This Flask app shows a form with name, email, and age fields. It uses validation rules to check the inputs. If the data is correct, it shows a success message. If not, it shows errors next to each field.
from flask import Flask, render_template_string, request
from flask_wtf import FlaskForm
from wtforms import StringField, IntegerField
from wtforms.validators import DataRequired, Email, NumberRange
app = Flask(__name__)
app.config['SECRET_KEY'] = 'secret-key'
class UserForm(FlaskForm):
name = StringField('Name', validators=[DataRequired()])
email = StringField('Email', validators=[DataRequired(), Email()])
age = IntegerField('Age', validators=[DataRequired(), NumberRange(min=18, max=99)])
form_template = '''
<form method="POST">
{{ form.hidden_tag() }}
<p>
{{ form.name.label }}<br>
{{ form.name(size=20) }}<br>
{% for error in form.name.errors %}<span style="color:red;">{{ error }}</span><br>{% endfor %}
</p>
<p>
{{ form.email.label }}<br>
{{ form.email(size=20) }}<br>
{% for error in form.email.errors %}<span style="color:red;">{{ error }}</span><br>{% endfor %}
</p>
<p>
{{ form.age.label }}<br>
{{ form.age() }}<br>
{% for error in form.age.errors %}<span style="color:red;">{{ error }}</span><br>{% endfor %}
</p>
<p><input type="submit" value="Submit"></p>
</form>
{% if success %}<p style="color:green;">Form submitted successfully!</p>{% endif %}
'''
@app.route('/', methods=['GET', 'POST'])
def index():
form = UserForm()
success = False
if form.validate_on_submit():
success = True
return render_template_string(form_template, form=form, success=success)
if __name__ == '__main__':
app.run(debug=True)
