本文實(shí)例講述了Zend Framework動(dòng)作助手(Zend_Controller_Action_Helper)用法。分享給大家供大家參考，具體如下：
通過(guò)助手模式，可以把一些經(jīng)常使用的功能模塊做封裝，從而在可以在需要的地方靈活使用，主要是在action使用。
Zend Framework中有兩種助手，動(dòng)作助手(Zend_Controller_Action_Helper)和試圖助手(Zend_View_Helper)。
動(dòng)作助手可以向任何Zend_Controller_Action的衍生動(dòng)作控制器中，即時(shí)的加入功能(runtime and/or on-demand functionality)，以使得增加公共的動(dòng)作控制器功能時(shí)，盡量減少衍生動(dòng)作控制器類的必要。
動(dòng)作助手在需要調(diào)用時(shí)加載，可以在請(qǐng)求的時(shí)候(bootstrap)或者動(dòng)作控制器創(chuàng)建的時(shí)候(init())實(shí)例化。
涉及到的相關(guān)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
常見(jiàn)的動(dòng)作助手有：
FlashMessenger 用來(lái)處理Flash Messenger會(huì)話；
Json 用來(lái)解碼和發(fā)送 JSON 響應(yīng)；
Url 用于創(chuàng)建Urls；
Redirector 提供另一種實(shí)現(xiàn)方式，幫助程序重定向到內(nèi)部或者外部頁(yè)面；
ViewRenderer 自動(dòng)的完成在控制器內(nèi)建立視圖對(duì)象并渲染視圖的過(guò)程；
AutoComplete 自動(dòng)響應(yīng) AJAX 的自動(dòng)完成；
ContextSwitch 和 AjaxContext 為你的動(dòng)作提供替代響應(yīng)格式；
Cache 實(shí)現(xiàn)cache的相關(guān)操作；
ActionStack 用于操作動(dòng)作堆棧。
動(dòng)手的幾種實(shí)例化使用方式
1.通過(guò)Zend_Controller_Action的 $_helper成員的getHelper()方法。直接調(diào)用getHelper()，傳入助手的名稱即可。
$redirector = $this->_helper->getHelper('Redirector');//$redirector->getName();$redirector->gotoSimple('index2'); 2.直接通過(guò)訪問(wèn)的_helper助手的屬性對(duì)應(yīng)的助手對(duì)象。
$redirector = $this->_helper->Redirector;
Zend_Controller_Action_HelperBroker
中文名稱譯作"助手經(jīng)紀(jì)人",顧名思義，是動(dòng)作助手的中間人。
在動(dòng)作的實(shí)例化使用的方式的第二種方式就是通過(guò)Zend_Controller_Action_HelperBroker的魔術(shù)方法__get()來(lái)實(shí)現(xiàn)的。
助手經(jīng)紀(jì)人用于注冊(cè)助手對(duì)象和助手路徑以及獲取助手等等功能。
Zend_Controller_Action_HelperBroker的實(shí)現(xiàn)以及常用方法列表
<?php/** * @see Zend_Controller_Action_HelperBroker_PriorityStack */require_once 'Zend/Controller/Action/HelperBroker/PriorityStack.php';/** * @see Zend_Loader */require_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 License */class 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); }} 助手經(jīng)紀(jì)人的常見(jiàn)用法：
一、注冊(cè)一個(gè)助手
1.
Zend_Controller_Action_HelperBroker::addHelper($helper);
2.通過(guò)addPrefix()方法帶有一個(gè)類前綴參數(shù)，用來(lái)加入自定義助手類的路徑。
要求前綴遵循Zend Framework的類命名慣例。
// Add helpers prefixed with My_Action_Helpers in My/Action/Helpers/Zend_Controller_Action_HelperBroker::addPrefix('My_Action_Helpers'); 3.使用addPath()方法第一個(gè)參數(shù)為一個(gè)目錄，第二個(gè)為類前綴(默認(rèn)為'Zend_Controller_Action_Helper')。
用來(lái)將自己的類前綴映射到指定的目錄。
// Add helpers prefixed with Helper in Plugins/Helpers/Zend_Controller_Action_HelperBroker::addPath('./Plugins/Helpers', 'Helper'); 二、判讀助手是否存在
使用hasHelper($name)方法來(lái)判定助手經(jīng)紀(jì)人中是否存在某助手，$name是助手的短名稱（去掉前綴的）：
// Check if 'redirector' helper is registered with the broker:if (Zend_Controller_Action_HelperBroker::hasHelper('redirector')) { echo 'Redirector helper registered';} 從助手經(jīng)紀(jì)人中獲取助手有兩個(gè)靜態(tài)方法：getExistingHelper() 和 getStaticHelper() 。getExistingHelper()將獲取助手僅當(dāng)它以前調(diào)用過(guò)或者顯性地通過(guò)助手經(jīng)紀(jì)人注冊(cè)過(guò)，否則就拋出一個(gè)異常。getStaticHelper() 的做法和getExistingHelper()一樣，但如果還沒(méi)有注冊(cè)助手堆棧，它將嘗試初始化助手，為獲取你要配置的的助手，getStaticHelper()是一個(gè)好的選擇。
兩個(gè)方法都帶一個(gè)參數(shù)，$name，它是助手的短名稱（去掉前綴）。
// 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($name)刪除助手經(jīng)紀(jì)人中的某個(gè)助手，$name是助手的短名稱。
// Conditionally remove the 'redirector' helper from the broker:if (Zend_Controller_Action_HelperBroker::hasHelper('redirector')) { Zend_Controller_Action_HelperBroker::removeHelper('redirector')} 
