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怎么样正确使用Zend Framework动作助手？

来源：www.45fan.com  2016-10-07 13:05:29

怎么样正确使用Zend Framework动作助手？

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。

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

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_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')
}

希望本文所述对大家PHP程序设计有所帮助。

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