Install Flask-WTF in Python - Quick Guide

Flask-WTF is a Flask extension for handling web forms. It integrates WTForms with Flask, making form creation and validation easy. This guide will show you how to install and use Flask-WTF.

What is Flask-WTF?

Flask-WTF simplifies form handling in Flask applications. It provides CSRF protection, file uploads, and validation. It works seamlessly with WTForms.

Prerequisites

Before installing Flask-WTF, ensure you have Python and Flask installed. If not, install Flask first.

pip install Flask

Install Flask-WTF

Use pip to install Flask-WTF. Run the following command in your terminal.

pip install Flask-WTF

This will download and install Flask-WTF and its dependencies.

Verify Installation

Check if Flask-WTF is installed correctly. Run the following Python code.

 
import flask_wtf
print(flask_wtf.__version__)

If installed correctly, it will print the version number.

Basic Flask-WTF Example

Here’s a simple example to create a form using Flask-WTF.

 
from flask import Flask, render_template
from flask_wtf import FlaskForm
from wtforms import StringField, SubmitField

app = Flask(__name__)
app.config['SECRET_KEY'] = 'your-secret-key'

class MyForm(FlaskForm):
    name = StringField('Name')
    submit = SubmitField('Submit')

@app.route('/', methods=['GET', 'POST'])
def index():
    form = MyForm()
    if form.validate_on_submit():
        return f'Hello, {form.name.data}!'
    return render_template('index.html', form=form)

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

This code creates a form with a name field and a submit button.

Create a Template

Create an index.html file in a templates folder.

 
<form method="POST">
    {{ form.hidden_tag() }}
    {{ form.name.label }} {{ form.name() }}
    {{ form.submit() }}
</form>

This template renders the form fields.

Run the Application

Start the Flask application.

python app.py

Open your browser and go to http://localhost:5000 to see the form.

Form Validation

Flask-WTF provides built-in validation. Add validators to your form fields.

 
from wtforms.validators import DataRequired

class MyForm(FlaskForm):
    name = StringField('Name', validators=[DataRequired()])
    submit = SubmitField('Submit')

The DataRequired validator ensures the field is not empty.

CSRF Protection

Flask-WTF includes CSRF protection. Always include {{ form.hidden_tag() }} in your templates.

Conclusion

Flask-WTF makes form handling in Flask easy and secure. It integrates well with WTForms and provides useful features like validation and CSRF protection. For more Flask extensions, check out our guide on How to Install Flask-Migrate in Python.

If you need to handle emails in Flask, read our Install Flask-Mail in Python - Quick Guide. For timezone handling, see How to Install pytz in Python - Quick Guide.