blog.log2e.com » Uncategorized http://blog.log2e.com Tutorials and Code Snippets Tue, 25 May 2010 12:47:32 +0000 en hourly 1 http://wordpress.org/?v=3.1.2 Utilizing the Zend AMF Server Inside a Zend Controller http://blog.log2e.com/2008/12/14/utilizing-the-zend-amf-server-inside-a-zend-controller/ http://blog.log2e.com/2008/12/14/utilizing-the-zend-amf-server-inside-a-zend-controller/#comments Sun, 14 Dec 2008 00:39:02 +0000 Stefan Schmalhaus http://blog.log2e.com/?p=199 Many tutorials suggest that you set up the Zend AMF server directly in the bootstrap or index.php file. But what if you want to build a hybrid application with both Flex and HTML interfaces? In this case it’s better to let the bootstrap file do its usual job of application dispatching, and to make the AMF gateway a controller.

Introducing the Gateway Controller

Setting up a Zend AMF server inside a Zend controller is pretty easy:

<?php
  1. class GatewayController extends Zend_Controller_Action
  2. {
  3.    public function indexAction()
  4.    {
  5.       $this->getHelper('ViewRenderer')->setNoRender();      
  6.       $server = new Zend_Amf_Server();
  7.       $server->addDirectory( dirname(__FILE__) . '/../services/' );
  8.       echo($server->handle());  
  9.    }
  10. }

Since we do not want to output any visible content we disable the view renderer (otherwise the action controller will look for a view script in a subdirectory named after the controller). The endpoint URI of our AMF server gateway is now something like http://www.mydomain.com/gateway/, and doesn’t interfere with our other controllers. By calling the addDirectory() method we tell the server where to look for the services. We only need to provide a base directory here. If we set up our remote objects in Flex with full namespaces the AMF server is able to resolve the dot syntax into the appropriate path.

For example, the dot syntax in the source attribute of this remote object

<mx:RemoteObject id="articlesRO" showBusyCursor="true" source="com.xeladon.cms.ArticlesService" destination="zend"/>

will be transformed into the path com/xeladon/cms/ArticlesService. Please note that in this setup there is no need for explicitly propagating each service class to the server with the setClass() method. For more information on the different approaches (addDirectory() vs. setClass()) please refer to Wade Arnold’s blog post on Lazy Loading Classes.

Organizing Value Objects with Namespaces

Now let’s take this one step further. As a long-time AMFPHP user, I have gotten in the habit of organizing my value objects with namespaces. I usually put my VOs in a folder below the service classes:

We can still do this with Zend but we have to make sure that Zend Loader is able to find the VO classes. I suggest adding the path to the include path in the index.php file:

<?php
  1. define('APPLICATION_PATH', realpath(dirname(__FILE__) . '/../application/'));
  2.  
  3. set_include_path(
  4.    get_include_path()
  5.    . PATH_SEPARATOR . APPLICATION_PATH . '/../library/'
  6.    . PATH_SEPARATOR . APPLICATION_PATH . '/models/'
  7.    . PATH_SEPARATOR . APPLICATION_PATH . '/services/com/xeladon/cms/vo/'
  8. );
  9.  
  10. require_once "Zend/Loader.php";
  11. Zend_Loader::registerAutoload();

Adding More Functionality

Based on the above setup, we can easily add more functionaliy to the bootstrap file without worrying about the AMF server gateway. We would probably want to make use of Zend_Config for configuring the application, and Zend_Db for managing database interactions. By adding a few more lines of code to the bootstrap file, these functions become automatically available to the AMF service classes.

Let’s assume we set up a database adapter in the bootstrap file. This allows us to write very clean code inside the service classes. The following code is just an example (where ArticleVO is a typical value object, and Articles is supposed to be a Zend model class that extends Zend_Db_Table):

<?php
  1. class ArticlesService
  2. {    
  3.    public function getArticles()
  4.    {
  5.       $articles = array();
  6.       $table = new Articles();
  7.       $result = $table->fetchAll();        
  8.       foreach ($result as $row)
  9.       {
  10.          $article = new ArticleVO();
  11.          $article->id = $row->id;
  12.          $article->author = $row->author;
  13.          $article->title = $row->title;
  14.          $article->teaser = $row->teaser;
  15.          $article->body = $row->body;
  16.          array_push($articles, $article);
  17.       }    
  18.       return $articles;        
  19.    }
  20. }

Summary

What do we gain with all this?

  1. We keep things organized and can rely on the same structures (packages, folders, namespaces) in both ActionScript and PHP.
  2. We can use other powerful features of the Zend framework for the application’s server-side logic.
  3. We have the flexibility of adding Flex/Flash and HTML interfaces to the same core application whenever and whereever needed.
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