environment.md

EnvironmentActivator

The EnvironmentActivator will use environment variables for enable or disable a feature. In some cases your environment variable names does not match your feature names. So you can define a simple map (array) as first constructor argument.

This activator use $_ENV first to get the environment value and getenv() as fallback.

Simple example: You have a feature foo_bar but your environment variables looks like FEATURE_FOO_BAR. Your class should be something like this:

// MyClass.php
class MyClass
{
    public function doSomething()
    {
        // Define the map: feature name (as key) => environment name (as value)
        $activator = new EnvironmentActivator([
            'foo_bar' => 'FEATURE_FOO_BAR'
        ]);

        $manager = new FeatureManager($activator);

        // Will return true
        if ($manager->isActive('foo_bar')) {
            // do something
        }

        // Will return false
        if ($manager->isActive('bazz_voo')) {
            // do something
        }
    }
}

If you don't need a map because your features names are identical to your environment names, you can skip the map and set the second constructor argument to true. This force the activator for checking the environment variable - equal if you have set a map or not:

// MyClass.php
class MyClass
{
    public function doSomething()
    {
        // putenv('foo_bar=true');
        $activator = new EnvironmentActivator([], true);

        $manager = new FeatureManager($activator);

        // Will return true
        if ($manager->isActive('foo_bar')) {
            // do something
        }

        // Will return false
        if ($manager->isActive('bazz_voo')) {
            // do something
        }
    }
}

Of course, you can set both arguments. In this case, the activator will use the map and, if there is no entry, query the environment variables directly:

// MyClass.php
class MyClass
{
    public function doSomething()
    {
        // putenv('feature_abc=true');
        $activator = new EnvironmentActivator([
            'foo_bar' => 'FEATURE_FOO_BAR'
        ], true);

        $manager = new FeatureManager($activator);

        // Will return true
        if ($manager->isActive('foo_bar')) {
            // do something
        }

        // Will return true also
        if ($manager->isActive('feature_abc')) {
            // do something
        }
        
        // Will return false
        if ($manager->isActive('feature_def')) {
            // do something
        }
    }
}