better handling of XRDS files

Our generated XRDS files contain 3 XRD elements: one for OAuth, one
for OMB, and one to point to the other two. Auth_Yadis only gives us
the last one, so we have to use it to find the other two, and then
extract service URLs from them.

Kind of fragile code, probably won't hold up under complicated
topologies, and won't work at all if the XRDs are in another XRDS
container. I tried to use XRDS filtering to get the top-priority
version of XRDs, services, and URIs, but Laconica's output doesn't use
any of that stuff and I don't particularly want to test it.

darcs-hash:20080602174249-84dde-b7ffdf7f21afb5b734def70530fc305689da471d.gz

actions/remotesubscribe.php

@@ -121,53 +121,101 @@ class RemotesubscribeAction extends Action {
 	}
 
 	function getOmb($xrds) {
-	    static $endpoints = array(OMB_ENDPOINT_UPDATEPROFILE, OMB_ENDPOINT_POSTNOTICE,
+		
-								  OAUTH_ENDPOINT_REQUEST, OAUTH_ENDPOINT_AUTHORIZE,
+	    static $omb_endpoints = array(OMB_ENDPOINT_UPDATEPROFILE, OMB_ENDPOINT_POSTNOTICE);
-								  OAUTH_ENDPOINT_ACCESS);
+		static $oauth_endpoints = array(OAUTH_ENDPOINT_REQUEST, OAUTH_ENDPOINT_AUTHORIZE,
+										OAUTH_ENDPOINT_ACCESS);
 		$omb = array();
-		$services = $xrds->services(); # ordered by priority
+
-		if (!$services) {
+		# XXX: the following code could probably be refactored to eliminate dupes
-			common_debug('remotesubscribe.php: Got no services back from XRDS.');
+		
+		$oauth_service = $xrds->services(array($this, 'matchOAuth'));
+		
+		if (!$oauth_service) {
 			return NULL;
 		}
 
-		common_debug('remotesubscribe.php: XRDS service count: '.count($services));
+		$xrd = $this->getXRD($oauth_service, $xrds);
+		$this->addServices($xrd, $oauth_endpoints, $omb);
 
-		foreach ($services as $service) {
+		$omb_service = $xrds->services(array($this, 'matchOMB'));
-			common_debug('remotesubscribe.php: XRDS service "'.print_r($service,TRUE).'"');
+
-			$types = $service->matchTypes($endpoints);
+		if (!$omb_service) {
-			foreach ($types as $type) {
+			return NULL;
-				# We take the first one, since it's the highest priority
-				if (!array_key_exists($type, $omb)) {
-					# URIs is an array, priority-ordered
-					$omb[$type] = $service->getURIs();
-					# Special handling for request
-					if ($type == OAUTH_ENDPOINT_REQUEST) {
-						$nodes = $service->getElements('LocalID');
-						if (!$nodes) {
-							# error
-							return NULL;
-						}
-						$omb['listener'] = $service->parser->content($nodes[0]);
-					}
-				}
-			}
 		}
-		foreach ($endpoints as $ep) {
+
-			if (!array_key_exists($ep, $omb)) {
+		$xrd = $this->getXRD($omb_service, $xrds);
+		$this->addServices($xrd, $omb_endpoints, $omb);
+		
+		# XXX: check that we got all the services we needed
+		
+		foreach (array_merge($omb_endpoints, $oauth_endpoints) as $type) {
+			if (!array_key_exists($type, $omb)) {
 				return NULL;
 			}
 		}
-		if (!array_key_exists('listener', $omb)) {
+		
+		if (!omb_local_id($omb[OAUTH_ENDPOINT_REQUEST])) {
 			return NULL;
 		}
+		
 		return $omb;
 	}
 
+	function getXRD($main_service, $main_xrds) {
+		$uri = omb_service_uri($main_service);
+		if (strpos($uri, "#") !== 0) {
+			# FIXME: more rigorous handling of external service definitions
+			return NULL;
+		}
+		$id = substr($uri, 1);
+		$nodes = $main_xrds->allXrdNodes;
+		$parser = $main_xrds->parser;
+		foreach ($nodes as $node) {
+			$attrs = $parser->attributes($node);
+			if (array_key_exists('xml:id', $attrs) &&
+				$attrs['xml:id'] == $id) {
+				return new Auth_Yadis_XRDS($parser, array($node));
+			}
+		}
+		return NULL;
+	}
+
+	function addServices($xrd, $types, &$omb) {
+		foreach ($types as $type) {
+			$filter = create_function('$s', 
+									  'return RemotesubscribeAction::matchService($s, \''.$type.'\'');
+			$matches = $xrd->services($filter);
+			if ($matches) {
+				$omb[$type] = $services[0];
+			} else {
+				# no match for type
+				return false;
+			}
+		}
+		return true;
+	}
+	
+	function matchOAuth($service) {
+		return $this->matchService($service, OAUTH_DISCOVERY);
+	}
+
+	function matchOMB($service) {
+		return $this->matchService($service, OMB_VERSION_01);
+	}
+
+	function matchService($service, $type) {
+		if ($service && $service->matchTypes(array($type))) {
+			return TRUE;
+		} else {
+			return FALSE;
+		}
+	}
+	
 	function request_token($omb) {
 		$con = omb_oauth_consumer();
 
-		$url = $omb[OAUTH_ENDPOINT_REQUEST][0];
+		$url = omb_service_uri($omb[OAUTH_ENDPOINT_REQUEST]);
 		
 		# XXX: Is this the right thing to do? Strip off GET params and make them
 		# POST params? Seems wrong to me.
@@ -178,7 +226,13 @@ class RemotesubscribeAction extends Action {
 
 		$req = OAuthRequest::from_consumer_and_token($con, NULL, "POST", $url, $params);
 
-		$req->set_parameter('omb_listener', $omb['listener']);
+		$listener = omb_local_id($omb[OAUTH_ENDPOINT_REQUEST]);
+		
+		if (!$listener) {
+			return NULL;
+		}
+		
+		$req->set_parameter('omb_listener', $listener);
 		$req->set_parameter('omb_version', OMB_VERSION_01);
 		
 		# XXX: test to see if endpoint accepts this signature method
@@ -206,7 +260,7 @@ class RemotesubscribeAction extends Action {
 		$con = omb_oauth_consumer();
 		$tok = new OAuthToken($token, $secret);
 		
-		$url = $omb[OAUTH_ENDPOINT_AUTHORIZE][0];
+		$url = omb_service_uri($omb[OAUTH_ENDPOINT_AUTHORIZE]);
 		
 		# XXX: Is this the right thing to do? Strip off GET params and make them
 		# POST params? Seems wrong to me.
@@ -222,7 +276,7 @@ class RemotesubscribeAction extends Action {
 		# user decide if they really want to authorize the subscription.
 		
 		$req->set_parameter('omb_version', OMB_VERSION_01);
-		$req->set_parameter('omb_listener', $omb['listener']);
+		$req->set_parameter('omb_listener', omb_local_id($omb[OAUTH_ENDPOINT_REQUEST]));
 		$req->set_parameter('omb_listenee', $user->uri);
 		$req->set_parameter('omb_listenee_profile', common_profile_url($user->nickname));
 		$req->set_parameter('omb_listenee_nickname', $user->nickname);

lib/omb.php

@@ -60,3 +60,17 @@ function omb_hmac_sha1() {
 	}
 	return $hmac_method;
 }
+
+function omb_service_uri($service) {
+	$uris = $service->getURIs();
+	if (!$uris) {
+		return NULL;
+	}
+	return $uris[0];
+}
+
+function omb_local_id($service) {
+	$els = $service->getElements('LocalID');
+	return ($els) ? $els[0] : NULL;
+}
+