Laravel: How to create custom model events

Address.php

<?php

// App\Address Model

namespace App;

use Illuminate\Database\Eloquent\Model;
use App\Observers\AddressObserver; // included our Model Observer

/**
 * Class Address
 * @package app
 */
class Address extends Model
{

    /**
    * Array of our custom model events declared under model property $observables
    * @var array
    */
  
    protected $observables = [
        'published',
        'unpublished',
    ];
  
  
  /**
  * Publish address & fire custom model event
  *
  */
  public function publish()
  {
    
    // logic to update Address status goes here
    
    // fire custom event on the model
    $this->fireModelEvent('published', false);
    
  }
  
  /**
  * Unpublish address & fire custom model event
  *
  */
  public function unPublish()
  {
    
    // logic to update Address status goes here
    
    // fire custom event on the model
    $this->fireModelEvent('unpublished', false);
    
  }
  
  
}
?>

AddressObserver.php

<?php

// App\Observers

namespace App\Observers;

use App\Address;  // model included to have access to data
use Illuminate\Support\Facades\Log; // Log included to log info

class AddressObserver
{

    /**
     * @param Address $address
     */

    public function published(Address $address)
    {
      
      // I am testing here by logging info into logs, you can do anything here,
      // like send emails, insert into database, or notify via sms,
      // all logic goes here
      
      Log::info('Address is published ('.$address->name.')');
      
    }

  
  /**
     * @param Address $address
     */

    public function unpublished(Address $address)
    {
      
      // logic goes here
      
    }

}

AppServiceProvider.php

<?php

// App\Providers

namespace App\Providers;

use App\Address; // model
use App\Observers\AddressObserver; // model observer
use Illuminate\Support\ServiceProvider;

class AppServiceProvider extends ServiceProvider
{
    /**
     * Bootstrap any application services.
     *
     * @return void
     */
    public function boot()
    {
      
      // https://laravel.com/docs/5.4/eloquent#observers
      // observer to group listeners into a single class,
      
      Address::observe(AddressObserver::class); 
    }

    /**
     * Register any application services.
     *
     * @return void
     */
    public function register()
    {
        //
    }
}

I'm doing the same as you but I get Method Illuminate\Database\Query\Builder::fireModelEvent does not exist.

Events are not in query builder, but the Eloquent Model thats why.

You could also use attribute events to automatically fire events on change of the status column:

class Address extends Model
{
    protected $dispatchesEvents = [
        'status:published' => AddressPublished::class,
        'status:unpublished' => AddressUnpublished::class,
    ];
}