PHP Object Config XML - php

Question

I'm using a single XML file to store configuration settings for multiple objects. For example:
<config>
<database>
<user>myuser</user>
</database>
<application>
<component1>mycomponent</component1>
</application>
<infrastructure>
<hostname1>server1</hostname1>
</infrastructure>
</config>
I want each of my objects to access different aspects of the xml; for instance the "database" class would access the database element.
What method could be used to quickly access this configuration across my objects without reproducing code?

Answer 1

You could create a Config object which reads the configuration from the XML file, then use a Configurable trait on the classes you want to be "automatically" configurable from the XML (see example below).
config.xml:
<config>
<database>
<user>myuser</user>
</database>
<application>
<component1>mycomponent</component1>
</application>
<infrastructure>
<hostname1>server1</hostname1>
</infrastructure>
</config>
PHP code:
class Config
{
/**
* Full XML configuration
*
* #var SimpleXMLElement
*/
private static $xml;
/**
* Parse XML configuration file into XML object (once)
*/
public function __construct()
{
if (!self::$xml) {
$xmlSource = file_get_contents('config.xml');
self::$xml = new SimpleXMLElement($xmlSource);
}
}
/**
* Returns the first node matching the specified xpath
*
* #param $xpath
*
* #return SimpleXMLElement
*/
public function getFirstByXpath($xpath)
{
// Return the first matching configuration
return self::$xml->xpath($xpath)[0];
}
}
trait Configurable
{
/**
* Class configuration XML element
*
* #var SimpleXMLElement
*/
private $configuration;
/**
* Get the class configuration XML element
*
* #return SimpleXMLElement
*/
function getConfiguration()
{
if (!$this->configuration) {
$tag = strtolower(get_class($this));
$xpath = '/config/' . $tag;
$this->configuration = (new Config())->getFirstByXpath($xpath);
}
return $this->configuration;
}
}
class application
{
use configurable;
}
class database
{
use configurable;
}
$app = new application();
echo "App component 1: ", $app->getConfiguration()->component1, PHP_EOL;
$db = new database();
echo "DB user: ", $db->getConfiguration()->user, PHP_EOL;
Output:
App component 1: mycomponent
DB user: myuser