Intercepting laravel 5 model save for unique constraint check - php

Question

I have a 3 column unique restraint to check before saving an entry.
In my case an entry is unique for a product_id, a product_attribute_id, and a product_option value.
For example product 1234 Size L should only have one entry, 1234 Color Orange should only have one entry.
When I double an entry '1-7-Fuscha Baby' in my test I will correctly receive an error
Integrity constraint violation:
1062 Duplicate entry '1-7-Fuscha Baby' for key 'p_a_v'
(SQL: insert into `product_options` (`product_attribute_id`, `value`, `product_id`, `updated_at`, `created_at`)
values (1, Fuscha Baby, 7, 2016-02-15 13:06:27, 2016-02-15 13:06:27))
So now I need to bypass creating that entry
On the ProductOption model, I am overriding the save method to add the check. This is the busted part, can't figure out the correct syntax.
public function save()
{
// before save code - Check for a unique value....
//
$product_option = ProductOption::where('product_id', $this->product_id)
->where('value' ,$this->value)
->where('product_attribute_id',$this->product_attribute_id)
->first()
;
if($product_option)
{
//i have the constraint violation, now how do I tell laravel to use $product_option instead of $this?
//return $product_option; messy error 1
//return $product_option->id; messy error 2
//$this = $product_option; sytnax error
//return; I think this works with the plain old save() call, but not for saveMany()
//$this->exists = true; //works for save(), fails for saveMany()
}
parent::save();
// after save code
}
Additionally this should work with the saveMany call:
public function saveOptionsArray($product_options)
{
/*
$product_options = [
['name' => 1, 'value' =>'Pink'],
['name' => 'Color', 'value' =>'Yellow'],
['name' => 'Color', 'value' =>'Yellow'], //constraint violation
['name' => 'Size', 'value' =>'1'],
['name' => 'Size', 'value' =>'2'],
['name' => 'Size', 'value' =>'3'],
];
*/
$options = [];
foreach ($product_options as $product_option)
{
$option = new ProductOption();
$option->product_attribute_id = $product_option['name'];
$option->value = $product_option['value'];
//$option = $option->checkBeforeSave(); //same as the save() pre-check above.. didn't work out too well
$options[] = $option;
}
return $this->options()->saveMany($options);
}

Answer 1

To achieve what you are looking for and in the proper Laravel way, you should leverage model events, as such:
public static function boot()
{
static::saving(function($model)
{
//run your logic here
});
}
saving will intercept create and save operations for the model.
This code should be placed in the model. Later on you can extend and extract it to a model observer.

Answer 2

Got it, basically return false......
However, if the string is too long the code again fails, so i'll pass on my truncator as well...
public function save(array $options = [])
{
// before save code - Check for a unique value....
// before check for unique, the value will truncate causing another issue...
$product_option = ProductOption::where('product_id', $this->product_id)
->where('value' ,$this->truncateString('value'))
->where('product_attribute_id',$this->product_attribute_id)
->first()
;
if($product_option)
{
return false;
}
parent::save();
// after save code
}
And the truncator which will read the max length from the db and chop your input before the entry does causing another constraint violation
public function truncateString($column)
{
$max_length = DB::connection()->getDoctrineColumn($this->getTable(), $column)->getLength();
$this->$column = substr ( $this->$column , 0 ,$max_length );
return $this->$column;
}