Flask Simple WebApp
Tags: python, flask
Published: 2021-08-27 20:39:28

![image](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/yjgxxc4g12n27oez36ok.png)

This project is a simple web app were user can register and login and the web app authenticates the user. Create a folder where the whole project will be located, inside the folder create a other folders named website and a file named main.py. Inside the website folder create two folders named static and templets, also inside the same folder creat four files : __init__.py, auth.py, models.py and views.py.

Requirements 

```python
requirements.txt

flask
Flask-SQLAlchemy
flask-login

```


```python 
__init__.py


from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from os import path
from flask_login import LoginManager

db = SQLAlchemy()
DB_NAME = "database.db"

def create_app():
app = Flask(__name__)
app.config['SECRET_KEY'] = 'hjshjhdjah kjshkjdhjs'
app.config['SQLALCHEMY_DATABASE_URI'] = f'sqlite:///{DB_NAME}'
db.init_app(app)

from .views import views
from .auth import auth

app.register_blueprint(views, url_prefix='/')
app.register_blueprint(auth, url_prefix='/')

from .models import User, Note

create_database(app)

login_manager = LoginManager()
login_manager.login_view = 'auth.login'
login_manager.init_app(app)

@login_manager.user_loader
def load_user(id):
return User.query.get(int(id))

return app

def create_database(app):
if not path.exists('website/' + DB_NAME):
db.create_all(app=app)
print('Created Database!')

```
```python

main.py


from website import create_app

app = create_app()

if __name__ == '__main__':
app.run(debug=True)

```

```python

models.py

from . import db
from flask_login import UserMixin
from sqlalchemy.sql import func

class Note(db.Model):
id = db.Column(db.Integer, primary_key=True)
data = db.Column(db.String(10000))
date = db.Column(db.DateTime(timezone=True), default=func.now())
user_id = db.Column(db.Integer, db.ForeignKey('user.id'))

class User(db.Model, UserMixin):
id = db.Column(db.Integer, primary_key=True)
email = db.Column(db.String(150), unique=True)
password = db.Column(db.String(150))
first_name = db.Column(db.String(150))
notes = db.relationship('Note')

```

```python

views.py

from flask import Blueprint, render_template, request, flash, jsonify
from flask_login import login_required, current_user
from .models import Note
from . import db
import json

views = Blueprint('views', __name__)

@views.route('/', methods=['GET', 'POST'])
@login_required
def home():
if request.method == 'POST':
note = request.form.get('note')

if len(note) < 1:
flash('Note is too short!', category='error')
else:
new_note = Note(data=note, user_id=current_user.id)
db.session.add(new_note)
db.session.commit()
flash('Note added!', category='success')

return render_template("home.html", user=current_user)

@views.route('/delete-note', methods=['POST'])
def delete_note():
note = json.loads(request.data)
noteId = note['noteId']
note = Note.query.get(noteId)
if note:
if note.user_id == current_user.id:
db.session.delete(note)
db.session.commit()

return jsonify({})

```

``` python

auth.py

from flask import Blueprint, render_template, request, flash, redirect, url_for
from .models import User
from werkzeug.security import generate_password_hash, check_password_hash
from . import db
from flask_login import login_user, login_required, logout_user, current_user

auth = Blueprint('auth', __name__)

@auth.route('/login', methods=['GET', 'POST'])
def login():
if request.method == 'POST':
email = request.form.get('email')
password = request.form.get('password')

user = User.query.filter_by(email=email).first()
if user:
if check_password_hash(user.password, password):
flash('Logged in successfully!', category='success')
login_user(user, remember=True)
return redirect(url_for('views.home'))
else:
flash('Incorrect password, try again.', category='error')
else:
flash('Email does not exist.', category='error')

return render_template("login.html", user=current_user)

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

@auth.route('/sign-up', methods=['GET', 'POST'])
def sign_up():
if request.method == 'POST':
email = request.form.get('email')
first_name = request.form.get('firstName')
password1 = request.form.get('password1')
password2 = request.form.get('password2')

user = User.query.filter_by(email=email).first()
if user:
flash('Email already exists.', category='error')
elif len(email) < 4:
flash('Email must be greater than 3 characters.', category='error')
elif len(first_name) < 2:
flash('First name must be greater than 1 character.', category='error')
elif password1 != password2:
flash('Passwords don\'t match.', category='error')
elif len(password1) < 7:
flash('Password must be at least 7 characters.', category='error')
else:
new_user = User(email=email, first_name=first_name, password=generate_password_hash(
password1, method='sha256'))
db.session.add(new_user)
db.session.commit()
login_user(new_user, remember=True)
flash('Account created!', category='success')
return redirect(url_for('views.home'))

return render_template("sign_up.html", user=current_user)

```

templets folder

```html

base.html

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1" />
<link
rel="stylesheet"
href="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css"
integrity="sha384-Vkoo8x4CGsO3+Hhxv8T/Q5PaXtkKtu6ug5TOeNV6gBiFeWPGFN9MuhOf23Q9Ifjh"
crossorigin="anonymous"
/>
<link
rel="stylesheet"
href="https://stackpath.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css"
crossorigin="anonymous"
/>

<title>{% block title %}Home{% endblock %}</title>
</head>
<body>
<nav class="navbar navbar-expand-lg navbar-dark bg-dark">
<button
class="navbar-toggler"
type="button"
data-toggle="collapse"
data-target="#navbar"
>
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbar">
<div class="navbar-nav">
{% if user.is_authenticated %}
<a class="nav-item nav-link" id="home" href="/">Home</a>
<a class="nav-item nav-link" id="logout" href="/logout">Logout</a>
{% else %}
<a class="nav-item nav-link" id="login" href="/login">Login</a>
<a class="nav-item nav-link" id="signUp" href="/sign-up">Sign Up</a>
{% endif %}
</div>
</div>
</nav>

{% with messages = get_flashed_messages(with_categories=true) %} {% if
messages %} {% for category, message in messages %} {% if category ==
'error' %}
<div class="alert alert-danger alter-dismissable fade show" role="alert">
{{ message }}
<button type="button" class="close" data-dismiss="alert">
<span aria-hidden="true">&times;</span>
</button>
</div>
{% else %}
<div class="alert alert-success alter-dismissable fade show" role="alert">
{{ message }}
<button type="button" class="close" data-dismiss="alert">
<span aria-hidden="true">&times;</span>
</button>
</div>
{% endif %} {% endfor %} {% endif %} {% endwith %}

<div class="container">{% block content %} {% endblock %}</div>
<script
src="https://code.jquery.com/jquery-3.2.1.slim.min.js"
integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN"
crossorigin="anonymous"
></script>
<script
src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js"
integrity="sha384-ApNbgh9B+Y1QKtv3Rn7W3mgPxhU9K/ScQsAP7hUibX39j7fakFPskvXusvfa0b4Q"
crossorigin="anonymous"
></script>
<script
src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js"
integrity="sha384-JZR6Spejh4U02d8jOt6vLEHfe/JQGiRRSQQxSfFWpi1MquVdAyjUar5+76PVCmYl"
crossorigin="anonymous"
></script>

<script
type="text/javascript"
src="{{ url_for('static', filename='index.js') }}"
></script>
</body>
</html>
```

```html

home.html

{% extends "base.html" %} {% block title %}Home{% endblock %} {% block content
%}
<h1 align="center">Notes</h1>
<ul class="list-group list-group-flush" id="notes">
{% for note in user.notes %}
<li class="list-group-item">
{{ note.data }}
<button type="button" class="close" onClick="deleteNote({{ note.id }})">
<span aria-hidden="true">&times;</span>
</button>
</li>
{% endfor %}
</ul>
<form method="POST">
<textarea name="note" id="note" class="form-control"></textarea>
<br />
<div align="center">
<button type="submit" class="btn btn-primary">Add Note</button>
</div>
</form>
{% endblock %}
```

```html

login.html

{% extends "base.html" %} {% block title %}Login{% endblock %} {% block content
%}
<form method="POST">
<h3 align="center">Login</h3>
<div class="form-group">
<label for="email">Email Address</label>
<input
type="email"
class="form-control"
id="email"
name="email"
placeholder="Enter email"
/>
</div>
<div class="form-group">
<label for="password">Password</label>
<input
type="password"
class="form-control"
id="password"
name="password"
placeholder="Enter password"
/>
</div>
<br />
<button type="submit" class="btn btn-primary">Login</button>
</form>
{% endblock %}

```

```html
sing_up.html

{% extends "base.html" %} {% block title %}Sign Up{% endblock %} {% block
content %}
<form method="POST">
<h3 align="center">Sign Up</h3>
<div class="form-group">
<label for="email">Email Address</label>
<input
type="email"
class="form-control"
id="email"
name="email"
placeholder="Enter email"
/>
</div>
<div class="form-group">
<label for="firstName">First Name</label>
<input
type="text"
class="form-control"
id="firstName"
name="firstName"
placeholder="Enter first name"
/>
</div>
<div class="form-group">
<label for="password1">Password</label>
<input
type="password"
class="form-control"
id="password1"
name="password1"
placeholder="Enter password"
/>
</div>
<div class="form-group">
<label for="password2">Password (Confirm)</label>
<input
type="password"
class="form-control"
id="password2"
name="password2"
placeholder="Confirm password"
/>
</div>
<br />
<button type="submit" class="btn btn-primary">Submit</button>
</form>
{% endblock %}

```
static folder

```js

function deleteNote(noteId) {
fetch("/delete-note", {
method: "POST",
body: JSON.stringify({ noteId: noteId }),
}).then((_res) => {
window.location.href = "/";
});
}

```