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<?php
/**
* @link http://www.yiiframework.com/
* @copyright Copyright (c) 2008 Yii Software LLC
* @license http://www.yiiframework.com/license/
*/
namespace yii\base;
use Yii;
use yii\base\Application;
use yii\helpers\FileHelper;
/**
* View represents a view object in the MVC pattern.
*
* View provides a set of methods (e.g. [[render()]]) for rendering purpose.
*
* @author Qiang Xue <qiang.xue@gmail.com>
* @since 2.0
*/
class View extends Component
{
/**
* @var object the object that owns this view. This can be a controller, a widget, or any other object.
*/
public $context;
/**
* @var mixed custom parameters that are shared among view templates.
*/
public $params;
/**
* @var ViewRenderer|array the view renderer object or the configuration array for
* creating the view renderer. If not set, view files will be treated as normal PHP files.
*/
public $renderer;
/**
* @var Theme|array the theme object or the configuration array for creating the theme.
* If not set, it means theming is not enabled.
*/
public $theme;
/**
* @var array a list of named output clips. You can call [[beginClip()]] and [[endClip()]]
* to capture small fragments of a view. They can be later accessed at somewhere else
* through this property.
*/
public $clips;
/**
* @var Widget[] the widgets that are currently being rendered (not ended). This property
* is maintained by [[beginWidget()]] and [[endWidget()]] methods. Do not modify it directly.
*/
public $widgetStack = array();
/**
* @var array a list of currently active fragment cache widgets. This property
* is used internally to implement the content caching feature. Do not modify it.
*/
public $cacheStack = array();
/**
* @var array a list of placeholders for embedding dynamic contents. This property
* is used internally to implement the content caching feature. Do not modify it.
*/
public $dynamicPlaceholders = array();
/**
* Initializes the view component.
*/
public function init()
{
parent::init();
if (is_array($this->renderer)) {
$this->renderer = Yii::createObject($this->renderer);
}
if (is_array($this->theme)) {
$this->theme = Yii::createObject($this->theme);
}
}
/**
* Renders a view.
*
* This method delegates the call to the [[context]] object:
*
* - If [[context]] is a controller, the [[Controller::renderPartial()]] method will be called;
* - If [[context]] is a widget, the [[Widget::render()]] method will be called;
* - Otherwise, an InvalidCallException exception will be thrown.
*
* @param string $view the view name. Please refer to [[Controller::findViewFile()]]
* and [[Widget::findViewFile()]] on how to specify this parameter.
* @param array $params the parameters (name-value pairs) that will be extracted and made available in the view file.
* @return string the rendering result
* @throws InvalidCallException if [[context]] is neither a controller nor a widget.
* @throws InvalidParamException if the view cannot be resolved or the view file does not exist.
* @see renderFile
*/
public function render($view, $params = array())
{
if ($this->context instanceof Controller) {
return $this->context->renderPartial($view, $params);
} elseif ($this->context instanceof Widget) {
return $this->context->render($view, $params);
} else {
throw new InvalidCallException('View::render() is not supported for the current context.');
}
}
/**
* Renders a view file.
*
* If [[theme]] is enabled (not null), it will try to render the themed version of the view file as long
* as it is available.
*
* The method will call [[FileHelper::localize()]] to localize the view file.
*
* If [[renderer]] is enabled (not null), the method will use it to render the view file.
* Otherwise, it will simply include the view file as a normal PHP file, capture its output and
* return it as a string.
*
* @param string $viewFile the view file. This can be either a file path or a path alias.
* @param array $params the parameters (name-value pairs) that will be extracted and made available in the view file.
* @param object $context the context that the view should use for rendering the view. If null,
* existing [[context]] will be used.
* @return string the rendering result
* @throws InvalidParamException if the view file does not exist
*/
public function renderFile($viewFile, $params = array(), $context = null)
{
$viewFile = Yii::getAlias($viewFile);
if (is_file($viewFile)) {
if ($this->theme !== null) {
$viewFile = $this->theme->applyTo($viewFile);
}
$viewFile = FileHelper::localize($viewFile);
} else {
throw new InvalidParamException("The view file does not exist: $viewFile");
}
$oldContext = $this->context;
if ($context !== null) {
$this->context = $context;
}
if ($this->renderer !== null) {
$output = $this->renderer->render($this, $viewFile, $params);
} else {
$output = $this->renderPhpFile($viewFile, $params);
}
$this->context = $oldContext;
return $output;
}
/**
* Renders a view file as a PHP script.
*
* This method treats the view file as a PHP script and includes the file.
* It extracts the given parameters and makes them available in the view file.
* The method captures the output of the included view file and returns it as a string.
*
* This method should mainly be called by view renderer or [[renderFile()]].
*
* @param string $_file_ the view file.
* @param array $_params_ the parameters (name-value pairs) that will be extracted and made available in the view file.
* @return string the rendering result
*/
public function renderPhpFile($_file_, $_params_ = array())
{
ob_start();
ob_implicit_flush(false);
extract($_params_, EXTR_OVERWRITE);
require($_file_);
return ob_get_clean();
}
/**
* Renders dynamic content returned by the given PHP statements.
* This method is mainly used together with content caching (fragment caching and page caching)
* when some portions of the content (called *dynamic content*) should not be cached.
* The dynamic content must be returned by some PHP statements.
* @param string $statements the PHP statements for generating the dynamic content.
* @return string the placeholder of the dynamic content, or the dynamic content if there is no
* active content cache currently.
*/
public function renderDynamic($statements)
{
if (!empty($this->cacheStack)) {
$n = count($this->dynamicPlaceholders);
$placeholder = "<![CDATA[YDP-$n]]>";
$this->addDynamicPlaceholder($placeholder, $statements);
return $placeholder;
} else {
return $this->evaluateDynamicContent($statements);
}
}
/**
* Adds a placeholder for dynamic content.
* This method is internally used.
* @param string $placeholder the placeholder name
* @param string $statements the PHP statements for generating the dynamic content
*/
public function addDynamicPlaceholder($placeholder, $statements)
{
foreach ($this->cacheStack as $cache) {
$cache->dynamicPlaceholders[$placeholder] = $statements;
}
$this->dynamicPlaceholders[$placeholder] = $statements;
}
/**
* Evaluates the given PHP statements.
* This method is mainly used internally to implement dynamic content feature.
* @param string $statements the PHP statements to be evaluated.
* @return mixed the return value of the PHP statements.
*/
public function evaluateDynamicContent($statements)
{
return eval($statements);
}
/**
* Creates a widget.
* This method will use [[Yii::createObject()]] to create the widget.
* @param string $class the widget class name or path alias
* @param array $properties the initial property values of the widget.
* @return Widget the newly created widget instance
*/
public function createWidget($class, $properties = array())
{
$properties['class'] = $class;
if (!isset($properties['view'])) {
$properties['view'] = $this;
}
return Yii::createObject($properties, $this);
}
/**
* Creates and runs a widget.
* Compared with [[createWidget()]], this method does one more thing: it will
* run the widget after it is created.
* @param string $class the widget class name or path alias
* @param array $properties the initial property values of the widget.
* @param boolean $captureOutput whether to capture the output of the widget and return it as a string
* @return string|Widget if $captureOutput is true, the output of the widget will be returned;
* otherwise the widget object will be returned.
*/
public function widget($class, $properties = array(), $captureOutput = false)
{
if ($captureOutput) {
ob_start();
ob_implicit_flush(false);
$widget = $this->createWidget($class, $properties);
$widget->run();
return ob_get_clean();
} else {
$widget = $this->createWidget($class, $properties);
$widget->run();
return $widget;
}
}
/**
* Begins a widget.
* This method is similar to [[createWidget()]] except that it will expect a matching
* [[endWidget()]] call after this.
* @param string $class the widget class name or path alias
* @param array $properties the initial property values of the widget.
* @return Widget the widget instance
*/
public function beginWidget($class, $properties = array())
{
$widget = $this->createWidget($class, $properties);
$this->widgetStack[] = $widget;
return $widget;
}
/**
* Ends a widget.
* Note that the rendering result of the widget is directly echoed out.
* If you want to capture the rendering result of a widget, you may use
* [[createWidget()]] and [[Widget::run()]].
* @return Widget the widget instance
* @throws InvalidCallException if [[beginWidget()]] and [[endWidget()]] calls are not properly nested
*/
public function endWidget()
{
$widget = array_pop($this->widgetStack);
if ($widget instanceof Widget) {
$widget->run();
return $widget;
} else {
throw new InvalidCallException("Unmatched beginWidget() and endWidget() calls.");
}
}
/**
* Begins recording a clip.
* This method is a shortcut to beginning [[yii\widgets\Clip]]
* @param string $id the clip ID.
* @param boolean $renderInPlace whether to render the clip content in place.
* Defaults to false, meaning the captured clip will not be displayed.
* @return \yii\widgets\Clip the Clip widget instance
* @see \yii\widgets\Clip
*/
public function beginClip($id, $renderInPlace = false)
{
return $this->beginWidget('yii\widgets\Clip', array(
'id' => $id,
'renderInPlace' => $renderInPlace,
));
}
/**
* Ends recording a clip.
*/
public function endClip()
{
$this->endWidget();
}
/**
* Begins the rendering of content that is to be decorated by the specified view.
* This method can be used to implement nested layout. For example, a layout can be embedded
* in another layout file specified as '@app/view/layouts/base' like the following:
*
* ~~~
* <?php $this->beginContent('@app/view/layouts/base'); ?>
* ...layout content here...
* <?php $this->endContent(); ?>
* ~~~
*
* @param string $viewFile the view file that will be used to decorate the content enclosed by this widget.
* This can be specified as either the view file path or path alias.
* @param array $params the variables (name=>value) to be extracted and made available in the decorative view.
* @return \yii\widgets\ContentDecorator the ContentDecorator widget instance
* @see \yii\widgets\ContentDecorator
*/
public function beginContent($viewFile, $params = array())
{
return $this->beginWidget('yii\widgets\ContentDecorator', array(
'viewFile' => $viewFile,
'params' => $params,
));
}
/**
* Ends the rendering of content.
*/
public function endContent()
{
$this->endWidget();
}
/**
* Begins fragment caching.
* This method will display cached content if it is available.
* If not, it will start caching and would expect an [[endCache()]]
* call to end the cache and save the content into cache.
* A typical usage of fragment caching is as follows,
*
* ~~~
* if($this->beginCache($id)) {
* // ...generate content here
* $this->endCache();
* }
* ~~~
*
* @param string $id a unique ID identifying the fragment to be cached.
* @param array $properties initial property values for [[\yii\widgets\FragmentCache]]
* @return boolean whether you should generate the content for caching.
* False if the cached version is available.
*/
public function beginCache($id, $properties = array())
{
$properties['id'] = $id;
/** @var $cache \yii\widgets\FragmentCache */
$cache = $this->beginWidget('yii\widgets\FragmentCache', $properties);
if ($cache->getCachedContent() !== false) {
$this->endCache();
return false;
} else {
return true;
}
}
/**
* Ends fragment caching.
*/
public function endCache()
{
$this->endWidget();
}
}