Do something before saving model to database in Laravel 5.1 - laravel

Question

How can I do something such as modify some data fields or more validate before writing data to database in Laravel 5.1 model ?
It's document about that problem is hard to use in real application: http://laravel.com/docs/5.1/eloquent#events
My code is
<?php
namespace App;
use Illuminate\Database\Eloquent\Model;
use App\Helpers\Tools as Tools;
class Atoken extends Model
{
/**
* The database table used by the model.
*
* #var string
*/
protected $table = 'atoken';
/**
* The attributes that are mass assignable.
*
* #var array
*/
protected $fillable = [
'token',
'user_id',
'role',
];
/**
* The attributes excluded from the model's JSON form.
*
* #var array
*/
protected $hidden = [
];
public static function newToken($userId, $role){
# Remove all token assoiciate with input user;
Atoken::where('user_id', $userId)->delete();
$params = [
'user_id' => $userId,
'role' => $role,
];
Atoken::insert($params);
$item = Atoken::where('user_id', $userId)->first();
return $item->token;
}
protected static function boot(){
static::creating(function ($model) {
$model->token = 'sometoken';
});
}
}
In this case, I always got error:
SQLSTATE[23502]: Not null violation: 7 ERROR: null value in column \"token\" violates not-null constraint (SQL: insert into \"atoken\" (\"user_id\", \"role\") values (2, USER))
How can I fix it?

Answer 1

class Lunch extends Eloquent
{
protected static function boot()
{
static::creating(function ($model) {
$model->topping = 'Butter';
return $model->validate();
});
}
protected function validate()
{
// Obviously do real validation here :)
return rand(0, 1) ? true : false;
}
public static function newToken($userId, $role)
{
static::where('user_id', $userId)->delete();
return static::create([
'user_id' => $userId,
'role' => $role,
])->token;
}
}

Answer 2

I would recommend to go into EventServiceProvider, and register event listeners
public function boot(DispatcherContract $events)
{
parent::boot($events);
// Register Event Listeners
\App\Product::updating(function ($product) {
$product->onUpdating();
});
...
then create function onUpdating within the model. You also can choose from saving, saved, creating, created, updating, updated..
This documentation has more:
https://laravel.com/docs/5.1/eloquent#events