Recommendation engine

Recommendation System/Functional Flow

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+RE

Recommendation System/app.py

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+from re import app
+import os
+
+app.secret_key = os.urandom(24)
+port = int(os.environ.get('PORT', 5000))
+app.run(host='0.0.0.0', port=port)
+

Recommendation System/re/__init__.py

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+from .views import app
+from .models import graph

Recommendation System/re/models.py

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+from py2neo import Graph, Node, Relationship
+from passlib.hash import bcrypt
+from datetime import datetime
+import os
+import uuid
+
+url = os.environ.get('GRAPHENEDB_URL', 'http://localhost:7474')
+username = os.environ.get('NEO4J_USERNAME')
+password = os.environ.get('NEO4J_PASSWORD')
+
+graph = Graph(url + '/db/data/', username=username, password=password)
+
+class User:
+    def __init__(self, username):
+        self.username = username
+
+    def find(self):
+        user = graph.find_one('User', 'username', self.username)
+        return user
+
+    def register(self, password):
+        if not self.find():
+            user = Node('User', username=self.username, password=bcrypt.encrypt(password))
+            graph.create(user)
+            return True
+        else:
+            return False
+
+    def verify_password(self, password):
+        user = self.find()
+        if user:
+            return bcrypt.verify(password, user['password'])
+        else:
+            return False
+
+    def add_post(self, title, tags, text):
+        user = self.find()
+        post = Node(
+            'Post',
+            id=str(uuid.uuid4()),
+            title=title,
+            text=text,
+            timestamp=timestamp(),
+            date=date()
+        )
+        rel = Relationship(user, 'PUBLISHED', post)
+        graph.create(rel)
+
+        tags = [x.strip() for x in tags.lower().split(',')]
+        for name in set(tags):
+            tag = Node('Tag', name=name)
+            graph.merge(tag)
+
+            rel = Relationship(tag, 'TAGGED', post)
+            graph.create(rel)
+
+    def like_post(self, post_id):
+        user = self.find()
+        post = graph.find_one('Post', 'id', post_id)
+        graph.merge(Relationship(user, 'LIKED', post))
+
+    def get_recent_posts(self):
+        query = '''
+        MATCH (user:User)-[:PUBLISHED]->(post:Post)<-[:TAGGED]-(tag:Tag)
+        WHERE user.username = {username}
+        RETURN post, COLLECT(tag.name) AS tags
+        ORDER BY post.timestamp DESC LIMIT 5
+        '''
+
+        return graph.run(query, username=self.username)
+
+    def get_products(self):
+        query = '''
+        MATCH (user:User)-[:PUBLISHED]->(post:Post)<-[:TAGGED]-(tag:Tag)
+        WHERE user.username = {username}
+        RETURN post, COLLECT(tag.name) AS tags
+        ORDER BY post.timestamp DESC LIMIT 5
+        '''
+
+        return graph.run(query, username=self.username)
+
+    def get_similar_users(self):
+
+        query = '''
+        MATCH (you:User)-[:PUBLISHED]->(:Post)<-[:TAGGED]-(tag:Tag),
+              (they:User)-[:PUBLISHED]->(:Post)<-[:TAGGED]-(tag)
+        WHERE you.username = {username} AND you <> they
+        WITH they, COLLECT(DISTINCT tag.name) AS tags
+        ORDER BY SIZE(tags) DESC LIMIT 3
+        RETURN they.username AS similar_user, tags
+        '''
+
+        return graph.run(query, username=self.username)
+
+    def get_commonality_of_user(self, other):
+
+        query = '''
+        MATCH (they:User {username: {they} })
+        MATCH (you:User {username: {you} })
+        OPTIONAL MATCH (they)-[:PUBLISHED]->(:Post)<-[:TAGGED]-(tag:Tag),
+                       (you)-[:PUBLISHED]->(:Post)<-[:TAGGED]-(tag)
+        RETURN SIZE((they)-[:LIKED]->(:Post)<-[:PUBLISHED]-(you)) AS likes,
+               COLLECT(DISTINCT tag.name) AS tags
+        '''
+
+        return graph.run(query, they=other.username, you=self.username).next
+
+def get_todays_recent_posts():
+    query = '''
+    MATCH (user:User)-[:PUBLISHED]->(post:Post)<-[:TAGGED]-(tag:Tag)
+    WHERE post.date = {today}
+    RETURN user.username AS username, post, COLLECT(tag.name) AS tags
+    ORDER BY post.timestamp DESC LIMIT 5
+    '''
+
+    return graph.run(query, today=date())
+
+def timestamp():
+    epoch = datetime.utcfromtimestamp(0)
+    now = datetime.now()
+    delta = now - epoch
+    return delta.total_seconds()
+
+def date():
+    return datetime.now().strftime('%Y-%m-%d')

Recommendation System/re/static/style.css

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+body            { font-family: sans-serif; background: #eee; }
+a, h1, h3       { color: #377ba8; }
+h1, h2, h3      { font-family: 'Georgia', serif; margin: 0; }
+h1, h2          { border-bottom: 2px solid #eee; padding: 3px; }
+h3              { padding: 3px; }
+dd              { display: block; margin-left: 0px; }
+dl              { font-weight: bold; }
+a:visited 		{ color: #800080; }
+.page           { margin: 2em auto; width: 35em; border: 5px solid #ccc; padding: 0.8em; background: white; }
+.posts          { list-style: none; margin: 0; padding: 0; }
+.posts li       { margin: 0.8em 1.2em; }
+.posts li h2    { margin-left: -1em; }
+.metanav        { text-align: right; font-size: 0.8em; padding: 0.3em; margin-bottom: 1em; background: #fafafa; }
+.flash          { background: #cee5F5; padding: 0.5em; border: 1px solid #aacbe2; }
+.error          { background: #f0d6d6; padding: 0.5em; }

Recommendation System/re/templates/display_host

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+<ul class="posts">
+  {% for row in posts %}
+    <li>
+    	<b>{{ row.post.title }}</b>
+        {% if request.path == "/" %}
+    	by <a href="{{ url_for('profile', username=row.username) }}">{{ row.username }}</a>
+        {% endif %}
+    	on {{ row.post.date }}
+    	<a href="{{ url_for('like_post', post_id=row.post.id) }}">like</a><br>
+    	<i>{{ ", ".join(row.tags) }}</i><br>
+    	{{ row.post.text }}
+  {% else %}
+    <li>There aren't any purchases yet!
+  {% endfor %}
+  </ul>

Recommendation System/re/templates/index.html

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+{% extends "layout.html" %}
+{% block body %}
+
+<h2>Home</h2>
+  {% if session.username %}
+    <h3>Purchase New Items</h3>
+    <form action="{{ url_for('add_product') }}" method="post">
+        <dl>
+            <dt>Product Name:</dt>
+            <dd><input type="text" size="30" name="title"></dd>
+            <dt>Categories (separated by commas):</dt>
+            <dd><input type="text" size="30" name="tags"></dd>
+            <dt>Description:</dt>
+            <dd><textarea name="text" rows="5" cols="40"></textarea></dd>
+        </dl>
+        <input type="submit" value="Share">
+    </form>
+  {% endif %}
+
+<br>
+
+<h3>Today's Recent Purchases</h3>
+{% include "display_posts.html" %}
+
+{% endblock %}

Recommendation System/re/templates/layout.html

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+<!doctype html>
+<title>My Recommendation Engine</title>
+<link rel="stylesheet" type="text/css" href="{{ url_for('static', filename='style.css') }}">
+<div class="page">
+  <h1>My Recommendation Site</h1>
+  <div class="metanav">
+  {% if session.username %}
+  Logged in as {{ session.username }}
+  {% endif %}
+  <a href="{{ url_for('index') }}">Home</a>
+  {% if not session.username %}
+    <a href="{{ url_for('register') }}">Register</a>
+    <a href="{{ url_for('login') }}">Login</a>
+  {% else %}
+    <a href="{{ url_for('profile', username=session.username) }}">Profile</a>
+    <a href="{{ url_for('logout') }}">Logout</a>
+  {% endif %}
+  </div>
+  {% for message in get_flashed_messages() %}
+    <div class="flash">{{ message }}</div>
+  {% endfor %}
+  {% block body %}{% endblock %}
+</div>

Recommendation System/re/templates/profile.html

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+{% extends "layout.html" %}
+{% block body %}
+
+<h2>{{ username }}'s profile</h2>
+
+{% if session.username %}
+    {% if session.username == username %}
+        <h3>Users who brought items similar to you:</h3>
+
+          {% for user in similar %}
+            <p>
+            <a href="{{ url_for('profile', username=user.similar_user) }}">{{ user.similar_user }}</a>
+            also purchased  <i>{{ ", ".join(user.tags) }}</i> {{ ", ".join(user.posts) }}
+            </p> 
+          {% else %}
+            <p>There aren't any users who've purchased products the same category as you!</p>
+          {% endfor %}
+
+        <h3>Recommendations for you</h3>
+            Based on your previous purchases
+            {% for product in products %}
+            <p>
+            {{ product.post.title }}
+            </p>
+
+
+          {% else %}
+            <p>There aren't any users who've purchased products the same category as you!</p>
+          {% endfor %}
+
+        <h3>Your recent purchases:</h3>
+
+
+    {% else %}
+
+      <p>{{ username }} has liked {{ common.likes }} of your purchases and
+        {% if common.tags %}
+        also purchased  <i>{{ ", ".join(common.tags) }}</i>
+        {% else %}
+        hasn't purchased any of the same category
+        {% endif %}
+      </p>
+
+    <h3>{{ username }}'s recent purchases:</h3>
+
+    {% endif %}
+{% endif %}
+
+{% include "display_posts.html" %}
+
+{% endblock %}

Recommendation System/re/views.py

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+from .models import User, get_todays_recent_posts
+from flask import Flask, request, session, redirect, url_for, render_template, flash
+
+app = Flask(__name__)
+
+@app.route('/')
+def index():
+    posts = get_todays_recent_posts()
+    return render_template('index.html', posts=posts)
+
+@app.route('/register', methods=['GET','POST'])
+def register():
+    if request.method == 'POST':
+        username = request.form['username']
+        password = request.form['password']
+
+        if len(username) < 1:
+            flash('Your username must be at least one character.')
+        elif len(password) < 5:
+            flash('Your password must be at least 5 characters.')
+        elif not User(username).register(password):
+            flash('A user with that username already exists.')
+        else:
+            session['username'] = username
+            flash('Logged in.')
+            return redirect(url_for('index'))
+
+    return render_template('register.html')
+
+@app.route('/login', methods=['GET', 'POST'])
+def login():
+    if request.method == 'POST':
+        username = request.form['username']
+        password = request.form['password']
+
+        if not User(username).verify_password(password):
+            flash('Invalid login.')
+        else:
+            session['username'] = username
+            flash('Logged in.')
+            return redirect(url_for('index'))
+
+    return render_template('login.html')
+
+@app.route('/logout')
+def logout():
+    session.pop('username', None)
+    flash('Logged out.')
+    return redirect(url_for('index'))
+
+@app.route('/add_product', methods=['POST'])
+def add_product():
+    title = request.form['title']
+    tags = request.form['tags']
+    text = request.form['text']
+
+    if not title:
+        flash('You must give your post a title.')
+    elif not tags:
+        flash('You must give your post at least one tag.')
+    elif not text:
+        flash('You must give your post a text body.')
+    else:
+        User(session['username']).add_post(title, tags, text)
+
+    return redirect(url_for('index'))
+
+@app.route('/like_post/<post_id>')
+def like_post(post_id):
+    username = session.get('username')
+
+    if not username:
+        flash('You must be logged in to like a post.')
+        return redirect(url_for('login'))
+
+    User(username).like_post(post_id)
+
+    flash('Liked post.')
+    return redirect(request.referrer)
+
+@app.route('/profile/<username>')
+def profile(username):
+    logged_in_username = session.get('username')
+    user_being_viewed_username = username
+
+    user_being_viewed = User(user_being_viewed_username)
+    posts = user_being_viewed.get_recent_posts()
+
+    similar = []
+    common = []
+    products = []
+
+    if logged_in_username:
+        logged_in_user = User(logged_in_username)
+
+        if logged_in_user.username == user_being_viewed.username:
+            similar = logged_in_user.get_similar_users()
+            products = logged_in_user.get_products()
+        else:
+            common = logged_in_user.get_commonality_of_user(user_being_viewed)
+
+    return render_template(
+        'profile.html',
+        username=username,
+        posts=posts,
+        similar=similar,
+        common=common,
+        products=products
+    )

Recommendation System/requirements.txt

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+bcrypt==3.1.0
+cffi==1.7.0
+click==6.6
+Flask==0.11.1
+itsdangerous==0.24
+Jinja2==2.8
+MarkupSafe==0.23
+passlib==1.6.5
+py2neo==3.1.1
+pycparser==2.14
+six==1.10.0
+Werkzeug==0.11.10
+