]> git.mxchange.org Git - friendica.git/blobdiff - src/Network/Probe.php
Merge pull request #8765 from annando/fix-pubkey
[friendica.git] / src / Network / Probe.php
index 05160771056a7c50a485440e07fdd8aa0949c2e0..dcb0bf192f68b84a0574e3f9e5a79129fe18ab80 100644 (file)
@@ -1,23 +1,37 @@
 <?php
 /**
- * @file src/Network/Probe.php
+ * @copyright Copyright (C) 2020, Friendica
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * 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 <https://www.gnu.org/licenses/>.
+ *
  */
-namespace Friendica\Network;
 
-/**
- * @file src/Network/Probe.php
- * @brief Functions for probing URL
- */
+namespace Friendica\Network;
 
 use DOMDocument;
 use DomXPath;
-use Friendica\Core\Cache;
-use Friendica\Core\Config;
+use Friendica\Core\Cache\Duration;
+use Friendica\Core\Hook;
 use Friendica\Core\Logger;
 use Friendica\Core\Protocol;
+use Friendica\Core\System;
 use Friendica\Database\DBA;
 use Friendica\DI;
 use Friendica\Model\Contact;
+use Friendica\Model\GServer;
 use Friendica\Model\Profile;
 use Friendica\Protocol\ActivityNamespace;
 use Friendica\Protocol\ActivityPub;
@@ -29,8 +43,7 @@ use Friendica\Util\Strings;
 use Friendica\Util\XML;
 
 /**
- * @brief This class contain functions for probing URL
- *
+ * This class contain functions for probing URL
  */
 class Probe
 {
@@ -38,7 +51,32 @@ class Probe
        private static $istimeout;
 
        /**
-        * @brief Rearrange the array so that it always has the same order
+        * Remove stuff from an URI that doesn't belong there
+        *
+        * @param string $URI
+        * @return string Cleaned URI
+        */
+       public static function cleanURI(string $URI)
+       {
+               // At first remove leading and trailing junk
+               $URI = trim($URI, "@#?:/ \t\n\r\0\x0B");
+
+               $parts = parse_url($URI);
+
+               if (empty($parts['scheme'])) {
+                       return $URI;
+               }
+
+               // Remove the URL fragment, since these shouldn't be part of any profile URL
+               unset($parts['fragment']);
+
+               $URI = Network::unparseURL($parts);
+
+               return $URI;
+       }
+
+       /**
+        * Rearrange the array so that it always has the same order
         *
         * @param array $data Unordered data
         *
@@ -47,17 +85,23 @@ class Probe
        private static function rearrangeData($data)
        {
                $fields = ["name", "nick", "guid", "url", "addr", "alias", "photo", "account-type",
-                               "community", "keywords", "location", "about", "gender", "hide",
-                               "batch", "notify", "poll", "request", "confirm", "poco",
+                               "community", "keywords", "location", "about", "hide",
+                               "batch", "notify", "poll", "request", "confirm", "subscribe", "poco",
                                "following", "followers", "inbox", "outbox", "sharedinbox",
-                               "priority", "network", "pubkey", "baseurl"];
+                               "priority", "network", "pubkey", "baseurl", "gsid"];
 
                $newdata = [];
                foreach ($fields as $field) {
                        if (isset($data[$field])) {
-                               $newdata[$field] = $data[$field];
-                       } else {
+                               if (in_array($field, ["gsid", "hide", "account-type"])) {
+                                       $newdata[$field] = (int)$data[$field];
+                               } else {        
+                                       $newdata[$field] = $data[$field];
+                               }
+                       } elseif ($field != "gsid") {
                                $newdata[$field] = "";
+                       } else {
+                               $newdata[$field] = null;
                        }
                }
 
@@ -68,7 +112,7 @@ class Probe
        }
 
        /**
-        * @brief Check if the hostname belongs to the own server
+        * Check if the hostname belongs to the own server
         *
         * @param string $host The hostname that is to be checked
         *
@@ -91,7 +135,7 @@ class Probe
        }
 
        /**
-        * @brief Probes for webfinger path via "host-meta"
+        * Probes for webfinger path via "host-meta"
         *
         * We have to check if the servers in the future still will offer this.
         * It seems as if it was dropped from the standard.
@@ -106,40 +150,50 @@ class Probe
                // Reset the static variable
                self::$baseurl = '';
 
-               $ssl_url = "https://".$host."/.well-known/host-meta";
-               $url = "http://".$host."/.well-known/host-meta";
+               // Handles the case when the hostname contains the scheme
+               if (!parse_url($host, PHP_URL_SCHEME)) {
+                       $ssl_url = "https://" . $host . "/.well-known/host-meta";
+                       $url = "http://" . $host . "/.well-known/host-meta";
+               } else {
+                       $ssl_url = $host . "/.well-known/host-meta";
+                       $url = '';
+               }
 
-               $xrd_timeout = Config::get('system', 'xrd_timeout', 20);
+               $xrd_timeout = DI::config()->get('system', 'xrd_timeout', 20);
 
-               Logger::log("Probing for ".$host, Logger::DEBUG);
+               Logger::info('Probing', ['host' => $host, 'ssl_url' => $ssl_url, 'url' => $url, 'callstack' => System::callstack(20)]);
                $xrd = null;
 
                $curlResult = Network::curl($ssl_url, false, ['timeout' => $xrd_timeout, 'accept_content' => 'application/xrd+xml']);
                $ssl_connection_error = ($curlResult->getErrorNumber() == CURLE_COULDNT_CONNECT) || ($curlResult->getReturnCode() == 0);
                if ($curlResult->isSuccess()) {
                        $xml = $curlResult->getBody();
-                       $xrd = XML::parseString($xml, false);
-                       $host_url = 'https://'.$host;
+                       $xrd = XML::parseString($xml, true);
+                       if (!empty($url)) {
+                               $host_url = 'https://' . $host;
+                       } else {
+                               $host_url = $host;
+                       }
                } elseif ($curlResult->isTimeout()) {
                        Logger::info('Probing timeout', ['url' => $ssl_url], Logger::DEBUG);
                        self::$istimeout = true;
-                       return false;
+                       return [];
                }
 
-               if (!is_object($xrd)) {
+               if (!is_object($xrd) && !empty($url)) {
                        $curlResult = Network::curl($url, false, ['timeout' => $xrd_timeout, 'accept_content' => 'application/xrd+xml']);
                        $connection_error = ($curlResult->getErrorNumber() == CURLE_COULDNT_CONNECT) || ($curlResult->getReturnCode() == 0);
                        if ($curlResult->isTimeout()) {
                                Logger::info('Probing timeout', ['url' => $url], Logger::DEBUG);
                                self::$istimeout = true;
-                               return false;
+                               return [];
                        } elseif ($connection_error && $ssl_connection_error) {
                                self::$istimeout = true;
-                               return false;
+                               return [];
                        }
 
                        $xml = $curlResult->getBody();
-                       $xrd = XML::parseString($xml, false);
+                       $xrd = XML::parseString($xml, true);
                        $host_url = 'http://'.$host;
                }
                if (!is_object($xrd)) {
@@ -179,7 +233,7 @@ class Probe
        }
 
        /**
-        * @brief Perform Webfinger lookup and return DFRN data
+        * Perform Webfinger lookup and return DFRN data
         *
         * Given an email style address, perform webfinger lookup and
         * return the resulting DFRN profile URL, or if no DFRN profile URL
@@ -222,18 +276,14 @@ class Probe
        }
 
        /**
-        * @brief Check an URI for LRDD data
-        *
-        * this is a replacement for the "lrdd" function.
-        * It isn't used in this class and has some redundancies in the code.
-        * When time comes we can check the existing calls for "lrdd" if we can rework them.
+        * Check an URI for LRDD data
         *
-        * @param string $uri Address that should be probed
+        * @param string $uri     Address that should be probed
         *
         * @return array uri data
         * @throws HTTPException\InternalServerErrorException
         */
-       public static function lrdd($uri)
+       public static function lrdd(string $uri)
        {
                $lrdd = self::hostMeta($uri);
                $webfinger = null;
@@ -248,7 +298,7 @@ class Probe
                                return [];
                        }
 
-                       $host = $parts["host"];
+                       $host = $parts['scheme'] . '://' . $parts["host"];
                        if (!empty($parts["port"])) {
                                $host .= ':'.$parts["port"];
                        }
@@ -295,9 +345,9 @@ class Probe
                        }
                }
 
-               if (!is_array($webfinger["links"])) {
+               if (empty($webfinger["links"])) {
                        Logger::log("No webfinger links found for ".$uri, Logger::DEBUG);
-                       return false;
+                       return [];
                }
 
                $data = [];
@@ -306,7 +356,7 @@ class Probe
                        $data[] = ["@attributes" => $link];
                }
 
-               if (is_array($webfinger["aliases"])) {
+               if (!empty($webfinger["aliases"]) && is_array($webfinger["aliases"])) {
                        foreach ($webfinger["aliases"] as $alias) {
                                $data[] = ["@attributes" =>
                                                        ["rel" => "alias",
@@ -318,7 +368,7 @@ class Probe
        }
 
        /**
-        * @brief Fetch information (protocol endpoints and user information) about a given uri
+        * Fetch information (protocol endpoints and user information) about a given uri
         *
         * @param string  $uri     Address that should be probed
         * @param string  $network Test for this specific network
@@ -353,7 +403,7 @@ class Probe
                // When the previous detection process had got a time out
                // we could falsely detect a Friendica profile as AP profile.
                if (!self::$istimeout) {
-                       $ap_profile = ActivityPub::probeProfile($uri);
+                       $ap_profile = ActivityPub::probeProfile($uri, !$cache);
 
                        if (empty($data) || (!empty($ap_profile) && empty($network) && (($data['network'] ?? '') != Protocol::DFRN))) {
                                $data = $ap_profile;
@@ -369,9 +419,7 @@ class Probe
                        $data['url'] = $uri;
                }
 
-               if (!empty($data['photo']) && !empty($data['baseurl'])) {
-                       $data['baseurl'] = Network::getUrlMatch(Strings::normaliseLink($data['baseurl']), Strings::normaliseLink($data['photo']));
-               } elseif (empty($data['photo'])) {
+               if (empty($data['photo'])) {
                        $data['photo'] = DI::baseUrl() . '/images/person-300.jpg';
                }
 
@@ -393,14 +441,23 @@ class Probe
                        }
                }
 
-               if (!empty(self::$baseurl)) {
+               if (empty($data['baseurl']) && !empty(self::$baseurl)) {
                        $data['baseurl'] = self::$baseurl;
                }
 
+               if (!empty($data['baseurl']) && empty($data['gsid'])) {
+                       $data['gsid'] = GServer::getID($data['baseurl']);
+               }
+
                if (empty($data['network'])) {
                        $data['network'] = Protocol::PHANTOM;
                }
 
+               // Ensure that local connections always are DFRN
+               if (($network == '') && ($data['network'] != Protocol::PHANTOM) && (self::ownHost($data['baseurl'] ?? '') || self::ownHost($data['url']))) {
+                       $data['network'] = Protocol::DFRN;
+               }
+
                if (!isset($data['hide']) && in_array($data['network'], Protocol::FEDERATED)) {
                        $data['hide'] = self::getHideStatus($data['url']);
                }
@@ -409,7 +466,7 @@ class Probe
 
                // Only store into the cache if the value seems to be valid
                if (!in_array($data['network'], [Protocol::PHANTOM, Protocol::MAIL])) {
-                       DI::cache()->set('Probe::uri:' . $network . ':' . $uri, $data, Cache::DAY);
+                       DI::cache()->set('Probe::uri:' . $network . ':' . $uri, $data, Duration::DAY);
                }
 
                return $data;
@@ -480,51 +537,29 @@ class Probe
        }
 
        /**
-        * @brief Checks if a profile url should be OStatus but only provides partial information
-        *
-        * @param array  $webfinger Webfinger data
-        * @param string $lrdd      Path template for webfinger request
-        * @param string $type      type
+        * Fetch the "subscribe" and add it to the result
         *
-        * @return array fixed webfinger data
-        * @throws HTTPException\InternalServerErrorException
+        * @param array $result
+        * @param array $webfinger
+        * @return array result
         */
-       private static function fixOStatus($webfinger, $lrdd, $type)
+       private static function getSubscribeLink(array $result, array $webfinger)
        {
-               if (empty($webfinger['links']) || empty($webfinger['subject'])) {
-                       return $webfinger;
+               if (empty($webfinger['links'])) {
+                       return $result;
                }
 
-               $is_ostatus = false;
-               $has_key = false;
-
                foreach ($webfinger['links'] as $link) {
-                       if ($link['rel'] == ActivityNamespace::OSTATUSSUB) {
-                               $is_ostatus = true;
+                       if (!empty($link['template']) && ($link['rel'] === ActivityNamespace::OSTATUSSUB)) {
+                               $result['subscribe'] = $link['template'];
                        }
-                       if ($link['rel'] == 'magic-public-key') {
-                               $has_key = true;
-                       }
-               }
-
-               if (!$is_ostatus || $has_key) {
-                       return $webfinger;
-               }
-
-               $url = Network::switchScheme($webfinger['subject']);
-               $path = str_replace('{uri}', urlencode($url), $lrdd);
-               $webfinger2 = self::webfinger($path, $type);
-
-               // Is the new webfinger detectable as OStatus?
-               if (self::ostatus($webfinger2, true)) {
-                       $webfinger = $webfinger2;
                }
 
-               return $webfinger;
+               return $result;
        }
 
        /**
-        * @brief Fetch information (protocol endpoints and user information) about a given uri
+        * Fetch information (protocol endpoints and user information) about a given uri
         *
         * This function is only called by the "uri" function that adds caching and rearranging of data.
         *
@@ -539,6 +574,19 @@ class Probe
        {
                $parts = parse_url($uri);
 
+               $hookData = [
+                       'uri'     => $uri,
+                       'network' => $network,
+                       'uid'     => $uid,
+                       'result'  => [],
+               ];
+
+               Hook::callAll('probe_detect', $hookData);
+
+               if ($hookData['result']) {
+                       return $hookData['result'];
+               }
+
                if (!empty($parts["scheme"]) && !empty($parts["host"])) {
                        $host = $parts["host"];
                        if (!empty($parts["port"])) {
@@ -602,7 +650,7 @@ class Probe
                        $addr = $uri;
                } else {
                        Logger::log("Uri ".$uri." was not detectable", Logger::DEBUG);
-                       return false;
+                       return [];
                }
 
                $webfinger = false;
@@ -614,39 +662,38 @@ class Probe
                                continue;
                        }
 
-                       // At first try it with the given uri
-                       $path = str_replace('{uri}', urlencode($uri), $template);
-                       $webfinger = self::webfinger($path, $type);
-
-                       // Fix possible problems with GNU Social probing to wrong scheme
-                       $webfinger = self::fixOStatus($webfinger, $template, $type);
-
-                       // We cannot be sure that the detected address was correct, so we don't use the values
-                       if ($webfinger && ($uri != $addr)) {
-                               $nick = "";
-                               $addr = "";
+                       // Try the URI first
+                       if ($uri != $addr) {
+                               $path = str_replace('{uri}', urlencode($uri), $template);
+                               $webfinger = self::webfinger($path, $type);
                        }
 
-                       // Try webfinger with the address (user@domain.tld)
+                       // Then try the address
                        if (!$webfinger) {
-                               $path = str_replace('{uri}', urlencode($addr), $template);
+                               $path = str_replace('{uri}', urlencode("acct:" . $addr), $template);
                                $webfinger = self::webfinger($path, $type);
                        }
 
-                       // Mastodon needs to have it with "acct:"
+                       // Finally try without the "acct"
                        if (!$webfinger) {
-                               $path = str_replace('{uri}', urlencode("acct:".$addr), $template);
+                               $path = str_replace('{uri}', urlencode($addr), $template);
                                $webfinger = self::webfinger($path, $type);
                        }
+
+                       // We cannot be sure that the detected address was correct, so we don't use the values
+                       if ($webfinger && ($uri != $addr)) {
+                               $nick = "";
+                               $addr = "";
+                       }
                }
 
                if (!$webfinger) {
                        return self::feed($uri);
                }
 
-               $result = false;
+               $result = [];
 
-               Logger::log("Probing ".$uri, Logger::DEBUG);
+               Logger::info("Probing", ['uri' => $uri]);
 
                if (in_array($network, ["", Protocol::DFRN])) {
                        $result = self::dfrn($webfinger);
@@ -677,6 +724,8 @@ class Probe
                        }
                }
 
+               $result = self::getSubscribeLink($result, $webfinger);
+
                if (empty($result["network"])) {
                        $result["network"] = Protocol::PHANTOM;
                }
@@ -687,12 +736,6 @@ class Probe
 
                Logger::log($uri." is ".$result["network"], Logger::DEBUG);
 
-               if (empty($result["baseurl"]) && ($result["network"] != Protocol::PHANTOM)) {
-                       $pos = strpos($result["url"], $host);
-                       if ($pos) {
-                               $result["baseurl"] = substr($result["url"], 0, $pos).$host;
-                       }
-               }
                return $result;
        }
 
@@ -812,9 +855,6 @@ class Probe
                        if (!empty($profile['description'])) {
                                $data['about'] = $profile['description'];
                        }
-                       if (!empty($profile['gender'])) {
-                               $data['gender'] = $profile['gender'];
-                       }
                        if (!empty($profile['keywords'])) {
                                $keywords = implode(', ', $profile['keywords']);
                                if (!empty($keywords)) {
@@ -829,9 +869,6 @@ class Probe
                        if (!empty($profile['country'])) {
                                $loc['country-name'] = $profile['country'];
                        }
-                       if (!empty($profile['hometown'])) {
-                               $loc['locality'] = $profile['hometown'];
-                       }
                        $location = Profile::formatLocation($loc);
                        if (!empty($location)) {
                                $data['location'] = $location;
@@ -842,7 +879,7 @@ class Probe
        }
 
        /**
-        * @brief Perform a webfinger request.
+        * Perform a webfinger request.
         *
         * For details see RFC 7033: <https://tools.ietf.org/html/rfc7033>
         *
@@ -852,37 +889,37 @@ class Probe
         * @return array webfinger data
         * @throws HTTPException\InternalServerErrorException
         */
-       private static function webfinger($url, $type)
+       public static function webfinger($url, $type)
        {
-               $xrd_timeout = Config::get('system', 'xrd_timeout', 20);
+               $xrd_timeout = DI::config()->get('system', 'xrd_timeout', 20);
 
                $curlResult = Network::curl($url, false, ['timeout' => $xrd_timeout, 'accept_content' => $type]);
                if ($curlResult->isTimeout()) {
                        self::$istimeout = true;
-                       return false;
+                       return [];
                }
                $data = $curlResult->getBody();
 
                $webfinger = json_decode($data, true);
-               if (is_array($webfinger)) {
+               if (!empty($webfinger)) {
                        if (!isset($webfinger["links"])) {
                                Logger::log("No json webfinger links for ".$url, Logger::DEBUG);
-                               return false;
+                               return [];
                        }
                        return $webfinger;
                }
 
                // If it is not JSON, maybe it is XML
-               $xrd = XML::parseString($data, false);
+               $xrd = XML::parseString($data, true);
                if (!is_object($xrd)) {
                        Logger::log("No webfinger data retrievable for ".$url, Logger::DEBUG);
-                       return false;
+                       return [];
                }
 
                $xrd_arr = XML::elementToArray($xrd);
                if (!isset($xrd_arr["xrd"]["link"])) {
                        Logger::log("No XML webfinger links for ".$url, Logger::DEBUG);
-                       return false;
+                       return [];
                }
 
                $webfinger = [];
@@ -912,7 +949,7 @@ class Probe
        }
 
        /**
-        * @brief Poll the Friendica specific noscrape page.
+        * Poll the Friendica specific noscrape page.
         *
         * "noscrape" is a faster alternative to fetch the data from the hcard.
         * This functionality was originally created for the directory.
@@ -928,18 +965,18 @@ class Probe
                $curlResult = Network::curl($noscrape_url);
                if ($curlResult->isTimeout()) {
                        self::$istimeout = true;
-                       return false;
+                       return [];
                }
                $content = $curlResult->getBody();
                if (!$content) {
                        Logger::log("Empty body for ".$noscrape_url, Logger::DEBUG);
-                       return false;
+                       return [];
                }
 
                $json = json_decode($content, true);
                if (!is_array($json)) {
                        Logger::log("No json data for ".$noscrape_url, Logger::DEBUG);
-                       return false;
+                       return [];
                }
 
                if (!empty($json["fn"])) {
@@ -978,10 +1015,6 @@ class Probe
                        $data["about"] = $json["about"];
                }
 
-               if (!empty($json["gender"])) {
-                       $data["gender"] = $json["gender"];
-               }
-
                if (!empty($json["key"])) {
                        $data["pubkey"] = $json["key"];
                }
@@ -1016,7 +1049,7 @@ class Probe
        }
 
        /**
-        * @brief Check for valid DFRN data
+        * Check for valid DFRN data
         *
         * @param array $data DFRN data
         *
@@ -1044,7 +1077,7 @@ class Probe
        }
 
        /**
-        * @brief Fetch data from a DFRN profile page and via "noscrape"
+        * Fetch data from a DFRN profile page and via "noscrape"
         *
         * @param string $profile_link Link to the profile page
         *
@@ -1096,7 +1129,7 @@ class Probe
        }
 
        /**
-        * @brief Check for DFRN contact
+        * Check for DFRN contact
         *
         * @param array $webfinger Webfinger data
         *
@@ -1153,7 +1186,7 @@ class Probe
                }
 
                if (!isset($data["network"]) || ($hcard_url == "")) {
-                       return false;
+                       return [];
                }
 
                // Fetch data via noscrape - this is faster
@@ -1176,7 +1209,7 @@ class Probe
        }
 
        /**
-        * @brief Poll the hcard page (Diaspora and Friendica specific)
+        * Poll the hcard page (Diaspora and Friendica specific)
         *
         * @param string  $hcard_url Link to the hcard page
         * @param array   $data      The already fetched data
@@ -1190,23 +1223,23 @@ class Probe
                $curlResult = Network::curl($hcard_url);
                if ($curlResult->isTimeout()) {
                        self::$istimeout = true;
-                       return false;
+                       return [];
                }
                $content = $curlResult->getBody();
                if (!$content) {
-                       return false;
+                       return [];
                }
 
                $doc = new DOMDocument();
                if (!@$doc->loadHTML($content)) {
-                       return false;
+                       return [];
                }
 
                $xpath = new DomXPath($doc);
 
                $vcards = $xpath->query("//div[contains(concat(' ', @class, ' '), ' vcard ')]");
                if (!is_object($vcards)) {
-                       return false;
+                       return [];
                }
 
                if (!isset($data["baseurl"])) {
@@ -1304,7 +1337,7 @@ class Probe
        }
 
        /**
-        * @brief Check for Diaspora contact
+        * Check for Diaspora contact
         *
         * @param array $webfinger Webfinger data
         *
@@ -1344,7 +1377,7 @@ class Probe
                }
 
                if (empty($data["url"]) || empty($hcard_url)) {
-                       return false;
+                       return [];
                }
 
                if (!empty($webfinger["aliases"]) && is_array($webfinger["aliases"])) {
@@ -1365,7 +1398,7 @@ class Probe
                $data = self::pollHcard($hcard_url, $data);
 
                if (!$data) {
-                       return false;
+                       return [];
                }
 
                if (!empty($data["url"])
@@ -1385,14 +1418,14 @@ class Probe
                        $data["notify"] = $data["baseurl"] . "/receive/users/" . $data["guid"];
                        $data["batch"]  = $data["baseurl"] . "/receive/public";
                } else {
-                       return false;
+                       return [];
                }
 
                return $data;
        }
 
        /**
-        * @brief Check for OStatus contact
+        * Check for OStatus contact
         *
         * @param array $webfinger Webfinger data
         * @param bool  $short     Short detection mode
@@ -1418,7 +1451,7 @@ class Probe
                        $data["addr"] = str_replace('acct:', '', $webfinger["subject"]);
                }
 
-               if (is_array($webfinger["links"])) {
+               if (!empty($webfinger["links"])) {
                        // The array is reversed to take into account the order of preference for same-rel links
                        // See: https://tools.ietf.org/html/rfc7033#section-4.4.4
                        foreach (array_reverse($webfinger["links"]) as $link) {
@@ -1426,7 +1459,7 @@ class Probe
                                        && (($link["type"] ?? "") == "text/html")
                                        && ($link["href"] != "")
                                ) {
-                                       $data["url"] = $link["href"];
+                                       $data["url"] = $data["alias"] = $link["href"];
                                } elseif (($link["rel"] == "salmon") && !empty($link["href"])) {
                                        $data["notify"] = $link["href"];
                                } elseif (($link["rel"] == ActivityNamespace::FEED) && !empty($link["href"])) {
@@ -1444,7 +1477,7 @@ class Probe
                                                $curlResult = Network::curl($pubkey);
                                                if ($curlResult->isTimeout()) {
                                                        self::$istimeout = true;
-                                                       return false;
+                                                       return $short ? false : [];
                                                }
                                                $pubkey = $curlResult->getBody();
                                        }
@@ -1466,7 +1499,7 @@ class Probe
                ) {
                        $data["network"] = Protocol::OSTATUS;
                } else {
-                       return false;
+                       return $short ? false : [];
                }
 
                if ($short) {
@@ -1477,12 +1510,12 @@ class Probe
                $curlResult = Network::curl($data["poll"]);
                if ($curlResult->isTimeout()) {
                        self::$istimeout = true;
-                       return false;
+                       return [];
                }
                $feed = $curlResult->getBody();
                $feed_data = Feed::import($feed);
                if (!$feed_data) {
-                       return false;
+                       return [];
                }
 
                if (!empty($feed_data["header"]["author-name"])) {
@@ -1509,8 +1542,7 @@ class Probe
                        $data["url"] = $feed_data["header"]["author-link"];
                }
 
-               if (($data['poll'] == $data['url']) && ($data["alias"] != '')) {
-                       $data['url'] = $data["alias"];
+               if ($data["url"] == $data["alias"]) {
                        $data["alias"] = '';
                }
 
@@ -1519,7 +1551,7 @@ class Probe
        }
 
        /**
-        * @brief Fetch data from a pump.io profile page
+        * Fetch data from a pump.io profile page
         *
         * @param string $profile_link Link to the profile page
         *
@@ -1529,12 +1561,12 @@ class Probe
        {
                $curlResult = Network::curl($profile_link);
                if (!$curlResult->isSuccess()) {
-                       return false;
+                       return [];
                }
 
                $doc = new DOMDocument();
                if (!@$doc->loadHTML($curlResult->getBody())) {
-                       return false;
+                       return [];
                }
 
                $xpath = new DomXPath($doc);
@@ -1580,7 +1612,7 @@ class Probe
        }
 
        /**
-        * @brief Check for pump.io contact
+        * Check for pump.io contact
         *
         * @param array  $webfinger Webfinger data
         * @param string $addr
@@ -1615,13 +1647,13 @@ class Probe
 
                        $data["network"] = Protocol::PUMPIO;
                } else {
-                       return false;
+                       return [];
                }
 
                $profile_data = self::pumpioProfileData($data["url"]);
 
                if (!$profile_data) {
-                       return false;
+                       return [];
                }
 
                $data = array_merge($data, $profile_data);
@@ -1637,7 +1669,7 @@ class Probe
        }
 
        /**
-        * @brief Check for twitter contact
+        * Check for twitter contact
         *
         * @param string $uri
         *
@@ -1660,91 +1692,95 @@ class Probe
                $data['network'] = Protocol::TWITTER;
                $data['baseurl'] = 'https://twitter.com';
 
-               $curlResult = Network::curl($data['url'], false);
-               if (!$curlResult->isSuccess()) {
-                       return [];
-               }
+               return $data;
+       }
 
-               $body = $curlResult->getBody();
+       /**
+        * Checks HTML page for RSS feed link
+        *
+        * @param string $url  Page link
+        * @param string $body Page body string
+        * @return string|false Feed link or false if body was invalid HTML document
+        */
+       public static function getFeedLink(string $url, string $body)
+       {
                $doc = new DOMDocument();
-               @$doc->loadHTML($body);
-               $xpath = new DOMXPath($doc);
+               if (!@$doc->loadHTML($body)) {
+                       return false;
+               }
 
-               $list = $xpath->query('//img[@class]');
-               foreach ($list as $node) {
-                       $img_attr = [];
-                       if ($node->attributes->length) {
-                               foreach ($node->attributes as $attribute) {
-                                       $img_attr[$attribute->name] = $attribute->value;
-                               }
-                       }
+               $xpath = new DOMXPath($doc);
 
-                       if (empty($img_attr['class'])) {
-                               continue;
-                       }
+               $feedUrl = $xpath->evaluate('string(/html/head/link[@type="application/rss+xml" and @rel="alternate"]/@href)');
 
-                       if (strpos($img_attr['class'], 'ProfileAvatar-image') !== false) {
-                               if (!empty($img_attr['src'])) {
-                                       $data['photo'] = $img_attr['src'];
-                               }
-                               if (!empty($img_attr['alt'])) {
-                                       $data['name'] = $img_attr['alt'];
-                               }
-                       }
-               }
+               $feedUrl = $feedUrl ? self::ensureAbsoluteLinkFromHTMLDoc($feedUrl, $url, $xpath) : '';
 
-               return $data;
+               return $feedUrl;
        }
 
        /**
-        * @brief Check page for feed link
+        * Return an absolute URL in the context of a HTML document retrieved from the provided URL.
+        *
+        * Loosely based on RFC 1808
         *
-        * @param string $url Page link
+        * @see https://tools.ietf.org/html/rfc1808
         *
-        * @return string feed link
+        * @param string   $href  The potential relative href found in the HTML document
+        * @param string   $base  The HTML document URL
+        * @param DOMXPath $xpath The HTML document XPath
+        * @return string
         */
-       private static function getFeedLink($url)
+       private static function ensureAbsoluteLinkFromHTMLDoc(string $href, string $base, DOMXPath $xpath)
        {
-               $curlResult = Network::curl($url);
-               if (!$curlResult->isSuccess()) {
-                       return false;
+               if (filter_var($href, FILTER_VALIDATE_URL)) {
+                       return $href;
                }
 
-               $doc = new DOMDocument();
-               if (!@$doc->loadHTML($curlResult->getBody())) {
-                       return false;
-               }
+               $base = $xpath->evaluate('string(/html/head/base/@href)') ?: $base;
 
-               $xpath = new DomXPath($doc);
+               $baseParts = parse_url($base);
 
-               //$feeds = $xpath->query("/html/head/link[@type='application/rss+xml']");
-               $feeds = $xpath->query("/html/head/link[@type='application/rss+xml' and @rel='alternate']");
-               if (!is_object($feeds)) {
-                       return false;
-               }
+               // Naked domain case (scheme://basehost)
+               $path = $baseParts['path'] ?? '/';
 
-               if ($feeds->length == 0) {
-                       return false;
-               }
+               // Remove the filename part of the path if it exists (/base/path/file)
+               $path = implode('/', array_slice(explode('/', $path), 0, -1));
 
-               $feed_url = "";
+               $hrefParts = parse_url($href);
 
-               foreach ($feeds as $feed) {
-                       $attr = [];
-                       foreach ($feed->attributes as $attribute) {
-                               $attr[$attribute->name] = trim($attribute->value);
+               // Root path case (/path) including relative scheme case (//host/path)
+               if ($hrefParts['path'] && $hrefParts['path'][0] == '/') {
+                       $path = $hrefParts['path'];
+               } else {
+                       $path = $path . '/' . $hrefParts['path'];
+
+                       // Resolve arbitrary relative path
+                       // Lifted from https://www.php.net/manual/en/function.realpath.php#84012
+                       $parts = array_filter(explode('/', $path), 'strlen');
+                       $absolutes = array();
+                       foreach ($parts as $part) {
+                               if ('.' == $part) continue;
+                               if ('..' == $part) {
+                                       array_pop($absolutes);
+                               } else {
+                                       $absolutes[] = $part;
+                               }
                        }
 
-                       if (empty($feed_url) && !empty($attr['href'])) {
-                               $feed_url = $attr["href"];
-                       }
+                       $path = '/' . implode('/', $absolutes);
                }
 
-               return $feed_url;
+               // Relative scheme case (//host/path)
+               $baseParts['host'] = $hrefParts['host'] ?? $baseParts['host'];
+               $baseParts['path'] = $path;
+               unset($baseParts['query']);
+               unset($baseParts['fragment']);
+
+               return Network::unparseURL($baseParts);
        }
 
        /**
-        * @brief Check for feed contact
+        * Check for feed contact
         *
         * @param string  $url   Profile link
         * @param boolean $probe Do a probe if the page contains a feed link
@@ -1757,20 +1793,20 @@ class Probe
                $curlResult = Network::curl($url);
                if ($curlResult->isTimeout()) {
                        self::$istimeout = true;
-                       return false;
+                       return [];
                }
                $feed = $curlResult->getBody();
                $feed_data = Feed::import($feed);
 
                if (!$feed_data) {
                        if (!$probe) {
-                               return false;
+                               return [];
                        }
 
-                       $feed_url = self::getFeedLink($url);
+                       $feed_url = self::getFeedLink($url, $feed);
 
                        if (!$feed_url) {
-                               return false;
+                               return [];
                        }
 
                        return self::feed($feed_url, false);
@@ -1807,7 +1843,7 @@ class Probe
        }
 
        /**
-        * @brief Check for mail contact
+        * Check for mail contact
         *
         * @param string  $uri Profile link
         * @param integer $uid User ID
@@ -1818,11 +1854,11 @@ class Probe
        private static function mail($uri, $uid)
        {
                if (!Network::isEmailDomainValid($uri)) {
-                       return false;
+                       return [];
                }
 
                if ($uid == 0) {
-                       return false;
+                       return [];
                }
 
                $user = DBA::selectFirst('user', ['prvkey'], ['uid' => $uid]);
@@ -1832,7 +1868,7 @@ class Probe
                $mailacct = DBA::selectFirst('mailacct', $fields, $condition);
 
                if (!DBA::isResult($user) || !DBA::isResult($mailacct)) {
-                       return false;
+                       return [];
                }
 
                $mailbox = Email::constructMailboxName($mailacct);
@@ -1840,14 +1876,14 @@ class Probe
                openssl_private_decrypt(hex2bin($mailacct['pass']), $password, $user['prvkey']);
                $mbox = Email::connect($mailbox, $mailacct['user'], $password);
                if (!$mbox) {
-                       return false;
+                       return [];
                }
 
                $msgs = Email::poll($mbox, $uri);
                Logger::log('searching '.$uri.', '.count($msgs).' messages found.', Logger::DEBUG);
 
                if (!count($msgs)) {
-                       return false;
+                       return [];
                }
 
                $phost = substr($uri, strpos($uri, '@') + 1);
@@ -1895,7 +1931,7 @@ class Probe
        }
 
        /**
-        * @brief Mix two paths together to possibly fix missing parts
+        * Mix two paths together to possibly fix missing parts
         *
         * @param string $avatar Path to the avatar
         * @param string $base   Another path that is hopefully complete