Flaskform validation with Flask - Form failure.validate_on_submit()

Question

Good afternoon guys, all right? I created a form using the flaskform class, from flask_wtf. I can send it to the front of the application and apparently the behavior is correct. However, when I submit it to do the validation, I end up not being able to "fall" in the block of it. The behavior that I would expect in app.py, when completing and submitting the data would be to fall into regForm.validate_on_submit() and thus give a redirect to the home. However, I am "falling" under the other condition (print "we are here 2") and rendering the admin-Register template (see app.py code below). Could someone please help me? I do not find the mistake I have searched in several ways. I am using the following versions of the technologies:

Python 3.7.4 ; email-Validator==1.1.2 ; Flask==1.1.2 ; Flask-Assets==2.0 ; Flask-WTF==0.14.3 ; Wtforms==2.3.3

Return when submitting the form

app file.py

from flask import Flask,flash, jsonify, request, render_template, url_for, redirect
from flask_assets import Environment, Bundle
from authforms import RegistrationForm, LoginForm
import json, secrets
from os import environ

########   APP START   ########

#initialize the app
app = Flask(__name__)

#routes - Web
@app.route('/', methods=['GET'])
def home():
    homeTitle = 'O melhor buscador de CID'
    return render_template('index.html', title=homeTitle)

#routes - Web (Admin)
@app.route('/cadastro-admin', methods=['GET', 'POST'])
def admin_register():
    regForm = RegistrationForm(request.form)
    if regForm.validate_on_submit():
        flash(f'Conta criada para {regForm.adminName.data} :)', 'message_success')
        return redirect(url_for('home'))
    registerTitle = "Cadastro para administradores do sistema de buscas inteligentes de CID"
    print("we are here 2")
    return render_template('admin-register.html', title=registerTitle, form=regForm)

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

authforms.py file (class responsible for registration and login forms):

from flask_wtf import FlaskForm
from wtforms import Form, StringField, PasswordField, SubmitField, BooleanField, validators
from wtforms.validators import Email, Length, DataRequired, EqualTo
import email_validator

class RegistrationForm(FlaskForm):
    adminName = StringField('Nome', validators=[DataRequired(), Length(min=3, max=30)], render_kw={'placeholder': 'Nome:'})
    adminSurname = StringField('Sobrenome', validators=[DataRequired(), Length(min=3, max=30)], render_kw={'placeholder': 'Sobrenome:'})
    adminEmail = StringField('Email', validators=[DataRequired(), Email()],render_kw={'placeholder': 'E-mail:'})
    adminPass = PasswordField('Senha', validators=[DataRequired(), Length(min=6, max = 20)], render_kw={'placeholder': 'Senha:'})
    confirmPass = PasswordField('Confirme a Senha', validators=[DataRequired(), EqualTo('password')], render_kw={'placeholder': 'Confirmação da senha:'})
    submit = SubmitField('Cadastrar')

HTML file where the form is being rendered

{% extends "base.html" %} {% block content %}
<header>
  <h1>Será um administrador do sistema? Cadastre-se aqui</h1>
</header>

<article>
  <form method="POST" action="" name="admin_register_form" enctype="multipart/form-data">
    {{form.hidden_tag()}}

    {%if form.adminName.errors%}
      {{form.adminName(class="registration_form_input")}}
      <div style="display:block; border: 1px solid red">
        {%for error in form.adminName.errors%}
          <span>{{error}}</span>
        {%endfor%}
      </div>
    {%else%}
      {{form.adminName(class="registration_form_input")}}
    {%endif%}
    
    {{form.adminSurname(class="registration_form_input")}}
    {{form.adminEmail(class="registration_form_input")}}
    {{form.adminPass(class="registration_form_input")}}
    {{form.confirmPass(class="registration_form_input")}}
    {{form.submit(class="registration_form_input")}}
  </form>
  <small>Possui cadastro? <a href="{{url_for('admin_login')}}">Login</a></small>
</article>
{% endblock content %}

Answer 1

For what I could reproduce here, the problem there is that the validation is failing and you are not seeing the errors.

You used {%if form.adminName.errors%} to check errors, but only from the field adminName, that is, if there are no errors in this field but there are in some other, you will not see this return.

To get all the errors, you can use a loop in the fields by iterating on form.errors.items() and return only the errors:

{% for campo, erros in form.errors.items() %} 
 <div class="alert alert-danger" role="alert"> # aqui você pode estilizar como quiser 
   {{ form[campo].label }} : {{''.join(erros)}}</h5>
 </div>
{% endfor %}

By passing two control variables, you will have access to both the field itself and the errors.

If you prefer, you can use this as a macro:

{% macro mostra_erros(form) %}
{% for campo, erros in form.errors.items() %}
 <div class="alert alert-danger" role="alert">
   {{ form[campo].label }} : {{''.join(erros)}}</h5>
 </div>
{% endfor %}
{% endmacro %}

And in the templates, just call her at the desired place:

{{ mostra_erros(form) }}

I hope I’ve helped and good studies!