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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('STATUSNET')) {
+ 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' => 'http://www.flickr.com/services/oembed/',
+ 'yfrog.com' => 'http://www.yfrog.com/api/oembed',
+ );
+ protected static $functionMap = array(
+ 'twitpic.com' => 'oEmbedHelper::twitPic',
+ );
+
+ /**
+ * 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 oohembed.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())
+ {
+ $host = parse_url($url, PHP_URL_HOST);
+ if (substr($host, 0, 4) == 'www.') {
+ $host = substr($host, 4);
+ }
+
+ // Blacklist: systems with no oEmbed API of their own, which are
+ // either missing from or broken on oohembed.com's proxy.
+ // we know how to look data up in another way...
+ if (array_key_exists($host, self::$functionMap)) {
+ $func = self::$functionMap[$host];
+ return call_user_func($func, $url, $params);
+ }
+
+ // Whitelist: known API endpoints for sites that don't provide discovery...
+ if (array_key_exists($host, self::$apiMap)) {
+ $api = self::$apiMap[$host];
+ } else {
+ try {
+ $api = self::discover($url);
+ } catch (Exception $e) {
+ // Discovery failed... fall back to oohembed if enabled.
+ $oohembed = common_config('oohembed', 'endpoint');
+ if ($oohembed) {
+ $api = $oohembed;
+ } else {
+ throw $e;
+ }
+ }
+ }
+ return self::getObjectFrom($api, $url, $params);
+ }
+
+ /**
+ * Perform basic discovery.
+ * @return string
+ */
+ static function discover($url)
+ {
+ // @fixme ideally skip this for non-HTML stuff!
+ $body = self::http($url);
+ return self::discoverFromHTML($url, $body);
+ }
+
+ /**
+ * Partially ripped from OStatus' FeedDiscovery class.
+ *
+ * @param string $url source URL, used to resolve relative links
+ * @param string $body HTML body text
+ * @return mixed string with URL or false if no target found
+ */
+ static function discoverFromHTML($url, $body)
+ {
+ // DOMDocument::loadHTML may throw warnings on unrecognized elements,
+ // and notices on unrecognized namespaces.
+ $old = error_reporting(error_reporting() & ~(E_WARNING | E_NOTICE));
+ $dom = new DOMDocument();
+ $ok = $dom->loadHTML($body);
+ error_reporting($old);
+
+ if (!$ok) {
+ throw new oEmbedHelper_BadHtmlException();
+ }
+
+ // 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 $params
+ * @return object
+ */
+ static function getObjectFrom($api, $url, $params=array())
+ {
+ $params['url'] = $url;
+ $params['format'] = 'json';
+ $data = self::json($api, $params);
+ return self::normalize($data);
+ }
+
+ /**
+ * Normalize oEmbed format.
+ *
+ * @param object $orig
+ * @return object
+ */
+ static function normalize($orig)
+ {
+ $data = clone($orig);
+
+ 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('attachments', 'thumb_width');
+ $data->thumbnail_height = common_config('attachments', 'thumb_height');
+ }
+ }
+
+ return $data;
+ }
+
+ /**
+ * Using a local function for twitpic lookups, as oohembed's adapter
+ * doesn't return a valid result:
+ * http://code.google.com/p/oohembed/issues/detail?id=19
+ *
+ * This code fetches metadata from Twitpic's own API, and attempts
+ * to guess proper thumbnail size from the original's size.
+ *
+ * @todo respect maxwidth and maxheight params
+ *
+ * @param string $url
+ * @param array $params
+ * @return object
+ */
+ static function twitPic($url, $params=array())
+ {
+ $matches = array();
+ if (preg_match('!twitpic\.com/(\w+)!', $url, $matches)) {
+ $id = $matches[1];
+ } else {
+ throw new Exception("Invalid twitpic URL");
+ }
+
+ // Grab metadata from twitpic's API...
+ // http://dev.twitpic.com/docs/2/media_show
+ $data = self::json('http://api.twitpic.com/2/media/show.json',
+ array('id' => $id));
+ $oembed = (object)array('type' => 'photo',
+ 'url' => 'http://twitpic.com/show/full/' . $data->short_id,
+ 'width' => $data->width,
+ 'height' => $data->height);
+ if (!empty($data->message)) {
+ $oembed->title = $data->message;
+ }
+
+ // Thumbnail is cropped and scaled to 150x150 box:
+ // http://dev.twitpic.com/docs/thumbnails/
+ $thumbSize = 150;
+ $oembed->thumbnail_url = 'http://twitpic.com/show/thumb/' . $data->short_id;
+ $oembed->thumbnail_width = $thumbSize;
+ $oembed->thumbnail_height = $thumbSize;
+
+ return $oembed;
+ }
+
+ /**
+ * Fetch some URL and return JSON data.
+ *
+ * @param string $url
+ * @param array $params query-string params
+ * @return object
+ */
+ static protected function json($url, $params=array())
+ {
+ $data = self::http($url, $params);
+ return json_decode($data);
+ }
+
+ /**
+ * Hit some web API and return data on success.
+ * @param string $url
+ * @param array $params
+ * @return string
+ */
+ static protected function http($url, $params=array())
+ {
+ $client = HTTPClient::start();
+ if ($params) {
+ $query = http_build_query($params, null, '&');
+ if (strpos($url, '?') === false) {
+ $url .= '?' . $query;
+ } else {
+ $url .= '&' . $query;
+ }
+ }
+ $response = $client->get($url);
+ if ($response->isOk()) {
+ return $response->getBody();
+ } else {
+ throw new Exception('Bad HTTP response code: ' . $response->getStatus());
+ }
+ }
+}
+
+class oEmbedHelper_Exception extends Exception
+{
+}
+
+class oEmbedHelper_BadHtmlException extends oEmbedHelper_Exception
+{
+ function __construct($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);
+ }
+}
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-20 12:33:04 +0000