46.3. 视图脚本

View脚本可能要被用来初始化和操作一个其它模板对象的实例，例如PHPLIB风格的模板。这时View脚本可能是这样的：

<?php
include_once 'template.inc';
$tpl = new Template();

if ($this->books) {
    $tpl->setFile(array(
        "booklist" => "booklist.tpl",
        "eachbook" => "eachbook.tpl",
    ));

    foreach ($this->books as $key => $val) {
        $tpl->set_var('author', $this->escape($val['author']);
        $tpl->set_var('title', $this->escape($val['title']);
        $tpl->parse("books", "eachbook", true);
    }

    $tpl->pparse("output", "booklist");
} else {
    $tpl->setFile("nobooks", "nobooks.tpl")
    $tpl->pparse("output", "nobooks");
}

下面是相关的模板文件：

<!-- booklist.tpl -->
<table>
    <tr>
        <th>Author</th>
        <th>Title</th>
    </tr>
    {books}
</table>

<!-- eachbook.tpl -->
    <tr>
        <td>{author}</td>
        <td>{title}</td>
    </tr>

<!-- nobooks.tpl -->
<p>There are no books to display.</p>>
           

实现一个与Zend_View兼容的模板系统是很简单的。你只需要实现Zend_View_Interface接口即可，该接口定义了要实现兼容的最低要求。

/**
 * Return the actual template engine object
 * 返回实际模板系统的对象
 */
public function getEngine();

/**
 * Set the path to view scripts/templates
 * 设置视图脚本/模板的路径
 */
public function setScriptPath($path);

/**
 * Set a base path to all view resources
 * 给所有视图资源设置基本路径
 */
public function setBasePath($path, $prefix = 'Zend_View');

/**
 * Add an additional base path to view resources
 * 给视图资源添加另外的基本路径
 */
public function addBasePath($path, $prefix = 'Zend_View');

/**
 * Retrieve the current script paths
 * 获取当前脚本路径
 */
public function getScriptPaths();

/**
 * Overloading methods for assigning template variables as object properties
 * 重载方法，用于将赋值给模板变量，以对象属性的形式
 */
public function __set($key, $value);
public function __get($key);
public function __isset($key);
public function __unset($key);

/**
 * Manual assignment of template variables, or ability to assign multiple
 * variables en masse.
 * 手动设置模板变量，或者一次赋值多个变量的功能
 */
public function assign($spec, $value = null);

/**
 * Unset all assigned template variables
 * 消除所有已赋值的变量
 */
public function clearVars();

/**
 * Render the template named $name
 * 输出参数$name指定的某个模板
 */
public function render($name);
            

使用这个接口，把第三方的模板系统封装成Zend_View兼容的类是相当容易的。例如，下面是封装Smarty的示例代码：

require_once 'Zend/View/Interface.php';
require_once 'Smarty.class.php';

class Zend_View_Smarty implements Zend_View_Interface
{
    /**
     * Smarty object
     * @var Smarty
     */
    protected $_smarty;

    /**
     * Constructor
     *
     * @param string $tmplPath
     * @param array $extraParams
     * @return void
     */
    public function __construct($tmplPath = null, $extraParams = array())
    {
        $this->_smarty = new Smarty;

        if (null !== $tmplPath) {
            $this->setScriptPath($tmplPath);
        }

        foreach ($extraParams as $key => $value) {
            $this->_smarty->$key = $value;
        }
    }

    /**
     * Return the template engine object	 
     *
     * @return Smarty
     */
    public function getEngine()
    {
        return $this->_smarty;
    }

    /**
     * Set the path to the templates
     *
     * @param string $path The directory to set as the path.
     * @return void
     */
    public function setScriptPath($path)
    {
        if (is_readable($path)) {
            $this->_smarty->template_dir = $path;
            return;
        }

        throw new Exception('Invalid path provided');
    }

    /**
     * Retrieve the current template directory
     *
     * @return string
     */
    public function getScriptPaths()
    {
        return array($this->_smarty->template_dir);
    }

    /**
     * Alias for setScriptPath
     *
     * @param string $path
     * @param string $prefix Unused
     * @return void
     */
    public function setBasePath($path, $prefix = 'Zend_View')
    {
        return $this->setScriptPath($path);
    }

    /**
     * Alias for setScriptPath
     *
     * @param string $path
     * @param string $prefix Unused
     * @return void
     */
    public function addBasePath($path, $prefix = 'Zend_View')
    {
        return $this->setScriptPath($path);
    }

    /**
     * Assign a variable to the template
     *
     * @param string $key The variable name.
     * @param mixed $val The variable value.
     * @return void
     */
    public function __set($key, $val)
    {
        $this->_smarty->assign($key, $val);
    }

    /**
     * Retrieve an assigned variable
     *
     * @param string $key The variable name.
     * @return mixed The variable value.
     */
    public function __get($key)
    {
        return $this->_smarty->get_template_vars($key);
    }

    /**
     * Allows testing with empty() and isset() to work
     *
     * @param string $key
     * @return boolean
     */
    public function __isset($key)
    {
         return (null !== $this->_smarty->get_template_vars($key));
    }

    /**
     * Allows unset() on object properties to work
     *
     * @param string $key
     * @return void
     */
    public function __unset($key)
    {
        $this->_smarty->clear_assign($key);
    }

    /**
     * Assign variables to the template
     *
     * Allows setting a specific key to the specified value, OR passing an array
     * of key => value pairs to set en masse.
     *
     * @see __set()
     * @param string|array $spec The assignment strategy to use (key or array of key
     * => value pairs)
     * @param mixed $value (Optional) If assigning a named variable, use this
     * as the value.
     * @return void
     */
    public function assign($spec, $value = null)
    {
        if (is_array($spec)) {
            $this->_smarty->assign($spec);
            return;
        }

        $this->_smarty->assign($spec, $value);
    }

    /**
     * Clear all assigned variables
     *
     * Clears all variables assigned to Zend_View either via {@link assign()} or
     * property overloading ({@link __get()}/{@link __set()}).
     *
     * @return void
     */
    public function clearVars()
    {
        $this->_smarty->clear_all_assign();
    }

    /**
     * Processes a template and returns the output.
     *
     * @param string $name The template to process.
     * @return string The output.
     */
    public function render($name)
    {
        return $this->_smarty->fetch($name);
    }
}
            

在这个示例中，实例化Zend_View_Smarty而不是Zend_View，然后就像使用 Zend_View一样地使用它。

$view = new Zend_View_Smarty();
$view->setScriptPath('/path/to/templates');
$view->book = 'Zend PHP 5 Certification Study Guide';
$view->author = 'Davey Shafik and Ben Ramsey'
$rendered = $view->render('bookinfo.tpl');