Suggetion: Event

[mdmunir]

I have some suggetions for event mecanism.

1. component->trigger() has extraParameters like jquery trigger.
2. Event object has result property like jquery event.

[cebe]

1. this is already supported, you can pass your own event object with configured params or even your own event class.
2. this is also supported using the Event class. the handler can modify its properties and you can check its values after event got handled.

[qiangxue]

Also, Event has a data property for you to pass along generic data.

[mdmunir]

@cebe

1. it's that i do now. I do like this.

class MyEvent extents Event
{
    public $param1;
    public $param2;
}

$event = new MyEvent();
$event->param1 = $param1;
$event->param2 = $param2;

Yii::$app->trigger('something',$event);

function hendler($event)
{
    $param1 = $event->param1;
    .....
}

But, i don't want create my own Event class. Most simple if I just do like this.

Yii::$app->trigger('something',null,[$param1,$param2]);

function hendler($event,$param1 [,$param2])
{
    .....
}

For $event->result, I have no reason for this. it's just want to know what result of previews handler.

Correct me. $event->data is assigned from $component->on(), not from $component->trigger().

[qiangxue]

@mdmunir You are right about data.

[mdmunir]

I do this for many place in my application. I wont do like this.

    public function closeOrder($id)
    {
        $order = Order::findOne($id);
        $order->status = Order::STATUS_CLOSE;
        Yii::$app->trigger('closeOrderBegin',null,[$order]);
        foreach ($order->items as $item) {
            Yii::$app->trigger('closeOrderBody',null,[$order,$item]);
        }
        Yii::$app->trigger('closeOrderEnd',null,[$order]);
        $order->save();
    }

If i must create my own Event class for each situation, it's not simple for me. Any better solution?

[qiangxue]

You can create your own Event class (only need one) which takes a set of parameters. Then in your event handler, you can access the parameters from $event.

Because this requires implicit coupling between event sender and receiver, we do not want to support it in the core.

[mdmunir]

Because this requires implicit coupling between event sender and receiver.

IMO this is not issue. Several language that i know (delphi, java, jquery) use this style. Second, old event handler implementation still can be used no matter what is triggered.

Yii::$app->trigger('closeOrderBody',null,[$order,$item]);

// this is still can be used
Yii::$app->on('closeOrderBody',function($event){
    Yii::info("event {$event-name} handled");
});

Usually, event receiver used in specific case. So, no matter if each event receiver has a different style.

use case:

$event = new MyEvent();
$event->params = [$model,$item];
Yii::$app->trigger('closeOrderBody',$event);

// ---
$closeOrderBodyHandler = function($event){
    list($model,$item) = $event->params;
    // do something
}
Yii::$app->on('closeOrderBody',$closeOrderBodyHandler);

vs

Yii::$app->trigger('closeOrderBody',null,[$model,$item]);

// ---
$closeOrderBodyHandler = function($event,$model,$item){
    // do something
}
Yii::$app->on('closeOrderBody',$closeOrderBodyHandler);

for the first way, $closeOrderBodyHandler cann't be used for other event (eg. 'closeOrderEnd'), because a different value that assigned to MyEvent::params. So no matter if $closeOrderBodyHandler declared as a second way.

pros:

• more flexible for general using.
• less code.
• no BC issue.

cros: