Developer
<?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;
/**
* 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 extends AbstractSurrogate
{
public function getName(): string
{
return 'esi';
}
/**
* {@inheritdoc}
*/
public function addSurrogateControl(Response $response)
{
if (str_contains($response->getContent(), '<esi:include')) {
$response->headers->set('Surrogate-Control', 'content="ESI/1.0"');
}
}
/**
* {@inheritdoc}
*/
public function renderIncludeTag(string $uri, string $alt = null, bool $ignoreErrors = true, string $comment = ''): string
{
$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;
}
/**
* {@inheritdoc}
*/
public function process(Request $request, Response $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 = [];
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($options['src'], true),
var_export($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
$this->removeFromControl($response);
return $response;
}
}
Developer
To ensure a smooth integration process and optimal performance, follow these best practices: