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Python Build a Social Network with Flask How to Win Friends Lunch Count

Welby Obeng
Welby Obeng
20,340 Points

You don't need to call `user.followers` or `user.following`. They're already querysets.

in the code how is user.followers and user.following already querysets?

why shouldn't I call

{{ user.followers().count() }} {{ user.following().count() }}

lunch.py
import datetime

from flask import Flask, g, render_template, flash, redirect, url_for
from flask.ext.bcrypt import check_password_hash
from flask.ext.login import LoginManager, login_user, current_user, login_required, logout_user

import forms
import models

app = Flask(__name__)
app.secret_key = 'this is our super secret key. do not share it with anyone!'
login_manager = LoginManager()
login_manager.init_app(app)
login_manager.login_view = 'login'


@login_manager.user_loader
def load_user(userid):
    try:
        return models.User.select().where(
            models.User.id == int(userid)
        ).get()
    except models.DoesNotExist:
        return None


@app.before_request
def before_request():
    g.db = models.DATABASE
    g.db.connect()
    g.user = current_user


@app.after_request
def after_request(response):
    g.db.close()
    return response


@app.route('/register', methods=('GET', 'POST'))
def register():
    form = forms.SignUpInForm()
    if form.validate_on_submit():
        models.User.new(
            email=form.email.data,
            password=form.password.data
        )
        flash("Thanks for registering!") 
    return render_template('register.html', form=form)


@app.route('/login', methods=('GET', 'POST'))
def login():
    form = forms.SignUpInForm()
    if form.validate_on_submit():
        try:
            user = models.User.get(
                models.User.email == form.email.data
            )
            if check_password_hash(user.password, form.password.data):
                login_user(user)
                flash("You're now logged in!")
            else:
                flash("No user with that email/password combo")
        except models.DoesNotExist:
              flash("No user with that email/password combo")
    return render_template('register.html', form=form)

@app.route('/secret')
@login_required
def secret():
    return "I should only be visible to logged-in users"

@app.route('/logout')
def logout():
    logout_user()
    return redirect(url_for('login'))


@app.route('/')
def index():
    return render_template('index.html')


@app.route('/order', methods=('GET', 'POST'))
def order_lunch():
    form = forms.LunchOrderForm()
    if form.validate_on_submit():
        models.LunchOrder.create(
            user=g.user._get_current_object(),
            date=form.date.data,
            order=form.order.data.strip()
        )
    return render_template('lunch.html', form=form)


@app.route('/today')
@login_required
def today():
    order = models.LunchOrder.select().where(
        models.LunchOrder.date == datetime.date.today() &
        models.LunchOrder.user == g.user._get_current_object()
    ).get()
    return render_template('today.html', order=order)


@app.route('/cancel_order/<int:order_id>')
@login_required
def cancel_order(order_id):
    try:
        order = models.LunchOrder.select().where(
            id=order_id,
            user=g.user._get_current_object()
        ).get()
    except models.DoesNotExist:
        pass
    else:
        order.delete_instance()
    return redirect(url_for('index'))


@app.route('/follow/<int:user_id>')
@login_required
def follow(user_id):
    try:
        user = models.User.get(
            models.User.id == user_id
        )
        models.Relationship.create(
            from_user=g.user._get_current_object(),
            to_user=user
        )
    except (models.DoesNotExist, models.IntegrityError):
        pass
    return redirect(url_for('index'))


@app.route('/unfollow/<int:user_id>')
@login_required
def unfollow(user_id):
    try:
        user = models.User.get(
            models.User.id == user_id
        )
        models.Relationship.get(
            models.Relationship.from_user==g.user._get_current_object(),
            models.Relationship.to_user==user
        ).delete_instance()
    except (models.DoesNotExist, models.IntegrityError):
        pass
    return redirect(url_for('index'))


@app.route('/profile/<int:user_id>')
def profile(user_id):
    user = models.User.select().where(
        models.User.id == user_id
    ).get()
    return render_template('profile.html', user=user)
models.py
import datetime

from flask.ext.bcrypt import generate_password_hash
from flask.ext.login import UserMixin
from peewee import *

DATABASE = SqliteDatabase(':memory:')


class User(UserMixin, Model):
    email = CharField(unique=True)
    password = CharField(max_length=100)
    join_date = DateTimeField(default=datetime.datetime.now)
    bio = CharField(default='')

    class Meta:
        database = DATABASE

    @property
    def following(self):
        return (
            User
            .select()
            .join(Relationship, on=Relationship.to_user)
            .where(Relationship.from_user == self)
        )

    @property
    def followers(self):
        return (
            User
            .select()
            .join(Relationship, on=Relationship.from_user)
            .where(Relationship.to_user == self)
        )


    @classmethod
    def new(cls, email, password):
        cls.create(
            email=email,
            password=generate_password_hash(password)
        )


class LunchOrder(Model):
    order = TextField()
    date = DateField()
    user = ForeignKeyField(User, related_name="orders")


class Relationship(Model):
    from_user = ForeignKeyField(User, related_name="relationships")
    to_user = ForeignKeyField(User, related_name="related_to")
    created_at = DateTimeField(default=datetime.datetime.now)

    class Meta:
        database = DATABASE
        indexes = (
            (('from_user', 'to_user'), True),
        )


def initialize():
    DATABASE.connect()
    DATABASE.create_tables([User, LunchOrder], safe=True)
    DATABASE.close()
templates/profile.html
{% extends "layout.html" %}
{% from "macro.html" import hide_email %}

{% block content %}

<h1>{{ hide_email(user) }}</h1>

<dl>
    <dt>Lunches:</dt>
    <dd><!-- total # of lunches ordered --></dd>
    <dt>Followers: {{ user.followers.count() }}</dt>
    <dd><!-- # of followers. user.followers is a queryset of followers --></dd>
    <dt>Following: {{ user.following.count() }}</dt>
    <dd><!-- # of users followed. user.following is a queryset of users followed --></dd>
</dl>

{% endblock %}
Chen Wang
Chen Wang
7,371 Points

I don't get this one, either.

The challenge seems as same as our project, why the project is using

{{ user.followers().count() }}

But the code challenge requires us to us

{{ user.followers.count() }}

??

1 Answer

The error message user.followers and user.following already querysets? refer to the fact that they are not conventional class methods like in the current project. Therefore you cannot call them by appending ()

Internally they behave the same way as methods but If you take a look at models.py you'll see the @property decorator before def followers and def following meaning these are treated as some kind of computed field, not as a method