Symfony2 Extension Configuration function to remap config tree builder to parameters

1. remapConfigsToParameters.php

<?php

    /**
     * Remaps Configurations to Parameters
     *
     * @param array $configs The array of configurations
     * @param ContainerBuilder $container The container builder
     * @param string $prefix A prefix to apply to all parameters
     * @param array $ignore An array of parameter namespaces to ignore
     * @param array $isArray An array of parameter namespaces which should be arrays
     */
    protected function remapConfigsToParameters(
        array $configs,
        ContainerBuilder $container,
        $prefix = '',
        array $ignore = array(),
        array $isArray = array()
    ) {
        foreach ($configs as $key => $config) {
            if (!is_integer($key) and !in_array($prefix, $isArray)) {
                $parameterKey = $prefix . '.' . strtolower($key);
                if (!in_array($parameterKey, $ignore)) {
                    if (is_array($config)) {
                        $this->remapConfigsToParameters(
                            $config,
                            $container,
                            $parameterKey,
                            $ignore,
                            $isArray
                        );
                    } else {
                        $container->setParameter($parameterKey, $config);
                    }
                }
                unset($configs[$key]);
            }
        }
        if (!empty($configs) or in_array($prefix, $isArray)) {
            $container->setParameter($prefix, $configs);
        }
    }

2. AcmeDemoExtension.php

<?php

namespace Acme\DemoBundle\DependencyInjection;

use Symfony\Component\DependencyInjection\ContainerBuilder;
use Symfony\Component\Config\FileLocator;
use Symfony\Component\HttpKernel\DependencyInjection\Extension;
use Symfony\Component\DependencyInjection\Loader;

/**
 * This is the class that loads and manages your bundle configuration
 */
class AcmeDemoExtension extends Extension
{
    /**
     * {@inheritDoc}
     */
    public function load(array $configs, ContainerBuilder $container)
    {
        $configuration = new Configuration();
        $config = $this->processConfiguration($configuration, $configs);

        $loader = new Loader\XmlFileLoader(
            $container,
            new FileLocator(__DIR__.'/../Resources/config')
        );
        $loader->load('services.xml');
        
        $prefix = 'acme_demo';
        
        $this->remapConfigsToParameters(
            $config,
            $container,
            $prefix,
            array(
                // Array of ignored parameters, which will not be created and set
                $prefix.'.members.enabled', // acme_demo.members.enabled
                $prefix.'.group_one.form.name' // acme_demo.group_one.form.name
            ),
            array(
                /* Array of parameters which will be arrays, prevents further namespaces being 
                 * created for each child element.
                 */
                 $prefix.'.group_one.form.tags' // acme_demo.group_one.form.tags
            )
        );
    }

    /**
     * remapConfigsToParameters
     *
     * @param array $configs
     * @param ContainerBuilder $container
     * @param string $prefix
     * @param array $ignore
     * @param array $isArray
     * @return array
     */
    protected function remapConfigsToParameters(
        array $configs,
        ContainerBuilder $container,
        $prefix = '',
        array $ignore = array(),
        array $isArray = array()
    )
    {
        foreach ($configs as $key => $config) {
            if (!is_integer($key) and !in_array($prefix, $isArray)) {
                $parameterKey = $prefix . '.' . strtolower($key);
                if (!in_array($parameterKey, $ignore)) {
                    if (is_array($config)) {
                        $this->remapConfigsToParameters($config,
                        $container,
                        $parameterKey,
                        $ignore,
                        $isArray
                    );
                    } else {
                        $container->setParameter($parameterKey, $config);
                    }
                }
                unset($configs[$key]);
            }
        }
        if (!empty($configs) or in_array($prefix, $isArray)) {
            $container->setParameter($prefix, $configs);
        }
    }
}

3. Configuration.php

<?php

namespace Acme\DemoBundle\DependencyInjection;

use Symfony\Component\Config\Definition\Builder\TreeBuilder;
use Symfony\Component\Config\Definition\ConfigurationInterface;

/**
 * This is the class that validates and merges configuration from your app/config files
 */
class Configuration implements ConfigurationInterface
{
    /**
     * {@inheritDoc}
     */
    public function getConfigTreeBuilder()
    {
        $treeBuilder = new TreeBuilder();
        $rootNode = $treeBuilder->root('acme_demo');

        $rootNode
            ->children()
                ->arrayNode('members')
                    ->addDefaultsIfNotSet()
                    ->canBeUnset()
                    ->children()
                        ->scalarNode('total')->defaultValue(0)->end()
                        ->booleanNode('enabled')->defaultFalse()->end()
                    ->end()
                ->end()
                ->arrayNode('group_one')
                    ->addDefaultsIfNotSet()
                    ->canBeUnset()
                    ->children()
                        ->arrayNode('form')
                            ->addDefaultsIfNotSet()
                            ->children()
                                ->scalarNode('type')->defaultValue('group_one_form_type_class')
                                ->end()
                                ->scalarNode('handler')->defaultValue('group_one_form_handler_class')
                                ->end()
                                ->scalarNode('name')->defaultValue('group_one_form_name')
                                ->end()
                                ->arrayNode('validation_groups')
                                    ->prototype('scalar')->end()
                                    ->defaultValue(array('ValidationA', 'ValidationB'))
                                ->end()
                                ->arrayNode('tags')
                                    ->prototype('scalar')->end()
                                    ->defaultValue(array(
                                        'tag1' => 'tag1 value',
                                        'tag2' => 'tag2 value'
                                    ))
                                ->end()
                            ->end()
                        ->end()
                    ->end()
                ->end()
            ->end();

        return $treeBuilder;
    }
}

4. Created Parameters.php

<?php

/* Below is a list of parameters created, by running the Configuration 
 * through the remapConfigsToParameters function.
 */

acme_demo.members.total                     = 0;
acme_demo.group_one.form.type               = 'group_one_form_type_class';
acme_demo.group_one.form.handler            = 'group_one_form_handler_class';
acme_demo.group_one.form.validation_groups  = array(
                                                  'ValidationA',
                                                  'ValidationB'
                                              );
acme_demo.group_one.form.tags               = array(
                                                  'tag1' => 'tag1 value',
                                                  'tag2' => 'tag2 value'
                                              );

/* Note -> acme_demo.group_one.form.tags is an array, because this
 * namespace was listed in the isArray setting
 * If we would leave this out, then we would have seperate namespaces for each tag
 */



// Please note that two parameters were not set because they were in the ignored array.
// They would have been as follows
acme_demo.members.enabled                   = false;
acme_demo.group_one.form.name               = 'group_one_form_name';
                                            

5. Debug Version.php

<?php

/**
 * This version of the function returns a debug array, showing all namespaces
 * that were created, and their values 
 */


/**
 * remapConfigsToParameters
 *
 * @param array $configs
 * @param ContainerBuilder $container
 * @param string $prefix
 * @param array $ignore
 * @param array $isArray
 * @param array $debug
 * @return array
 */
protected function remapConfigsToParameters(
    array $configs,
    ContainerBuilder $container,
    $prefix = '',
    array $ignore = array(),
    array $isArray = array(),
    array $debug = array()
)
{
    foreach ($configs as $key => $config) {
        if (!is_integer($key) and !in_array($prefix, $isArray)) {
            $parameterKey = $prefix . '.' . strtolower($key);
            if (!in_array($parameterKey, $ignore)) {
                if (is_array($config)) {
                    $debug = array_merge($debug, $this->remapConfigsToParameters(
                                $config,
                                $container,
                                $parameterKey,
                                $ignore,
                                $isArray,
                                $debug
                            )
                        );
                } else {
                    $debug[$parameterKey] = $config;
                    $container->setParameter($parameterKey, $config);
                }
            }
            unset($configs[$key]);
        }
    }
    if (!empty($configs) or in_array($prefix, $isArray)) {
        $debug[$prefix] = $configs;
        $container->setParameter($prefix, $configs);
    }
    return $debug;
}