# Observers

Observers maybe used for creating and clearing cache purposes

## Example observer use

Create you own class with observer:

```php
<?php namespace Dimti\Mirsporta\Classes\Observers;

use Dimti\Mirsporta\Models;
use Wpstudio\Helpers\Classes\Observer\BaseObserver;

class TagObserver extends BaseObserver
{
    public static function getClass(): string
    {
        return Models\Tag::class;
    }
}
```

Use in models:

```php
<?php namespace Dimti\Mirsporta\Models;

use Dimti\Mirsporta\Classes\Observers;

class Tag extends Model
{
    //...

    public function afterSave()
    {
        Observers\TagObserver::clearCache();
    }
    
    //...
}
```

And in your code for caching data based on this model/observer:

```php
use Dimti\Mirsporta\Classes\Observers;
//...

$cacheTags = Observers\TagObserver::getCacheTag();

$cacheKey = CacheManager::formatCacheKey([__CLASS__, __METHOD__, $siteId]);

\Cache::tags($cacheTags)->rememberForever($cacheKey, fn() =>
     Models\Tag::all()
));
```

* CacheManager::formatCacheKey - that is simple helper for concatenate array elements to string

## Clearing cache from admin dashboard widget

### Template

```html
<input
    type="button"
    class='btn btn-primary'
    value="Clear tag model cache"
    data-request="<?= $this->getEventHandler('onClearTagCache') ?>"
    data-request-success="$.oc.flashMsg({text: 'Cache of tag model is clearing', 'class': 'success', 'interval': 5}); return false;"
/>
```

### Controller widget action

```php
use Dimti\Mirsporta\Classes\Observers;

//...

public function onClearTagCache()
{
    Observers\TagObserver::clearCache();

    return ['status' => 1];
}

//...
```