gnu-social/lib/activitystreams/activityutils.php

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<?php
/**
* StatusNet, the distributed open-source microblogging tool
*
* An activity
*
* PHP version 5
*
* LICENCE: 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/>.
*
* @category Feed
* @package StatusNet
* @author Evan Prodromou <evan@status.net>
* @author Zach Copley <zach@status.net>
* @copyright 2010 StatusNet, Inc.
* @license http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPLv3
* @link http://status.net/
*/
if (!defined('STATUSNET')) {
exit(1);
}
/**
* Utilities for turning DOMish things into Activityish things
*
* Some common functions that I didn't have the bandwidth to try to factor
* into some kind of reasonable superclass, so just dumped here. Might
* be useful to have an ActivityObject parent class or something.
*
* @category OStatus
* @package StatusNet
* @author Evan Prodromou <evan@status.net>
* @copyright 2010 StatusNet, Inc.
* @license http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPLv3
* @link http://status.net/
*/
class ActivityUtils
{
const ATOM = 'http://www.w3.org/2005/Atom';
const LINK = 'link';
const REL = 'rel';
const TYPE = 'type';
const HREF = 'href';
const CONTENT = 'content';
const SRC = 'src';
/**
* Get the permalink for an Activity object
*
* @param DOMElement $element A DOM element
*
* @return string related link, if any
*/
static function getPermalink(DOMNode $element)
{
return self::getLink($element, 'alternate', 'text/html');
}
static function getSelfLink(DOMNode $element)
{
return self::getLink($element, 'self', 'application/atom+xml');
}
/**
* Get the permalink for an Activity object
*
* @param DOMElement $element A DOM element
*
* @return string related link, if any
*/
static function getLink(DOMNode $element, $rel, $type=null)
{
$els = $element->childNodes;
foreach ($els as $link) {
if (!($link instanceof DOMElement)) {
continue;
}
if ($link->localName == self::LINK && $link->namespaceURI == self::ATOM) {
$linkRel = $link->getAttribute(self::REL);
$linkType = $link->getAttribute(self::TYPE);
// XXX: Am I allowed to do this according to specs? (matching using common_bare_mime)
if ($linkRel == $rel &&
(is_null($type) || common_bare_mime($linkType) == common_bare_mime($type))) {
return $link->getAttribute(self::HREF);
}
}
}
return null;
}
static function getLinks(DOMNode $element, $rel, $type=null)
{
$els = $element->childNodes;
$out = array();
for ($i = 0; $i < $els->length; $i++) {
$link = $els->item($i);
if ($link->localName == self::LINK && $link->namespaceURI == self::ATOM) {
$linkRel = $link->getAttribute(self::REL);
$linkType = $link->getAttribute(self::TYPE);
if ($linkRel == $rel &&
(is_null($type) || $linkType == $type)) {
$out[] = $link;
}
}
}
return $out;
}
/**
* Gets the first child element with the given tag
*
* @param DOMElement $element element to pick at
* @param string $tag tag to look for
* @param string $namespace Namespace to look under
*
* @return DOMElement found element or null
*/
static function child(DOMNode $element, $tag, $namespace=self::ATOM)
{
$els = $element->childNodes;
if (empty($els) || $els->length == 0) {
return null;
} else {
for ($i = 0; $i < $els->length; $i++) {
$el = $els->item($i);
if ($el->localName == $tag && $el->namespaceURI == $namespace) {
return $el;
}
}
}
}
/**
* Gets all immediate child elements with the given tag
*
* @param DOMElement $element element to pick at
* @param string $tag tag to look for
* @param string $namespace Namespace to look under
*
* @return array found element or null
*/
static function children(DOMNode $element, $tag, $namespace=self::ATOM)
{
$results = array();
$els = $element->childNodes;
if (!empty($els) && $els->length > 0) {
for ($i = 0; $i < $els->length; $i++) {
$el = $els->item($i);
if ($el->localName == $tag && $el->namespaceURI == $namespace) {
$results[] = $el;
}
}
}
return $results;
}
/**
* Grab the text content of a DOM element child of the current element
*
* @param DOMElement $element Element whose children we examine
* @param string $tag Tag to look up
* @param string $namespace Namespace to use, defaults to Atom
*
* @return string content of the child
*/
static function childContent(DOMNode $element, $tag, $namespace=self::ATOM)
{
$el = self::child($element, $tag, $namespace);
if (empty($el)) {
return null;
} else {
return $el->textContent;
}
}
static function childHtmlContent(DOMNode $element, $tag, $namespace=self::ATOM)
{
$el = self::child($element, $tag, $namespace);
if (empty($el)) {
return null;
} else {
return self::textConstruct($el);
}
}
/**
* Get the content of an atom:entry-like object
*
* @param DOMElement $element The element to examine.
*
* @return string unencoded HTML content of the element, like "This -&lt; is <b>HTML</b>."
*
* @todo handle remote content
* @todo handle embedded XML mime types
* @todo handle base64-encoded non-XML and non-text mime types
*/
static function getContent($element)
{
return self::childHtmlContent($element, self::CONTENT, self::ATOM);
}
static function textConstruct($el)
{
$src = $el->getAttribute(self::SRC);
if (!empty($src)) {
// TRANS: Client exception thrown when there is no source attribute.
throw new ClientException(_("Can't handle remote content yet."));
}
$type = $el->getAttribute(self::TYPE);
// slavishly following http://atompub.org/rfc4287.html#rfc.section.4.1.3.3
if (empty($type) || $type == 'text') {
// We have plaintext saved as the XML text content.
// Since we want HTML, we need to escape any special chars.
return htmlspecialchars($el->textContent);
} else if ($type == 'html') {
// We have HTML saved as the XML text content.
// No additional processing required once we've got it.
$text = $el->textContent;
return $text;
} else if ($type == 'xhtml') {
// Per spec, the <content type="xhtml"> contains a single
// HTML <div> with XHTML namespace on it as a child node.
// We need to pull all of that <div>'s child nodes and
// serialize them back to an (X)HTML source fragment.
$divEl = ActivityUtils::child($el, 'div', 'http://www.w3.org/1999/xhtml');
if (empty($divEl)) {
return null;
}
$doc = $divEl->ownerDocument;
$text = '';
$children = $divEl->childNodes;
for ($i = 0; $i < $children->length; $i++) {
$child = $children->item($i);
$text .= $doc->saveXML($child);
}
return trim($text);
} else if (in_array($type, array('text/xml', 'application/xml')) ||
preg_match('#(+|/)xml$#', $type)) {
// TRANS: Client exception thrown when there embedded XML content is found that cannot be processed yet.
throw new ClientException(_("Can't handle embedded XML content yet."));
} else if (strncasecmp($type, 'text/', 5)) {
return $el->textContent;
} else {
// TRANS: Client exception thrown when base64 encoded content is found that cannot be processed yet.
throw new ClientException(_("Can't handle embedded Base64 content yet."));
}
}
/**
* Is this a valid URI for remote profile/notice identification?
* Does not have to be a resolvable URL.
* @param string $uri
* @return boolean
*/
static function validateUri($uri)
{
// Check mailto: URIs first
$validate = new Validate();
if (preg_match('/^mailto:(.*)$/', $uri, $match)) {
return $validate->email($match[1], common_config('email', 'check_domain'));
}
if ($validate->uri($uri)) {
return true;
}
// Possibly an upstream bug; tag: URIs aren't validated properly
// unless you explicitly ask for them. All other schemes are accepted
// for basic URI validation without asking.
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if ($validate->uri($uri, array('allowed_schemes' => array('tag')))) {
return true;
}
return false;
}
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static function getFeedAuthor(DOMElement $feedEl)
{
// Try old and deprecated activity:subject
$subject = ActivityUtils::child($feedEl, Activity::SUBJECT, Activity::SPEC);
if (!empty($subject)) {
return new ActivityObject($subject);
}
// Try the feed author
$author = ActivityUtils::child($feedEl, Activity::AUTHOR, Activity::ATOM);
if (!empty($author)) {
return new ActivityObject($author);
}
// Sheesh. Not a very nice feed! Let's try fingerpoken in the
// entries.
$entries = $feedEl->getElementsByTagNameNS(Activity::ATOM, 'entry');
if (!empty($entries) && $entries->length > 0) {
$entry = $entries->item(0);
// Try the (deprecated) activity:actor
$actor = ActivityUtils::child($entry, Activity::ACTOR, Activity::SPEC);
if (!empty($actor)) {
return new ActivityObject($actor);
}
// Try the author
$author = ActivityUtils::child($entry, Activity::AUTHOR, Activity::ATOM);
if (!empty($author)) {
return new ActivityObject($author);
}
}
return null;
}
static function compareTypes($type, $objects)
{
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$type = self::resolveUri($type, false);
foreach ((array)$objects as $object) {
if ($type === self::resolveUri($object)) {
return true;
}
}
return false;
}
static function compareVerbs($type, $objects)
{
return self::compareTypes($type, $objects);
}
static function resolveUri($uri, $make_relative=false)
{
if (empty($uri)) {
throw new ServerException('No URI to resolve in ActivityUtils::resolveUri');
}
if (!$make_relative && parse_url($uri, PHP_URL_SCHEME) == '') { // relative -> absolute
$uri = Activity::SCHEMA . $uri;
} elseif ($make_relative) { // absolute -> relative
$uri = basename($uri); //preg_replace('/^http:\/\/activitystrea\.ms\/schema\/1\.0\//', '', $uri);
} // absolute schemas pass through unharmed
return $uri;
}
static function findLocalObject(array $uris, $type=ActivityObject::NOTE) {
$obj_class = null;
// TODO: Extend this in plugins etc. and describe in EVENTS.txt
if (Event::handle('StartFindLocalActivityObject', array($uris, $type, &$obj_class))) {
switch (self::resolveUri($type)) {
case ActivityObject::PERSON:
// GROUP will also be here in due time...
$obj_class = 'Profile';
break;
default:
$obj_class = 'Notice';
}
}
$object = null;
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$uris = array_unique($uris);
foreach ($uris as $uri) {
try {
// the exception thrown will cancel before reaching $object
$object = call_user_func("{$obj_class}::fromUri", $uri);
break;
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} catch (UnknownUriException $e) {
common_debug('Could not find local activity object from uri: '.$e->object_uri);
}
}
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if (!$object instanceof Managed_DataObject) {
throw new ServerException('Could not find any activityobject stored locally with given URIs: '.var_export($uris,true));
}
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Event::handle('EndFindLocalActivityObject', array($object->getUri(), $object->getObjectType(), $object));
return $object;
}
// Check authorship by supplying a Profile as a default and letting plugins
// set it to something else if the activity's author is actually someone
// else (like with a group or peopletag feed as handled in OStatus).
//
// NOTE: Returned is not necessarily the supplied profile! For example,
// the "feed author" may be a group, but the "activity author" is a person!
static function checkAuthorship(Activity $activity, Profile $profile)
{
if (Event::handle('CheckActivityAuthorship', array($activity, &$profile))) {
// if (empty($activity->actor)), then we generated this Activity ourselves and can trust $profile
$actor_uri = $profile->getUri();
if (!in_array($actor_uri, array($activity->actor->id, $activity->actor->link))) {
// A mismatch between our locally stored URI and the supplied author?
// Probably not more than a blog feed or something (with multiple authors or so)
// but log it for future inspection.
common_log(LOG_WARNING, "Got an actor '{$activity->actor->title}' ({$activity->actor->id}) on single-user feed for " . $actor_uri);
} elseif (empty($activity->actor->id)) {
// Plain <author> without ActivityStreams actor info.
// We'll just ignore this info for now and save the update under the feed's identity.
}
}
if (!$profile instanceof Profile) {
throw new ServerException('Could not get an author Profile for activity');
}
return $profile;
}
static public function typeToTitle($type)
{
return ucfirst(self::resolveUri($type, true));
}
static public function verbToTitle($verb)
{
return ucfirst(self::resolveUri($verb, true));
}
}