gnu-social/plugins/Embed/EmbedPlugin.php

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<?php
// 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 Stephen Paul Weber
* @author hannes
* @author Mikael Nordfeldth
* @author Diogo Cordeiro <diogo@fc.up.pt>
* @author Miguel Dantas <biodantasgs@gmail.com>
* @copyright 2019 Free Software Foundation, Inc http://www.fsf.org
* @license https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
*/
defined('GNUSOCIAL') || die();
use Embed\Embed;
/**
* Base class for the Embed plugin that does most of the heavy lifting to get
* and display representations for remote content.
*
* @copyright 2019 Free Software Foundation, Inc http://www.fsf.org
* @license https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
*/
class EmbedPlugin extends Plugin
{
const PLUGIN_VERSION = '0.1.0';
// settings which can be set in config.php with addPlugin('Embed', ['param'=>'value', ...]);
// WARNING, these are _regexps_ (slashes added later). Always escape your dots and end ('$') your strings
public $domain_whitelist = [
// hostname => service provider
'^i\d*\.ytimg\.com$' => 'YouTube',
'^i\d*\.vimeocdn\.com$' => 'Vimeo',
];
public $append_whitelist = []; // fill this array as domain_whitelist to add more trusted sources
public $check_whitelist = false; // security/abuse precaution
public $thumbnail_width = 128;
public $thumbnail_height = 128;
public $thumbnail_crop = true;
protected $imgData = [];
/**
* Initialize the Embed plugin and set up the environment it needs for it.
* Returns true if it initialized properly, the exception object if it
* doesn't.
*/
public function initialize()
{
parent::initialize();
$this->domain_whitelist = array_merge($this->domain_whitelist, $this->append_whitelist);
}
/**
* The code executed on GNU social checking the database schema, which in
* this case is to make sure we have the plugin table we need.
*
* @return bool true if it ran successfully, the exception object if it doesn't.
*/
public function onCheckSchema()
{
$this->onEndUpgrade(); // Ensure rename
$schema = Schema::get();
$schema->ensureTable('file_embed', File_embed::schemaDef());
return true;
}
public function onEndUpgrade()
{
$schema = Schema::get();
return $schema->renameTable('file_oembed', 'file_embed');
}
/**
* 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 URLMapper the router that was initialized.
* @return void true if successful, the exception object if it isn't.
* @throws Exception
*/
public function onRouterInitialized(URLMapper $m)
{
$m->connect('main/oembed', ['action' => 'oembed']);
}
/**
* This event executes when GNU social encounters a remote URL we then decide
* to interrogate for metadata. Embed gloms onto it to see if we have an
* oEmbed endpoint or image to try to represent in the post.
*
* @param $url string the remote URL we're looking at
* @param $dom DOMDocument the document we're getting metadata from
* @param $metadata stdClass class representing the metadata
* @return bool true if successful, the exception object if it isn't.
*/
public function onGetRemoteUrlMetadataFromDom($url, DOMDocument $dom, stdClass &$metadata)
{
try {
common_log(LOG_INFO, "Trying to find Embed data for {$url} with 'oscarotero/Embed'");
$info = Embed::create($url);
$metadata->version = '1.0'; // Yes.
$metadata->provider_name = $info->authorName;
$metadata->title = $info->title;
$metadata->html = common_purify($info->description);
$metadata->type = $info->type;
$metadata->url = $info->url;
$metadata->thumbnail_height = $info->imageHeight;
$metadata->thumbnail_width = $info->imageWidth;
if (substr($info->image, 0, 4) === 'data') {
// Inline image
$imgData = base64_decode(substr($info->image, stripos($info->image, 'base64,') + 7));
list($filename, , ) = $this->validateAndWriteImage($imgData);
// Use a file URI for images, as file_embed can't store a filename
$metadata->thumbnail_url = 'file://' . File_thumbnail::path($filename);
} else {
$metadata->thumbnail_url = $info->image;
}
} catch (Exception $e) {
common_log(LOG_INFO, "Failed to find Embed data for {$url} with 'oscarotero/Embed'" .
", got exception: " . get_class($e));
}
if (isset($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 /
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if ($metadata->thumbnail_url[0] == '/') {
$thumbnail_url_parsed = parse_url($metadata->url);
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$metadata->thumbnail_url = "{$thumbnail_url_parsed['scheme']}://".
"{$thumbnail_url_parsed['host']}{$metadata->thumbnail_url}";
}
// some wordpress opengraph implementations sometimes return a white blank image
// no need for us to save that!
if ($metadata->thumbnail_url == 'https://s0.wp.com/i/blank.jpg') {
unset($metadata->thumbnail_url);
}
// FIXME: this is also true of locally-installed wordpress so we should watch out for that.
}
return true;
}
public function onEndShowHeadElements(Action $action)
{
switch ($action->getActionName()) {
case 'attachment':
$url = common_local_url('attachment', ['attachment' => $action->attachment->getID()]);
break;
case 'shownotice':
if (!$action->notice->isLocal()) {
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return true;
}
try {
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$url = $action->notice->getUrl();
} catch (InvalidUrlException $e) {
// The notice is probably a share or similar, which don't
// have a representational URL of their own.
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return true;
}
break;
}
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if (isset($url)) {
foreach (['xml', 'json'] as $format) {
$action->element(
'link',
['rel' =>'alternate',
'type' => "application/{$format}+oembed",
'href' => common_local_url(
'oembed',
[],
['format' => $format, 'url' => $url]
),
'title' => 'oEmbed']
);
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}
}
return true;
}
public function onEndShowStylesheets(Action $action)
{
$action->cssLink($this->path('css/embed.css'));
return true;
}
/**
* Save embedding information for a File, if applicable.
*
* Normally this event is called through File::saveNew()
*
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* @param File $file The newly inserted File object.
*
* @return boolean success
*/
public function onEndFileSaveNew(File $file)
{
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$fe = File_embed::getKV('file_id', $file->getID());
if ($fe instanceof File_embed) {
common_log(LOG_WARNING, "Strangely, a File_embed object exists for new file {$file->getID()}", __FILE__);
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return true;
}
if (isset($file->mimetype)
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&& (('text/html' === substr($file->mimetype, 0, 9) ||
'application/xhtml+xml' === substr($file->mimetype, 0, 21)))) {
try {
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$embed_data = File_embed::getEmbed($file->url);
if ($embed_data === false) {
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throw new Exception("Did not get Embed data from URL {$file->url}");
}
$file->setTitle($embed_data->title);
} catch (Exception $e) {
common_log(LOG_WARNING, sprintf(
__METHOD__.': %s thrown when getting embed data: %s',
get_class($e),
_ve($e->getMessage())
));
return true;
}
File_embed::saveNew($embed_data, $file->getID());
}
return true;
}
public function onEndShowAttachmentLink(HTMLOutputter $out, File $file)
{
$embed = File_embed::getKV('file_id', $file->getID());
if (empty($embed->author_name) && empty($embed->provider)) {
return true;
}
$out->elementStart('div', ['id'=>'oembed_info', 'class'=>'e-content']);
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foreach (['author_name' => ['class' => ' author', 'url' => 'author_url'],
'provider' => ['class' => '', 'url' => 'provider_url']]
as $field => $options) {
if (!empty($embed->{$field})) {
$out->elementStart('div', "fn vcard" . $options['class']);
if (empty($embed->{$options['url']})) {
$out->text($embed->{$field});
} else {
$out->element(
'a',
['href' => $embed->{$options['url']},
'class' => 'url'],
$embed->{$field}
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);
}
}
}
$out->elementEnd('div');
}
public function onFileEnclosureMetadata(File $file, &$enclosure)
{
// Never treat generic HTML links as an enclosure type!
// But if we have embed info, we'll consider it golden.
$embed = File_embed::getKV('file_id', $file->getID());
if (!$embed instanceof File_embed || !in_array($embed->type, ['photo', 'video'])) {
return true;
}
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foreach (['mimetype', 'url', 'title', 'modified', 'width', 'height'] as $key) {
if (isset($embed->{$key}) && !empty($embed->{$key})) {
$enclosure->{$key} = $embed->{$key};
}
}
return true;
}
public function onStartShowAttachmentRepresentation(HTMLOutputter $out, File $file)
{
try {
$embed = File_embed::getByFile($file);
} catch (NoResultException $e) {
return true;
}
// Show thumbnail as usual if it's a photo.
if ($embed->type === 'photo') {
return true;
}
$out->elementStart('article', ['class'=>'h-entry embed']);
$out->elementStart('header');
try {
$thumb = $file->getThumbnail($this->thumbnail_width, $this->thumbnail_height);
$out->element('img', $thumb->getHtmlAttrs(['class'=>'u-photo embed']));
unset($thumb);
} catch (FileNotFoundException $e) {
// Nothing to show
} catch (Exception $e) {
$out->element('div', ['class'=>'error'], $e->getMessage());
}
$out->elementStart('h5', ['class'=>'p-name embed']);
$out->element('a', ['class'=>'u-url', 'href'=>$file->getUrl()], common_strip_html($embed->title));
$out->elementEnd('h5');
$out->elementStart('div', ['class'=>'p-author embed']);
if (!empty($embed->author_name)) {
// TRANS: text before the author name of embed attachment representation
// FIXME: The whole "By x from y" should be i18n because of different language constructions.
$out->text(_('By '));
$attrs = ['class'=>'h-card p-author'];
if (!empty($embed->author_url)) {
$attrs['href'] = $embed->author_url;
$tag = 'a';
} else {
$tag = 'span';
}
$out->element($tag, $attrs, $embed->author_name);
}
if (!empty($embed->provider)) {
// TRANS: text between the embed author name and provider url
// FIXME: The whole "By x from y" should be i18n because of different language constructions.
$out->text(_(' from '));
$attrs = ['class'=>'h-card'];
if (!empty($embed->provider_url)) {
$attrs['href'] = $embed->provider_url;
$tag = 'a';
} else {
$tag = 'span';
}
$out->element($tag, $attrs, $embed->provider);
}
$out->elementEnd('div');
$out->elementEnd('header');
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$out->elementStart('div', ['class'=>'p-summary embed']);
$out->raw(common_purify($embed->html));
$out->elementEnd('div');
$out->elementStart('footer');
$out->elementEnd('footer');
$out->elementEnd('article');
return false;
}
public function onShowUnsupportedAttachmentRepresentation(HTMLOutputter $out, File $file)
{
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try {
$embed = File_embed::getByFile($file);
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} catch (NoResultException $e) {
return true;
}
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// the 'photo' type is shown through ordinary means, using StartShowAttachmentRepresentation!
switch ($embed->type) {
case 'video':
case 'link':
if (!empty($embed->html)
&& (GNUsocial::isAjax() || common_config('attachments', 'show_html'))) {
require_once INSTALLDIR.'/extlib/HTMLPurifier/HTMLPurifier.auto.php';
$purifier = new HTMLPurifier();
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// FIXME: do we allow <object> and <embed> here? we did that when we used htmLawed,
// but I'm not sure anymore...
$out->raw($purifier->purify($embed->html));
}
return false;
}
return true;
}
/**
* This event executes when GNU social is creating a file thumbnail entry in
* the database. We glom onto this to create proper information for Embed
* object thumbnails.
*
* @param $file File the file of the created thumbnail
* @param &$imgPath string = the path to the created thumbnail
* @return bool true if it succeeds (including non-action
* states where it isn't oEmbed data, so it doesn't mess up the event handle
* for other things hooked into it), or the exception if it fails.
*/
public function onCreateFileImageThumbnailSource(File $file, &$imgPath, $media)
{
// If we are on a private node, we won't do any remote calls (just as a precaution until
// we can configure this from config.php for the private nodes)
if (common_config('site', 'private')) {
return true;
}
// All our remote Embed images lack a local filename property in the File object
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if (!is_null($file->filename)) {
common_debug(sprintf('Filename of file id==%d is not null (%s), so nothing Embed '.
'should handle.', $file->getID(), _ve($file->filename)));
return true;
}
try {
// If we have proper Embed data, there should be an entry in the File_thumbnail table.
// If not, we're not going to do anything.
$thumbnail = File_thumbnail::byFile($file);
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} catch (NoResultException $e) {
// Not Embed data, or at least nothing we either can or want to use.
common_debug('No Embed data found for file id=='.$file->getID());
return true;
}
try {
$this->storeRemoteFileThumbnail($thumbnail);
} catch (AlreadyFulfilledException $e) {
// aw yiss!
} catch (Exception $e) {
common_debug(sprintf(
'Embed encountered an exception (%s) for file id==%d: %s',
get_class($e),
$file->getID(),
_ve($e->getMessage())
));
throw $e;
}
// Out
$imgPath = $thumbnail->getPath();
return !file_exists($imgPath);
}
/**
* @return bool false on no check made, provider name on success
* @throws ServerException if check is made but fails
*/
protected function checkWhitelist($url)
{
if (!$this->check_whitelist) {
return false; // indicates "no check made"
}
$host = parse_url($url, PHP_URL_HOST);
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foreach ($this->domain_whitelist as $regex => $provider) {
if (preg_match("/$regex/", $host)) {
return $provider; // we trust this source, return provider name
}
}
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throw new ServerException(sprintf(_('Domain not in remote thumbnail source whitelist: %s'), $host));
}
/**
* Check the file size of a remote file using a HEAD request and checking
* the content-length variable returned. This isn't 100% foolproof but is
* reliable enough for our purposes.
*
* @return string|bool the file size if it succeeds, false otherwise.
*/
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private function getRemoteFileSize($url, $headers = null)
{
try {
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if ($headers === null) {
if (!common_valid_http_url($url)) {
common_log(LOG_ERR, "Invalid URL in Embed::getRemoteFileSize()");
return false;
}
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$head = (new HTTPClient())->head($url);
$headers = $head->getHeader();
$headers = array_change_key_case($headers, CASE_LOWER);
}
return isset($headers['content-length']) ? $headers['content-length'] : false;
} catch (Exception $err) {
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common_log(LOG_ERR, __CLASS__.': getRemoteFileSize on URL : '._ve($url).
' threw exception: '.$err->getMessage());
return false;
}
}
/**
* A private helper function that uses a CURL lookup to check the mime type
* of a remote URL to see it it's an image.
*
* @return bool true if the remote URL is an image, or false otherwise.
*/
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private function isRemoteImage($url, $headers = null)
{
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if (empty($headers)) {
if (!common_valid_http_url($url)) {
common_log(LOG_ERR, "Invalid URL in Embed::isRemoteImage()");
return false;
}
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$head = (new HTTPClient())->head($url);
$headers = $head->getHeader();
$headers = array_change_key_case($headers, CASE_LOWER);
}
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return !empty($headers['content-type']) && common_get_mime_media($headers['content-type']) === 'image';
}
/**
* Validate that $imgData is a valid image before writing it to
* disk, as well as resizing it to at most $this->thumbnail_width
* by $this->thumbnail_height
*
* @param $imgData - The image data to validate. Taken by reference to avoid copying
* @param string|null $url - The url where the image came from, to fetch metadata
* @param array|null $headers - The headers possible previous request to $url
* @param int|null $file_id - The id of the file this image belongs to, used for logging
*/
protected function validateAndWriteImage(&$imgData, $url = null, $headers = null, $file_id = 0) : array
{
$info = @getimagesizefromstring($imgData);
// array indexes documented on php.net:
// https://php.net/manual/en/function.getimagesize.php
if ($info === false) {
throw new UnsupportedMediaException(_('Remote file format was not identified as an image.'), $url);
} elseif (!$info[0] || !$info[1]) {
throw new UnsupportedMediaException(_('Image file had impossible geometry (0 width or height)'));
}
$width = min($info[0], $this->thumbnail_width);
$height = min($info[1], $this->thumbnail_height);
$filehash = hash(File::FILEHASH_ALG, $imgData);
try {
if (!empty($url)) {
$original_name = HTTPClient::get_filename($url, $headers);
}
$filename = MediaFile::encodeFilename($original_name ?? '', $filehash);
$fullpath = File_thumbnail::path($filename);
// Write the file to disk. Throw Exception on failure
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if (!file_exists($fullpath)) {
if (strpos($fullpath, INSTALLDIR) !== 0 || file_put_contents($fullpath, $imgData) === false) {
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throw new ServerException(_('Could not write downloaded file to disk.'));
}
if (common_get_mime_media(MediaFile::getUploadedMimeType($fullpath)) !== 'image') {
@unlink($fullpath);
throw new UnsupportedMediaException(
_('Remote file format was not identified as an image.'),
$url
);
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}
// If the image is not of the desired size, resize it
if ($info[0] > $this->thumbnail_width || $info[1] > $this->thumbnail_height) {
// Temporary object, not stored in DB
$img = new ImageFile(-1, $fullpath);
$box = $img->scaleToFit($this->thumbnail_width, $this->thumbnail_height, $this->thumbnail_crop);
$outpath = $img->resizeTo($fullpath, $box);
$filename = basename($outpath);
if ($fullpath !== $outpath) {
@unlink($fullpath);
}
}
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} else {
throw new AlreadyFulfilledException('A thumbnail seems to already exist for remote file' .
($file_id ? 'with id==' . $file_id : '') . ' at path ' . $fullpath);
}
} catch (AlreadyFulfilledException $e) {
// Carry on
} catch (Exception $err) {
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common_log(LOG_ERR, "Went to write a thumbnail to disk in EmbedPlugin::storeRemoteThumbnail " .
"but encountered error: {$err}");
throw $err;
} finally {
unset($imgData);
}
return [$filename, $width, $height];
}
/**
* Function to create and store a thumbnail representation of a remote image
*
* @param $thumbnail File_thumbnail object containing the file thumbnail
* @return bool true if it succeeded, the exception if it fails, or false if it
* is limited by system limits (ie the file is too large.)
*/
protected function storeRemoteFileThumbnail(File_thumbnail $thumbnail)
{
if (!empty($thumbnail->filename) && file_exists($thumbnail->getPath())) {
throw new AlreadyFulfilledException(
sprintf('A thumbnail seems to already exist for remote file with id==%u', $thumbnail->file_id)
);
}
$url = $thumbnail->getUrl();
if (substr($url, 0, 7) == 'file://') {
$filename = substr($url, 7);
$info = getimagesize($filename);
$filename = basename($filename);
$width = $info[0];
$height = $info[1];
} else {
$this->checkWhitelist($url);
$head = (new HTTPClient())->head($url);
$headers = $head->getHeader();
$headers = array_change_key_case($headers, CASE_LOWER);
try {
$is_image = $this->isRemoteImage($url, $headers);
if ($is_image == true) {
$max_size = common_get_preferred_php_upload_limit();
$file_size = $this->getRemoteFileSize($url, $headers);
if (($file_size!=false) && ($file_size > $max_size)) {
common_debug("Went to store remote thumbnail of size " . $file_size .
" but the upload limit is " . $max_size . " so we aborted.");
return false;
}
} else {
return false;
}
} catch (Exception $err) {
common_debug("Could not determine size of remote image, aborted local storage.");
return $err;
}
// First we download the file to memory and test whether it's actually an image file
// FIXME: To support remote video/whatever files, this needs reworking.
common_debug(sprintf(
'Downloading remote thumbnail for file id==%u with thumbnail URL: %s',
$thumbnail->file_id,
$url
));
try {
$imgData = HTTPClient::quickGet($url);
if (isset($imgData)) {
list($filename, $width, $height) = $this->validateAndWriteImage($imgData, $url, $headers,
$thumbnail->file_id);
} else {
throw new UnsupportedMediaException('HTTPClient returned an empty result');
}
} catch(UnsupportedMediaException $e) {
// Couldn't find anything that looks like an image, nothing to do
common_debug("Embed was not able to find an image for URL `{$url}`: " . $e->getMessage());
return false;
}
}
try {
// Update our database for the file record
$orig = clone($thumbnail);
$thumbnail->filename = $filename;
$thumbnail->width = $width;
$thumbnail->height = $height;
// Throws exception on failure.
$thumbnail->updateWithKeys($orig);
} catch (Exception $err) {
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common_log(LOG_ERR, "Went to write a thumbnail entry to the database in " .
"EmbedPlugin::storeRemoteThumbnail but encountered error: ".$err);
return $err;
}
return true;
}
/**
* Event raised when GNU social polls the plugin for information about it.
* Adds this plugin's version information to $versions array
*
* @param &$versions array inherited from parent
* @return bool true hook value
*/
public function onPluginVersion(array &$versions): bool
{
$versions[] = ['name' => 'Embed',
'version' => self::PLUGIN_VERSION,
'author' => 'Mikael Nordfeldth',
'homepage' => 'http://gnu.io/social/',
'description' =>
// TRANS: Plugin description.
_m('Plugin for using and representing oEmbed, OpenGraph and other data.')];
return true;
}
}