请检查我为构建一些 XML 框架而创建的以下类..

class CommandBuilder
{
    public function __construct()
    {
        //
    }

    public function login($username, $password)
    {
        $frame = $this->frame();

        $command = $frame->addChild('command');
        $login = $command->addChild('login');
        $login->addChild('username', $username);
        $login->addChild('password', $password);
        $command->addChild('authKey', 'authkey');

        return $frame->asXML();
    }

    public function info($id)
    {
        $frame = $this->frame();

        $command = $frame->addChild('command');
        $login = $command->addChild('product');
        $login->addChild('id', $id);
        $command->addChild('authKey', 'authkey');

        return $frame->asXML();
    }

    protected function frame()
    {
        return new SimpleXMLElement(
            '<app/>'
        );
    }
}

避免 $frame->addChild('command') 和 $command->addChild('authKey', 'authkey') 重复的最佳方法是什么？不改变元素的顺序？

请帮助改进代码。谢谢

最佳答案

像这样创建一个单独的构建器类怎么样:

class CommandBuilder
{
  private $commandName;

  private $params = [];

  public function __construct( $commandName ) {
    $this->commandName = $commandName;
  }

  // convenience method, to allow for cleaner fluent interface usage
  public static function create( $commandName ) {
    return new self( $commandName );
  }

  public function addParam( $paramName, $paramValue ) {
    $this->params[] = [ 'name' => $paramName, 'value' => $paramValue ];

    return $this;
  }

  public function build() {
    $app = new SimpleXMLElement( '<app/>' );
    $commandContainer = $app->addChild( 'command' );
    $command = $commandContainer->addChild( $this->commandName );
    foreach( $this->params as $param ) {
      $command->addChild( $param[ 'name' ], $param[ 'value' ] );
    }
    $commandContainer->addChild( 'authKey', 'authKey' );

    return $app->asXML();
  }  
}

然后有一个单独的类来构建特定的应用程序命令:

class AppCommands
{
  public function login( $username, $password ) {
    return CommandBuilder::create( 'login' )->addParam( 'username', $username )
                                            ->addParam( 'password', $password )
                                            ->build();
  }

  public function info( $id ) {
    return CommandBuilder::create( 'product' )->addParam( 'id', $id )
                                              ->build();
  }
}

用法保持不变，除了您实例化 AppCommands，而不是 CommandBuilder:

$ac = new AppCommands;

echo $ac->login( 'MyUsername', 'MyPassword' );
echo PHP_EOL;
echo $ac->info( 5 );

^{View this example on eval.in}

如果您愿意，您当然也可以动态地将 authKey 传递给 CommandBuilder 而不是在内部对其进行硬编码，例如:

class CommandBuilder
{
  private $commandName;

  private $authKey;

  private $params = [];

  public function __construct( $commandName, $authKey ) {
    $this->commandName = $commandName;
    $this->authKey = $authKey;
  }

  public static function create( $commandName, $authKey ) {
    return new self( $commandName, $authKey );
  }

  /* ... */

  public function build() {

    /* ... */

    $commandContainer->addChild( 'authKey', $this->authKey );

    return $app->asXML();
  }

关于php - 扩展或实现 simplexml 以避免 DRY，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/47355845/