gnu-social/plugins/Oembed/lib/oembedhelper.php

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<?php
/*
* StatusNet - the distributed open-source microblogging tool
* Copyright (C) 2008-2010, StatusNet, Inc.
*
* This program 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.
*
* This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
*/
if (!defined('GNUSOCIAL')) { exit(1); }
/**
* Utility class to wrap basic oEmbed lookups.
*
* Blacklisted hosts will use an alternate lookup method:
* - Twitpic
*
* Whitelisted hosts will use known oEmbed API endpoints:
* - Flickr, YFrog
*
* Sites that provide discovery links will use them directly; a bug
* in use of discovery links with query strings is worked around.
*
* Others will fall back to oohembed (unless disabled).
* The API endpoint can be configured or disabled through config
* as 'oohembed'/'endpoint'.
*/
class oEmbedHelper
{
protected static $apiMap = array(
'flickr.com' => 'https://www.flickr.com/services/oembed/',
'youtube.com' => 'https://www.youtube.com/oembed',
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'viddler.com' => 'http://lab.viddler.com/services/oembed/',
'revision3.com' => 'https://revision3.com/api/oembed/',
'vimeo.com' => 'https://vimeo.com/api/oembed.json',
);
/**
* Perform or fake an oEmbed lookup for the given resource.
*
* Some known hosts are whitelisted with API endpoints where we
* know they exist but autodiscovery data isn't available.
* If autodiscovery links are missing and we don't recognize the
* host, we'll pass it to noembed.com's public service which
* will either proxy or fake info on a lot of sites.
*
* A few hosts are blacklisted due to known problems with oohembed,
* in which case we'll look up the info another way and return
* equivalent data.
*
* Throws exceptions on failure.
*
* @param string $url
* @param array $params
* @return object
*/
public static function getObject($url, $params=array())
{
common_log(LOG_INFO, 'Checking for remote URL metadata for ' . $url);
// TODO: Make this class something like UrlMetadata, or use a dataobject?
$metadata = new stdClass();
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if (Event::handle('GetRemoteUrlMetadata', array($url, &$metadata))) {
// If that event didn't return anything, try downloading the body and parse it
// don't use quickGet since we want to check Content-Type header for utf-8
$client = new HTTPClient();
$response = $client->get($url);
if (!$response->isOk()) {
// TRANS: Exception. %s is the URL we tried to GET.
throw new Exception(sprintf(_m('Could not GET URL %s.'), $url), $response->getStatus());
}
$body = $response->getBody();
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// DOMDocument::loadHTML may throw warnings on unrecognized elements,
// and notices on unrecognized namespaces.
$old = error_reporting(error_reporting() & ~(E_WARNING | E_NOTICE));
// DOMDocument assumes ISO-8859-1 per HTML spec
// use UTF-8 if we find any evidence of that encoding
$utf8_evidence = false;
$unicode_check_dom = new DOMDocument();
$ok = $unicode_check_dom->loadHTML($body);
if (!$ok) throw new oEmbedHelper_BadHtmlException();
$metaNodes = $unicode_check_dom->getElementsByTagName('meta');
foreach($metaNodes as $metaNode) {
// case in-sensitive since Content-type and utf-8 can be written in many ways
if(stristr($metaNode->getAttribute('http-equiv'),'content-type')
&& stristr($metaNode->getAttribute('content'),'utf-8')) {
$utf8_evidence = true;
break;
} elseif(stristr($metaNode->getAttribute('charset'),'utf-8')) {
$utf8_evidence = true;
break;
}
}
unset($unicode_check_dom);
// The Content-Type HTTP response header overrides encoding metatags in DOM
if(stristr($response->getHeader('Content-Type'),'utf-8')) {
$utf8_evidence = true;
}
// add utf-8 encoding prolog if we have reason to believe this is utf-8 content
// DOMDocument('1.0', 'UTF-8') does not work!
$utf8_tag = $utf8_evidence ? '<?xml encoding="utf-8" ?>' : '';
$dom = new DOMDocument();
$ok = $dom->loadHTML($utf8_tag.$body);
unset($body); // storing the DOM in memory is enough...
error_reporting($old);
if (!$ok) {
throw new oEmbedHelper_BadHtmlException();
}
Event::handle('GetRemoteUrlMetadataFromDom', array($url, $dom, &$metadata));
}
return self::normalize($metadata);
}
/**
* Partially ripped from OStatus' FeedDiscovery class.
*
* @param string $url source URL, used to resolve relative links
* @param string $body HTML body text
* @return mixed string with URL or false if no target found
*/
static function oEmbedEndpointFromHTML(DOMDocument $dom)
{
// Ok... now on to the links!
$feeds = array(
'application/json+oembed' => false,
);
$nodes = $dom->getElementsByTagName('link');
for ($i = 0; $i < $nodes->length; $i++) {
$node = $nodes->item($i);
if ($node->hasAttributes()) {
$rel = $node->attributes->getNamedItem('rel');
$type = $node->attributes->getNamedItem('type');
$href = $node->attributes->getNamedItem('href');
if ($rel && $type && $href) {
$rel = array_filter(explode(" ", $rel->value));
$type = trim($type->value);
$href = trim($href->value);
if (in_array('alternate', $rel) && array_key_exists($type, $feeds) && empty($feeds[$type])) {
// Save the first feed found of each type...
$feeds[$type] = $href;
}
}
}
}
// Return the highest-priority feed found
foreach ($feeds as $type => $url) {
if ($url) {
return $url;
}
}
throw new oEmbedHelper_DiscoveryException();
}
/**
* Actually do an oEmbed lookup to a particular API endpoint.
*
* @param string $api oEmbed API endpoint URL
* @param string $url target URL to look up info about
* @param array $params
* @return object
*/
static function getOembedFrom($api, $url, $params=array())
{
if (empty($api)) {
// TRANS: Server exception thrown in oEmbed action if no API endpoint is available.
throw new ServerException(_('No oEmbed API endpoint available.'));
}
$params['url'] = $url;
$params['format'] = 'json';
$key=common_config('oembed','apikey');
if(isset($key)) {
$params['key'] = common_config('oembed','apikey');
}
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$oembed_data = HTTPClient::quickGetJson($api, $params);
return $oembed_data;
}
/**
* Normalize oEmbed format.
*
* @param object $orig
* @return object
*/
static function normalize(stdClass $data)
{
if (empty($data->type)) {
throw new Exception('Invalid oEmbed data: no type field.');
}
if ($data->type == 'image') {
// YFrog does this.
$data->type = 'photo';
}
if (isset($data->thumbnail_url)) {
if (!isset($data->thumbnail_width)) {
// !?!?!
$data->thumbnail_width = common_config('thumbnail', 'width');
$data->thumbnail_height = common_config('thumbnail', 'height');
}
}
return $data;
}
}
class oEmbedHelper_Exception extends Exception
{
public function __construct($message = "", $code = 0, $previous = null)
{
parent::__construct($message, $code);
}
}
class oEmbedHelper_BadHtmlException extends oEmbedHelper_Exception
{
function __construct($previous=null)
{
return parent::__construct('Bad HTML in discovery data.', 0, $previous);
}
}
class oEmbedHelper_DiscoveryException extends oEmbedHelper_Exception
{
function __construct($previous=null)
{
return parent::__construct('No oEmbed discovery data.', 0, $previous);
}
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}