Zend_View is a class for working with the "view" portion of the model-view-controller pattern. That is, it exists to help keep the view script separate from the model and controller scripts. It provides a system of helpers, output filters, and variable escaping.
Zend_View is template system agnostic; you may use PHP as your template language, or create instances of other template systems and manipulate them within your view script.
Essentially, using Zend_View happens in two major steps: 1. Your controller script creates an instance of Zend_View and assigns variables to that instance. 2. The controller tells the Zend_View to render a particular view, thereby handing control over the view script, which generates the view output.
As a simple example, let us say your controller has a list of book data that it wants to have rendered by a view. The controller script might look something like this:
<?php
// use a model to get the data for book authors and titles.
$data = array(
array(
'author' => 'Hernando de Soto',
'title' => 'The Mystery of Capitalism'
),
array(
'author' => 'Henry Hazlitt',
'title' => 'Economics in One Lesson'
),
array(
'author' => 'Milton Friedman',
'title' => 'Free to Choose'
)
);
// now assign the book data to a Zend_View instance
Zend_Loader::loadClass('Zend_View');
$view = new Zend_View();
$view->books = $data;
// and render a view script called "booklist.php"
echo $view->render('booklist.php');
?>
Now we need the associated view script, "booklist.php". This is a PHP script like any other, with one exception: it executes inside the scope of the Zend_View instance, which means that references to $this point to the Zend_View instance properties and methods. (Variables assigned to the instance by the controller are public properties of the Zend_View instance.) Thus, a very basic view script could look like this:
<?php if ($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; ?>
Note how we use the "escape()" method to apply output escaping to variables.
Zend_View has several options that may be set to
configure the behaviour of your view scripts.
basePath: indicate a base path from which to set
the script, helper, and filter path. It assumes a directory
structure of:
base/path/
helpers/
filters/
scripts/
]
This may be set via setBasePath(),
addBasePath(), or the basePath
option to the constructor.
encoding: indicate the character encoding to use
with htmlentities(),
htmlspecialchars(), and other operations. Defaults
to ISO-8859-1 (latin1). May be set via
setEncoding() or the encoding option
to the constructor.
escape: indicate a callback to be used by
escape(). May be set via setEscape()
or the escape option to the constructor.
filter: indicate a filter to use after rendering
a view script. May be set via setFilter(),
addFilter(), or the filter option to
the constructor.
strictVars: force Zend_View to emit
notices and warnings when uninitialized view variables are
accessed. This may be set by calling
strictVars(true) or passing the
strictVars option to the constructor.
Typically, you'll only ever need to call on assign(),
render(), or one of the methods for setting/adding
filter, helper, and script paths. However, if you wish to extend
Zend_View yourself, or need access to some of its
internals, a number of accessors exist:
getVars() will return all assigned variables.
clearVars() will clear all assigned variables;
useful when you wish to re-use a view object, but want to
control what variables are available..
getScriptPath($script) will retrieve the
resolved path to a given view script.
getScriptPaths() will retrieve all registered
script paths.
getHelperPath($helper) will retrieve the
resolved path to the named helper class.
getHelperPaths() will retrieve all registered
helper paths.
getFilterPath($filter) will retrieve the
resolved path to the named filter class.
getFilterPaths() will retrieve all registered
filter paths.