Cakephp: combine input values to create hidden name input - cakephp

Question

I've searched high and low for a solution but can't seem to get this figured out. What I'm trying to do is upon adding a product, I want the name field to be populated from the inputs in the form. So the name would include the values the user selects for type_id,category_id and subcategory_id. Does anyone know of a way to accomplish this?
Add product View page
<fieldset>
<legend><?php echo __('Add Product'); ?></legend>
<?php
echo $this->Form->input('type_id');
echo $this->Form->input('category_id', array('label' => 'Vendor'));
echo $this->Form->input('subcategory_id', array('label' => 'Model'));
echo $this->Form->input('location', array('label' => 'Location'));
echo $this->Form->input('sku', array('label' => 'Asset Tag'));
echo $this->Form->input('mac');
echo $this->Form->input('description', array('label' => 'Notes'));
echo $this->Form->input('name', array( 'value' => ['type_id']['category_id'] , 'type' => 'hidden'));
//echo $this->Form->input('cost');
// echo $this->Form->input('Tag');
?>
</fieldset>
Product controller add function
public function add() {
if ($this->request->is('post')) {
$this->Product->create();
if ($this->Product->save($this->request->data)) {
$this->Session->setFlash(__('The product has been saved'));
$this->redirect(array('action' => 'index'));
} else {
$this->Session->setFlash(__('The product could not be saved. Please, try again.'));
}
}
$subcategories = $this->Product->Subcategory->find('list',array('order'=>'Subcategory.name asc'));
$categories = $this->Product->Category->find('list',array('order'=>'Category.name asc'));
$types = $this->Product->Type->find('list',array('order'=>'Type.name asc'));
$this->set(compact('subcategories', 'categories', 'types'));
}

Answer 1

In order to do it the way you are trying to do it, you would have to use client-side javascript to update the input value "on-the-fly", but that's not very safe and can easily be messed with. It would make much more sense to drop the name input altogether and just handle this in the beforeSave method of your Product model (or alternatively by defining the name value in your Controller just before saving).
public function beforeSave($options = array()) {
// Generate the name based on type and category
$this->data['Product']['name'] = $this->data['Product']['type_id'] .
$this->data['Product']['category_id'];
return true;
}
Update based on your comment.
In order to get the names, just find those names (assuming your models are associated) and define those:
public function beforeSave($options = array()) {
// Get the type name
$type = $this->Type->field('name', array(
// Set the condition for the field
'Type.id' => $this->data['Product']['type_id']
));
// Get the category name
$category = $this->Category->field('name', array(
// Set the condition for the field
'Category.id' => $this->data['Product']['category_id']
));
// Generate the name based on type and category
$this->data['Product']['name'] = $type . $category;
return true;
}