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Friday, November 5, 2010

A simple tutorial about creating Zend_Rest_Server based RESTful service.

It seems that RESTful WS is attracting more people to consider as RPC solution. Compared with SOAP based Web Service, RESTful has its advantage and disadvantage. RESTful WS is declared to be more scalability as it exactly maps HTTP methods  POST, GET, PUT, DELETE as a CRUD (Create, Request, Update, Delete) operations. So, if we design our RESTful WS as stateless, it could be more scalable in a cluster farm. It can get benefit from Cache mechanism of HTTP (limited to HTTP GET method configuration on proxy server in most time). However, it could be problem or ask for cost if we do not want the result to be cached. Furthermore, we can not always assume client Web browser has cache enabled. So, RESTful is not always right choice. Especially, it is not good choice when we develop an enterprise application which ask for complex data structure delivered between sub systems and it does not have extremely large volume of the concurrent accessing.

I will compose another post to describe my comparison about SOAP WS and RESTful WS and JSON-RPC. Here, I will show a simple demo about how to create Zend_Rest_Server based RESTful WS in Zend Studio. Zend_Rest_Server is not perfect. For instances, it can not work together with Zend_Action_Router_Route. It also asked for calling function by put "method=functionName" in requesting URL after the "?". This make some guys think it is not RESTful WS as some person said it is not good design. But, I think it is not wrong design at least.  Below is source for simple ZF based RESTful WS.
  1. Create a new ZF project in Zend Studio and name it as jiaRESTfulWS.
  2. Add autoloaderNamespaces[] = "Jia_" in application.ini to allow Zend Autoloader load Jia_* classes.
  3. Creating a action class DummyController under directory /application/controllers. 
  4. creating a function restAction() in DummyController .
  5. Creating a Jia_Hello class with sayHello($name) function under /library/Jia directory.
It is done. You need to pay attention on how to specify web service URI in the code if you use different project name and function names. Or, you might want to add alias in your apache httpd configuration file to simplify the URL. On my machine, this demo RESTful WS can be accessed with following URL: http://localhost/jiaRESTfulWS/public/index.php/Dummy/rest?method=sayHello&name=jia . See key source code as below,

Jia_Hello class
/**
 * This class contains function which will be used by Web service caller.
 * All business logics will be implented or called in these functions.
 * 
 * @author Yiyu Jia
 *
 */
class Jia_Hello {

 /**
  * 
  * @param string $name
  * @return string
  * 
  */
 public function sayHello($name){
  return "hello ".$name;
 }
}


DummyController class
/**
 * This class includes one function restAction(), wich has Zend_Rest_Server initialized.
 * However, you can only use URI with "?" like this "/rest?method=sayHello&name=jia". You 
 * can not have URI like "/rest/name/jia"
 * 
 * @author yiyu
 *
 */
class DummyController extends Zend_Controller_Action
{
 /**
  *  action named as rest.
  */
 public function restAction() {
  
  // disable layouts and renderers
  $this->getHelper ( 'viewRenderer' )->setNoRender ( true );
  
  // initialize REST server
  $server = new Zend_Rest_Server();
  // set REST service class
  $server->setClass ( 'Jia_Hello' ); 
    
  // handle request
  $server->handle ();
 
 }
 
}

Zend Studio 7.2 project file can be downloaded here. Also, I do not recommend to use Zend_Rest_Server for developing RESTful WS as I think it is old and uncompleted class. Zend_Rest_Route should be a better choice to make RESTful Web Service in PHP. Here is a simple tutorial about how to use Zend_Rest_Route and Zend_Rest_Controller to create RESTful Web Service. Creating RESTful service with Zend_Rest_Route and Zend_Rest_Controller

3 comments:

  1. Thanks for the post.

    ReplyDelete
  2. how to test the web service??? it seems to work without errors on compilation but have no idea how to consume it.... thanks

    ReplyDelete
  3. When you say it works without errors, you consumed it already. You can use any computer language to write HTTP client to consume the RESTful Web service.

    ReplyDelete