Making configuration node support both string and array in Symfony 2 configuration?

Question

Can my configuration node source support both string and array values?

Sourcing from string:

# Valid configuration 1
my_bundle:
    source: %kernel.root_dir%/../Resources/config/source.json

Sourcing from array:

# Valid configuration 2
my_bundle:
    source:
        operations: []
        commands: []

The extension class would be able to distinguish between them:

if (is_array($config['source']) {
    // Bootstrap from array
} else {
    // Bootstrap from file
}

I might use something like this:

$rootNode->children()
    ->variableNode('source')
        ->validate()
            ->ifTrue(function ($v) { return !is_string($v) && !is_array($v); })
            ->thenInvalid('Configuration value must be either string or array.')
        ->end()
    ->end()
->end();

But how ca I add constraints on the structure of source (operations, commands, etc...) to the variable node (that should only be enforced when its value is of type array)?

Answer 1

I think you can use the config normalization by refactoring your extension.

In your extension change your code to check if a path is set

if ($config['path'] !== null) {
    // Bootstrap from file.
} else {
    // Bootstrap from array.
}

And allow the user to use a string for config.

$rootNode
    ->children()
        ->arrayNode('source')
            ->beforeNormalization()
            ->ifString()
                ->then(function($value) { return array('path' => $value); })
            ->end()
            ->children()
                ->scalarNode('foo')
                // ...
            ->end()
        ->end()
    ->end()
;

Like this you can allow the user to use a string or an array which can be validate.

See the symfony documentation for normalisation

Hope it's helpful. Best regard.