Esi implements the ESI capabilities to Request and Response instances.
For more information, read the following W3C notes:
@author Fabien Potencier <fabien@symfony.com>
Expanded class hierarchy of Esi
class Esi {
private $contentTypes;
/**
* Constructor.
*
* @param array $contentTypes An array of content-type that should be parsed for ESI information.
* (default: text/html, text/xml, application/xhtml+xml, and application/xml)
*/
public function __construct(array $contentTypes = array(
'text/html',
'text/xml',
'application/xhtml+xml',
'application/xml',
)) {
$this->contentTypes = $contentTypes;
}
/**
* Returns a new cache strategy instance.
*
* @return EsiResponseCacheStrategyInterface A EsiResponseCacheStrategyInterface instance
*/
public function createCacheStrategy() {
return new EsiResponseCacheStrategy();
}
/**
* Checks that at least one surrogate has ESI/1.0 capability.
*
* @param Request $request A Request instance
*
* @return Boolean true if one surrogate has ESI/1.0 capability, false otherwise
*/
public function hasSurrogateEsiCapability(Request $request) {
if (null === ($value = $request->headers
->get('Surrogate-Capability'))) {
return false;
}
return false !== strpos($value, 'ESI/1.0');
}
/**
* Adds ESI/1.0 capability to the given Request.
*
* @param Request $request A Request instance
*/
public function addSurrogateEsiCapability(Request $request) {
$current = $request->headers
->get('Surrogate-Capability');
$new = 'symfony2="ESI/1.0"';
$request->headers
->set('Surrogate-Capability', $current ? $current . ', ' . $new : $new);
}
/**
* Adds HTTP headers to specify that the Response needs to be parsed for ESI.
*
* This method only adds an ESI HTTP header if the Response has some ESI tags.
*
* @param Response $response A Response instance
*/
public function addSurrogateControl(Response $response) {
if (false !== strpos($response
->getContent(), '<esi:include')) {
$response->headers
->set('Surrogate-Control', 'content="ESI/1.0"');
}
}
/**
* Checks that the Response needs to be parsed for ESI tags.
*
* @param Response $response A Response instance
*
* @return Boolean true if the Response needs to be parsed, false otherwise
*/
public function needsEsiParsing(Response $response) {
if (!($control = $response->headers
->get('Surrogate-Control'))) {
return false;
}
return (bool) preg_match('#content="[^"]*ESI/1.0[^"]*"#', $control);
}
/**
* Renders an ESI tag.
*
* @param string $uri A URI
* @param string $alt An alternate URI
* @param Boolean $ignoreErrors Whether to ignore errors or not
* @param string $comment A comment to add as an esi:include tag
*
* @return string
*/
public function renderIncludeTag($uri, $alt = null, $ignoreErrors = true, $comment = '') {
$html = sprintf('<esi:include src="%s"%s%s />', $uri, $ignoreErrors ? ' onerror="continue"' : '', $alt ? sprintf(' alt="%s"', $alt) : '');
if (!empty($comment)) {
return sprintf("<esi:comment text=\"%s\" />\n%s", $comment, $html);
}
return $html;
}
/**
* Replaces a Response ESI tags with the included resource content.
*
* @param Request $request A Request instance
* @param Response $response A Response instance
*
* @return Response
*/
public function process(Request $request, Response $response) {
$this->request = $request;
$type = $response->headers
->get('Content-Type');
if (empty($type)) {
$type = 'text/html';
}
$parts = explode(';', $type);
if (!in_array($parts[0], $this->contentTypes)) {
return $response;
}
// we don't use a proper XML parser here as we can have ESI tags in a plain text response
$content = $response
->getContent();
$content = str_replace(array(
'<?',
'<%',
), array(
'<?php echo "<?"; ?>',
'<?php echo "<%"; ?>',
), $content);
$content = preg_replace_callback('#<esi\\:include\\s+(.*?)\\s*(?:/|</esi\\:include)>#', array(
$this,
'handleEsiIncludeTag',
), $content);
$content = preg_replace('#<esi\\:comment[^>]*(?:/|</esi\\:comment)>#', '', $content);
$content = preg_replace('#<esi\\:remove>.*?</esi\\:remove>#', '', $content);
$response
->setContent($content);
$response->headers
->set('X-Body-Eval', 'ESI');
// remove ESI/1.0 from the Surrogate-Control header
if ($response->headers
->has('Surrogate-Control')) {
$value = $response->headers
->get('Surrogate-Control');
if ('content="ESI/1.0"' == $value) {
$response->headers
->remove('Surrogate-Control');
}
elseif (preg_match('#,\\s*content="ESI/1.0"#', $value)) {
$response->headers
->set('Surrogate-Control', preg_replace('#,\\s*content="ESI/1.0"#', '', $value));
}
elseif (preg_match('#content="ESI/1.0",\\s*#', $value)) {
$response->headers
->set('Surrogate-Control', preg_replace('#content="ESI/1.0",\\s*#', '', $value));
}
}
}
/**
* Handles an ESI from the cache.
*
* @param HttpCache $cache An HttpCache instance
* @param string $uri The main URI
* @param string $alt An alternative URI
* @param Boolean $ignoreErrors Whether to ignore errors or not
*
* @return string
*
* @throws \RuntimeException
* @throws \Exception
*/
public function handle(HttpCache $cache, $uri, $alt, $ignoreErrors) {
$subRequest = Request::create($uri, 'get', array(), $cache
->getRequest()->cookies
->all(), array(), $cache
->getRequest()->server
->all());
try {
$response = $cache
->handle($subRequest, HttpKernelInterface::SUB_REQUEST, true);
if (!$response
->isSuccessful()) {
throw new \RuntimeException(sprintf('Error when rendering "%s" (Status code is %s).', $subRequest
->getUri(), $response
->getStatusCode()));
}
return $response
->getContent();
} catch (\Exception $e) {
if ($alt) {
return $this
->handle($cache, $alt, '', $ignoreErrors);
}
if (!$ignoreErrors) {
throw $e;
}
}
}
/**
* Handles an ESI include tag (called internally).
*
* @param array $attributes An array containing the attributes.
*
* @return string The response content for the include.
*
* @throws \RuntimeException
*/
private function handleEsiIncludeTag($attributes) {
$options = array();
preg_match_all('/(src|onerror|alt)="([^"]*?)"/', $attributes[1], $matches, PREG_SET_ORDER);
foreach ($matches as $set) {
$options[$set[1]] = $set[2];
}
if (!isset($options['src'])) {
throw new \RuntimeException('Unable to process an ESI tag without a "src" attribute.');
}
return sprintf('<?php echo $this->esi->handle($this, \'%s\', \'%s\', %s) ?>' . "\n", $options['src'], isset($options['alt']) ? $options['alt'] : null, isset($options['onerror']) && 'continue' == $options['onerror'] ? 'true' : 'false');
}
}
Name | Modifiers | Type | Description | Overrides |
---|---|---|---|---|
Esi:: |
private | property | ||
Esi:: |
public | function | Adds HTTP headers to specify that the Response needs to be parsed for ESI. | |
Esi:: |
public | function | Adds ESI/1.0 capability to the given Request. | |
Esi:: |
public | function | Returns a new cache strategy instance. | |
Esi:: |
public | function | Handles an ESI from the cache. | |
Esi:: |
private | function | Handles an ESI include tag (called internally). | |
Esi:: |
public | function | Checks that at least one surrogate has ESI/1.0 capability. | |
Esi:: |
public | function | Checks that the Response needs to be parsed for ESI tags. | |
Esi:: |
public | function | Replaces a Response ESI tags with the included resource content. | |
Esi:: |
public | function | Renders an ESI tag. | |
Esi:: |
public | function | Constructor. |