X-Git-Url: https://git.mxchange.org/?a=blobdiff_plain;f=src%2FProtocol%2FActivityPub.php;h=78d5d44daff8fc82f58402348089a2f3f12d70e2;hb=6a8ebc8639507404be07bb7d6fd5a37189e46563;hp=83aae72aa52c599d5cca7f54e690d992d49c1bd5;hpb=67fa0ed433fa2519108e5f9b4715b3fdea1cb9fd;p=friendica.git

diff --git a/src/Protocol/ActivityPub.php b/src/Protocol/ActivityPub.php
index 83aae72aa5..78d5d44daf 100644
--- a/src/Protocol/ActivityPub.php
+++ b/src/Protocol/ActivityPub.php
@@ -10,11 +10,15 @@ use Friendica\BaseObject;
 use Friendica\Util\Network;
 use Friendica\Util\HTTPSignature;
 use Friendica\Core\Protocol;
+use Friendica\Model\Conversation;
+use Friendica\Model\Contact;
 use Friendica\Model\Item;
 use Friendica\Model\User;
 use Friendica\Util\DateTimeFormat;
 use Friendica\Util\Crypto;
 use Friendica\Content\Text\BBCode;
+use Friendica\Content\Text\HTML;
+use Friendica\Network\Probe;
 
 /**
  * @brief ActivityPub Protocol class
@@ -28,12 +32,29 @@ use Friendica\Content\Text\BBCode;
  *
  * Digest: https://tools.ietf.org/html/rfc5843
  * https://tools.ietf.org/html/draft-cavage-http-signatures-10#ref-15
+ *
+ * Part of the code for HTTP signing is taken from the Osada project.
+ * 
+ *
+ * To-do:
+ *
+ * Receiver:
+ * - Activities: Undo, Update
+ * - Object Types: Person, Tombstome
+ *
+ * Transmitter:
+ * - Activities: Like, Dislike, Update, Undo
+ * - Object Tyoes: Article, Announce, Person, Tombstone
+ *
+ * General:
+ * - Message distribution
+ * - Endpoints: Outbox, Object, Follower, Following
  */
 class ActivityPub
 {
 	const PUBLIC = 'https://www.w3.org/ns/activitystreams#Public';
 
-	public static function transmit($content, $target, $uid)
+	public static function transmit($data, $target, $uid)
 	{
 		$owner = User::getOwnerDataById($uid);
 
@@ -41,6 +62,8 @@ class ActivityPub
 			return;
 		}
 
+		$content = json_encode($data);
+
 		$host = parse_url($target, PHP_URL_HOST);
 		$path = parse_url($target, PHP_URL_PATH);
 		$date = date('r');
@@ -57,7 +80,7 @@ class ActivityPub
 		Network::post($target, $content, $headers);
 		$return_code = BaseObject::getApp()->get_curl_code();
 
-		echo $return_code."\n";
+		logger('Transmit to ' . $target . ' returned ' . $return_code);
 	}
 
 	/**
@@ -130,12 +153,10 @@ class ActivityPub
 			'toot' => 'http://joinmastodon.org/ns#']]];
 
 		$data['type'] = 'Create';
-		$data['id'] = $item['plink'];
+		$data['id'] = $item['uri'];
 		$data['actor'] = $item['author-link'];
 		$data['to'] = 'https://www.w3.org/ns/activitystreams#Public';
 		$data['object'] = self::createNote($item);
-//		print_r($data);
-//		print_r($item);
 		return $data;
 	}
 
@@ -143,28 +164,76 @@ class ActivityPub
 	{
 		$data = [];
 		$data['type'] = 'Note';
-		$data['id'] = $item['plink'];
-		//$data['context'] = $data['conversation'] = $item['parent-uri'];
+		$data['id'] = $item['uri'];
+
+		if ($item['uri'] != $item['thr-parent']) {
+			$data['inReplyTo'] = $item['thr-parent'];
+		}
+
+		$conversation = DBA::selectFirst('conversation', ['conversation-uri'], ['item-uri' => $item['parent-uri']]);
+		if (DBA::isResult($conversation) && !empty($conversation['conversation-uri'])) {
+			$conversation_uri = $conversation['conversation-uri'];
+		} else {
+			$conversation_uri = $item['parent-uri'];
+		}
+
+		$data['context'] = $data['conversation'] = $conversation_uri;
 		$data['actor'] = $item['author-link'];
-//		if (!$item['private']) {
-//			$data['to'] = [];
-//			$data['to'][] = '"https://pleroma.soykaf.com/users/heluecht"';
-			$data['to'] = 'https://www.w3.org/ns/activitystreams#Public';
-//			$data['cc'] = 'https://pleroma.soykaf.com/users/heluecht';
-//		}
+		$data['to'] = [];
+		if (!$item['private']) {
+			$data['to'][] = 'https://www.w3.org/ns/activitystreams#Public';
+		}
 		$data['published'] = DateTimeFormat::utc($item["created"]."+00:00", DateTimeFormat::ATOM);
 		$data['updated'] = DateTimeFormat::utc($item["edited"]."+00:00", DateTimeFormat::ATOM);
 		$data['attributedTo'] = $item['author-link'];
 		$data['name'] = BBCode::convert($item['title'], false, 7);
 		$data['content'] = BBCode::convert($item['body'], false, 7);
-		//$data['summary'] = '';
-		//$data['sensitive'] = false;
-		//$data['emoji'] = [];
-		//$data['tag'] = [];
-		//$data['attachment'] = [];
+		$data['source'] = ['content' => $item['body'], 'mediaType' => "text/bbcode"];
+		//$data['summary'] = ''; // Ignore by now
+		//$data['sensitive'] = false; // - Query NSFW
+		//$data['emoji'] = []; // Ignore by now
+		//$data['tag'] = []; /// @ToDo
+		//$data['attachment'] = []; // @ToDo
 		return $data;
 	}
 
+	public static function transmitActivity($activity, $target, $uid)
+	{
+		$profile = Probe::uri($target, Protocol::ACTIVITYPUB);
+
+		$owner = User::getOwnerDataById($uid);
+
+		$data = ['@context' => 'https://www.w3.org/ns/activitystreams',
+			'id' => 'https://pirati.ca/activity/' . System::createGUID(),
+			'type' => $activity,
+			'actor' => $owner['url'],
+			'object' => $profile['url']];
+
+		logger('Sending activity ' . $activity . ' to ' . $target . ' for user ' . $uid, LOGGER_DEBUG);
+		return self::transmit($data,  $profile['notify'], $uid);
+	}
+
+	public static function transmitContactActivity($activity, $target, $id, $uid)
+	{
+		$profile = Probe::uri($target, Protocol::ACTIVITYPUB);
+
+		if (empty($id)) {
+			$id = 'https://pirati.ca/activity/' . System::createGUID();
+		}
+
+		$owner = User::getOwnerDataById($uid);
+		$data = ['@context' => 'https://www.w3.org/ns/activitystreams',
+			'id' => 'https://pirati.ca/activity/' . System::createGUID(),
+			'type' => $activity,
+			'actor' => $owner['url'],
+			'object' => ['id' => $id, 'type' => 'Follow',
+				'actor' => $owner['url'],
+				'object' => $profile['url']]];
+
+		logger('Sending ' . $activity . ' to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
+		return self::transmit($data,  $profile['notify'], $uid);
+	}
+
 	/**
 	 * Fetches ActivityPub content from the given url
 	 *
@@ -300,7 +369,7 @@ class ActivityPub
 				$hashalg = 'sha512';
 			}
 
-			/// @todo addd all hashes from the rfc
+			/// @todo add all hashes from the rfc
 
 			if (!empty($hashalg) && base64_encode(hash($hashalg, $content, true)) != $digest[1]) {
 				return false;
@@ -322,11 +391,11 @@ class ActivityPub
 	{
 		$url = (strpos($id, '#') ? substr($id, 0, strpos($id, '#')) : $id);
 
-		$profile = self::fetchProfile($url);
+		$profile = Probe::uri($url, Protocol::ACTIVITYPUB);
 		if (!empty($profile)) {
 			return $profile['pubkey'];
 		} elseif ($url != $actor) {
-			$profile = self::fetchProfile($actor);
+			$profile = Probe::uri($actor, Protocol::ACTIVITYPUB);
 			if (!empty($profile)) {
 				return $profile['pubkey'];
 			}
@@ -395,19 +464,21 @@ class ActivityPub
 		$profile['name'] = defaults($data, 'name', $profile['nick']);
 		$profile['guid'] = defaults($data, 'uuid', null);
 		$profile['url'] = $data['id'];
-		$profile['alias'] = self::processElement($data, 'url', 'href');
 
 		$parts = parse_url($profile['url']);
 		unset($parts['scheme']);
 		unset($parts['path']);
 		$profile['addr'] = $profile['nick'] . '@' . str_replace('//', '', Network::unparseURL($parts));
-
+		$profile['alias'] = self::processElement($data, 'url', 'href');
 		$profile['photo'] = self::processElement($data, 'icon', 'url');
+		// $profile['community']
+		// $profile['keywords']
+		// $profile['location']
 		$profile['about'] = defaults($data, 'summary', '');
 		$profile['batch'] = self::processElement($data, 'endpoints', 'sharedInbox');
-		$profile['pubkey'] = self::processElement($data, 'publicKey', 'publicKeyPem');
 		$profile['notify'] = $data['inbox'];
 		$profile['poll'] = $data['outbox'];
+		$profile['pubkey'] = self::processElement($data, 'publicKey', 'publicKeyPem');
 
 		// Check if the address is resolvable
 		if (self::addrToUrl($profile['addr']) == $profile['url']) {
@@ -429,19 +500,7 @@ class ActivityPub
 			}
 		}
 
-		// Handled
-		unset($data['id']);
-		unset($data['inbox']);
-		unset($data['outbox']);
-		unset($data['preferredUsername']);
-		unset($data['name']);
-		unset($data['summary']);
-		unset($data['url']);
-		unset($data['publicKey']);
-		unset($data['endpoints']);
-		unset($data['icon']);
-		unset($data['uuid']);
-
+/*
 		// To-Do
 		unset($data['type']);
 		unset($data['manuallyApprovesFollowers']);
@@ -462,15 +521,29 @@ class ActivityPub
 		unset($data['isCat']); // Misskey
 		unset($data['kroeg:blocks']); // Kroeg
 		unset($data['updated']); // Kroeg
-
-/*		if (!empty($data)) {
-			print_r($data);
-			die();
-		}
 */
 		return $profile;
 	}
 
+	public static function processInbox($body, $header, $uid)
+	{
+		logger('Incoming message for user ' . $uid, LOGGER_DEBUG);
+
+		if (!self::verifySignature($body, $header)) {
+			logger('Invalid signature, message will be discarded.', LOGGER_DEBUG);
+			return;
+		}
+
+		$activity = json_decode($body, true);
+
+		if (!is_array($activity)) {
+			logger('Invalid body.', LOGGER_DEBUG);
+			return;
+		}
+
+		self::processActivity($activity, $body, $uid);
+	}
+
 	public static function fetchOutbox($url)
 	{
 		$data = self::fetchContent($url);
@@ -490,26 +563,31 @@ class ActivityPub
 		}
 
 		foreach ($items as $activity) {
-			self::processActivity($activity, $url);
+			self::processActivity($activity);
 		}
 	}
 
-	function processActivity($activity, $url)
+	function processActivity($activity, $body = '', $uid = null)
 	{
 		if (empty($activity['type'])) {
+			logger('Empty type', LOGGER_DEBUG);
 			return;
 		}
 
 		if (empty($activity['object'])) {
+			logger('Empty object', LOGGER_DEBUG);
 			return;
 		}
 
 		if (empty($activity['actor'])) {
+			logger('Empty actor', LOGGER_DEBUG);
 			return;
+
 		}
 
 		$actor = self::processElement($activity, 'actor', 'id');
 		if (empty($actor)) {
+			logger('Empty actor - 2', LOGGER_DEBUG);
 			return;
 		}
 
@@ -518,15 +596,12 @@ class ActivityPub
 		} elseif (!empty($activity['object']['id'])) {
 			$object_url = $activity['object']['id'];
 		} else {
-			return;
-		}
-
-		$receivers = self::getReceivers($activity);
-		if (empty($receivers)) {
+			logger('No object found', LOGGER_DEBUG);
 			return;
 		}
 
 		// ----------------------------------
+/*
 		// unhandled
 		unset($activity['@context']);
 		unset($activity['id']);
@@ -537,37 +612,43 @@ class ActivityPub
 		unset($activity['context_id']);
 		unset($activity['statusnetConversationId']);
 
-		$structure = $activity;
-
 		// To-Do?
 		unset($activity['context']);
 		unset($activity['location']);
+		unset($activity['signature']);
+*/
+		// Fetch all receivers from to, cc, bto and bcc
+		$receivers = self::getReceivers($activity);
 
-		// handled
-		unset($activity['to']);
-		unset($activity['cc']);
-		unset($activity['bto']);
-		unset($activity['bcc']);
-		unset($activity['type']);
-		unset($activity['actor']);
-		unset($activity['object']);
-		unset($activity['published']);
-		unset($activity['updated']);
-		unset($activity['instrument']);
-		unset($activity['inReplyTo']);
-
-		if (!empty($activity)) {
-			echo "Activity\n";
-			print_r($activity);
-			die($url."\n");
-		}
-
-		$activity = $structure;
-		// ----------------------------------
+		// When it is a delivery to a personal inbox we add that user to the receivers
+		if (!empty($uid)) {
+			$owner = User::getOwnerDataById($uid);
+			$additional = [$owner['url'] => $uid];
+			$receivers = array_merge($receivers, $additional);
+		}
 
-		$item = self::fetchObject($object_url, $url);
-		if (empty($item)) {
-			return;
+		logger('Receivers: ' . json_encode($receivers), LOGGER_DEBUG);
+
+		logger('Processing activity: ' . $activity['type'], LOGGER_DEBUG);
+
+		// Fetch the content only on activities where this matters
+		if (in_array($activity['type'], ['Create', 'Update', 'Announce'])) {
+			$item = self::fetchObject($object_url, $activity['object']);
+			if (empty($item)) {
+				logger("Object data couldn't be processed", LOGGER_DEBUG);
+				return;
+			}
+		} else {
+			if (in_array($activity['type'], ['Accept'])) {
+				$item['object'] = self::processElement($activity, 'object', 'actor', 'type', 'Follow');
+			} elseif (in_array($activity['type'], ['Undo'])) {
+				$item['object'] = self::processElement($activity, 'object', 'object', 'type', 'Follow');
+			} else {
+				$item['object'] = $object_url;
+			}
+			$item['id'] = $activity['id'];
+			$item['receiver'] = [];
+			$item['type'] = $activity['type'];
 		}
 
 		$item = self::addActivityFields($item, $activity);
@@ -579,25 +660,34 @@ class ActivityPub
 		switch ($activity['type']) {
 			case 'Create':
 			case 'Update':
-				self::createItem($item);
-				break;
-
 			case 'Announce':
-				self::announceItem($item);
+				self::createItem($item, $body);
 				break;
 
 			case 'Like':
+				self::likeItem($item, $body);
+				break;
+
 			case 'Dislike':
-				self::activityItem($item);
+				break;
+
+			case 'Delete':
 				break;
 
 			case 'Follow':
+				self::followUser($item);
+				break;
+
+			case 'Accept':
+				self::acceptFollowUser($item);
+				break;
+
+			case 'Undo':
+				self::undoFollowUser($item);
 				break;
 
 			default:
-				echo "Unknown activity: ".$activity['type']."\n";
-				print_r($item);
-				die();
+				logger('Unknown activity: ' . $activity['type'], LOGGER_DEBUG);
 				break;
 		}
 	}
@@ -623,11 +713,11 @@ class ActivityPub
 				}
 
 				$condition = ['self' => true, 'nurl' => normalise_link($receiver)];
-				$contact = DBA::selectFirst('contact', ['id'], $condition);
+				$contact = DBA::selectFirst('contact', ['uid'], $condition);
 				if (!DBA::isResult($contact)) {
 					continue;
 				}
-				$receivers[$receiver] = $contact['id'];
+				$receivers[$receiver] = $contact['uid'];
 			}
 		}
 		return $receivers;
@@ -648,69 +738,77 @@ class ActivityPub
 		}
 
 		if (!empty($activity['instrument'])) {
-			$item['service'] = self::processElement($activity, 'instrument', 'name', 'Service');
-		}
-
-		// Remove all "null" fields
-		foreach ($item as $field => $content) {
-			if (is_null($content)) {
-				unset($item[$field]);
-			}
+			$item['service'] = self::processElement($activity, 'instrument', 'name', 'type', 'Service');
 		}
-
 		return $item;
 	}
 
-	private static function fetchObject($object_url, $url)
+	private static function fetchObject($object_url, $object = [])
 	{
 		$data = self::fetchContent($object_url);
 		if (empty($data)) {
-			return false;
+			$data = $object;
+			if (empty($data)) {
+				logger('Empty content', LOGGER_DEBUG);
+				return false;
+			} elseif (is_string($data)) {
+				logger('No object array provided.', LOGGER_DEBUG);
+				$item = Item::selectFirst([], ['uri' => $data]);
+				if (!DBA::isResult($item)) {
+					logger('Object with url ' . $data . ' was not found locally.', LOGGER_DEBUG);
+					return false;
+				}
+				logger('Using already stored item', LOGGER_DEBUG);
+				$data = self::createNote($item);
+			} else {
+				logger('Using provided object', LOGGER_DEBUG);
+			}
 		}
 
 		if (empty($data['type'])) {
+			logger('Empty type', LOGGER_DEBUG);
 			return false;
 		} else {
 			$type = $data['type'];
+			logger('Type ' . $type, LOGGER_DEBUG);
 		}
 
 		if (in_array($type, ['Note', 'Article', 'Video'])) {
-			$common = self::processCommonData($data, $url);
+			$common = self::processCommonData($data);
 		}
 
 		switch ($type) {
 			case 'Note':
-				return array_merge($common, self::processNote($data, $url));
+				return array_merge($common, self::processNote($data));
 			case 'Article':
-				return array_merge($common, self::processArticle($data, $url));
+				return array_merge($common, self::processArticle($data));
 			case 'Video':
-				return array_merge($common, self::processVideo($data, $url));
+				return array_merge($common, self::processVideo($data));
 
 			case 'Announce':
 				if (empty($data['object'])) {
 					return false;
 				}
-				return self::fetchObject($data['object'], $url);
+				return self::fetchObject($data['object']);
 
 			case 'Person':
 			case 'Tombstone':
 				break;
 
 			default:
-				echo "Unknown object type: ".$data['type']."\n";
-				print_r($data);
-				die($url."\n");
+				logger('Unknown object type: ' . $data['type'], LOGGER_DEBUG);
 				break;
 		}
 	}
 
-	private static function processCommonData(&$object, $url)
+	private static function processCommonData(&$object)
 	{
 		if (empty($object['id']) || empty($object['attributedTo'])) {
 			return false;
 		}
 
 		$item = [];
+		$item['type'] = $object['type'];
 		$item['uri'] = $object['id'];
 
 		if (!empty($object['inReplyTo'])) {
@@ -735,37 +833,15 @@ class ActivityPub
 		$item['name'] = defaults($object, 'name', $item['name']);
 		$item['summary'] = defaults($object, 'summary', null);
 		$item['content'] = defaults($object, 'content', null);
-		$item['location'] = self::processElement($object, 'location', 'name', 'Place');
+		$item['source'] = defaults($object, 'source', null);
+		$item['location'] = self::processElement($object, 'location', 'name', 'type', 'Place');
 		$item['attachments'] = defaults($object, 'attachment', null);
 		$item['tags'] = defaults($object, 'tag', null);
-		$item['service'] = self::processElement($object, 'instrument', 'name', 'Service');
+		$item['service'] = self::processElement($object, 'instrument', 'name', 'type', 'Service');
 		$item['alternate-url'] = self::processElement($object, 'url', 'href');
 		$item['receiver'] = self::getReceivers($object);
 
-		// handled
-		unset($object['id']);
-		unset($object['inReplyTo']);
-		unset($object['published']);
-		unset($object['updated']);
-		unset($object['uuid']);
-		unset($object['attributedTo']);
-		unset($object['context']);
-		unset($object['conversation']);
-		unset($object['sensitive']);
-		unset($object['name']);
-		unset($object['title']);
-		unset($object['content']);
-		unset($object['summary']);
-		unset($object['location']);
-		unset($object['attachment']);
-		unset($object['tag']);
-		unset($object['instrument']);
-		unset($object['url']);
-		unset($object['to']);
-		unset($object['cc']);
-		unset($object['bto']);
-		unset($object['bcc']);
-
+/*
 		// To-Do
 		unset($object['source']);
 
@@ -779,17 +855,17 @@ class ActivityPub
 		unset($object['replies']);
 		unset($object['icon']);
 
-		/*
+		// Also missing:
 		audience, preview, endTime, startTime, generator, image
-		*/
-
+*/
 		return $item;
 	}
 
-	private static function processNote($object, $url)
+	private static function processNote($object)
 	{
 		$item = [];
 
+/*
 		// To-Do?
 		unset($object['emoji']);
 		unset($object['atomUri']);
@@ -806,37 +882,21 @@ class ActivityPub
 		unset($object['shares']);
 		unset($object['quoteUrl']);
 		unset($object['statusnetConversationId']);
-
-		if (empty($object))
-			return $item;
-
-		echo "Unknown Note\n";
-		print_r($object);
-		print_r($item);
-		die($url."\n");
-
-		return [];
+*/
+		return $item;
 	}
 
-	private static function processArticle($object, $url)
+	private static function processArticle($object)
 	{
 		$item = [];
 
-		if (empty($object))
-			return $item;
-
-		echo "Unknown Article\n";
-		print_r($object);
-		print_r($item);
-		die($url."\n");
-
-		return [];
+		return $item;
 	}
 
-	private static function processVideo($object, $url)
+	private static function processVideo($object)
 	{
 		$item = [];
-
+/*
 		// To-Do?
 		unset($object['category']);
 		unset($object['licence']);
@@ -853,19 +913,11 @@ class ActivityPub
 		unset($object['dislikes']);
 		unset($object['shares']);
 		unset($object['comments']);
-
-		if (empty($object))
-			return $item;
-
-		echo "Unknown Video\n";
-		print_r($object);
-		print_r($item);
-		die($url."\n");
-
-		return [];
+*/
+		return $item;
 	}
 
-	private static function processElement($array, $element, $key, $type = null)
+	private static function processElement($array, $element, $key, $type = null, $type_value = null)
 	{
 		if (empty($array)) {
 			return false;
@@ -879,7 +931,7 @@ class ActivityPub
 			return $array[$element];
 		}
 
-		if (is_null($type)) {
+		if (is_null($type_value)) {
 			if (!empty($array[$element][$key])) {
 				return $array[$element][$key];
 			}
@@ -891,7 +943,7 @@ class ActivityPub
 			return false;
 		}
 
-		if (!empty($array[$element][$key]) && !empty($array[$element]['type']) && ($array[$element]['type'] == $type)) {
+		if (!empty($array[$element][$key]) && !empty($array[$element][$type]) && ($array[$element][$type] == $type_value)) {
 			return $array[$element][$key];
 		}
 
@@ -900,19 +952,213 @@ class ActivityPub
 		return false;
 	}
 
-	private static function createItem($item)
+	private static function convertMentions($body)
+	{
+		$URLSearchString = "^\[\]";
+		$body = preg_replace("/\[url\=([$URLSearchString]*)\]([#@!])(.*?)\[\/url\]/ism", '$2[url=$1]$3[/url]', $body);
+
+		return $body;
+	}
+
+	private static function constructTagList($tags, $sensitive)
+	{
+		if (empty($tags)) {
+			return '';
+		}
+
+		$tag_text = '';
+		foreach ($tags as $tag) {
+			if (in_array($tag['type'], ['Mention', 'Hashtag'])) {
+				if (!empty($tag_text)) {
+					$tag_text .= ',';
+				}
+
+				$tag_text .= substr($tag['name'], 0, 1) . '[url=' . $tag['href'] . ']' . substr($tag['name'], 1) . '[/url]';
+			}
+		}
+
+		/// @todo add nsfw for $sensitive
+
+		return $tag_text;
+	}
+
+	private static function constructAttachList($attachments, $item)
+	{
+		if (empty($attachments)) {
+			return $item;
+		}
+
+		foreach ($attachments as $attach) {
+			$filetype = strtolower(substr($attach['mediaType'], 0, strpos($attach['mediaType'], '/')));
+			if ($filetype == 'image') {
+				$item['body'] .= "\n[img]".$attach['url'].'[/img]';
+			} else {
+				if (!empty($item["attach"])) {
+					$item["attach"] .= ',';
+				} else {
+					$item["attach"] = '';
+				}
+				if (!isset($attach['length'])) {
+					$attach['length'] = "0";
+				}
+				$item["attach"] .= '[attach]href="'.$attach['url'].'" length="'.$attach['length'].'" type="'.$attach['mediaType'].'" title="'.defaults($attach, 'name', '').'"[/attach]';
+			}
+		}
+
+		return $item;
+	}
+
+	private static function createItem($activity, $body)
+	{
+		$item = [];
+		$item['verb'] = ACTIVITY_POST;
+		$item['parent-uri'] = $activity['reply-to-uri'];
+
+		if ($activity['reply-to-uri'] == $activity['uri']) {
+			$item['gravity'] = GRAVITY_PARENT;
+			$item['object-type'] = ACTIVITY_OBJ_NOTE;
+		} else {
+			$item['gravity'] = GRAVITY_COMMENT;
+			$item['object-type'] = ACTIVITY_OBJ_COMMENT;
+		}
+
+		self::postItem($activity, $item, $body);
+	}
+
+	private static function likeItem($activity, $body)
+	{
+		$item = [];
+		$item['verb'] = ACTIVITY_LIKE;
+		$item['parent-uri'] = $activity['object'];
+		$item['gravity'] = GRAVITY_ACTIVITY;
+		$item['object-type'] = ACTIVITY_OBJ_NOTE;
+
+		self::postItem($activity, $item, $body);
+	}
+
+	private static function postItem($activity, $item, $body)
 	{
-//		print_r($item);
+		/// @todo What to do with $activity['context']?
+
+		$item['network'] = Protocol::ACTIVITYPUB;
+		$item['private'] = !in_array(0, $activity['receiver']);
+		$item['author-id'] = Contact::getIdForURL($activity['author'], 0, true);
+		$item['owner-id'] = Contact::getIdForURL($activity['owner'], 0, true);
+		$item['uri'] = $activity['uri'];
+		$item['created'] = $activity['published'];
+		$item['edited'] = $activity['updated'];
+		$item['guid'] = $activity['uuid'];
+		$item['title'] = HTML::toBBCode($activity['name']);
+		$item['content-warning'] = HTML::toBBCode($activity['summary']);
+		$item['body'] = self::convertMentions(HTML::toBBCode($activity['content']));
+		$item['location'] = $activity['location'];
+		$item['tag'] = self::constructTagList($activity['tags'], $activity['sensitive']);
+		$item['app'] = $activity['service'];
+		$item['plink'] = defaults($activity, 'alternate-url', $item['uri']);
+
+		$item = self::constructAttachList($activity['attachments'], $item);
+
+		$source = self::processElement($activity, 'source', 'content', 'mediaType', 'text/bbcode');
+		if (!empty($source)) {
+			$item['body'] = $source;
+		}
+
+		$item['protocol'] = Conversation::PARCEL_ACTIVITYPUB;
+		$item['source'] = $body;
+		$item['conversation-uri'] = $activity['conversation'];
+
+		foreach ($activity['receiver'] as $receiver) {
+			$item['uid'] = $receiver;
+			$item['contact-id'] = Contact::getIdForURL($activity['author'], $receiver, true);
+
+			if (($receiver != 0) && empty($item['contact-id'])) {
+				$item['contact-id'] = Contact::getIdForURL($activity['author'], 0, true);
+			}
+
+			$item_id = Item::insert($item);
+			logger('Storing for user ' . $item['uid'] . ': ' . $item_id);
+			if (!empty($item_id) && ($item['uid'] == 0)) {
+				Item::distribute($item_id);
+			}
+		}
 	}
 
-	private static function announceItem($item)
+	private static function followUser($activity)
 	{
-//		print_r($item);
+		if (empty($activity['receiver'][$activity['object']])) {
+			return;
+		}
+
+		$uid = $activity['receiver'][$activity['object']];
+		$owner = User::getOwnerDataById($uid);
+
+		$cid = Contact::getIdForURL($activity['owner'], $uid);
+		if (!empty($cid)) {
+			$contact = DBA::selectFirst('contact', [], ['id' => $cid]);
+		} else {
+			$contact = false;
+		}
+
+		$item = ['author-id' => Contact::getIdForURL($activity['owner'])];
+
+		Contact::addRelationship($owner, $contact, $item);
+
+		$cid = Contact::getIdForURL($activity['owner'], $uid);
+		if (empty($cid)) {
+			return;
+		}
+
+		$contact = DBA::selectFirst('contact', ['network'], ['id' => $cid]);
+		if ($contact['network'] != Protocol::ACTIVITYPUB) {
+			Contact::updateFromProbe($cid, Protocol::ACTIVITYPUB);
+		}
+
+		DBA::update('contact', ['hub-verify' => $activity['id']], ['id' => $cid]);
+		logger('Follow user ' . $uid . ' from contact ' . $cid . ' with id ' . $activity['id']);
 	}
 
-	private static function activityItem($item)
+	private static function acceptFollowUser($activity)
 	{
-	//	print_r($item);
+		if (empty($activity['receiver'][$activity['object']])) {
+			return;
+		}
+
+		$uid = $activity['receiver'][$activity['object']];
+		$owner = User::getOwnerDataById($uid);
+
+		$cid = Contact::getIdForURL($activity['owner'], $uid);
+		if (empty($cid)) {
+			logger('No contact found for ' . $activity['owner'], LOGGER_DEBUG);
+			return;
+		}
+
+		$fields = ['pending' => false];
+		$condition = ['id' => $cid, 'pending' => true];
+		DBA::update('comtact', $fields, $condition);
+		logger('Accept contact request from contact ' . $cid . ' for user ' . $uid, LOGGER_DEBUG);
 	}
 
+	private static function undoFollowUser($activity)
+	{
+		if (empty($activity['receiver'][$activity['object']])) {
+			return;
+		}
+
+		$uid = $activity['receiver'][$activity['object']];
+		$owner = User::getOwnerDataById($uid);
+
+		$cid = Contact::getIdForURL($activity['owner'], $uid);
+		if (empty($cid)) {
+			logger('No contact found for ' . $activity['owner'], LOGGER_DEBUG);
+			return;
+		}
+
+		$contact = DBA::selectFirst('contact', [], ['id' => $cid]);
+		if (!DBA::isResult($contact)) {
+			return;
+		}
+
+		Contact::removeFollower($owner, $contact);
+		logger('Undo following request from contact ' . $cid . ' for user ' . $uid, LOGGER_DEBUG);
+	}
 }