Add util to unfurl urls

diff --git a/wcfsetup/install/files/lib/util/UnfurlUrlUtil.class.php b/wcfsetup/install/files/lib/util/UnfurlUrlUtil.class.php
new file mode 100644 (file)
index 0000000..6814d68
--- /dev/null
+++ b/wcfsetup/install/files/lib/util/UnfurlUrlUtil.class.php
@@ -0,0 +1,254 @@
+<?php
+
+namespace wcf\util;
+
+use GuzzleHttp\Exception\BadResponseException;
+use GuzzleHttp\Exception\TooManyRedirectsException;
+use GuzzleHttp\Exception\TransferException;
+use GuzzleHttp\Psr7\Request;
+use GuzzleHttp\RequestOptions;
+use wcf\system\io\HttpFactory;
+
+/**
+ * Helper class to unfurl specific urls.
+ *
+ * @author      Joshua Ruesweg
+ * @copyright   2001-2021 WoltLab GmbH
+ * @license     GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
+ * @package     WoltLabSuite\Core\Util
+ * @since       5.4
+ */
+final class UnfurlUrlUtil
+{
+    /**
+     * 10 Mebibyte
+     */
+    private const MAX_SIZE = (10 * (1 << 20));
+
+    /**
+     * 3 Mebibyte
+     */
+    private const MAX_IMAGE_SIZE = (3 * (1 << 20));
+
+    /**
+     * @var string
+     */
+    private $url;
+    
+    /**
+     * @var string
+     */
+    private $body;
+    
+    /**
+     * @var \DOMDocument
+     */
+    private $domDocument;
+    
+    public function __construct(string $url)
+    {
+        if (!Url::is($url)) {
+            throw new \InvalidArgumentException('Given URL "' . $url . '" is not a valid URL.');
+        }
+        
+        $this->url = $url;
+        
+        $this->fetchUrl();
+    }
+    
+    /**
+     * Fetches the body of the given url and converts the body to utf-8.
+     */
+    private function fetchUrl(): void
+    {
+        try {
+            $client = HttpFactory::makeClient([
+                RequestOptions::TIMEOUT => 10,
+                RequestOptions::STREAM => true,
+            ]);
+            $request = new Request('GET', $this->url, [
+                'range' => \sprintf('bytes=%d-%d', 0, self::MAX_SIZE - 1),
+            ]);
+            $response = $client->send($request);
+            
+            $this->body = "";
+            while (!$response->getBody()->eof()) {
+                $this->body .= $response->getBody()->read(8192);
+
+                if ($response->getBody()->tell() >= self::MAX_SIZE) {
+                    break;
+                }
+            }
+            $response->getBody()->close();
+            
+            if (\mb_detect_encoding($this->body) !== 'UTF-8') {
+                $this->body = StringUtil::convertEncoding(\mb_detect_encoding($this->body), 'UTF-8', $this->body);
+            }
+        } catch (TooManyRedirectsException | BadResponseException | TransferException $e) {
+            // Ignore these exceptions.
+        }
+    }
+    
+    /**
+     * Returns the dom document of the website.
+     */
+    private function getDomDocument(): \DOMDocument
+    {
+        if ($this->domDocument === null) {
+            \libxml_use_internal_errors(true);
+            $this->domDocument = new \DOMDocument();
+            $this->domDocument->loadHTML('<?xml version="1.0" encoding="UTF-8"?>' . $this->body);
+        }
+        
+        return $this->domDocument;
+    }
+    
+    /**
+     * Determines the title of the website.
+     */
+    public function getTitle(): ?string
+    {
+        if (!empty($this->body)) {
+            $metaTags = $this->getDomDocument()->getElementsByTagName('meta');
+            
+            // og
+            foreach ($metaTags as $metaTag) {
+                foreach ($metaTag->attributes as $attr) {
+                    if ($attr->nodeName == 'property' && $attr->value == 'og:title') {
+                        foreach ($attr->parentNode->attributes as $attr) {
+                            if ($attr->nodeName == 'content') {
+                                return $attr->value;
+                            }
+                        }
+                    }
+                }
+            }
+            
+            // title tag
+            $title = $this->getDomDocument()->getElementsByTagName('title');
+            if ($title->length) {
+                return $title->item(0)->nodeValue;
+            }
+        }
+
+        return null;
+    }
+    
+    /**
+     * Determines the description of the website.
+     */
+    public function getDescription(): ?string
+    {
+        if (!empty($this->body)) {
+            $metaTags = $this->getDomDocument()->getElementsByTagName('meta');
+
+            // og:description
+            foreach ($metaTags as $metaTag) {
+                foreach ($metaTag->attributes as $attr) {
+                    if ($attr->nodeName == 'property' && $attr->value == 'og:description') {
+                        foreach ($attr->parentNode->attributes as $attr) {
+                            if ($attr->nodeName == 'content') {
+                                return $attr->value;
+                            }
+                        }
+                    }
+                }
+            }
+        }
+
+        return null;
+    }
+    
+    /**
+     * Returns the image url for the current url.
+     */
+    public function getImageUrl(): ?string
+    {
+        if (!empty($this->body)) {
+            $metaTags = $this->getDomDocument()->getElementsByTagName('meta');
+            
+            // og:image
+            foreach ($metaTags as $metaTag) {
+                foreach ($metaTag->attributes as $attr) {
+                    if ($attr->nodeName == 'property' && $attr->value == 'og:image') {
+                        foreach ($attr->parentNode->attributes as $attr) {
+                            if ($attr->nodeName == 'content') {
+                                return $attr->value;
+                            }
+                        }
+                    }
+                }
+            }
+        }
+
+        return null;
+    }
+    
+    /**
+     * Downloads the image from a url and returns the image body.
+     */
+    public static function downloadImageFromUrl(string $url): ?string
+    {
+        try {
+            // Rewrite schemaless URLs to https.
+            $scheme = \parse_url($url, \PHP_URL_SCHEME);
+            if (!$scheme) {
+                if (StringUtil::startsWith($url, '//')) {
+                    $url = 'https:' . $url;
+                } else {
+                    throw new \DomainException();
+                }
+            }
+
+            // download image
+            try {
+                $client = HttpFactory::makeClient([
+                    RequestOptions::TIMEOUT => 10,
+                    RequestOptions::STREAM => true,
+                ]);
+                $request = new Request('GET', $url, [
+                    'via' => '1.1 wsc',
+                    'accept' => 'image/*',
+                    'range' => 'bytes=0-' . (self::MAX_IMAGE_SIZE - 1),
+                ]);
+                $response = $client->send($request);
+
+                $image = "";
+                while (!$response->getBody()->eof()) {
+                    $image .= $response->getBody()->read(8192);
+
+                    if ($response->getBody()->tell() >= self::MAX_IMAGE_SIZE) {
+                        break;
+                    }
+                }
+                $response->getBody()->close();
+            } catch (TransferException $e) {
+                throw new \DomainException('Failed to request', 0, $e);
+            }
+
+            // check file type
+            $imageData = @\getimagesizefromstring($image);
+            if (!$imageData) {
+                throw new \DomainException();
+            }
+
+            switch ($imageData[2]) {
+                case \IMAGETYPE_PNG:
+                    $extension = 'png';
+                    break;
+                case \IMAGETYPE_GIF:
+                    $extension = 'gif';
+                    break;
+                case \IMAGETYPE_JPEG:
+                    $extension = 'jpg';
+                    break;
+                default:
+                    throw new \DomainException();
+            }
+
+            return $image;
+        } catch (\DomainException $e) {
+            return null;
+        }
+    }
+}