Welcome to the Treehouse Community

The Treehouse Community is a meeting place for developers, designers, and programmers of all backgrounds and skill levels to get support. Collaborate here on code errors or bugs that you need feedback on, or asking for an extra set of eyes on your latest project. Join thousands of Treehouse students and alumni in the community today. (Note: Only Treehouse students can comment or ask questions, but non-students are welcome to browse our conversations.)

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and a supportive community. Start your free trial today.

Python Build a Social Network with Flask Takin' Names Macros

Daniel Bowen
Daniel Bowen
8,127 Points

Unexpected key error from peewee

Getting an error with peewee and not sure what is going on.

Here is my terminal log

(api) Is-iMac:Flask_Social hellspawn$ python app.py
/Users/hellspawn/virtualenvs/api/lib/python2.7/site-packages/flask/exthook.py:71: ExtDeprecationWarning: Importing flask.ext.login is deprecated, use flask_login instead.
  .format(x=modname), ExtDeprecationWarning
/Users/hellspawn/virtualenvs/api/lib/python2.7/site-packages/flask/exthook.py:71: ExtDeprecationWarning: Importing flask.ext.bcrypt is deprecated, use flask_bcrypt instead.
  .format(x=modname), ExtDeprecationWarning
Traceback (most recent call last):
  File "app.py", line 4, in <module>
    import forms
  File "/Users/hellspawn/Documents/Python Projects/Flask_Social/forms.py", line 6, in <module>
    from models import User
  File "/Users/hellspawn/Documents/Python Projects/Flask_Social/models.py", line 9, in <module>
    class User(UserMixin, Model):
  File "/Users/hellspawn/virtualenvs/api/lib/python2.7/site-packages/peewee.py", line 4490, in __new__
    cls._meta.prepared()
  File "/Users/hellspawn/virtualenvs/api/lib/python2.7/site-packages/peewee.py", line 4294, in prepared
    field = self.fields[item.lstrip('-')]
KeyError: ''

forms.py

from flask_wtf import Form
from wtforms import StringField, PasswordField
from wtforms.validators import (DataRequired, Regexp, ValidationError , Email,
                                Length, EqualTo)

from models import User

def name_exists(form, field):
    if User.select().where(User.username == field.data).exists():
        raise ValidationError('User with that name already exists.')

def email_exists(form, field):
    if User.select().where(User.email == field.data).exists():
        raise ValidationError('User with that email already exists.')

class RegisterForm(Form):
    username=StringField(
    'Username',
    validators=[
        DataRequired(),
        Regexp(
            r'^[a-zA-Z0-9_]+$',
            message="Username should be one word, letters,"
            " numbers, and underscores only."),
        name_exists])
    email = StringField(
        'Email',
        validators=[
            DataRequired(),
            Email(),
            email_exists
        ])
    password = PasswordField(
        'Password',
        validators=[
            DataRequired(),
            Length(min=2),
            EqualTo('password2', message='Passwords must match')
        ])
    password2 = PasswordField(
        'Confirm Password',
        validators=[DataRequired()])

app.py

from flask import (Flask, g, render_template, flash, redirect, url_for)
from flask.ext.login import LoginManager

import forms
import models

DEBUG = True
PORT = 8000
HOST = '0.0.0.0'

app = Flask(__name__)
app.secret_key = 'as;dklfjpoqwijfl;waj;fisjdlfijapwejifpsjadifpoij!'

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.get(models.User.id == userid)
    except models.DoesNotExist:
        return None

@app.before_request
def before_request():
    """Connect to database before each request"""
    g.db = models.DATABASE
    g.db.connect()

@app.after_request
def after_request(response):
    """CLose database connection after each request."""
    g.db.close()
    return response

@app.route('/register', methods=('GET', 'POST'))
def register():
    form = forms.RegisterForm()
    if form.validate_on_submit():
        flash("Yay, you registered!", "success")
        models.User.create_user(
            username=form.username.data,
            email=form.email.data,
            password=form.password.data
        )
        return redirect(url_for('index'))
    return render_template('register.html', form=form)

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


if __name__ == '__main__':
    models.initialize()
    try:
        models.User.create_user(
        username='kennethlove',
        email='kenneth@teamtreehouse.com',
        password='password',
        admin=True
        )
    except ValueError:
        pass

    app.run(debug=DEBUG, host=HOST, port=PORT)

And models.py

import datetime

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

DATABASE = SqliteDatabase('social.db')

class User(UserMixin, Model):
    username = CharField(unique=True)
    email = CharField(unique=True)
    password = CharField(max_length=100)
    joined_at = DateTimeField(default=datetime.datetime.now)
    is_admin = BooleanField(default=False)

    class Meta:
        database = DATABASE
        order_by = ('-joined_at')

    @classmethod
    def create_user(cls, username, email, password, admin=False):
        try:
            cls.create(
            username=username,
            email=email,
            password=generate_password_hash(password),
            is_admin=admin)
        except IntegrityError:
            raise ValueError("User already exists")

    def initialize():
        DATABASE.connect()
        DATABASE.create_tables([User], safe=True)
        DATABASE.close()

1 Answer

Martin Cornejo Saavedra
Martin Cornejo Saavedra
18,132 Points

Check out the class "Meta" inside your models.py, there's a missing comma, because order_by accepts tuples.

class Meta:
        database = DATABASE
        order_by = ('-joined_at',)   #add here a comma after the string '-joined_at'
Daniel Bowen
Daniel Bowen
8,127 Points

I had one other error too, had to remove the indent from initialize in models.py. Thank you for pointing that out though, I had seen others have that error, but not with an empty key error, so I didn't think to check that part myself.