Event Event Handling

webman/event provides an elegant event mechanism that allows you to execute some business logic without modifying the code, achieving decoupling between business modules. For example, when a new user is successfully registered, you can simply publish a custom event like user.register, and each module can receive the event and execute the corresponding business logic.

Installation

composer require webman/event

Subscribe to Events

Event subscriptions are configured through the config/event.php file.

<?php
return [
    'user.register' => [
        [app\event\User::class, 'register'],
        // ...other event handling functions...
    ],
    'user.logout' => [
        [app\event\User::class, 'logout'],
        // ...other event handling functions...
    ]
];

Note:

• user.register and user.logout are event names, which are strings. It's recommended to use lowercase words separated by dots (.).
• An event can have multiple event handling functions, which are executed in the order specified in the configuration.

Event Handling Functions

Event handling functions can be any class methods, functions, closure functions, etc.

For example, create an event handling class app/event/User.php (create the directory if it doesn't exist).

<?php
namespace app\event;
class User
{
    function register($user)
    {
        var_export($user);
    }

    function logout($user)
    {
        var_export($user);
    }
}

Publish an Event

Use Event::emit($event_name, $data); to publish an event. For example:

<?php
namespace app\controller;
use support\Request;
use Webman\Event\Event;
class User
{
    public function register(Request $request)
    {
        $user = [
            'name' => 'webman',
            'age' => 2
        ];
        Event::emit('user.register', $user);
    }
}

Note:
The $data parameter of Event::emit($event_name, $data); can be any data, such as an array, an object instance, a string, etc.

Wildcard Event Listening

You can use wildcard event subscriptions to handle multiple events on the same listener. For example, in the config/event.php file:

<?php
return [
    'user.*' => [
        [app\event\User::class, 'deal']
    ],
];

In the event handling function, you can get the specific event name through the second parameter $event_data.

<?php
namespace app\event;
class User
{
    function deal($user, $event_name)
    {
        echo $event_name; // specific event name, such as user.register, user.logout, etc.
        var_export($user);
    }
}

Stopping Event Broadcasting

When we return false in the event handling function, the event broadcasting will be stopped.

Closure Function for Event Handling

The event handling function can also be a closure function. For example:

<?php
return [
    'user.login' => [
        function($user){
            var_dump($user);
        }
    ]
];

Viewing Events and Listeners

Use the command php webman event:list to view all the events and listeners configured in the project.

Note

Event handling is not asynchronous. Events are not suitable for handling slow business logic, which should be done using message queues. For example, webman/redis-queue.