Do something before saving model to database in Laravel 5.1

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