Detailed explanation of Application and Bootstrap usage in Zend Framework tutorial

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In an MVC application, we need to initialize and establish a database link, configure views and view assistants, configure layout, register related plug-ins, register action assistants, etc., these We need to complete the configuration and preparation work one by one. Sometimes some initialization operations may be required, but in some cases these initialization may not be needed. Zend_Application can not only complete these operations, but also make these configuration and initialization tasks more unified and orderly, with higher reusability.

Zend_Application usage can be subdivided into three types:

Zend_Application: loads the PHP environment, including include_paths and automatic loading, and instantiates the boot class.

Zend_Application_Bootstrap: Provides an interface for boot classes.

Zend_Application_Bootstrap_Bootstrap completes most common functions that boot needs to provide, including dependency checking and loading boot resources on demand.

Zend_Application_Resource provides on-demand resource loading function

Developers can inherit Zend_Application_Bootstrap_Bootstrap or implement the Zend_Application_Bootstrap_Bootstrapper interface as needed. Zend_Application is loaded in the entry file (for example, public/index.php) and instantiated according to the boot options and current environment configuration.

Boot options include the specified boot class file and boot class path. The options are as follows:

Required include_paths

The automatic loading function additionally loads the registered namespace

php.ini initialization settings

Specify the bootstrap class name, if it is not "Bootstrap"

The resource prefix key-value pair key represents the resource prefix name

The resource Class name or alias

Additional loaded configuration file path

Additional configuration options

Options can be an array, or a Zend_Config object, or a configuration file at a specified location

Bootstrapper

The second function of Zend_Application is to guide the application. Bootstraps must implement the Zend_Application_Bootstrap_Bootstrapper interface. The specific interface API is as follows:

interface Zend_Application_Bootstrap_Bootstrapper
{
  public function __construct($application);
  public function setOptions(array $options);
  public function getApplication();
  public function getEnvironment();
  public function getClassResources();
  public function getClassResourceNames();
  public function bootstrap($resource = null);
  public function run();
}

api mainly provides environment configuration and obtains guidance. Loaded resources, and bootstrap

You can implement the interface or inherit Zend_Application_Bootstrap_BootstrapAbstract, or Zend_Application_Bootstrap_Bootstrap.

Resource method

The resource method that implements the Zend_Application_Bootstrap_BootstrapAbstract interface must follow the following rules. Method The type is protected, and the prefix of the method must start with _init will.

If you want to load and use a resource method, just add the resource name in bootstrap(). The resource name is the resource method without the _init prefix.

If you want to load multiple resource methods, you can specify them through an array.

For example, bootstrap class:

class Bootstrap extends Zend_Application_Bootstrap_Bootstrap
{
  protected function _initFoo()
  {
    // ...
  }
  protected function _initBar()
  {
    // ...
  }
  protected function _initBaz()
  {
    // ...
  }
}

Only load using _initFoo():

$bootstrap->bootstrap('foo');

Load using _initFoo() and _initBar():

$bootstrap->bootstrap(array('foo', 'bar'));

Load and use all resource methods, use bootstrap() without parameters:

$bootstrap->bootstrap();

New first_web project

root@coder-671T-M:/mydev_src/zend_framework_learn/www# tree first_web/
first_web/
├── application
│ ├── Bootstrap.php
│ ├── configs
│ │ └── application.ini
│ ├── controllers
| scripts
│                                                                                                                                                                                                                                                                                                   error #│ └ ── README.txt
├── library
├── public
│ └── index.php
└── tests
├── application
│ └── controllers
│ └── IndexControllerTest.php
├── bootstrap.php
├── library
└── phpunit.xml
16 directories, 11 files

Newer versions of zend framework introduced Zend_Application and Bootstrap. Zend_Application provides a bootstrap of reusable resources, generic and modular bootstrap classes and dependency checks. It is also responsible for setting PHP environment variables and automatic loading functions by default.

By default, after creating a new project, the following files will be given:

1. Bootstrap of the project

first_web/
├── application
│ ├── Bootstrap.php

The specific code is as follows:

<?php
class Bootstrap extends Zend_Application_Bootstrap_Bootstrap
{
}

2. Configuration file

│   ├── configs
│   │   └── application.ini

具体代码如下：

[production]
phpSettings.display_startup_errors = 0
phpSettings.display_errors = 0
includePaths.library = APPLICATION_PATH "/../library"
bootstrap.path = APPLICATION_PATH "/Bootstrap.php"
bootstrap.class = "Bootstrap"
appnamespace = "Application"
resources.frontController.controllerDirectory = APPLICATION_PATH "/controllers"
resources.frontController.params.displayExceptions = 0
[staging : production]
[testing : production]
phpSettings.display_startup_errors = 1
phpSettings.display_errors = 1
[development : production]
phpSettings.display_startup_errors = 1
phpSettings.display_errors = 1
resources.frontController.params.displayExceptions = 1

3.项目入口文件

├── public
│   └── index.php

<?php
// Define path to application directory
defined(&#39;APPLICATION_PATH&#39;)
  || define(&#39;APPLICATION_PATH&#39;, realpath(dirname(__FILE__) . &#39;/../application&#39;));
// Define application environment
defined(&#39;APPLICATION_ENV&#39;)
  || define(&#39;APPLICATION_ENV&#39;, (getenv(&#39;APPLICATION_ENV&#39;) ? getenv(&#39;APPLICATION_ENV&#39;) : &#39;production&#39;));
// Ensure library/ is on include_path
set_include_path(implode(PATH_SEPARATOR, array(
  realpath(APPLICATION_PATH . &#39;/../library&#39;),
  get_include_path(),
)));
/** Zend_Application */
require_once &#39;Zend/Application.php&#39;;
// Create application, bootstrap, and run
$application = new Zend_Application(
  APPLICATION_ENV,
  APPLICATION_PATH . &#39;/configs/application.ini&#39;
);
$application->bootstrap()
      ->run();

以上代码就是基本的使用Zend_Application方式，完成了环境变量的初始化，加载配置文件，初始化环境，加载模块，完成web应用程序的引导功能。

资源插件

资源插件只需要实现Zend_Application_Resource_Resource，或者，更简单的是，继承Zend_Application_Resource_ResourceAbstract。接口如下：

interface Zend_Application_Resource_Resource
{
  public function __construct($options = null);
  public function setBootstrap(
    Zend_Application_Bootstrap_Bootstrapper $bootstrap
  );
  public function getBootstrap();
  public function setOptions(array $options);
  public function getOptions();
  public function init();
}

例如

class My_Resource_View extends Zend_Application_Resource_ResourceAbstract
{
  protected $_view;
  public function init()
  {
    // Return view so bootstrap will store it in the registry
    return $this->getView();
  }
  public function getView()
  {
    if (null === $this->_view) {
      $options = $this->getOptions();
      $title  = '';
      if (array_key_exists('title', $options)) {
        $title = $options['title'];
        unset($options['title']);
      }
      $view = new Zend_View($options);
      $view->doctype('XHTML1_STRICT');
      $view->headTitle($title);
      $view->headLink()->appendStylesheet('/css/site.css');
      $view->headScript()->appendfile('/js/analytics.js');
      $viewRenderer =
        Zend_Controller_Action_HelperBroker::getStaticHelper(
          'ViewRenderer'
        );
      $viewRenderer->setView($view);
      $this->_view = $view;
    }
    return $this->_view;
  }
}

加载使用资源插件

我了提供资源的重用性，可以将资源方法定义为资源插件。。

为了让bootstrap能够识别资源插件，定义资源插件时，需要实现Zend_Application_Bootstrap_ResourceBootstrapper. 接口定义了查找插件，注册插件和加载插件的api:

interface Zend_Application_Bootstrap_ResourceBootstrapper
{
  public function registerPluginResource($resource, $options = null);
  public function unregisterPluginResource($resource);
  public function hasPluginResource($resource);
  public function getPluginResource($resource);
  public function getPluginResources();
  public function getPluginResourceNames();
  public function setPluginLoader(Zend_Loader_PluginLoader_Interface $loader);
  public function getPluginLoader();
}

采用资源插件，不仅可以让资源可以重复利用，同时让bootstrap更简洁，如果要修改，新增资源也无需修改你的bootstrap。

通过实现Zend_Application_Bootstrap_BootstrapAbstract (被 Zend_Application_Bootstrap_Bootstrap 继承) ,才可以使用定义的资源插件

通过将指定的选项传递到application object and/or bootstrap，来注册使用资源插件。这些选项可能会从一个配置文件，或通过手动指定。规则是选项必须是键值对，键代表资源名称。资源名称，是资源插件类的类前缀。例如，Zend框架自带的资源类前缀“Zend_Application_Resource_”;任何以下，这都是资源的名称。例如，

$application = new Zend_Application(APPLICATION_ENV, array(
  'resources' => array(
    'FrontController' => array(
      'controllerDirectory' => APPLICATION_PATH . '/controllers',
    ),
  ),
));

"FrontController"资源是个特例。他的选项比较特殊。

无论是使用自己的写的资源插件还是使用第三方的资源插件。你必须保证bootstrap能找到他们，bootstrap 内部通过 Zend_Loader_PluginLoader可以让我们只需要指定资源插件的类前缀，值为资源类的类路径便可以轻松注册资源插件。

例如，如果编写的资源插件存放在APPLICATION_PATH/resources/ 下，类前缀为My_Resource. 可以使用如下方法注册加载:

$application = new Zend_Application(APPLICATION_ENV, array(
  'pluginPaths' => array(
    'My_Resource' => APPLICATION_PATH . '/resources/',
  ),
  'resources' => array(
    'FrontController' => array(
      'controllerDirectory' => APPLICATION_PATH . '/controllers',
    ),
  ),
));

在应用程序中比可以使用指定目录下的资源。

和资源方法类似，通过使用 the bootstrap() 方法可以加载资源插件。加载单一，多个，全部的资源插件的配置方式也类似.

例如：

// Execute one:
$bootstrap->bootstrap('FrontController');
// Execute several:
$bootstrap->bootstrap(array('FrontController', 'Foo'));
// Execute all resource methods and plugins:
$bootstrap->bootstrap();

资源注册表

为了避免资源的重复注册，导致不必要的浪费Zend_Application_Bootstrap_BootstrapAbstract 提供了一个本地注册表对象存储这些资源对象.当你想要存放一个资源的时候，只需要在方法中返回这个资源即可。

为了灵活性，注册表是作为一个内部“容器”存在的。只要是对象都可以存入到容器中。资源名称对应为容器的属性。默认情况下，可以通过Zend_Registry获取实例使用，也可以自定义其他对象。 setContainer() and getContainer() 方法可用于操纵容器本身。getResource($resource) 可用于获取一个指定资源。hasResource($resource) 可以检查资源是否已经注册存在

例如，注册一个view资源:

class Bootstrap extends Zend_Application_Bootstrap_Bootstrap
{
  protected function _initView()
  {
    $view = new Zend_View();
    // more initialization...
    return $view;
  }
}

资源的相关操作：

// Using the has/getResource() pair:
if ($bootstrap->hasResource('view')) {
  $view = $bootstrap->getResource('view');
}
// Via the container:
$container = $bootstrap->getContainer();
if (isset($container->view)) {
  $view = $container->view;
}

请注意：注册表容器是不是全局的。这意味着你需要通过访问的bootstrap来获取资源。 Zend_Application_Bootstrap_Bootstrap提供了 run() ， 执行了 run() 之后，它会注册为前端控制器参数的“bootstrap”，通过他可以获取路由器，分发器，插件和动作控制器。

具体使用方法：

class FooController extends Zend_Controller_Action
{
  public function init()
  {
    $bootstrap = $this->getInvokeArg('bootstrap');
    $view = $bootstrap->getResource('view');
    // ...
  }
}

为了防止重复注册加载资源方法和插件或一些资源可能依赖于其他资源。为了解决这两个问题，Zend_Application_Bootstrap_BootstrapAbstract提供了一个简单的依赖性跟踪机制。

如前所述，所有的资源 - 无论是方法或插件 - 是通过 bootstrap($resource)加载运行的,其中 $resource是资源的名称，或者资源名称数组，或者为空，为空表示加载运行所有资源。

class Bootstrap extends Zend_Application_Bootstrap_Bootstrap
{
  protected function _initRequest()
  {
    // Ensure the front controller is initialized
    $this->bootstrap('FrontController');
    // Retrieve the front controller from the bootstrap registry
    $front = $this->getResource('FrontController');
    $request = new Zend_Controller_Request_Http();
    $request->setBaseUrl('/foo');
    $front->setRequest($request);
    // Ensure the request is stored in the bootstrap registry
    return $request;
  }
}

希望本文所述对大家PHP程序设计有所帮助。

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