adding a new, more generic "discovery" class that does LRDD disco

(rather than webfinger specific)

diff --git a/plugins/OStatus/lib/discovery.php b/plugins/OStatus/lib/discovery.php
new file mode 100644 (file)
index 0000000..1159f21
--- /dev/null
+++ b/plugins/OStatus/lib/discovery.php
@@ -0,0 +1,303 @@
+<?php
+/**
+ * StatusNet - the distributed open-source microblogging tool
+ * Copyright (C) 2010, StatusNet, Inc.
+ *
+ * A sample module to show best practices for StatusNet plugins
+ *
+ * PHP version 5
+ *
+ * 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/>.
+ *
+ * @package   StatusNet
+ * @author    James Walker <james@status.net>
+ * @copyright 2010 StatusNet, Inc.
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPL 3.0
+ * @link      http://status.net/
+ */
+
+/**
+ * This class implements LRDD-based service discovery based on the "Hammer Draft"
+ * (including webfinger)
+ *
+ * @see http://groups.google.com/group/webfinger/browse_thread/thread/9f3d93a479e91bbf
+ */
+class Discovery
+{
+
+    const LRDD_REL = 'lrdd';
+    const PROFILEPAGE = 'http://webfinger.net/rel/profile-page';
+    const UPDATESFROM = 'http://schemas.google.com/g/2010#updates-from';
+
+    public $methods = array();
+
+    public function __construct()
+    {
+        $this->registerMethod('Discovery_LRDD_Host_Meta');
+        $this->registerMethod('Discovery_LRDD_Link_Header');
+        $this->registerMethod('Discovery_LRDD_Link_HTML');
+    }
+
+
+    public function registerMethod($class)
+    {
+        $this->methods[] = $class;
+    }
+    
+    /**
+     * Given a "user id" make sure it's normalized to either a webfinger
+     * acct: uri or a profile HTTP URL.
+     */
+    public static function normalize($user_id)
+    {
+        if (substr($user_id, 0, 5) == 'http:' ||
+            substr($user_id, 0, 6) == 'https:' ||
+            substr($user_id, 0, 5) == 'acct:') {
+            return $user_id;
+        }
+
+        if (strpos($user_id, '@') !== FALSE) {
+            return 'acct:' . $user_id;
+        }
+
+        return 'http://' . $user_id;
+    }
+
+    public static function isWebfinger($user_id)
+    {
+        $uri = Discovery::normalize($user_id);
+        
+        return (substr($uri, 0, 5) == 'acct:');
+    }
+
+    /**
+     * This implements the actual lookup procedure
+     */
+    public function lookup($id)
+    {
+        // Normalize the incoming $id to make sure we have a uri
+        $uri = $this->normalize($id);
+
+        foreach ($this->methods as $class) {
+            $links = call_user_func(array($class, 'discover'), $uri);
+
+            if ($link = Discovery::getService($links, Discovery::LRDD_REL)) {
+                // Load the LRDD XRD
+                if ($link['template']) {
+                    $xrd_uri = Discovery::applyTemplate($link['template'], $uri);
+                } else {
+                    $xrd_uri = $link['href'];
+                }
+                
+                $xrd = $this->fetchXrd($xrd_uri);
+                if ($xrd) {
+                    return $xrd;
+                }
+            }
+        }
+
+        throw new Exception('Unable to find services for '. $id);
+    }
+
+    public static function getService($links, $service) {
+        foreach ($links as $link) {
+            if ($link['rel'] == $service) {
+                return $link;
+            }
+        }
+    }
+    
+
+    public static function applyTemplate($template, $id)
+    {
+        $template = str_replace('{uri}', urlencode($id), $template);
+
+        return $template;
+    }
+
+    
+    public static function fetchXrd($url)
+    {
+        try {
+            $client = new HTTPClient();
+            $response = $client->get($url);
+        } catch (HTTP_Request2_Exception $e) {
+            return false;
+        }
+
+        if ($response->getStatus() != 200) {
+            return false;
+        }
+
+        return XRD::parse($response->getBody());
+    }    
+}
+
+interface Discovery_LRDD
+{
+    public function discovery($uri);
+}
+
+class Discovery_LRDD_Host_Meta implements Discovery_LRDD
+{
+    function discover($uri)
+    {
+        if (Discovery::isWebfinger($uri)) {
+            // We have a webfinger acct: - start with host-meta
+            list($name, $domain) = explode('@', $id);
+        } else {
+            $domain = @parse_url($uri, PHP_URL_HOST);
+        }
+
+        $url = 'http://'. $domain .'/.well-known/host-meta';
+
+        $xrd = Discovery::fetchXrd($url);
+
+        if ($xrd) {
+            if ($xrd->host != $domain) {
+                return false;
+            }
+            
+            return $xrd->links;
+        }
+    }
+}
+
+class Discovery_LRDD_Link_Header implements Discovery_LRDD
+{
+    public function discover($uri)
+    {
+        try {
+            $client = new HTTPClient();
+            $response = $client->get($url);
+        } catch (HTTP_Request2_Exception $e) {
+            return false;
+        }
+
+        if ($response->getStatus() != 200) {
+            return false;
+        }
+
+        $link_header = $response->getHeader('Link');
+        if (!$link_header) {
+            return false;
+        }
+        
+        return Discovery_LRDD_Link_Header::parseHeader($header);
+    }
+
+    protected static function parseHeader($header)
+    {
+        preg_match('/^<[^>]+>/', $header, $uri_reference);
+        if (empty($uri_reference)) return;
+        
+        $link_uri = trim($uri_reference[0], '<>');
+        $link_rel = array();
+        $link_type = null;
+        
+        // remove uri-reference from header
+        $header = substr($header, strlen($uri_reference[0]));
+        
+        // parse link-params
+        $params = explode($header, ';');
+        
+        foreach ($params as $param) {
+            if (empty($param)) continue;
+            list($param_name, $param_value) = explode('=', $param, 2);
+            $param_name = trim($param_name);
+            $param_value = preg_replace('(^"|"$)', '', trim($param_value));
+            
+            // for now we only care about 'rel' and 'type' link params
+            // TODO do something with the other links-params
+            switch ($param_name) {
+            case 'rel':
+                $link_rel = trim($param_value);
+                break;
+                
+            case 'type':
+                $link_type = trim($param_value);
+            }
+        }
+        
+        return array(
+            'href' => $link_uri,
+            'rel' => $link_rel,
+            'type' => $link_type);
+    }
+}
+
+class Discovery_LRDD_Link_HTML implements Discovery_LRDD
+{
+    public function discover($uri)
+    {
+        try {
+            $client = new HTTPClient();
+            $response = $client->get($url);
+        } catch (HTTP_Request2_Exception $e) {
+            return false;
+        }
+
+        if ($response->getStatus() != 200) {
+            return false;
+        }
+
+        return Discovery_LRDD_Link_HTML::parse($response->getBody());
+    }
+
+
+    public function parse($html)
+    {
+        $links = array();
+        
+        preg_match('/<head(\s[^>]*)?>(.*?)<\/head>/is', $html, $head_matches);
+        $head_html = $head_matches[2];
+        
+        preg_match_all('/<link\s[^>]*>/i', $head_html, $link_matches);
+        
+        foreach ($link_matches[0] as $link_html) {
+            $link_url = null;
+            $link_rel = null;
+            $link_type = null;
+            
+            preg_match('/\srel=(("|\')([^\\2]*?)\\2|[^"\'\s]+)/i', $link_html, $rel_matches);
+            if ( isset($rel_matches[3]) ) {
+                $link_rel = $rel_matches[3];
+            } else if ( isset($rel_matches[1]) ) {
+                $link_rel = $rel_matches[1];
+            }
+            
+            preg_match('/\shref=(("|\')([^\\2]*?)\\2|[^"\'\s]+)/i', $link_html, $href_matches);
+            if ( isset($href_matches[3]) ) {
+                $link_uri = $href_matches[3];
+            } else if ( isset($href_matches[1]) ) {
+                $link_uri = $href_matches[1];
+            }
+            
+            preg_match('/\stype=(("|\')([^\\2]*?)\\2|[^"\'\s]+)/i', $link_html, $type_matches);
+            if ( isset($type_matches[3]) ) {
+                $link_type = $type_matches[3];
+            } else if ( isset($type_matches[1]) ) {
+                $link_type = $type_matches[1];
+            }
+            
+            $links[] = array(
+                'href' => $link_url,
+                'rel' => $link_rel,
+                'type' => $link_type,
+            );
+        }
+        
+        return $links;
+    }
+}