Zend Framework动作助手的用法解析

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
│ │ html' target='_blank'>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

1.通过Zend_Controller_Action的 $_helper成员的getHelper()方法。直接调用getHelper()，传入助手的名称即可。

$redirector = $this- _helper- getHelper( Redirector //$redirector- getName();$redirector- gotoSimple( index2 

2.直接通过访问的_helper助手的属性对应的助手对象。

$redirector = $this- _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 * @see Zend_Controller_Action_HelperBroker_PriorityStackrequire_once Zend/Controller/Action/HelperBroker/PriorityStack.php  * @see Zend_Loaderrequire_once Zend/Loader.php  * @category Zend * @package Zend_Controller * @subpackage Zend_Controller_Action * @copyright Copyright (c) 2005-2011 Zend Technologies USA Inc. (http://www.zend.com) * @license http://framework.zend.com/license/new-bsd New BSD Licenseclass Zend_Controller_Action_HelperBroker * $_actionController - ActionController reference * @var Zend_Controller_Action protected $_actionController; * @var Zend_Loader_PluginLoader_Interface protected static $_pluginLoader; * $_helpers - Helper array * @var Zend_Controller_Action_HelperBroker_PriorityStack protected static $_stack = null; * Set PluginLoader for use with broker * @param Zend_Loader_PluginLoader_Interface $loader * @return void public static function setPluginLoader($loader) if ((null !== $loader) (!$loader instanceof Zend_Loader_PluginLoader_Interface)) { require_once Zend/Controller/Action/Exception.php  throw new Zend_Controller_Action_Exception( Invalid plugin loader provided to HelperBroker  self::$_pluginLoader = $loader; * Retrieve PluginLoader * @return Zend_Loader_PluginLoader public static function getPluginLoader() if (null === self::$_pluginLoader) { require_once Zend/Loader/PluginLoader.php  self::$_pluginLoader = new Zend_Loader_PluginLoader(array( Zend_Controller_Action_Helper = Zend/Controller/Action/Helper/ , return self::$_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 , 0, $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：

一、注册一个助手

1.

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。

// 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。

// Add helpers prefixed with Helper in Plugins/Helpers/Zend_Controller_Action_HelperBroker::addPath( ./Plugins/Helpers , Helper 

二、判读助手是否存在

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）：

// 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）。

// 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 }

三、removeHelper($name)删除助手经纪人中的某个助手，$name是助手的短名称。

// Conditionally remove the redirector helper from the broker:if (Zend_Controller_Action_HelperBroker::hasHelper( redirector )) { Zend_Controller_Action_HelperBroker::removeHelper( redirector )}

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