Formulář Flask

views.py

@blueprint.route('/formularhodnota', methods=['GET', 'POST'])
def formularhodnotanew():
    form = FormularHodnota()
    if form.validate_on_submit():
        return form.hodnota1.data + form.hodnota2.data
    return render_template("public/formularhodnota.tmpl", form=form)

forms.py – validace

class FormularHodnota(Form):
    hodnota1 = TextField('Hodnota1', validators=[
        Predicate(safe_characters, message="Please use only letters (a-z) and numbers"),
        Length(min=3, max=20, message="Please use between 3 and 30 characters"),
        InputRequired(message="You can't leave this empty")
    ])
    hodnota2 = TextField('Hodnota2', validators=[
        Predicate(safe_characters, message="Please use only letters (a-z) and numbers"),
        Length(min=3, max=30, message="Please use between 3 and 30 characters"),
        InputRequired(message="You can't leave this empty")
    ])

template

{% from "macros/fields.tmpl" import render_input_field, render_password_field,
                                    render_submit %}
{% extends "shared/layout.tmpl" %}

{% block title %}Hodnota{% endblock %}

{% block content %}
  <h3>hodnota</h3>
  <form method="POST" id="register-form">
    {{ form.hidden_tag() }}
    {{ render_input_field(form.hodnota1) }}
    {{ render_input_field(form.hodnota2) }}
    {{ render_submit() }}
  </form>
{% endblock %}