Sending form errors back to view via redirect - cakephp

Question

I recently started picking up on CakePHP and now I'm trying to build a contact form for my site.
It seems to work in validating the forms, but there's something I want to do now.
I want it to show any errors that occur (like missing a required field).
However, I want it to show 2 different possible states:
- A user error (user forgot a field or the field doesn't meet the requirements), show this below the field (using Bootstrap 4)
- A server error (mail couldn't send from the server - for example, the SMTP server is down), shown using the Flash
I've been searching far and wide for this, but I couldn't get any further on this without posting a question myself.
Below is all the code that I'm using (running CakePHP 3.6)
src/Template/Pages/contact.ctp (controlled by the PagesController):
<div class="container">
<div class="row no-banner">
<div class="col-md-6">
<h4>Contact Form</h4>
<div style="padding-bottom:25px;">
Got a question? we'd love to hear it from you!<br />
Send us a message and we'll respond as soon as possible!
</div>
<?= $this->Flash->render(); ?>
<?= $this->Form->create("Contact",array("url"=>"/contact","class"=>"contact-form","id"=>"contact-form")); ?>
<?= $this->Form->control("name",array("placeholder"=>"Your Name","label"=>false,"class"=>"form-control")); ?>
<?= $this->Form->control("email",array("placeholder"=>"Your Email","label"=>false,"class"=>"form-control")); ?>
<?= $this->Form->control("subject",array("placeholder"=>"The Subject","label"=>false,"class"=>"form-control")); ?>
<?= $this->Form->textarea("message",array("placeholder"=>"Your Message","label"=>false,"class"=>"form-control")); ?>
<?= $this->Form->button('Submit',array("class"=>"btn")); ?>
<?= $this->Form->end(); ?>
</div>
<div class="col-md-6">
<h4>Social Media</h4>
<div style="padding-bottom:25px;">
We are active on a variety of of social media, feel free to like and follow us!
</div>
<i class="fab fa-facebook social-media-icon"></i>
<i class="fab fa-discord social-media-icon"></i>
<?= $this->Form->errors; ?>
</div>
</div>
</div>
src/Controller/ContactController.php:
<?php
namespace App\Controller;
use App\Controller\AppController;
use App\Form\ContactForm;
class ContactController extends AppController {
public function add() {
$contact = new ContactForm();
if ($this->request->is('post')) {
if ($contact->execute($this->request->getData())) {
$this->Flash->success('We will get back to you asap!');
$this->redirect($this->referer());
} else {
$this->Flash->error('There was an issue sending your mail. Please try again later!');
$this->redirect($this->referer());
}
}
$this->set('contact', $contact);
}
}
src/Form/ContactForm.php:
<?php
namespace App\Controller;
use App\Controller\AppController;
use App\Form\ContactForm;
class ContactController extends AppController {
public function add() {
$contact = new ContactForm();
if ($this->request->is('post')) {
if ($contact->execute($this->request->getData())) {
$this->Flash->success('We will get back to you asap!');
$this->redirect(array('controller' => 'Pages','action' => 'display','contact'));
} else {
$this->Flash->error('There was an issue sending your mail. Please try again later!');
$this->redirect($this->referer());
}
}
$this->set('contact', $contact);
}
}

Answer 1

Don't redirect, because you don't need to. Instead of using the Pages controller to display the form put the form in your controllers view: /Contacts/add.ctp. No need to call redirect() then.
The errors are already added to the form and the form helper will find them because you're passing the form object to Form->create().
If you want to make it more complicated than needed stick to your implementation and simply write the errors to the session and in the action that receives it read them from the session and set them to the form object via setErrors().