Zend Framework动作助手(Zend_Controller_Action_Helper)用法详解

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本文实例讲述了Zend Framework动作助手(Zend_Controller_Action_Helper)用法分享给大家供大家参考,具体如下:

通过助手模式,可以把一些经常使用的功能模块做封装,从而在可以在需要的地方灵活使用,主要是在action使用。

Zend Framework中有两种助手,动作助手(Zend_Controller_Action_Helper)和试图助手(Zend_View_Helper)。

动作助手可以向任何Zend_Controller_Action的衍生动作控制器中,即时的加入功能(runtime and/or on-demand functionality),以使得增加公共的动作控制器功能时,尽量减少衍生动作控制器类的必要。

动作助手在需要调用时加载,可以在请求的时候(bootstrap)或者动作控制器创建的时候(init())实例化。

涉及到的相关文件

在/library/Zend/Controller/Action/中

│ Exception.PHP │ HelperBroker.PHP │ Interface.PHP │ ├─Helper │ │ Abstract.PHP │ │ ActionStack.PHP │ │ AjaxContext.PHP │ │ AutoCompleteDojo.PHP │ │ AutoCompleteScriptaculous.PHP │ │ Cache.PHP │ │ ContextSwitch.PHP │ │ FlashMessenger.PHP │ │ Json.PHP │ │ Redirector.PHP │ │ Url.PHP │ │ ViewRenderer.PHP │ │ │ └─AutoComplete │ Abstract.PHP │ └─HelperBroker PriorityStack.PHP

常见的动作助手有

FlashMessenger 用来处理Flash Messenger会话; Json 用来解码和发送 JSON 响应; Url 用于创建Urls; Redirector 提供另一种实现方式,帮助程序重定向到内部或者外部页面; ViewRenderer 自动的完成在控制器内建立视图对象并渲染视图的过程; AutoComplete 自动响应 AJAX 的自动完成; ContextSwitch 和 AjaxContext 为你的动作提供替代响应格式; Cache 实现cache的相关操作; ActionStack 用于操作动作堆栈。

动手的几种实例化使用方式

方法。直接调用getHelper(),传入助手的名称即可。

_helper->getHelper('Redirector'); //$redirector->getName(); $redirector->gotoSimple('index2');

属性对应的助手对象。

_helper->Redirector;

Zend_Controller_Action_HelperBroker

中文名称译作"助手经纪人",顾名思义,是动作助手的中间人。

在动作的实例化使用的方式的第二种方式就是通过Zend_Controller_Action_HelperBroker的魔术方法__get()来实现的。

助手经纪人用于注册助手对象和助手路径以及获取助手等等功能

Zend_Controller_Action_HelperBroker的实现以及常用方法列表

PHP;"> 'Zend/Controller/Action/Helper/',)); } return self::$_pluginLoader; } /** * addPrefix() - Add repository of helpers by prefix * * @param string $prefix */ static public function addPrefix($prefix) { $prefix = rtrim($prefix,'_'); $path = str_replace('_',DIRECTORY_SEPARATOR,$prefix); self::getPluginLoader()->addPrefixPath($prefix,$path); } /** * addPath() - Add path to repositories where Action_Helpers could be found. * * @param string $path * @param string $prefix Optional; defaults to 'Zend_Controller_Action_Helper' * @return void */ static public function addPath($path,$prefix = 'Zend_Controller_Action_Helper') { self::getPluginLoader()->addPrefixPath($prefix,$path); } /** * addHelper() - Add helper objects * * @param Zend_Controller_Action_Helper_Abstract $helper * @return void */ static public function addHelper(Zend_Controller_Action_Helper_Abstract $helper) { self::getStack()->push($helper); return; } /** * resetHelpers() * * @return void */ static public function resetHelpers() { self::$_stack = null; return; } /** * Retrieve or initialize a helper statically * * Retrieves a helper object statically,loading on-demand if the helper * does not already exist in the stack. Always returns a helper,unless * the helper class cannot be found. * * @param string $name * @return Zend_Controller_Action_Helper_Abstract */ public static function getStaticHelper($name) { $name = self::_normalizeHelperName($name); $stack = self::getStack(); if (!isset($stack->{$name})) { self::_loadHelper($name); } return $stack->{$name}; } /** * getExistingHelper() - get helper by name * * Static method to retrieve helper object. Only retrieves helpers already * initialized with the broker (either via addHelper() or on-demand loading * via getHelper()). * * Throws an exception if the referenced helper does not exist in the * stack; use {@link hasHelper()} to check if the helper is registered * prior to retrieving it. * * @param string $name * @return Zend_Controller_Action_Helper_Abstract * @throws Zend_Controller_Action_Exception */ public static function getExistingHelper($name) { $name = self::_normalizeHelperName($name); $stack = self::getStack(); if (!isset($stack->{$name})) { require_once 'Zend/Controller/Action/Exception.PHP'; throw new Zend_Controller_Action_Exception('Action helper "' . $name . '" has not been registered with the helper broker'); } return $stack->{$name}; } /** * Return all registered helpers as helper => object pairs * * @return array */ public static function getExistingHelpers() { return self::getStack()->getHelpersByName(); } /** * Is a particular helper loaded in the broker? * * @param string $name * @return boolean */ public static function hasHelper($name) { $name = self::_normalizeHelperName($name); return isset(self::getStack()->{$name}); } /** * Remove a particular helper from the broker * * @param string $name * @return boolean */ public static function removeHelper($name) { $name = self::_normalizeHelperName($name); $stack = self::getStack(); if (isset($stack->{$name})) { unset($stack->{$name}); } return false; } /** * Lazy load the priority stack and return it * * @return Zend_Controller_Action_HelperBroker_PriorityStack */ public static function getStack() { if (self::$_stack == null) { self::$_stack = new Zend_Controller_Action_HelperBroker_PriorityStack(); } return self::$_stack; } /** * Constructor * * @param Zend_Controller_Action $actionController * @return void */ public function __construct(Zend_Controller_Action $actionController) { $this->_actionController = $actionController; foreach (self::getStack() as $helper) { $helper->setActionController($actionController); $helper->init(); } } /** * notifyPreDispatch() - called by action controller dispatch method * * @return void */ public function notifyPreDispatch() { foreach (self::getStack() as $helper) { $helper->preDispatch(); } } /** * notifyPostDispatch() - called by action controller dispatch method * * @return void */ public function notifyPostDispatch() { foreach (self::getStack() as $helper) { $helper->postDispatch(); } } /** * getHelper() - get helper by name * * @param string $name * @return Zend_Controller_Action_Helper_Abstract */ public function getHelper($name) { $name = self::_normalizeHelperName($name); $stack = self::getStack(); if (!isset($stack->{$name})) { self::_loadHelper($name); } $helper = $stack->{$name}; $initialize = false; if (null === ($actionController = $helper->getActionController())) { $initialize = true; } elseif ($actionController !== $this->_actionController) { $initialize = true; } if ($initialize) { $helper->setActionController($this->_actionController) ->init(); } return $helper; } /** * Method overloading * * @param string $method * @param array $args * @return mixed * @throws Zend_Controller_Action_Exception if helper does not have a direct() method */ public function __call($method,$args) { $helper = $this->getHelper($method); if (!method_exists($helper,'direct')) { require_once 'Zend/Controller/Action/Exception.PHP'; throw new Zend_Controller_Action_Exception('Helper "' . $method . '" does not support overloading via direct()'); } return call_user_func_array(array($helper,'direct'),$args); } /** * Retrieve helper by name as object property * * @param string $name * @return Zend_Controller_Action_Helper_Abstract */ public function __get($name) { return $this->getHelper($name); } /** * Normalize helper name for lookups * * @param string $name * @return string */ protected static function _normalizeHelperName($name) { if (strpos($name,'_') !== false) { $name = str_replace(' ','',ucwords(str_replace('_',' ',$name))); } return ucfirst($name); } /** * Load a helper * * @param string $name * @return void */ protected static function _loadHelper($name) { try { $class = self::getPluginLoader()->load($name); } catch (Zend_Loader_PluginLoader_Exception $e) { require_once 'Zend/Controller/Action/Exception.PHP'; throw new Zend_Controller_Action_Exception('Action Helper by name ' . $name . ' not found',$e); } $helper = new $class(); if (!$helper instanceof Zend_Controller_Action_Helper_Abstract) { require_once 'Zend/Controller/Action/Exception.PHP'; throw new Zend_Controller_Action_Exception('Helper name ' . $name . ' -> class ' . $class . ' is not of type Zend_Controller_Action_Helper_Abstract'); } self::getStack()->push($helper); } }

助手经纪人的常见用法

注册一个助手

1.

PHP;"> Zend_Controller_Action_HelperBroker::addHelper($helper);

2.通过addPrefix()方法带有一个类前缀参数,用来加入自定义助手类的路径。 要求前缀遵循Zend Framework的类命名惯例。

PHP;"> // Add helpers prefixed with My_Action_Helpers in My/Action/Helpers/ Zend_Controller_Action_HelperBroker::addPrefix('My_Action_Helpers');

3.使用addPath()方法第一个参数为一个目录,第二个为类前缀(默认为'Zend_Controller_Action_Helper')。

用来将自己的类前缀映射到指定的目录。

PHP;"> // Add helpers prefixed with Helper in Plugins/Helpers/ Zend_Controller_Action_HelperBroker::addPath('./Plugins/Helpers','Helper');

使用hasHelper($name)方法来判定助手经纪人中是否存在某助手,$name是助手的短名称(去掉前缀的):

PHP;"> // Check if 'redirector' helper is registered with the broker: if (Zend_Controller_Action_HelperBroker::hasHelper('redirector')) { echo 'Redirector helper registered'; }

从助手经纪人中获取助手有两个静态方法:getExistingHelper() 和 getStaticHelper() 。getExistingHelper()将获取助手仅当它以前调用过或者显性地通过助手经纪人注册过,否则就抛出一个异常。getStaticHelper() 的做法和getExistingHelper()一样,但如果还没有注册助手堆栈,它将尝试初始化助手,为获取你要配置的的助手,getStaticHelper()是一个好的选择。

两个方法都带一个参数,$name,它是助手的短名称(去掉前缀)。

PHP;"> // Check if 'redirector' helper is registered with the broker,and fetch: if (Zend_Controller_Action_HelperBroker::hasHelper('redirector')) { $redirector = Zend_Controller_Action_HelperBroker::getExistingHelper('redirector'); } // Or,simply retrieve it,not worrying about whether or not it was // prevIoUsly registered: $redirector = Zend_Controller_Action_HelperBroker::getStaticHelper('redirector'); }

删除助手经纪人中的某个助手,$name是助手的短名称

PHP;"> // Conditionally remove the 'redirector' helper from the broker: if (Zend_Controller_Action_HelperBroker::hasHelper('redirector')) { Zend_Controller_Action_HelperBroker::removeHelper('redirector') }

更多关于zend相关内容感兴趣的读者可查看本站专题:《》、《》、《》、《》、《》、《》及《PHP常见数据库操作技巧汇总》

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