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<?php
/*
* This file is part of the Symfony package.
*
* (c) Fabien Potencier <fabien@symfony.com>
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
namespace Symfony\Component\HttpKernel\HttpCache;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\HttpKernel\HttpKernelInterface;
/**
* Esi implements the ESI capabilities to Request and Response instances.
*
* For more information, read the following W3C notes:
*
* * ESI Language Specification 1.0 (http://www.w3.org/TR/esi-lang)
*
* * Edge Architecture Specification (http://www.w3.org/TR/edge-arch)
*
* @author Fabien Potencier <fabien@symfony.com>
*/
class Esi implements SurrogateInterface
{
private $contentTypes;
private $phpEscapeMap = array(
array('<?', '<%', '<s', '<S'),
array('<?php echo "<?"; ?>', '<?php echo "<%"; ?>', '<?php echo "<s"; ?>', '<?php echo "<S"; ?>'),
);
/**
* 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;
}
public function getName()
{
return 'esi';
}
/**
* Returns a new cache strategy instance.
*
* @return ResponseCacheStrategyInterface A ResponseCacheStrategyInterface instance
*/
public function createCacheStrategy()
{
return new ResponseCacheStrategy();
}
/**
* Checks that at least one surrogate has ESI/1.0 capability.
*
* @param Request $request A Request instance
*
* @return bool true if one surrogate has ESI/1.0 capability, false otherwise
*/
public function hasSurrogateCapability(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 addSurrogateCapability(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 bool true if the Response needs to be parsed, false otherwise
*/
public function needsParsing(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 bool $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)
{
$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 = preg_replace('#<esi\:remove>.*?</esi\:remove>#s', '', $content);
$content = preg_replace('#<esi\:comment[^>]+>#s', '', $content);
$chunks = preg_split('#<esi\:include\s+(.*?)\s*(?:/|</esi\:include)>#', $content, -1, PREG_SPLIT_DELIM_CAPTURE);
$chunks[0] = str_replace($this->phpEscapeMap[0], $this->phpEscapeMap[1], $chunks[0]);
$i = 1;
while (isset($chunks[$i])) {
$options = array();
preg_match_all('/(src|onerror|alt)="([^"]*?)"/', $chunks[$i], $matches, PREG_SET_ORDER);
foreach ($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.');
}
$chunks[$i] = sprintf('<?php echo $this->surrogate->handle($this, %s, %s, %s) ?>'."\n",
var_export($options['src'], true),
var_export(isset($options['alt']) ? $options['alt'] : '', true),
isset($options['onerror']) && 'continue' === $options['onerror'] ? 'true' : 'false'
);
++$i;
$chunks[$i] = str_replace($this->phpEscapeMap[0], $this->phpEscapeMap[1], $chunks[$i]);
++$i;
}
$content = implode('', $chunks);
$response->setContent($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 bool $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;
}
}
}
}
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