README.md

OpenFeature SDK for PHP

Overview

This package provides a functional SDK for an OpenFeature API and client. It also builds on various PSRs (PHP Standards Recommendations) such as the Logger interfaces (PSR-3) and the Basic and Extended Coding Standards (PSR-1 and PSR-12).

Future development goals for the package include:

• Integrate container standards (PSR-11)
• Build on PHP HTTP Promises to support async clients

Installation

composer require open-feature/sdk

Usage

While Boolean provides the simplest introduction, we offer a variety of flag types.

use OpenFeature\OpenFeatureClient;

class MyClass 
{
  private OpenFeatureClient $client;

  public function __construct() 
  {
    $this->client = OpenFeatureAPI::getInstance()->getClient('MyClass');
  }

  public function booleanExample(): UI
  {
      // Should we render the redesign? Or the default webpage? 
      if ($this->client->getBooleanValue('redesign_enabled', false)) {
          return render_redesign();
      }
      return render_normal();
  }

  public function stringExample(): Template
  {
      // Get the template to load for the custom new homepage
      $template = $this->client->getStringValue('homepage_template', 'default-homepage.html');

      return render_template($template);
  }

  public function numberExample(): array
  {
      // How many modules should we be fetching?
      $count = $this->client->getIntegerValue('module-fetch-count', 4);

      return fetch_modules($count);
  }

  public function structureExample(): HomepageModule
  {
      $obj = $this->client->getObjectValue('hero-module', $previouslyDefinedDefaultStructure);

      return HomepageModuleBuilder::new()
              ->title($obj->getValue('title'))
              ->body($obj->getValue('description'))
              ->build();
  }
}

Configuration

To configure OpenFeature, you'll need to add a provider to the global singleton OpenFeatureAPI. From there, you can generate a Client which is usable by your code. If you do not set a provider, then the NoOpProvider, which simply returns the default passed in, will be used.

use OpenFeature\OpenFeatureAPI;
use OpenFeature\Providers\Flagd\FlagdProvider;

class MyApp 
{
    public function bootstrap() 
    {
        $api = OpenFeatureAPI::getInstance();
        $api->setProvider(new FlagdProvider());
        $client = $api->getClient();

        // Now use your `$client` instance to evaluate some feature flags!
    }
}

Providers & Hooks

The OpenFeature project maintains the open-feature/php-sdk-contrib repository, which includes contributed providers and hooks. Vendors can also implement and maintain their own providers as well. We update the PHP docs page with these vendors as often as possible.

Development

PHP Versioning

This library targets PHP version 8.0 and newer. As long as you have any compatible version of PHP on your system you should be able to utilize the OpenFeature SDK.

asdf

This package has a .tool-versions file for use with PHP version managers like asdf.

Nix

This package includes a flake.nix file which defines reproducible development shells powered by Nix. You can manually drop into a shell with nix develop, or provide a specific PHP minor version target with nix develop .#php82.

direnv

This package includes a .envrc file which automatically infers the usage of the default shell for the project, which is set to the minimum supported version of PHP.

Installation and Dependencies

Install dependencies with composer install. composer install will update the composer.lock with the most recent compatible versions.

We value having as few runtime dependencies as possible. The addition of any dependencies requires careful consideration and review.

Testing

Run tests with composer run test.