Hoa is a modular, extensible and structured set of PHP libraries.
Moreover, Hoa aims at being a bridge between industrial and research worlds.

Hoa\Event

This library allows to use events and listeners in PHP. This is an observer design-pattern implementation.

Learn more.

Installation

With Composer, to include this library into your dependencies, you need to require hoa/event:

$ composer require hoa/event '~2.0'

For more installation procedures, please read the Source page.

Testing

Before running the test suites, the development dependencies must be installed:

$ composer install

Then, to run all the test suites:

$ vendor/bin/hoa test:run

For more information, please read the contributor guide.

Quick usage

We propose a quick overview of how to use events and listeners.

Events

An event is:

Asynchronous when registering, because the observable may not exist yet while observers start to observe,
Anonymous when using, because the observable has no idea how many and what observers are observing,
It aims at a large diffusion of data through isolated components. Wherever is the observable, we can observe its data.

In Hoa, an event channel has the following form: hoa://Event/LibraryName/AnId:pseudo-class#anAnchor. For instance, the hoa://Event/Exception channel contains all exceptions that have been thrown. The hoa://Event/Stream/StreamName:close-before contains all streams that are about to close. Thus, the following example will observe all thrown exceptions:

Hoa\Event\Event::getEvent('hoa://Event/Exception')->attach(
    function (Hoa\Event\Bucket $bucket) {
        var_dump(
            $bucket->getSource(),
            $bucket->getData()
        );
    }
);

Because attach expects a callable and because Hoa's callable implementation is smart, we can directly attach a stream to an event, like:

Hoa\Event\Event::getEvent('hoa://Event/Exception')->attach(
    new Hoa\File\Write('Foo.log')
);

This way, all exceptions will be printed on the Foo.log file.

Listeners

Contrary to an event, a listener is:

Synchronous when registering, because the observable must exist before observers can observe,
Identified when using, because the observable knows how many observers are observing,
It aims at a close diffusion of data. The observers must have an access to the observable to observe.

The Hoa\Event\Listenable interface requires the on method to be present to register a listener to a listener ID. For instance, the following example listens the message listener ID, i.e. when a message is received by the WebSocket server, the closure is executed:

$server = new Hoa\Websocket\Server(…);
$server->on('message', function (Hoa\Event\Bucket $bucket) {
    var_dump(
        $bucket->getSource(),
        $bucket->getData()
    );
});

Documentation

The hack book of Hoa\Event contains detailed information about how to use this library and how it works.

To generate the documentation locally, execute the following commands:

$ composer require --dev hoa/devtools
$ vendor/bin/hoa devtools:documentation --open

More documentation can be found on the project's website: hoa-project.net.

Getting help

There are mainly two ways to get help:

On the #hoaproject IRC channel,
On the forum at users.hoa-project.net.

Contribution

Do you want to contribute? Thanks! A detailed contributor guide explains everything you need to know.

License

Hoa is under the New BSD License (BSD-3-Clause). Please, see LICENSE for details.

jemdev/Event