* * For the full copyright and license information, please view the LICENSE * file that was distributed with this source code. */ namespace Symfony\Bridge\Twig\Extension; use Fig\Link\GenericLinkProvider; use Fig\Link\Link; use Symfony\Component\HttpFoundation\RequestStack; use Twig\Extension\AbstractExtension; use Twig\TwigFunction; /** * Twig extension for the Symfony WebLink component. * * @author Kévin Dunglas */ class WebLinkExtension extends AbstractExtension { private $requestStack; public function __construct(RequestStack $requestStack) { $this->requestStack = $requestStack; } /** * {@inheritdoc} */ public function getFunctions() { return array( new TwigFunction('link', array($this, 'link')), new TwigFunction('preload', array($this, 'preload')), new TwigFunction('dns_prefetch', array($this, 'dnsPrefetch')), new TwigFunction('preconnect', array($this, 'preconnect')), new TwigFunction('prefetch', array($this, 'prefetch')), new TwigFunction('prerender', array($this, 'prerender')), ); } /** * Adds a "Link" HTTP header. * * @param string $uri The relation URI * @param string $rel The relation type (e.g. "preload", "prefetch", "prerender" or "dns-prefetch") * @param array $attributes The attributes of this link (e.g. "array('as' => true)", "array('pr' => 0.5)") * * @return string The relation URI */ public function link($uri, $rel, array $attributes = array()) { if (!$request = $this->requestStack->getMasterRequest()) { return $uri; } $link = new Link($rel, $uri); foreach ($attributes as $key => $value) { $link = $link->withAttribute($key, $value); } $linkProvider = $request->attributes->get('_links', new GenericLinkProvider()); $request->attributes->set('_links', $linkProvider->withLink($link)); return $uri; } /** * Preloads a resource. * * @param string $uri A public path * @param array $attributes The attributes of this link (e.g. "array('as' => true)", "array('crossorigin' => 'use-credentials')") * * @return string The path of the asset */ public function preload($uri, array $attributes = array()) { return $this->link($uri, 'preload', $attributes); } /** * Resolves a resource origin as early as possible. * * @param string $uri A public path * @param array $attributes The attributes of this link (e.g. "array('as' => true)", "array('pr' => 0.5)") * * @return string The path of the asset */ public function dnsPrefetch($uri, array $attributes = array()) { return $this->link($uri, 'dns-prefetch', $attributes); } /** * Initiates a early connection to a resource (DNS resolution, TCP handshake, TLS negotiation). * * @param string $uri A public path * @param array $attributes The attributes of this link (e.g. "array('as' => true)", "array('pr' => 0.5)") * * @return string The path of the asset */ public function preconnect($uri, array $attributes = array()) { return $this->link($uri, 'preconnect', $attributes); } /** * Indicates to the client that it should prefetch this resource. * * @param string $uri A public path * @param array $attributes The attributes of this link (e.g. "array('as' => true)", "array('pr' => 0.5)") * * @return string The path of the asset */ public function prefetch($uri, array $attributes = array()) { return $this->link($uri, 'prefetch', $attributes); } /** * Indicates to the client that it should prerender this resource . * * @param string $uri A public path * @param array $attributes The attributes of this link (e.g. "array('as' => true)", "array('pr' => 0.5)") * * @return string The path of the asset */ public function prerender($uri, array $attributes = array()) { return $this->link($uri, 'prerender', $attributes); } }