Day 5 - User Account Creation with Python Flask

Introduction:
In Day 5 of our Python Flask series, we will focus on user account creation functionality within a Role-Based Access Control (RBAC) system. We'll cover essential concepts such as form validation, displaying error messages, retaining form data, and inserting user information into a database.

Prerequisites:
Before proceeding, ensure you have Python and Flask installed on your system. Additionally, install the following packages using pip:

```bash
pip install flask-wtf
pip install email_validator
```

Setting Up Flask Form:
To handle user input effectively, we'll use Flask-WTF for form creation and validation. First, create a `SignupForm` class within your `UserModel.py` file:

```python
from flask_wtf import FlaskForm
from wtforms import StringField, PasswordField, SubmitField, BooleanField
from wtforms.validators import DataRequired, Email

class SignupForm(FlaskForm):
    username = StringField('Username', validators=[DataRequired()])
    email = StringField('Email', validators=[DataRequired(), Email()])
    password = PasswordField('Password', validators=[DataRequired()])
    submit = SubmitField('Sign Up')
```

Displaying Error Messages:
In our Flask view, we'll utilize Flash messages to display error messages to the user. Here's how you can achieve this:

```python
from flask import flash

flash('Error: Duplicate email address.', 'error')
```

Retaining Form Data:
To retain form data in case of validation errors, use the `request.form.get()` method in your HTML template:

```html
<input type="text" name="username" value="{{ request.form.get('username', '') }}">
```

Inserting into Database:
Once the form is validated, we'll hash the password using Werkzeug's `generate_password_hash` function and insert the user information into the database:

```python
from werkzeug.security import generate_password_hash
from your_app_name.models import User
from your_app_name import db

hashed_password = generate_password_hash(password)
new_user = User(username=username, email=email, password=hashed_password)

db.session.add(new_user)
db.session.commit()

flash('Registration successful!', 'success')
```

Conclusion:
In Day 5, we've implemented user account creation functionality using Python Flask. We covered form validation, error message display, form data retention, and database insertion. By following these steps, you can enhance the user experience and security of your Flask application. Stay tuned for more Flask tutorials in our series!

Source Code on GitHub
Click here to access or download the source code.