README

A lightweight PHP event manager library that provides a simple yet powerful pattern for event-driven development. Create objects that emit events and register listeners to handle them with support for priorities, namespaces, and wildcard matching.

Features

• Priority-based event handling - Control execution order with built-in priority levels
• Namespace support with wildcards - Listen to item.*, *.save, or *.* patterns
• Multiple callback types - Closures, functions, static methods, and object methods
• Event propagation control - Stop event chains with ExceptionStop
• One-time listeners - Auto-removing listeners with once()
• Reference parameter passing - Communicate between listeners
• High performance - Optimized for speed with comprehensive benchmarks
• PHP 8.2+ with strict types - Modern PHP with full type safety

Installation

composer require jbzoo/event

Usage

Quick Start

use JBZoo\Event\EventManager;

$eManager = new EventManager();

// Simple
$eManager->on('create', function () {
    echo "Something action";
});

// Just do it!
$eManager->trigger('create');

Priority-Based Execution

By supplying a priority, you are ensured that subscribers handle in a specific order. The default priority is EventManager::MID. Anything below that will be triggered earlier, anything higher later. If there are two subscribers with the same priority, they will execute in an undefined, but deterministic order.

// Run it first
$eManager->on('create', function () {
    echo "Something high priority action";
}, EventManager::HIGH);

// Run it latest
$eManager->on('create', function () {
    echo "Something another action";
}, EventManager::LOW);

// Custom index
$eManager->on('create', function () {
    echo "Something action";
}, 42);

// Don't care...
$eManager->on('create', function () {
    echo "Something action";
});

Callback Types

All standard PHP callable types are supported:

$eManager->on('create', function(){ /* ... */ }); // Custom function
$eManager->on('create', 'myFunction');            // Custom function name
$eManager->on('create', ['myClass', 'myMethod']); // Static function
$eManager->on('create', [$object, 'Method']);     // Method of instance

Event Propagation Control

use JBZoo\Event\ExceptionStop;

$eManager->on('create', function () {
    throw new ExceptionStop('Some reason'); // Special exception for JBZoo/Event
});

$eManager->trigger('create'); // Returns count of executed listeners

Passing Arguments

Event data can be passed to listeners as function arguments:

$eManager->on('create', function ($entityId) {
    echo "An entity with id ", $entityId, " just got created.\n";
});
$entityId = 5;
$eManager->trigger('create', [$entityId]);

Because you cannot really do anything with the return value of a listener, you can pass arguments by reference to communicate between listeners and back to the emitter.

$eManager->on('create', function ($entityId, &$warnings) {
    echo "An entity with id ", $entityId, " just got created.\n";
    $warnings[] = "Something bad may or may not have happened.\n";
});
$warnings = [];
$eManager->trigger('create', [$entityId, &$warnings]);

Namespace Wildcards

Use wildcards to listen to multiple related events:

$eManager->on('item.*', function () {
    // item.init
    // item.save
    echo "Any actions with item";
});

$eManager->on('*.init', function () {
    // tag.init
    // item.init
    echo "Init any entity";
});

$eManager->on('*.save', function () {
    // tag.save
    // item.save
    echo "Saving any entity in system";
});

$eManager->on('*.save.after', function () {
    // tag.save.after
    // item.save.after
    echo "Any entity on after save";
});

$eManager->trigger('tag.init');
$eManager->trigger('tag.save.before');
$eManager->trigger('tag.save');
$eManager->trigger('tag.save.after');

$eManager->trigger('item.init');
$eManager->trigger('item.save.before');
$eManager->trigger('item.save');
$eManager->trigger('item.save.after');

One-Time Listeners

For events that should only be handled once:

$eManager->once('app.init', function () {
    echo "This will only run once, then auto-remove itself";
});

$eManager->trigger('app.init'); // Executes
$eManager->trigger('app.init'); // Does nothing - listener was removed

Advanced Usage

use JBZoo\Event\EventManager;

// Create a global event manager
EventManager::setDefault(new EventManager());
$globalManager = EventManager::getDefault();

// Get summary of registered events
$summary = $eManager->getSummeryInfo();
// Returns: ['user.create' => 3, 'user.update' => 1, ...]

// Remove specific listeners
$callback = function() { echo "test"; };
$eManager->on('test', $callback);
$eManager->removeListener('test', $callback);

// Remove all listeners for an event
$eManager->removeListeners('test');

// Remove ALL listeners
$eManager->removeListeners();

Performance Benchmarks

Extensive performance testing with 100,000 iterations shows excellent performance characteristics. Benchmark tests use phpbench/phpbench - see detailed results in tests/phpbench.

Note: 1μs = 1/1,000,000 of a second - these are microseconds!

benchmark: ManyCallbacks

benchmark: ManyCallbacksWithPriority

benchmark: OneCallback

benchmark: Random

Development

Setup

make update  # Install dependencies

Testing

make test      # Run PHPUnit tests
make test-all  # Run tests + code style checks
make codestyle # Run all linters

License

MIT