how to match input field before save it in cakephp - cakephp

Question

when user enter the full url..i want to save only youtube id... pregmatch examine and extract video id and then it will be saved into database..the problem is how to make this pregmatch check and extract youtube id before save the full url
thanks for helping
// this is add() function in videos_controller
function add() {
if (!empty($this->data)) {
$this->Video->create();
if ($this->Video->save($this->data)) {
$this->Session->setFlash(__('The Video has been saved', true));
$this->redirect(array('action' => 'admin_index'));
} else {
$this->Session->setFlash(__('The Video could not be saved. Please, try again.', true));
}
}
$vcats = $this->Video->Vcat->find('list');
$this->set(compact('vcats'));
}
// this is add.ctp file
<div class="videos form">
<?php // echo $this->Form->create('Image');?>
<?php echo $form->create('Video'); ?>
<fieldset>
<legend><?php __('Add Video'); ?></legend>
<?php
echo $this->Form->input('vcat_id');
echo $this->Form->input('title');
$url= $this->Form->input('link');
echo $url
?>
</fieldset>
<?php echo $this->Form->end(__('Submit', true)); ?>
</div>
<div class="actions">
<h3><?php __('Actions'); ?></h3>
<ul>
<li><?php echo $this->Html->link(__('List Videos', true), array('action' => 'index')); ?></li>
<li><?php echo $this->Html->link(__('List Vcats', true), array('controller' => 'vcats', 'action' => 'index')); ?> </li>
<li><?php echo $this->Html->link(__('New Vcat', true), array('controller' => 'vcats', 'action' => 'add')); ?> </li>
</ul>
</div>
// we get the unique video id from the url by matching the pattern but where i put this code to match before save
preg_match("/v=([^&]+)/i", $url, $matches);
$id = $matches[1];

Answer 1

Here
function add() {
if (!empty($this->data)) {
$this->Video->create();
$url = $this->data['Video']['link'];
/*assuming you have a column `id` in your `videos` table
where you want to store the id,
replace this if you have different column for this*/
preg_match("/v=([^&]+)/i", $url, $matches);
$this->data['Video']['id'] = $matches[1];
//rest of the code
}
}

Answer 2

I guess a better place for it is in the Model's beforeSave or beforeValidate method:
class Video extends AppModel {
...
public function beforeSave() {
if (!empty($this->data[$this->alias]['link'])) {
if (preg_match("/v=([^&]+)/i", $this->data[$this->alias]['link'], $matches)) {
$this->data[$this->alias]['some_id_field'] = $matches[1];
}
}
return true;
}
...
}