gnu-social/plugins/Embed/Embed.php

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<?php
// {{{ License
// This file is part of GNU social - https://www.gnu.org/software/social
//
// GNU social is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// GNU social is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with GNU social. If not, see <http://www.gnu.org/licenses/>.
// }}}
/**
* OEmbed and OpenGraph implementation for GNU social
*
* @package GNUsocial
*
* @author Mikael Nordfeldth
* @author Stephen Paul Weber
* @author hannes
* @author Mikael Nordfeldth
* @author Miguel Dantas
* @author Hugo Sales <hugo@hsal.es>
* @author Diogo Peralta Cordeiro <mail@diogo.site>
* @copyright 2014-2021 Free Software Foundation, Inc http://www.fsf.org
* @license https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
*/
namespace Plugin\Embed;
use App\Core\Cache;
use App\Core\DB\DB;
use App\Core\Event;
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use App\Core\GSFile;
use App\Core\HTTPClient;
use function App\Core\I18n\_m;
use App\Core\Log;
use App\Core\Modules\Plugin;
use App\Core\Router\RouteLoader;
use App\Core\Router\Router;
use App\Entity\Attachment;
use App\Entity\Link;
use App\Entity\Note;
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use App\Util\Common;
use App\Util\Exception\DuplicateFoundException;
use App\Util\Exception\NotFoundException;
use App\Util\Exception\ServerException;
use App\Util\Formatting;
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use App\Util\TemporaryFile;
use Embed\Embed as LibEmbed;
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use Exception;
use Symfony\Component\HttpFoundation\Request;
/**
* Base class for the Embed plugin that does most of the heavy lifting to get
* and display representations for remote content.
*
* @copyright 2014-2021 Free Software Foundation, Inc http://www.fsf.org
* @license https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
*/
class Embed extends Plugin
{
public function version(): string
{
return '3.0.0';
}
/**
* Settings which can be set in social.local.yaml
* WARNING, these are _regexps_ (slashes added later). Always escape your dots and end ('$') your strings
*/
public array $domain_whitelist = [
// hostname => service provider
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'.*' => '', // Default to allowing any host
];
/**
* This code executes when GNU social creates the page routing, and we hook
* on this event to add our action handler for Embed.
*
* @param $m RouteLoader the router that was initialized.
*
* @throws Exception
*
* @return bool
*
*
*/
public function onAddRoute(RouteLoader $m): bool
{
$m->connect('oembed', 'main/oembed', Controller\Embed::class);
$m->connect('embed', 'main/embed', Controller\Embed::class);
return Event::next;
}
/**
* Insert oembed and opengraph tags in all HTML head elements
*/
public function onShowHeadElements(Request $request, array &$result): bool
{
$matches = [];
preg_match(',/?([^/]+)/?(.*),', $request->getPathInfo(), $matches);
$url = match ($matches[1]) {
'attachment' => "{$matches[1]}/{$matches[2]}",
default => null,
};
if (is_null($url)) {
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foreach (['xml', 'json'] as $format) {
$result[] = [
'link' => [
'rel' => 'alternate',
'type' => "application/{$format}+oembed",
'href' => Router::url('embed', ['format' => $format, 'url' => $url]),
'title' => 'oEmbed',
], ];
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}
}
return Event::next;
}
/**
* Show this attachment enhanced with the corresponding Embed data, if available
*
* @param array $vars
* @param array $res
*
* @return bool
*/
public function onViewLink(array $vars, array &$res): bool
{
$link = $vars['link'];
try {
$embed = Cache::get('attachment-embed-' . $link->getId(),
fn () => DB::findOneBy('attachment_embed', ['link_id' => $link->getId()]));
} catch (DuplicateFoundException $e) {
Log::warning($e);
return Event::next;
} catch (NotFoundException) {
Log::debug("Embed doesn't have a representation for the link id={$link->getId()}. Must have been stored before the plugin was enabled.");
return Event::next;
}
$attributes = $embed->getImageHTMLAttributes(['class' => 'u-photo embed']);
$res[] = Formatting::twigRenderFile('embed/embedView.html.twig',
['embed' => $embed, 'attributes' => $attributes, 'link' => $link]);
return Event::stop;
}
/**
* Save embedding information for an Attachment, if applicable.
*
* @param Link $link
* @param Note $note
*
*@throws DuplicateFoundException
*
* @return bool
*
*/
public function onNewLinkFromNote(Link $link, Note $note): bool
{
// Only handle text mime
$mimetype = $link->getMimetype();
if (!(Formatting::startsWith($mimetype, 'text/html') || Formatting::startsWith($mimetype, 'application/xhtml+xml'))) {
return Event::next;
}
// Ignore if already handled
$attachment_embed = DB::find('attachment_embed', ['link_id' => $link->getId()]);
if (!is_null($attachment_embed)) {
return Event::next;
}
// If an attachment already exist, do not create an Embed for it. Some other plugin must have done things
$link_to_attachment = DB::find('link_to_attachment', ['link_id' => $link->getId()]);
if (!is_null($link_to_attachment)) {
$attachment_id = $link_to_attachment->getAttachmentId();
try {
$attachment = DB::findOneBy('attachment', ['id' => $attachment_id]);
$attachment->livesIncrementAndGet();
return Event::next;
} catch (DuplicateFoundException | NotFoundException $e) {
Log::error($e);
}
}
// Create an Embed representation for this URL
$embed_data = $this->getEmbedLibMetadata($link->getUrl());
$embed_data['link_id'] = $link->getId();
$img_data = $this->downloadThumbnail($embed_data['thumbnail_url']);
switch ($img_data) {
case null: // URL isn't usable
$embed_data['thumbnail_url'] = null;
// no break
case false: // Thumbnail isn't acceptable
DB::persist($attachment = Attachment::create(['mimetype' => $link->getMimetype()]));
Event::handle('AttachmentStoreNew', [&$attachment]);
break;
default: // String is valid image data
$temp_file = new TemporaryFile();
$temp_file->write($img_data);
$attachment = GSFile::sanitizeAndStoreFileAsAttachment($temp_file);
$embed_data['attachment_id'] = $attachment->getId();
}
$embed_data['attachment_id'] = $attachment->getId();
DB::persist(Entity\AttachmentEmbed::create($embed_data));
DB::flush();
return Event::stop;
}
/**
* Perform an oEmbed or OpenGraph lookup for the given $url.
*
* Some known hosts are whitelisted with API endpoints where we
* know they exist but autodiscovery data isn't available.
*
* Throws exceptions on failure.
*
* @param string $url
*
* @return array
*/
private function getEmbedLibMetadata(string $url): array
{
Log::info("Trying to find Embed data for {$url} with 'oscarotero/Embed'");
$embed = new LibEmbed();
$info = $embed->get($url);
$metadata['title'] = $info->title;
$metadata['description'] = $info->description;
$metadata['author_name'] = $info->authorName;
$metadata['author_url'] = (string) $info->authorUrl;
$metadata['provider_name'] = $info->providerName;
$metadata['provider_url'] = (string) $info->providerUrl;
if (!is_null($info->image)) {
$thumbnail_url = (string) $info->image;
} else {
$thumbnail_url = (string) $info->favicon;
}
// Check thumbnail URL validity
$metadata['thumbnail_url'] = $thumbnail_url;
return self::normalizeEmbedLibMetadata($metadata);
}
/**
* Normalize fetched info.
*
* @param array $metadata
*
* @return array
*/
private static function normalizeEmbedLibMetadata(array $metadata): array
{
if (isset($metadata['thumbnail_url'])) {
// sometimes sites serve the path, not the full URL, for images
// let's "be liberal in what you accept from others"!
// add protocol and host if the thumbnail_url starts with /
if ($metadata['thumbnail_url'][0] == '/') {
$thumbnail_url_parsed = parse_url($metadata['thumbnail_url']);
$metadata['thumbnail_url'] = "{$thumbnail_url_parsed['scheme']}://{$thumbnail_url_parsed['host']}{$metadata['url']}";
}
// Some wordpress opengraph implementations sometimes return a white blank image
// no need for us to save that!
if ($metadata['thumbnail_url'] == 'https://s0.wp.com/i/blank.jpg') {
$metadata['thumbnail_url'] = null;
}
}
return $metadata;
}
/**
* @param string $url
*
* @return bool true if allowed by the lists, false otherwise
*/
private function allowedLink(string $url): bool
{
return true;
if ($this->check_whitelist ?? false) {
return false; // indicates "no check made"
}
$host = parse_url($url, PHP_URL_HOST);
foreach ($this->domain_whitelist as $regex => $provider) {
if (preg_match("/{$regex}/", $host)) {
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return $provider; // we trust this source, return provider name
}
}
return false;
}
/**
* Private helper that:
* - checks if given URL is valid and is in fact an image (basic test), returns null if not;
* - checks if respects file quota and whitelist/blacklist, returns false if not;
* - downloads the thumbnail, returns a string if successful.
*
* @param string $url URL to the remote thumbnail
*
* @return null|bool|string
*/
private function downloadThumbnail(string $url): bool|string|null
{
// Is this a valid URL?
if (!Common::isValidHttpUrl($url)) {
Log::debug("Invalid URL ({$url}) in Embed->downloadThumbnail.");
return null;
}
// Is this URL trusted?
if (!$this->allowedLink($url)) {
Log::info("Blocked URL ({$url}) in Embed->downloadThumbnail.");
return false;
}
// Validate if the URL really does point to a remote image
$head = HTTPClient::head($url);
$headers = $head->getHeaders();
$headers = array_change_key_case($headers, CASE_LOWER);
if (empty($headers['content-type']) || GSFile::mimetypeMajor($headers['content-type'][0]) !== 'image') {
Log::debug("URL ({$url}) doesn't point to an image (content-type: " . (!empty($headers['content-type'][0]) ? $headers['content-type'][0] : 'not available') . ') in Embed->downloadThumbnail.');
return null;
}
// Does it respect the file quota?
$file_size = $headers['content-length'][0];
$max_size = Common::config('attachments', 'file_quota');
if ($file_size > $max_size) {
Log::debug("Went to download remote thumbnail of size {$file_size} but the upload limit is {$max_size} so we aborted in Embed->downloadThumbnail.");
return false;
}
// Download and return the file
Log::debug("Downloading remote thumbnail from URL: {$url} in Embed->downloadThumbnail.");
return HTTPClient::get($url)->getContent();
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}
/**
* Event raised when GNU social polls the plugin for information about it.
* Adds this plugin's version information to $versions array
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*
* @param &$versions array inherited from parent
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*
* @throws ServerException
*
* @return bool true hook value
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*/
public function onPluginVersion(array &$versions): bool
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{
$versions[] = [
'name' => 'Embed',
'version' => $this->version(),
'author' => 'Mikael Nordfeldth, Hugo Sales, Diogo Peralta Cordeiro',
'homepage' => GNUSOCIAL_PROJECT_URL,
'description' => // TRANS: Plugin description.
_m('Plugin for using and representing oEmbed, OpenGraph and other data.'),
];
return Event::next;
}
}