allow for multiple pubsub hubs so everything can still work when/if one goes flaky

(Google's hub has been particularly unreliable recently and the symptoms are that
you just stop receiving updates, and/or updates you send are silently dropped and
never delivered). Also add more instrumentation to help debug pubsub issues.

3 files changed, 61 insertions, 17 deletions

diff --git a/include/items.php b/include/items.php
index 7958c78c3..7647eed5c 100644
--- a/include/items.php
+++ b/include/items.php
@@ -125,7 +125,18 @@ function get_feed_for(&$a, $dfrn_id, $owner_id, $last_update, $direction = 0) {
 
 	$hub = get_config('system','huburl');
 
-	$hubxml = ((strlen($hub)) ? '<link rel="hub" href="' . xmlify($hub) . '" />' . "\n" : '');
+	$hubxml = '';
+	if(strlen($hub)) {
+		$hubs = explode(',', $hub);
+		if(count($hubs)) {
+			foreach($hubs as $h) {
+				$h = trim($h);
+				if(! strlen($h))
+					continue;
+				$hubxml .= '<link rel="hub" href="' . xmlify($h) . '" />' . "\n" ;
+			}
+		}
+	}
 
 	$salmon = '<link rel="salmon" href="' . xmlify($a->get_baseurl() . '/salmon/' . $owner_nick) . '" />' . "\n" ; 
 	$salmon = ''; // remove this line when salmon handler is finished
@@ -599,10 +610,10 @@ function consume_feed($xml,$importer,$contact, &$hub) {
 	$photo_url = '';
 
 
-	$foundhub = $feed->get_link(0,'hub');
+	$hubs = $feed->get_links('hub');
 
-	if(strlen($foundhub))
-		$hub = $foundhub;
+	if(count($hubs))
+		$hub = implode(',', $hubs);
 
 	$rawtags = $feed->get_feed_tags( SIMPLEPIE_NAMESPACE_ATOM_10, 'author');
 	if($rawtags) {
@@ -834,14 +845,18 @@ function subscribe_to_hub($url,$importer,$contact) {
 
 	$push_url = get_config('system','url') . '/pubsub/' . $r[0]['nickname'] . '/' . $contact['id'];
 
-	$verify_token = random_string();
+	// Use a single verify token, even if multiple hubs
+
+	$verify_token = ((strlen($contact['hub-verify'])) ? $contact['hub-verify'] : random_string());
 
 	$params= 'hub.mode=subscribe&hub.callback=' . urlencode($push_url) . '&hub.topic=' . urlencode($contact['poll']) . '&hub.verify=async&hub.verify_token=' . $verify_token;
 
-	$r = q("UPDATE `contact` SET `hub-verify` = '%s' WHERE `id` = %d LIMIT 1",
-		dbesc($verify_token),
-		intval($contact['id'])
-	);
+	if(! strlen($contact['hub-verify'])) {
+		$r = q("UPDATE `contact` SET `hub-verify` = '%s' WHERE `id` = %d LIMIT 1",
+			dbesc($verify_token),
+			intval($contact['id'])
+		);
+	}
 
 	post_url($url,$params);			
 	return;
diff --git a/include/notifier.php b/include/notifier.php
index 9866c0232..bef46677c 100644
--- a/include/notifier.php
+++ b/include/notifier.php
@@ -149,8 +149,18 @@
 
 	$atom = '';
 
-	$hubxml = ((strlen($hub)) ? '<link rel="hub" href="' . xmlify($hub) . '" />' . "\n" : '');
-	
+	$hubxml = '';
+	if(strlen($hub)) {
+		$hubs = explode(',', $hub);
+		if(count($hubs)) {
+			foreach($hubs as $h) {
+				$h = trim($h);
+				if(! strlen($h))
+					continue;
+				$hubxml .= '<link rel="hub" href="' . xmlify($h) . '" />' . "\n" ;
+			}
+		}
+	}
 
 	$atom .= replace_macros($feed_template, array(
 			'$feed_id'      => xmlify($a->get_baseurl() . '/profile/' . $owner['nickname'] ),
@@ -314,10 +324,21 @@
 	}
 
 	if((strlen($hub)) && ($notify_hub)) {
-		$params = 'hub.mode=publish&hub.url=' . urlencode($a->get_baseurl() . '/dfrn_poll/' . $owner['nickname'] );
-		post_url($hub,$params);
-		if($debugging) {
-			file_put_contents('pubsub.out', "\n\n" . "Pinged hub at " . datetime_convert() . "\n" . "Hub returned " . $a->get_curl_code() . "\n\n" , FILE_APPEND);
+		$hubs = explode(',', $hub);
+		if(count($hubs)) {
+			foreach($hubs as $h) {
+				$h = trim($h);
+				if(! strlen($h))
+					continue;
+				$params = 'hub.mode=publish&hub.url=' . urlencode($a->get_baseurl() . '/dfrn_poll/' . $owner['nickname'] );
+				post_url($h,$params);
+				if($debugging) {
+					file_put_contents('pubsub.out', "\n\n" . "Pinged hub " . $h . ' at ' 
+						. datetime_convert() . "\n" . "Hub returned " . $a->get_curl_code() . "\n\n" , FILE_APPEND);
+				}
+				if(count($hubs) > 1)
+					sleep(7);				// try and avoid multiple hubs responding at precisely the same time
+			}
 		}
 	}
 
diff --git a/include/poller.php b/include/poller.php
index bf2803b63..bb82e5eda 100644
--- a/include/poller.php
+++ b/include/poller.php
@@ -22,7 +22,7 @@
 	$a->set_baseurl(get_config('system','url'));
 
 	$contacts = q("SELECT * FROM `contact` 
-		WHERE ( `dfrn-id` != '' OR (`issued-id` != '' AND `duplex` = 1)) 
+		WHERE `network` = 'dfrn' AND ( `dfrn-id` != '' OR (`issued-id` != '' AND `duplex` = 1)) 
 		AND `self` = 0 AND `blocked` = 0 AND `readonly` = 0 ORDER BY RAND()");
 
 	if(! count($contacts))
@@ -174,7 +174,15 @@
 		
 
 		if((strlen($hub)) && ($contact['rel'] == REL_BUD) && ($contact['priority'] == 0)) {
-			subscribe_to_hub($hub,$importer,$contact);
+			$hubs = explode(',', $hub);
+			if(count($hubs)) {
+				foreach($hubs as $h) {
+					$h = trim($h);
+					if(! strlen($h))
+						continue;
+					subscribe_to_hub($h,$importer,$contact);
+				}
+			}
 		}