gistfile1.php

<?php

namespace Kunstmaan\LiveReloadBundle\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
 *
 * To learn more see {@link
 * http://symfony.com/doc/current/cookbook/bundles/extension.html#cookbook-bundles-extension-config-class}
 */
class Configuration implements ConfigurationInterface
{
    /**
     * {@inheritDoc}
     */
    public function getConfigTreeBuilder()
    {
        $treeBuilder = new TreeBuilder();
        $rootNode    = $treeBuilder->root('kunstmaan_live_reload');

        $rootNode
            ->normalize()
                ->ifTrue(function ($v) { return isset($v['host']) && isset($v['port']); })
                ->then(function ($v) {
                    $url = 'http://' . $v['host'] . ':' . $v['port'] . '/livereload.js';
                    $v['server_url'] = $url;
                    $v['script_url'] = $url;
                    
                    return $v;
                })
            ->end()
            ->children()
                ->booleanNode('enabled')
                    ->defaultTrue()
                ->end()
                ->scalarNode('host')
                ->end()
                ->scalarNode('port')
                ->end()
                ->scalarNode('server_url')
                    ->defaultValue('http://localhost:35729/livereload.js')
                ->end()
                ->scalarNode('script_url')
                    ->defaultValue('http://localhost:35729/livereload.js')
                ->end()
                ->booleanNode('check_server_presence')
                    ->defaultTrue()
                ->end()
            ->end()
            ->validate()
                ->ifTrue(function($v) {
                    return array_key_exists('host', $v) || array_key_exists('port', $v)
                    && (array_key_exists('server_url', $v) || array_key_exists('script_url', $v));
                })
                ->thenInvalid('"host" and "port" cannot be used together with "script_url" or "server_url"')
            ->end()
        ;
        return $treeBuilder;
    }
}