DIRS': [],
+        'APP_DIRS': True,
+        'OPTIONS': {
+            'context_processors': [
+                'django.template.context_processors.debug',
+                'django.template.context_processors.request',
+                'django.contrib.auth.context_processors.auth',
+                'django.contrib.messages.context_processors.messages',
+            ],
+        },
+    },
+]
+
+WSGI_APPLICATION = 'challenge.wsgi.application'
+
+# Database
+# https://docs.djangoproject.com/en/1.11/ref/settings/#databases
+
+DATABASES = {
+    'default': {
+        'ENGINE': 'django.db.backends.sqlite3',
+        'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),
+    }
+}
+
+# Password validation
+# https://docs.djangoproject.com/en/1.11/ref/settings/#auth-password-validators
+
+AUTH_PASSWORD_VALIDATORS = [
+    {
+        'NAME':
+            'django.contrib.auth.password_validation.UserAttributeSimilarityValidator',
+    },
+    {
+        'NAME':
+            'django.contrib.auth.password_validation.MinimumLengthValidator',
+    },
+    {
+        'NAME':
+            'django.contrib.auth.password_validation.CommonPasswordValidator',
+    },
+    {
+        'NAME':
+            'django.contrib.auth.password_validation.NumericPasswordValidator',
+    },
+]
+
+# Internationalization
+# https://docs.djangoproject.com/en/1.11/topics/i18n/
+
+LANGUAGE_CODE = 'en-us'
+
+TIME_ZONE = 'UTC'
+
+USE_I18N = True
+
+USE_L10N = True
+
+USE_TZ = True
+
+# Static files (CSS, JavaScript, Images)
+# https://docs.djangoproject.com/en/1.11/howto/static-files/
+
+STATIC_URL = '/static/'

challenge/urls.py

@@ -0,0 +1,22 @@
+"""challenge URL Configuration
+
+The `urlpatterns` list routes URLs to views. For more information please see:
+    https://docs.djangoproject.com/en/1.11/topics/http/urls/
+Examples:
+Function views
+    1. Add an import:  from my_app import views
+    2. Add a URL to urlpatterns:  url(r'^$', views.home, name='home')
+Class-based views
+    1. Add an import:  from other_app.views import Home
+    2. Add a URL to urlpatterns:  url(r'^$', Home.as_view(), name='home')
+Including another URLconf
+    1. Import the include() function: from django.conf.urls import url, include
+    2. Add a URL to urlpatterns:  url(r'^blog/', include('blog.urls'))
+"""
+from django.conf.urls import url, include
+from django.contrib import admin
+
+urlpatterns = [
+    url(r'^', include('list_posts.urls')),
+    url(r'^admin/', admin.site.urls),
+]

challenge/wsgi.py

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+"""
+WSGI config for challenge project.
+
+It exposes the WSGI callable as a module-level variable named ``application``.
+
+For more information on this file, see
+https://docs.djangoproject.com/en/1.11/howto/deployment/wsgi/
+"""
+
+import os
+
+from django.core.wsgi import get_wsgi_application
+
+os.environ.setdefault("DJANGO_SETTINGS_MODULE", "challenge.settings")
+
+application = get_wsgi_application()

list_posts/admin.py

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+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.contrib import admin
+
+# Register your models here.

list_posts/apps.py

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+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.apps import AppConfig
+
+
+class ListPostsConfig(AppConfig):
+    name = 'list_posts'

list_posts/migrations/0001_initial.py

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+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.15 on 2018-09-17 22:48
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    initial = True
+
+    dependencies = [
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Post',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('post_text', models.CharField(max_length=500, verbose_name='Post content')),
+                ('up_votes', models.PositiveIntegerField(default=0, verbose_name='Up votes')),
+                ('down_votes', models.PositiveIntegerField(default=0, verbose_name='Down votes')),
+            ],
+        ),
+    ]

list_posts/migrations/0002_post_pub_date.py

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+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.15 on 2018-09-18 14:05
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+import django.utils.timezone
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('list_posts', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='post',
+            name='pub_date',
+            field=models.DateTimeField(default=django.utils.timezone.now, verbose_name='Date Published'),
+            preserve_default=False,
+        ),
+    ]

list_posts/migrations/0003_post_score.py

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+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.15 on 2018-09-18 19:51
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('list_posts', '0002_post_pub_date'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='post',
+            name='score',
+            field=models.FloatField(default=0, verbose_name='Post Score'),
+        ),
+    ]

list_posts/models.py

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+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+import numpy as np
+from django.utils import timezone
+from math import sqrt
+from django.db import models
+from django.utils.encoding import python_2_unicode_compatible
+
+
+@python_2_unicode_compatible
+class Post(models.Model):
+    pub_date = models.DateTimeField('Date Published', default=timezone.now)
+    post_text = models.CharField('Post content', max_length=500)
+    up_votes = models.PositiveIntegerField('Up votes', default=0)
+    down_votes = models.PositiveIntegerField('Down votes', default=0)
+    score = models.FloatField('Post Score', default=0)
+
+    def __str__(self):
+        return self.post_text
+
+    def compute_score(self):
+        """
+        The compute_score function will compute the Wilson-score Interval,
+        which calculation depends on the number of up/down votes and the total
+        number of votes.
+        Where:
+         - p_hat - is the fraction of up votes out of total votes
+         - total_votes - is the total number of votes
+         - z - is the normal distribution, which, in order to have 95%
+               of confidence, has to be equal to 1.96
+        """
+
+        total_votes = self.up_votes + self.down_votes
+        if self.up_votes == 0:
+            return 0
+        else:
+            p_hat = np.float64(self.up_votes) / total_votes
+            z = np.float64(1.96)
+
+            lower_bound = (((p_hat + z * z / (2 * total_votes)) - z * sqrt(
+                (p_hat * (1 - p_hat) + z * z /
+                 (4 * total_votes)) / total_votes)) / (1 + z * z / total_votes))
+
+            return lower_bound

list_posts/static/list_posts/style.css

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+body {
+  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
+}

list_posts/templates/list_posts/index.html

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+{% load static %}
+
+<link rel="stylesheet" type="text/css" href="{% static 'list_posts/style.css' %}" />
+
+{% if latest_posts_list %}
+<ul style="list-style: none;">
+  {% for post in latest_posts_list %}
+  <li style="font-family: Arial, Helvetica, sans-serif;">
+    <a href="{% url 'list_posts:post' post.id %}">{{post.post_text}}</a>, published on {{post.pub_date}}
+  </li><br />
+  {% endfor %}
+</ul>
+{% else %}
+<p>No posts are available.</p>
+{% endif %}