Online Voting System Project In Flask

Creating an advanced-level Online Voting System using Flask and Bootstrap 5 involves designing a robust database structure, implementing Flask routes, and creating responsive and interactive web pages. Below is a detailed guide:

1. Database Structure

The database will store users, candidates, elections, votes, and other related data. We'll use SQLAlchemy (an ORM for Flask) to manage the database.

Database Models


from flask_sqlalchemy import SQLAlchemy
from datetime import datetime
db = SQLAlchemy()
class User(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.String(50), unique=True, nullable=False)
    email = db.Column(db.String(100), unique=True, nullable=False)
    password = db.Column(db.String(200), nullable=False)
    created_at = db.Column(db.DateTime, default=datetime.utcnow)
    votes = db.relationship('Vote', backref='user', lazy=True)
class Candidate(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(100), nullable=False)
    party = db.Column(db.String(100), nullable=False)
    election_id = db.Column(db.Integer, db.ForeignKey('election.id'), nullable=False)
    votes = db.relationship('Vote', backref='candidate', lazy=True)
class Election(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(100), nullable=False)
    start_date = db.Column(db.DateTime, nullable=False)
    end_date = db.Column(db.DateTime, nullable=False)
    candidates = db.relationship('Candidate', backref='election', lazy=True)
    votes = db.relationship('Vote', backref='election', lazy=True)
class Vote(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    user_id = db.Column(db.Integer, db.ForeignKey('user.id'), nullable=False)
    candidate_id = db.Column(db.Integer, db.ForeignKey('candidate.id'), nullable=False)
    election_id = db.Column(db.Integer, db.ForeignKey('election.id'), nullable=False)
    created_at = db.Column(db.DateTime, default=datetime.utcnow)

2. Flask Application Structure

Organize the project into the following structure:


online_voting_system/
│
├── app/
│   ├── __init__.py
│   ├── models.py
│   ├── routes/
│   │   ├── auth.py
│   │   ├── elections.py
│   │   ├── candidates.py
│   │   ├── votes.py
│   │   └── main.py
│   ├── templates/
│   │   ├── base.html
│   │   ├── index.html
│   │   ├── login.html
│   │   ├── register.html
│   │   ├── dashboard.html
│   │   ├── add_election.html
│   │   ├── add_candidate.html
│   │   ├── vote.html
│   │   └── results.html
│   ├── static/
│   │   ├── css/
│   │   │   └── styles.css
│   │   └── js/
│   │       └── scripts.js
│   └── utils.py
│
├── config.py
├── requirements.txt
└── run.py

3. Flask Application Code

app/init.py


from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from flask_login import LoginManager
db = SQLAlchemy()
login_manager = LoginManager()
def create_app():
    app = Flask(__name__)
    app.config.from_pyfile('config.py')
    db.init_app(app)
    login_manager.init_app(app)
    login_manager.login_view = 'auth.login'
    from .routes.auth import auth_bp
    from .routes.elections import elections_bp
    from .routes.candidates import candidates_bp
    from .routes.votes import votes_bp
    from .routes.main import main_bp
    app.register_blueprint(auth_bp)
    app.register_blueprint(elections_bp)
    app.register_blueprint(candidates_bp)
    app.register_blueprint(votes_bp)
    app.register_blueprint(main_bp)
    return app

config.py


import os
basedir = os.path.abspath(os.path.dirname(__file__))
class Config:
    SECRET_KEY = os.environ.get('SECRET_KEY') or 'your-secret-key'
    SQLALCHEMY_DATABASE_URI = os.environ.get('DATABASE_URL') or \
        'sqlite:///' + os.path.join(basedir, 'online_voting_system.db')
    SQLALCHEMY_TRACK_MODIFICATIONS = False

run.py


from app import create_app, db
app = create_app()
if __name__ == '__main__':
    with app.app_context():
        db.create_all()
    app.run(debug=True)

4. Flask Routes

routes/auth.py


from flask import Blueprint, render_template, redirect, url_for, flash
from flask_login import login_user, logout_user, login_required, current_user
from .forms import LoginForm, RegistrationForm
from ..models import User, db
auth_bp = Blueprint('auth', __name__)
@auth_bp.route('/login', methods=['GET', 'POST'])
def login():
    form = LoginForm()
    if form.validate_on_submit():
        user = User.query.filter_by(email=form.email.data).first()
        if user and user.verify_password(form.password.data):
            login_user(user)
            return redirect(url_for('main.dashboard'))
        flash('Invalid email or password.')
    return render_template('login.html', form=form)
@auth_bp.route('/logout')
@login_required
def logout():
    logout_user()
    return redirect(url_for('auth.login'))
@auth_bp.route('/register', methods=['GET', 'POST'])
def register():
    form = RegistrationForm()
    if form.validate_on_submit():
        user = User(username=form.username.data, email=form.email.data, password=form.password.data)
        db.session.add(user)
        db.session.commit()
        flash('Registration successful! You can now log in.')
        return redirect(url_for('auth.login'))
    return render_template('register.html', form=form)

routes/elections.py


from flask import Blueprint, render_template, redirect, url_for, flash
from flask_login import login_required
from ..models import Election, db
from ..forms import ElectionForm
elections_bp = Blueprint('elections', __name__)
@elections_bp.route('/add_election', methods=['GET', 'POST'])
@login_required
def add_election():
    form = ElectionForm()
    if form.validate_on_submit():
        election = Election(name=form.name.data, start_date=form.start_date.data, end_date=form.end_date.data)
        db.session.add(election)
        db.session.commit()
        flash('Election added successfully!')
        return redirect(url_for('main.dashboard'))
    return render_template('add_election.html', form=form)
@elections_bp.route('/elections')
@login_required
def view_elections():
    elections = Election.query.all()
    return render_template('view_elections.html', elections=elections)

routes/candidates.py


from flask import Blueprint, render_template, redirect, url_for, flash
from flask_login import login_required
from ..models import Candidate, Election, db
from ..forms import CandidateForm
candidates_bp = Blueprint('candidates', __name__)
@candidates_bp.route('/add_candidate', methods=['GET', 'POST'])
@login_required
def add_candidate():
    form = CandidateForm()
    form.election.choices = [(e.id, e.name) for e in Election.query.all()]
    if form.validate_on_submit():
        candidate = Candidate(name=form.name.data, party=form.party.data, election_id=form.election.data)
        db.session.add(candidate)
        db.session.commit()
        flash('Candidate added successfully!')
        return redirect(url_for('main.dashboard'))
    return render_template('add_candidate.html', form=form)
@candidates_bp.route('/candidates')
@login_required
def view_candidates():
    candidates = Candidate.query.all()
    return render_template('view_candidates.html', candidates=candidates)

routes/votes.py


from flask import Blueprint, render_template, redirect, url_for, flash
from flask_login import login_required, current_user
from ..models import Vote, Candidate, Election, db
from ..forms import VoteForm
votes_bp = Blueprint('votes', __name__)
@votes_bp.route('/vote/<int:election_id>', methods=['GET', 'POST'])
@login_required
def vote(election_id):
    election = Election.query.get_or_404(election_id)
    candidates = Candidate.query.filter_by(election_id=election.id).all()
    form = VoteForm()
    form.candidate.choices = [(c.id, c.name) for c in candidates]
    if form.validate_on_submit():
        if Vote.query.filter_by(user_id=current_user.id, election_id=election.id).first():
            flash('You have already voted in this election.')
            return redirect(url_for('main.dashboard'))
        vote = Vote(user_id=current_user.id, candidate_id=form.candidate.data, election_id=election.id)
        db.session.add(vote)
        db.session.commit()
        flash('Vote cast successfully!')
        return redirect(url_for('main.dashboard'))
    return render_template('vote.html', election=election, form=form, candidates=candidates)
@votes_bp.route('/results/<int:election_id>')
@login_required
def results(election_id):
    election = Election.query.get_or_404(election_id)
    results = db.session.query(Candidate, db.func.count(Vote.id)).outerjoin(Vote).filter(Candidate.election_id == election.id).group_by(Candidate.id).all()
    return render_template('results.html', election=election, results=results)

routes/main.py


from flask import Blueprint, render_template
from flask_login import login_required
main_bp = Blueprint('main', __name__)
@main_bp.route('/')
def index():
    return render_template('index.html')
@main_bp.route('/dashboard')
@login_required
def dashboard():
    return render_template('dashboard.html')

5. HTML Templates with Bootstrap 5

templates/base.html


<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.1.3/dist/css/bootstrap.min.css" rel="stylesheet">
    <link rel="stylesheet" href="{{ url_for('static', filename='css/styles.css') }}">
    <title>{% block title %}Online Voting System{% endblock %}</title>
</head>
<body>
    <nav class="navbar navbar-expand-lg navbar-light bg-light">
        <div class="container-fluid">
            <a class="navbar-brand" href="{{ url_for('main.index') }}">Online Voting System</a>
            <div class="collapse navbar-collapse">
                <ul class="navbar-nav me-auto">
                    {% if current_user.is_authenticated %}
                        <li class="nav-item">
                            <a class="nav-link" href="{{ url_for('main.dashboard') }}">Dashboard</a>
                        </li>
                        <li class="nav-item">
                            <a class="nav-link" href="{{ url_for('elections.view_elections') }}">View Elections</a>
                        </li>
                        <li class="nav-item">
                            <a class="nav-link" href="{{ url_for('candidates.view_candidates') }}">View Candidates</a>
                        </li>
                        <li class="nav-item">
                            <a class="nav-link" href="{{ url_for('votes.vote', election_id=1) }}">Vote</a>
                        </li>
                        <li class="nav-item">
                            <a class="nav-link" href="{{ url_for('auth.logout') }}">Logout</a>
                        </li>
                    {% else %}
                        <li class="nav-item">
                            <a class="nav-link" href="{{ url_for('auth.login') }}">Login</a>
                        </li>
                        <li class="nav-item">
                            <a class="nav-link" href="{{ url_for('auth.register') }}">Register</a>
                        </li>
                    {% endif %}
                </ul>
            </div>
        </div>
    </nav>
    <div class="container mt-4">
        {% with messages = get_flashed_messages() %}
            {% if messages %}
                <div class="alert alert-info">
                    {% for message in messages %}
                        <p>{{ message }}</p>
                    {% endfor %}
                </div>
            {% endif %}
        {% endwith %}
        {% block content %}{% endblock %}
    </div>
    <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.1.3/dist/js/bootstrap.bundle.min.js"></script>
</body>
</html>

templates/index.html


{% extends 'base.html' %}
{% block title %}Home{% endblock %}
{% block content %}
<h1>Welcome to the Online Voting System</h1>
<p>Participate in elections and make your voice heard!</p>
{% endblock %}

templates/login.html


{% extends 'base.html' %}
{% block title %}Login{% endblock %}
{% block content %}
<h2>Login</h2>
<form method="POST">
    {{ form.hidden_tag() }}
    <div class="mb-3">
        {{ form.email.label(class="form-label") }}
        {{ form.email(class="form-control") }}
    </div>
    <div class="mb-3">
        {{ form.password.label(class="form-label") }}
        {{ form.password(class="form-control") }}
    </div>
    <button type="submit" class="btn btn-primary">Login</button>
</form>
{% endblock %}

templates/register.html


{% extends 'base.html' %}
{% block title %}Register{% endblock %}
{% block content %}
<h2>Register</h2>
<form method="POST">
    {{ form.hidden_tag() }}
    <div class="mb-3">
        {{ form.username.label(class="form-label") }}
        {{ form.username(class="form-control") }}
    </div>
    <div class="mb-3">
        {{ form.email.label(class="form-label") }}
        {{ form.email(class="form-control") }}
    </div>
    <div class="mb-3">
        {{ form.password.label(class="form-label") }}
        {{ form.password(class="form-control") }}
    </div>
    <div class="mb-3">
        {{ form.confirm_password.label(class="form-label") }}
        {{ form.confirm_password(class="form-control") }}
    </div>
    <button type="submit" class="btn btn-primary">Register</button>
</form>
{% endblock %}

templates/dashboard.html


{% extends 'base.html' %}
{% block title %}Dashboard{% endblock %}
{% block content %}
<h2>Dashboard</h2>
<p>Welcome, {{ current_user.username }}!</p>
{% endblock %}

templates/add_election.html


{% extends 'base.html' %}
{% block title %}Add Election{% endblock %}
{% block content %}
<h2>Add Election</h2>
<form method="POST">
    {{ form.hidden_tag() }}
    <div class="mb-3">
        {{ form.name.label(class="form-label") }}
        {{ form.name(class="form-control") }}
    </div>
    <div class="mb-3">
        {{ form.start_date.label(class="form-label") }}
        {{ form.start_date(class="form-control") }}
    </div>
    <div class="mb-3">
        {{ form.end_date.label(class="form-label") }}
        {{ form.end_date(class="form-control") }}
    </div>
    <button type="submit" class="btn btn-primary">Add Election</button>
</form>
{% endblock %}

templates/add_candidate.html


{% extends 'base.html' %}
{% block title %}Add Candidate{% endblock %}
{% block content %}
<h2>Add Candidate</h2>
<form method="POST">
    {{ form.hidden_tag() }}
    <div class="mb-3">
        {{ form.name.label(class="form-label") }}
        {{ form.name(class="form-control") }}
    </div>
    <div class="mb-3">
        {{ form.party.label(class="form-label") }}
        {{ form.party(class="form-control") }}
    </div>
    <div class="mb-3">
        {{ form.election.label(class="form-label") }}
        {{ form.election(class="form-control") }}
    </div>
    <button type="submit" class="btn btn-primary">Add Candidate</button>
</form>
{% endblock %}

templates/vote.html


{% extends 'base.html' %}
{% block title %}Vote{% endblock %}
{% block content %}
<h2>Vote for {{ election.name }}</h2>
<form method="POST">
    {{ form.hidden_tag() }}
    <div class="mb-3">
        {{ form.candidate.label(class="form-label") }}
        {{ form.candidate(class="form-control") }}
    </div>
    <button type="submit" class="btn btn-primary">Cast Vote</button>
</form>
{% endblock %}

templates/results.html


{% extends 'base.html' %}
{% block title %}Election Results{% endblock %}
{% block content %}
<h2>Results for {{ election.name }}</h2>
<table class="table">
    <thead>
        <tr>
            <th scope="col">Candidate</th>
            <th scope="col">Votes</th>
        </tr>
    </thead>
    <tbody>
        {% for candidate, vote_count in results %}
        <tr>
            <td>{{ candidate.name }}</td>
            <td>{{ vote_count }}</td>
        </tr>
        {% endfor %}
    </tbody>
</table>
{% endblock %}

6. Forms for Flask-WTF

forms.py


from flask_wtf import FlaskForm
from wtforms import StringField, PasswordField, DateTimeField, SelectField, SubmitField
from wtforms.validators import DataRequired, Length, Email, EqualTo
class LoginForm(FlaskForm):
    email = StringField('Email', validators=[DataRequired(), Email()])
    password = PasswordField('Password', validators=[DataRequired()])
    submit = SubmitField('Login')
class RegistrationForm(FlaskForm):
    username = StringField('Username', validators=[DataRequired(), Length(min=2, max=50)])
    email = StringField('Email', validators=[DataRequired(), Email()])
    password = PasswordField('Password', validators=[DataRequired()])
    confirm_password = PasswordField('Confirm Password', validators=[DataRequired(), EqualTo('password')])
    submit = SubmitField('Register')
class ElectionForm(FlaskForm):
    name = StringField('Election Name', validators=[DataRequired()])
    start_date = DateTimeField('Start Date', format='%Y-%m-%d %H:%M:%S', validators=[DataRequired()])
    end_date = DateTimeField('End Date', format='%Y-%m-%d %H:%M:%S', validators=[DataRequired()])
    submit = SubmitField('Add Election')
class CandidateForm(FlaskForm):
    name = StringField('Candidate Name', validators=[DataRequired()])
    party = StringField('Party', validators=[DataRequired()])
    election = SelectField('Election', coerce=int, validators=[DataRequired()])
    submit = SubmitField('Add Candidate')
class VoteForm(FlaskForm):
    candidate = SelectField('Candidate', coerce=int, validators=[DataRequired()])
    submit = SubmitField('Vote')

7. Static Files

static/css/styles.css


body {
    background-color: #f8f9fa;
}
.navbar {
    margin-bottom: 20px;
}
.table {
    margin-top: 20px;
}

8. JavaScript (if needed)

static/js/scripts.js


// Custom JavaScript can be added here

9. Running the Application

To run the application, ensure you have the required packages installed as specified in requirements.txt, then execute:


python run.py

This structure and code provide a comprehensive foundation for an advanced Online Voting System using Flask and Bootstrap 5, allowing for user authentication, election management, candidate management, and voting functionality.