Using Alternative Template Syntax

Yii allows developers to use their own favorite template syntax (e.g. Prado, Smarty) to write controller or widget views. This is achieved by writing and installing a viewRenderer application component. The view renderer intercepts the invocations of CBaseController::renderFile, compiles the view file with customized template syntax, and renders the compiling results.

Info: It is recommended to use customized template syntax only when writing views that are less likely to be reused. Otherwise, people who are reusing the views would be forced to use the same customized template syntax in their applications.

In the following, we introduce how to use CPradoViewRenderer, a view renderer that allows developers to use the template syntax similar to that in Prado framework. For people who want to develop their own view renderers, CPradoViewRenderer is a good reference.

1. Using CPradoViewRenderer

To use CPradoViewRenderer, we just need to configure the application as follows:

return array(
    'components'=>array(
        ......,
        'viewRenderer'=>array(
            'class'=>'CPradoViewRenderer',
        ),
    ),
);

By default, CPradoViewRenderer will compile source view files and save the resulting PHP files under the runtime directory. Only when the source view files are changed, will the PHP files be re-generated. Therefore, using CPradoViewRenderer incurs very little performance degradation.

Tip: While CPradoViewRenderer mainly introduces some new template tags to make writing views easier and faster, you can still write PHP code as usual in the source views.

In the following, we introduce the template tags that are supported by CPradoViewRenderer.

Short PHP Tags

Short PHP tags are shortcuts to writing PHP expressions and statements in a view. The expression tag <%= expression %> is translated into <?php echo expression ?>; while the statement tag <% statement %> to <?php statement ?>. For example,

<%= CHtml::textField($name,'value'); %>
<% foreach($models as $model): %>

is translated into

<?php echo CHtml::textField($name,'value'); ?>
<?php foreach($models as $model): ?>

Component Tags

Component tags are used to insert a widget in a view. It uses the following syntax:

<com:WidgetClass property1=value1 property2=value2 ...>
    // body content for the widget
</com:WidgetClass>
 
// a widget without body content
<com:WidgetClass property1=value1 property2=value2 .../>

where WidgetClass specifies the widget class name or class path alias, and property initial values can be either quoted strings or PHP expressions enclosed within a pair of curly brackets. For example,

<com:CCaptcha captchaAction="captcha" showRefreshButton={false} />

would be translated as

<?php $this->widget('CCaptcha', array(
    'captchaAction'=>'captcha',
    'showRefreshButton'=>false)); ?>

Note: The value for showRefreshButton is specified as {false} instead of "false" because the latter means a string instead of a boolean.

Cache Tags

Cache tags are shortcuts to using fragment caching. Its syntax is as follows,

<cache:fragmentID property1=value1 property2=value2 ...>
    // content being cached
</cache:fragmentID >

where fragmentID should be an identifier that uniquely identifies the content being cached, and the property-value pairs are used to configure the fragment cache. For example,

<cache:profile duration={3600}>
    // user profile information here
</cache:profile >

would be translated as

<?php if($this->beginCache('profile', array('duration'=>3600))): ?>
    // user profile information here
<?php $this->endCache(); endif; ?>

Clip Tags

Like cache tags, clip tags are shortcuts to calling CBaseController::beginClip and CBaseController::endClip in a view. The syntax is as follows,

<clip:clipID>
    // content for this clip
</clip:clipID >

where clipID is an identifier that uniquely identifies the clip content. The clip tags will be translated as

<?php $this->beginClip('clipID'); ?>
    // content for this clip
<?php $this->endClip(); ?>

Comment Tags

Comment tags are used to write view comments that should only be visible to developers. Comment tags will be stripped off when the view is displayed to end users. The syntax for comment tags is as follows,

<!---
view comments that will be stripped off
--->

2. Mixing Template Formats

Starting from version 1.1.2, it is possible to mix the usage of some alternative template syntax with the normal PHP syntax. To do so, the CViewRenderer::fileExtension property of the installed view renderer must be configured with a value other than .php. For example, if the property is set as .tpl, then any view file ending with .tpl will be rendered using the installed view renderer, while all other view files ending with .php will be treated as normal PHP view script.

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