Initial support for third-party fallback hub such as Superfeedr for feed subscriptions.

If set up, this hub will be used to subscribe to feeds that don't specify a hub of their own.
Assumes that the fallback hub will, in fact, handle polling and updates for any feed we throw at it!
Authentication may be specified for the fallback hub.

Example:

  $config['feedsub']['fallback_hub'] = 'https://superfeedr.com/hubbub';
  $config['feedsub']['hub_user'] = 'abcd';
  $config['feedsub']['hub_pass'] = 'ckcmdkmckdmkcdk';

Also:
* Fix for WordPress-RSS-via-Superfeedr-Atom; if we have <author> info but no ID from a native ActivityStreams actor, don't freak out in the low-level processing code that checks for identity matches.
* enhanced messages for low-level FeedSub exceptions if they make it to outside display

plugins/OStatus/OStatusPlugin.php

@@ -28,6 +28,15 @@ set_include_path(get_include_path() . PATH_SEPARATOR . dirname(__FILE__) . '/ext
 
 class FeedSubException extends Exception
 {
+    function __construct($msg=null)
+    {
+        $type = get_class($this);
+        if ($msg) {
+            parent::__construct("$type: $msg");
+        } else {
+            parent::__construct($type);
+        }
+    }
 }
 
 class OStatusPlugin extends Plugin

plugins/OStatus/README

@@ -1,18 +1,42 @@
-Plugin to support importing updates from external RSS and Atom feeds into your timeline.
+Plugin to support importing and exporting notices through Atom and RSS feeds.
+The OStatus plugin concentrates on user-to-user cases for federating StatusNet
+and similar social networking / microblogging / blogging sites, but includes
+low-level feed subscription systems which are used by some other plugins.
+
+Uses PubSubHubbub for push feed updates; currently non-PuSH feeds cannot be
+subscribed unless an external PuSH hub proxy is used.
 
-Uses PubSubHubbub for push feed updates; currently non-PuSH feeds cannot be subscribed.
 
 Configuration options available:
 
 $config['ostatus']['hub']
     (default internal hub)
-    Set to URL of an external PuSH hub to use it instead of our internal hub.
+    Set to URL of an external PuSH hub to use it instead of our internal hub
+    for sending outgoing updates in user and group feeds.
 
 $config['ostatus']['hub_retries']
     (default 0)
     Number of times to retry a PuSH send to consumers if using internal hub
 
 
+Settings controlling incoming feed subscription:
+
+$config['feedsub']['fallback_hub']
+    To subscribe to feeds that don't have a hub, an external PuSH proxy hub
+    such as Superfeedr may be used. Any feed without a hub of its own will
+    be subscribed through the specified hub URL instead. If the external hub
+    has usage charges, be aware that there is no restriction placed to how
+    many feeds may be subscribed!
+
+    $config['feedsub']['fallback_hub'] = 'https://superfeedr.com/hubbub';
+
+$config['feedsub']['hub_user']
+$config['feedsub']['hub_password']
+    If using the fallback hub mode, these settings may be used to provide
+    HTTP authentication credentials for contacting the hub. Default hubs
+    specified from feeds are assumed to not require
+
+
 For testing, shouldn't be used in production:
 
 $config['ostatus']['skip_signatures']
@@ -23,12 +47,11 @@ $config['feedsub']['nohub']
     (default require hub)
     Allow low-level feed subscription setup for feeds without hubs.
     Not actually usable at this stage, OStatus will check for hubs too
-    and we have no polling backend.
+    and we have no polling backend. (The fallback hub option can be used
+    with a 3rd-party service to provide such polling.)
 
 
 Todo:
-* fully functional l10n
+* better support for feeds that aren't natively oriented at social networking
-* redo non-OStatus feed support
-** rssCloud support?
-** possibly a polling daemon to support non-PuSH feeds?
 * make use of tags/categories from feeds
+* better repeat handling

plugins/OStatus/classes/FeedSub.php

@@ -207,8 +207,8 @@ class FeedSub extends Memcached_DataObject
         $discover = new FeedDiscovery();
         $discover->discoverFromFeedURL($feeduri);
 
-        $huburi = $discover->getAtomLink('hub');
+        $huburi = $discover->getHubLink();
-        if (!$huburi) {
+        if (!$huburi && !common_config('feedsub', 'fallback_hub')) {
             throw new FeedSubNoHubException();
         }
 
@@ -241,8 +241,12 @@ class FeedSub extends Memcached_DataObject
             common_log(LOG_WARNING, "Attempting to (re)start PuSH subscription to $this->uri in unexpected state $this->sub_state");
         }
         if (empty($this->huburi)) {
-            if (common_config('feedsub', 'nohub')) {
+            if (common_config('feedsub', 'fallback_hub')) {
+                // No native hub on this feed?
+                // Use our fallback hub, which handles polling on our behalf.
+            } else if (common_config('feedsub', 'nohub')) {
                 // Fake it! We're just testing remote feeds w/o hubs.
+                // We'll never actually get updates in this mode.
                 return true;
             } else {
                 throw new ServerException("Attempting to start PuSH subscription for feed with no hub");
@@ -267,8 +271,12 @@ class FeedSub extends Memcached_DataObject
             common_log(LOG_WARNING, "Attempting to (re)end PuSH subscription to $this->uri in unexpected state $this->sub_state");
         }
         if (empty($this->huburi)) {
-            if (common_config('feedsub', 'nohub')) {
+            if (common_config('feedsub', 'fallback_hub')) {
+                // No native hub on this feed?
+                // Use our fallback hub, which handles polling on our behalf.
+            } else if (common_config('feedsub', 'nohub')) {
                 // Fake it! We're just testing remote feeds w/o hubs.
+                // We'll never actually get updates in this mode.
                 return true;
             } else {
                 throw new ServerException("Attempting to end PuSH subscription for feed with no hub");
@@ -326,7 +334,21 @@ class FeedSub extends Memcached_DataObject
                           'hub.secret' => $this->secret,
                           'hub.topic' => $this->uri);
             $client = new HTTPClient();
-            $response = $client->post($this->huburi, $headers, $post);
+            if ($this->huburi) {
+                $hub = $this->huburi;
+            } else {
+                if (common_config('feedsub', 'fallback_hub')) {
+                    $hub = common_config('feedsub', 'fallback_hub');
+                    if (common_config('feedsub', 'hub_user')) {
+                        $u = common_config('feedsub', 'hub_user');
+                        $p = common_config('feedsub', 'hub_pass');
+                        $client->setAuth($u, $p);
+                    }
+                } else {
+                    throw new FeedSubException('WTF?');
+                }
+            }
+            $response = $client->post($hub, $headers, $post);
             $status = $response->getStatus();
             if ($status == 202) {
                 common_log(LOG_INFO, __METHOD__ . ': sub req ok, awaiting verification callback');

plugins/OStatus/classes/Ostatus_profile.php

@@ -493,8 +493,14 @@ class Ostatus_profile extends Memcached_DataObject
                 // OK here! assume the default
             } else if ($actor->id == $this->uri || $actor->link == $this->uri) {
                 $this->updateFromActivityObject($actor);
-            } else {
+            } else if ($actor->id) {
+                // We have an ActivityStreams actor with an explicit ID that doesn't match the feed owner.
+                // This isn't what we expect from mainline OStatus person feeds!
+                // Group feeds go down another path, with different validation.
                 throw new Exception("Got an actor '{$actor->title}' ({$actor->id}) on single-user feed for {$this->uri}");
+            } else {
+                // Plain <author> without ActivityStreams actor info.
+                // We'll just ignore this info for now and save the update under the feed's identity.
             }
 
             $oprofile = $this;
@@ -869,12 +875,12 @@ class Ostatus_profile extends Memcached_DataObject
         $feeduri = $discover->discoverFromFeedURL($feed_url);
         $hints['feedurl'] = $feeduri;
 
-        $huburi = $discover->getAtomLink('hub');
+        $huburi = $discover->getHubLink();
         $hints['hub'] = $huburi;
         $salmonuri = $discover->getAtomLink(Salmon::NS_REPLIES);
         $hints['salmon'] = $salmonuri;
 
-        if (!$huburi) {
+        if (!$huburi && !common_config('feedsub', 'fallback_hub')) {
             // We can only deal with folks with a PuSH hub
             throw new FeedSubNoHubException();
         }
@@ -1270,10 +1276,10 @@ class Ostatus_profile extends Memcached_DataObject
                 $discover = new FeedDiscovery();
                 $discover->discoverFromFeedURL($hints['feedurl']);
             }
-            $huburi = $discover->getAtomLink('hub');
+            $huburi = $discover->getHubLink();
         }
 
-        if (!$huburi) {
+        if (!$huburi && !common_config('feedsub', 'fallback_hub')) {
             // We can only deal with folks with a PuSH hub
             throw new FeedSubNoHubException();
         }

plugins/OStatus/lib/feeddiscovery.php

@@ -87,6 +87,16 @@ class FeedDiscovery
         return ActivityUtils::getLink($this->root, $rel, $type);
     }
 
+    /**
+     * Get the referenced PuSH hub link from an Atom feed.
+     *
+     * @return mixed string or false
+     */
+    public function getHubLink()
+    {
+        return $this->getAtomLink('hub');
+    }
+
     /**
      * @param string $url
      * @param bool $htmlOk pass false here if you don't want to follow web pages.

plugins/OStatus/scripts/update-profile.php

@@ -55,7 +55,7 @@ print "Re-running feed discovery for profile URL $oprofile->uri\n";
 // @fixme will bork where the URI isn't the profile URL for now
 $discover = new FeedDiscovery();
 $feedurl = $discover->discoverFromURL($oprofile->uri);
-$huburi = $discover->getAtomLink('hub');
+$huburi = $discover->getHubLink();
 $salmonuri = $discover->getAtomLink(Salmon::NS_REPLIES);
 
 print "  Feed URL: $feedurl\n";