service model example with transaction for CakePHP

articles_controller.php

<?php

class ArticlesController extends AppController {

	function add() {
		if (!empty($this->data)) {
			if ($this->Service->transaction()->saveNewArticle($this->data)) {
				$this->Session->setFlash(__('Article has been saved.', true));
				$this->redirect(array('action' => 'index'));
			} else {
				$this->Session->setFlash(__('Article was not saved. Please, try again.', true));
			}
		}
	}

}

service.php

<?php

class Service extends Overloadable2 {

	function get__($name) {
		return $this->$name = ClassRegistry::init($name);
	}

	function set__($name, &$val) {
		return $this->$name =& $val;
	}

	function saveNewArticle($data) {
		return $this->Article->add($data);
	}

	function &transaction($datasources = 'default') {
		$ts =& $this->TransactionService->setDataSources($datasources)->setService($this);
		return $ts;
	}

}

service.test.php

<?php

App::import('Model', array('Article', 'TransactionService'));

Mock::generate('Article');
Mock::generatePartial('TransactionService', null, array('begin', 'commit', 'rollback'));

class ServiceTest extends CakeTestCase {

	function startTest() {
		$this->_setupMockModel('Article', 'TransactionService');
		$this->Service = ClassRegistry::init('Service');
	}

	function endTest() {
		unset($this->Service);
		ClassRegistry::flush();
	}

	function _setupMockModel() {
		$models = func_get_args();
		foreach ($models as $model) {
			$mockClass = 'Mock' . $model;
			$Mock =& ClassRegistry::init($mockClass);
			ClassRegistry::addObject($model, $Mock);
		}
	}

	function testSuccessSaveNewArticle() {
		$data = array(
			'title' => 'test title',
			'body' => "test\nbody",
		);
		$this->Service->Article->expectOnce('add');
		$this->Service->Article->setReturnvalue('add', true);
		$this->Service->TransactionService->expectOnce('begin');
		$this->Service->TransactionService->expectOnce('commit');
		$this->Service->TransactionService->expectNever('rollback');
		$this->Service->transaction()->saveNewArticle($data);
	}

	function testFailedSaveNewArticle() {
		$data = array(
			'title' => 'test title',
			'body' => "test\nbody",
		);
		$this->Service->Article->expectOnce('add');
		$this->Service->Article->setReturnvalue('add', false);
		$this->Service->TransactionService->expectOnce('begin');
		$this->Service->TransactionService->expectNever('commit');
		$this->Service->TransactionService->expectOnce('rollback');
		$this->Service->transaction()->saveNewArticle($data);
	}

}

transaction_service.php

<?php

class TransactionService extends Overloadable2 {

	var $_ds = array('default');
	var $Service;

	function call__($method, $params = array()) {
		$this->begin();
		$result = call_user_func_array(array($this->Service, $method), $params);
		if (!$result) {
			$this->rollback();
			return $result;
		}
		$this->commit();
		return $result;
	}

	function &setDataSources($ds) {
		$this->_ds = (array)$ds;
		return $this;
	}

	function &setService(&$Service) {
		$this->Service =& $Service;
		return $this;
	}

	function begin() {
		$this->_transaction(__FUNCTION__);
	}

	function commit() {
		$this->_transaction(__FUNCTION__);
	}

	function rollback() {
		$this->_transaction(__FUNCTION__);
	}

	function _transaction($method) {
		foreach ($this->_ds as $ds) {
			ConnectionManager::getDataSource($ds)->$method($this->Service);
		}
	}

}