17.3. View Scripts
السابق | فصل 17. Zend_View | التالي

## 17.3. View Scripts

Once your controller has assigned variables and called render(), Zend_View then includes the requested view script and executes it "inside" the scope of the Zend_View instance. Therefore, in your view scripts, references to $this actually point to the Zend_View instance itself.

Variables assigned to the view from the controller are referred to as instance properties. For example, if the controller were to assign a variable 'something', you would refer to it as $this->something in the view script. (This allows you to keep track of which values were assigned to the script, and which are internal to the script itself.)

By way of reminder, here is the example view script from the Zend_View introduction.

    <?php if ($this->books): ?>

        <!-- A table of some books. -->
        <table>
            <tr>
                <th>Author</th>
                <th>Title</th>
            </tr>

            <?php foreach ($this->books as $key => $val): ?>
            <tr>
                <td><?php echo $this->escape($val['author']) ?></td>
                <td><?php echo $this->escape($val['title']) ?></td>
            </tr>
            <?php endforeach; ?>

        </table>

    <?php else: ?>

        <p>There are no books to display.</p>

    <?php endif; ?>

### 17.3.1. Escaping Output

One of the most important tasks to perform in a view script is to make sure that output is escaped properly; among other things, this helps to avoid cross-site scripting attacks. Unless you are using a function, method, or helper that does escaping on its own, you should always escape variables when you output them.

Zend_View comes with a method called escape() that does such escaping for you.

    <?php
    // bad view-script practice:
    echo $this->variable;

    // good view-script practice:
    echo $this->escape($this->variable);
    ?>

By default, the escape() method uses the PHP htmlspecialchars() function for escaping. However, depending on your environment, you may wish for escaping to occur in a different way. Use the setEscape() method at the controller level to tell Zend_View what escaping callback to use.

    <?php
    // create a Zend_View instance
    $view = new Zend_View();

    // tell it to use htmlentities as the escaping callback
    $view->setEscape('htmlentities');

    // or tell it to use a static class method as the callback
    $view->setEscape(array('SomeClass', 'methodName'));

    // or even an instance method
    $obj = new SomeClass();
    $view->setEscape(array($obj, 'methodName'));

    // and then render your view
    echo $view->render(...);
    ?>

The callback function or method should take the value to be escaped as its first parameter, and all other parameters should be optional.

### 17.3.2. Template Systems

Although PHP is itself a powerful template system, many developers feel it is too powerful or complex for their template designers. As such, the view script may be used to instantiate and manipulate a separate template object, such as a PHPLIB-style template. The view script for that kind of activity might look something like this:

    <?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");
    }
    ?>

These would be the related template files:

    <!-- 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>

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17.2. Controller Scripts | البداية | 17.4. View Helpers