storing-metadata.md

title	weight
Storing metadata	3

You can add metadata, such as the id of the logged in user, to a stored event.

Storing metadata on all events

If you need to store metadata on all events you can leverage Laravel's native models events when using the EloquentStoredEventRepository.

You must configure the package to use your own eloquent event storage model that extends the EloquentStoredEvent model. On that model you can hook into the model lifecycle hooks.

use Spatie\EventSourcing\Models\EloquentStoredEvent;

class CustomStoredEvent extends EloquentStoredEvent
{
    public static function boot()
    {
        parent::boot();
        
        static::creating(function(CustomStoredEvent $storedEvent) {
            $storedEvent->meta_data['user_id'] = auth()->user()->id;
        });
    }
}

Storing metadata via a projector

The StoredEvent instance will be passed on to any projector method that has a variable named $storedEvent. You'll also need the StoredEventRepository that is used by the application to update the stored event. On the StoredEvent instance there is a property, meta_data, that returns an array. You can update this array to store any metadata you like.

Here's an example:

namespace App\Projectors;

use Spatie\EventSourcing\Projectors\Projector;
use Spatie\EventSourcing\Projectors\ProjectsEvents;
use Spatie\EventSourcing\Models\StoredEvent;
use Spatie\EventSourcing\Facades\Projectionist;
use App\Events\MoneyAdded;

class MetaDataProjector implements Projector
{
    use ProjectsEvents;

    /*
     * Here you can specify which event should trigger which method.
     */
    public array $handlesEvents = [
        MoneyAdded::class => 'onMoneyAdded',
    ];

    public function onMoneyAdded(StoredEvent $storedEvent, StoredEventRepository $repository)
    {
        if (! Projectionist::isReplaying()) {
            $storedEvent->meta_data['user_id'] = auth()->user()->id;

            $repository->update($storedEvent);
        }
        
        // ...
    }
}