byjg / featureflag

6.0.0 2025-11-26 03:10 UTC

Requires

• php: >=8.3 <8.6
• psr/container: ^1.0|^2.0|^3.0

Requires (Dev)

• phpunit/phpunit: ^10.5|^11.5
• vimeo/psalm: ^5.9|^6.13

Unknown License

Published on Packagist.org on 2025-11-26 03:14 UTC

README

sidebar_key	featureflag
tags	php

FeatureFlag Dispatcher

A simple feature flag dispatcher that allows conditional code execution based on enabled feature flags.

Feature flags are a powerful technique for managing features in your application, enabling you to toggle functionality on/off without deploying new code. This library provides a clean, interface-based approach to dispatch handlers based on feature flag states.

Basic Usage

use ByJG\FeatureFlag\FeatureFlags;
use ByJG\FeatureFlag\FeatureFlagDispatcher;
use ByJG\FeatureFlag\FeatureFlagSelector;
use ByJG\FeatureFlag\FeatureFlagHandlerInterface;

// Initialize the enabled features
FeatureFlags::addFlag('flag1', 'value1');
FeatureFlags::addFlag('flag2', 'value2');
FeatureFlags::addFlag('flag3');

// Create handler implementations
class MyHandler implements FeatureFlagHandlerInterface
{
    public function execute(mixed ...$args): mixed
    {
        echo "Handler executed!\n";
        return null;
    }
}

// Create a Dispatcher
$dispatcher = new FeatureFlagDispatcher();

// Add feature flag handlers
$dispatcher->add(FeatureFlagSelector::whenFlagIs('flag2', 'value1', new MyHandler()));
$dispatcher->add(FeatureFlagSelector::whenFlagIs('flag2', 'value2', new MyHandler()));

// Dispatch the request
$dispatcher->dispatch();

// Since there is a feature flag 'flag2' with value 'value2', the corresponding handler will be executed

:::note If one or more feature flags match the condition, all matching handlers will be executed in the order they were added. :::

Managing the Flags

FeatureFlags keeps the enabled flags in a static list shared by every dispatcher:

use ByJG\FeatureFlag\FeatureFlags;

FeatureFlags::addFlag('flag1', 'value1');              // a flag with a value
FeatureFlags::addFlag('flag3');                        // a flag with no value (null): only whenFlagIsSet() matches it
FeatureFlags::addFromContainer('flag4', $container);   // added only if the PSR-11 container has 'flag4'

FeatureFlags::hasFlag('flag1');   // true
FeatureFlags::getFlag('flag1');   // 'value1'; throws InvalidArgumentException if the flag was not added
FeatureFlags::getFlags();         // ['flag1' => 'value1', 'flag3' => null, ...]
FeatureFlags::clearFlags();       // remove every flag

Handler Types

• Handler Interface - Create custom handlers implementing FeatureFlagHandlerInterface
• Attributes - Use PHP 8 attributes to mark methods as handlers

Selector Types

• FeatureFlagSelector - Single condition selectors
• FeatureFlagSelectorSet - Multiple condition selectors (ALL must match)

Advanced Usage

• Search Order - Control the order of handler execution
• Passing Arguments - Pass runtime arguments to handlers

Installation

composer require "byjg/featureflag"

Requirements

• PHP 8.3 to 8.6
• PSR-11 Container (optional, for container integration)

Running Tests

composer test

Open source ByJG