Merge branch '0.7.x' of git@gitorious.org:laconica/dev into 0.7.x

7 files changed, 1006 insertions, 26 deletions

diff --git a/lib/action.php b/lib/action.php
index bd38bf79c..926fe93fb 100644
--- a/lib/action.php
+++ b/lib/action.php
@@ -82,6 +82,11 @@ class Action extends HTMLOutputter // lawsuit
      */
     function prepare($argarray)
     {
+     
+        // For PEAR_Errors comming from DB_DataObject
+        PEAR::setErrorHandling(PEAR_ERROR_CALLBACK, 
+               array($this, "handleError"));
+        
         $this->args =& common_copy_args($argarray);
         return true;
     }
@@ -845,6 +850,32 @@ class Action extends HTMLOutputter // lawsuit
     }
 
     /**
+     * Handle old fashioned PEAR_Error msgs coming from DB_DataObject
+     *
+     * Logs the DB_DataObject error. Override to do something else.
+     * 
+     * @param PEAR_Error 
+     *
+     * @return nothing
+     */
+     
+    function handleError($error) {
+                        
+        common_log(LOG_ERR, "PEAR error: " . $error->getMessage());
+         $msg = sprintf(_('The database for %s isn\'t responding correctly, '.
+                          'so the site won\'t work properly. '.
+                          'The site admins probably know about the problem, '.
+                          'but you can contact them at %s to make sure. '.
+                          'Otherwise, wait a few minutes and try again.'),
+                        common_config('site', 'name'),
+                        common_config('site', 'email'));
+
+         $dac = new DBErrorAction($msg, 500);
+         $dac->showPage();
+         exit(-1);            
+    }
+    
+    /**
      * Returns the current URL
      *
      * @return string current URL
diff --git a/lib/channel.php b/lib/channel.php
new file mode 100644
index 000000000..f1e205546
--- /dev/null
+++ b/lib/channel.php
@@ -0,0 +1,237 @@
+<?php
+/*
+ * Laconica - a distributed open-source microblogging tool
+ * Copyright (C) 2008, Controlez-Vous, Inc.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+if (!defined('LACONICA')) { exit(1); }
+
+class Channel
+{
+    function on($user)
+    {
+        return false;
+    }
+
+    function off($user)
+    {
+        return false;
+    }
+
+    function output($user, $text)
+    {
+        return false;
+    }
+
+    function error($user, $text)
+    {
+        return false;
+    }
+
+    function source()
+    {
+        return null;
+    }
+}
+
+class XMPPChannel extends Channel
+{
+
+    var $conn = null;
+
+    function source()
+    {
+        return 'xmpp';
+    }
+
+    function __construct($conn)
+    {
+        $this->conn = $conn;
+    }
+
+    function on($user)
+    {
+        return $this->set_notify($user, 1);
+    }
+
+    function off($user)
+    {
+        return $this->set_notify($user, 0);
+    }
+
+    function output($user, $text)
+    {
+        $text = '['.common_config('site', 'name') . '] ' . $text;
+        jabber_send_message($user->jabber, $text);
+    }
+
+    function error($user, $text)
+    {
+        $text = '['.common_config('site', 'name') . '] ' . $text;
+        jabber_send_message($user->jabber, $text);
+    }
+
+    function set_notify(&$user, $notify)
+    {
+        $orig = clone($user);
+        $user->jabbernotify = $notify;
+        $result = $user->update($orig);
+        if (!$result) {
+            $last_error = &PEAR::getStaticProperty('DB_DataObject','lastError');
+            common_log(LOG_ERR,
+                       'Could not set notify flag to ' . $notify .
+                       ' for user ' . common_log_objstring($user) .
+                       ': ' . $last_error->message);
+            return false;
+        } else {
+            common_log(LOG_INFO,
+                       'User ' . $user->nickname . ' set notify flag to ' . $notify);
+            return true;
+        }
+    }
+}
+
+class WebChannel extends Channel
+{
+    var $out = null;
+
+    function __construct($out=null)
+    {
+        $this->out = $out;
+    }
+
+    function source()
+    {
+        return 'web';
+    }
+
+    function on($user)
+    {
+        return false;
+    }
+
+    function off($user)
+    {
+        return false;
+    }
+
+    function output($user, $text)
+    {
+        # XXX: buffer all output and send it at the end
+        # XXX: even better, redirect to appropriate page
+        #      depending on what command was run
+        $this->out->startHTML();
+        $this->out->elementStart('head');
+        $this->out->element('title', null, _('Command results'));
+        $this->out->elementEnd('head');
+        $this->out->elementStart('body');
+        $this->out->element('p', array('id' => 'command_result'), $text);
+        $this->out->elementEnd('body');
+        $this->out->endHTML();
+    }
+
+    function error($user, $text)
+    {
+        common_user_error($text);
+    }
+}
+
+class AjaxWebChannel extends WebChannel
+{
+    function output($user, $text)
+    {
+        $this->out->startHTML('text/xml;charset=utf-8');
+        $this->out->elementStart('head');
+        $this->out->element('title', null, _('Command results'));
+        $this->out->elementEnd('head');
+        $this->out->elementStart('body');
+        $this->out->element('p', array('id' => 'command_result'), $text);
+        $this->out->elementEnd('body');
+        $this->out->endHTML();
+    }
+
+    function error($user, $text)
+    {
+        $this->out->startHTML('text/xml;charset=utf-8');
+        $this->out->elementStart('head');
+        $this->out->element('title', null, _('Ajax Error'));
+        $this->out->elementEnd('head');
+        $this->out->elementStart('body');
+        $this->out->element('p', array('id' => 'error'), $text);
+        $this->out->elementEnd('body');
+        $this->out->endHTML();
+    }
+}
+
+class MailChannel extends Channel
+{
+
+    var $addr = null;
+
+    function source()
+    {
+        return 'mail';
+    }
+
+    function __construct($addr=null)
+    {
+        $this->addr = $addr;
+    }
+
+    function on($user)
+    {
+        return $this->set_notify($user, 1);
+    }
+
+    function off($user)
+    {
+        return $this->set_notify($user, 0);
+    }
+
+    function output($user, $text)
+    {
+
+        $headers['From'] = $user->incomingemail;
+        $headers['To'] = $this->addr;
+
+        $headers['Subject'] = _('Command complete');
+
+        return mail_send(array($this->addr), $headers, $text);
+    }
+
+    function error($user, $text)
+    {
+
+        $headers['From'] = $user->incomingemail;
+        $headers['To'] = $this->addr;
+
+        $headers['Subject'] = _('Command failed');
+
+        return mail_send(array($this->addr), $headers, $text);
+    }
+
+    function set_notify($user, $value)
+    {
+        $orig = clone($user);
+        $user->smsnotify = $value;
+        $result = $user->update($orig);
+        if (!$result) {
+            common_log_db_error($user, 'UPDATE', __FILE__);
+            return false;
+        }
+        return true;
+    }
+}
diff --git a/lib/command.php b/lib/command.php
new file mode 100644
index 000000000..507990a0b
--- /dev/null
+++ b/lib/command.php
@@ -0,0 +1,419 @@
+<?php
+/*
+ * Laconica - a distributed open-source microblogging tool
+ * Copyright (C) 2008, Controlez-Vous, Inc.
+ *
+ * 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/>.
+ */
+
+if (!defined('LACONICA')) { exit(1); }
+
+require_once(INSTALLDIR.'/lib/channel.php');
+
+class Command
+{
+
+    var $user = null;
+
+    function __construct($user=null)
+    {
+        $this->user = $user;
+    }
+
+    function execute($channel)
+    {
+        return false;
+    }
+}
+
+class UnimplementedCommand extends Command
+{
+    function execute($channel)
+    {
+        $channel->error($this->user, _("Sorry, this command is not yet implemented."));
+    }
+}
+
+class TrackingCommand extends UnimplementedCommand
+{
+}
+
+class TrackOffCommand extends UnimplementedCommand
+{
+}
+
+class TrackCommand extends UnimplementedCommand
+{
+    var $word = null;
+    function __construct($user, $word)
+    {
+        parent::__construct($user);
+        $this->word = $word;
+    }
+}
+
+class UntrackCommand extends UnimplementedCommand
+{
+    var $word = null;
+    function __construct($user, $word)
+    {
+        parent::__construct($user);
+        $this->word = $word;
+    }
+}
+
+class NudgeCommand extends UnimplementedCommand
+{
+    var $other = null;
+    function __construct($user, $other)
+    {
+        parent::__construct($user);
+        $this->other = $other;
+    }
+}
+
+class InviteCommand extends UnimplementedCommand
+{
+    var $other = null;
+    function __construct($user, $other)
+    {
+        parent::__construct($user);
+        $this->other = $other;
+    }
+}
+
+class StatsCommand extends Command
+{
+    function execute($channel)
+    {
+
+        $subs = new Subscription();
+        $subs->subscriber = $this->user->id;
+        $subs_count = (int) $subs->count() - 1;
+
+        $subbed = new Subscription();
+        $subbed->subscribed = $this->user->id;
+        $subbed_count = (int) $subbed->count() - 1;
+
+        $notices = new Notice();
+        $notices->profile_id = $this->user->id;
+        $notice_count = (int) $notices->count();
+
+        $channel->output($this->user, sprintf(_("Subscriptions: %1\$s\n".
+                                   "Subscribers: %2\$s\n".
+                                   "Notices: %3\$s"),
+                                 $subs_count,
+                                 $subbed_count,
+                                 $notice_count));
+    }
+}
+
+class FavCommand extends Command
+{
+
+    var $other = null;
+
+    function __construct($user, $other)
+    {
+        parent::__construct($user);
+        $this->other = $other;
+    }
+
+    function execute($channel)
+    {
+
+        $recipient =
+          common_relative_profile($this->user, common_canonical_nickname($this->other));
+
+        if (!$recipient) {
+            $channel->error($this->user, _('No such user.'));
+            return;
+        }
+        $notice = $recipient->getCurrentNotice();
+        if (!$notice) {
+            $channel->error($this->user, _('User has no last notice'));
+            return;
+        }
+
+        $fave = Fave::addNew($this->user, $notice);
+
+        if (!$fave) {
+            $channel->error($this->user, _('Could not create favorite.'));
+            return;
+        }
+
+        $other = User::staticGet('id', $recipient->id);
+
+        if ($other && $other->id != $user->id) {
+            if ($other->email && $other->emailnotifyfav) {
+                mail_notify_fave($other, $this->user, $notice);
+            }
+        }
+
+        $this->user->blowFavesCache();
+
+        $channel->output($this->user, _('Notice marked as fave.'));
+    }
+}
+
+class WhoisCommand extends Command
+{
+    var $other = null;
+    function __construct($user, $other)
+    {
+        parent::__construct($user);
+        $this->other = $other;
+    }
+
+    function execute($channel)
+    {
+        $recipient =
+          common_relative_profile($this->user, common_canonical_nickname($this->other));
+
+        if (!$recipient) {
+            $channel->error($this->user, _('No such user.'));
+            return;
+        }
+
+        $whois = sprintf(_("%1\$s (%2\$s)"), $recipient->nickname,
+                         $recipient->profileurl);
+        if ($recipient->fullname) {
+            $whois .= "\n" . sprintf(_('Fullname: %s'), $recipient->fullname);
+        }
+        if ($recipient->location) {
+            $whois .= "\n" . sprintf(_('Location: %s'), $recipient->location);
+        }
+        if ($recipient->homepage) {
+            $whois .= "\n" . sprintf(_('Homepage: %s'), $recipient->homepage);
+        }
+        if ($recipient->bio) {
+            $whois .= "\n" . sprintf(_('About: %s'), $recipient->bio);
+        }
+        $channel->output($this->user, $whois);
+    }
+}
+
+class MessageCommand extends Command
+{
+    var $other = null;
+    var $text = null;
+    function __construct($user, $other, $text)
+    {
+        parent::__construct($user);
+        $this->other = $other;
+        $this->text = $text;
+    }
+
+    function execute($channel)
+    {
+        $other = User::staticGet('nickname', common_canonical_nickname($this->other));
+        $len = mb_strlen($this->text);
+        if ($len == 0) {
+            $channel->error($this->user, _('No content!'));
+            return;
+        } else if ($len > 140) {
+            $content = common_shorten_links($content);
+            if (mb_strlen($content) > 140) {
+                $channel->error($this->user, sprintf(_('Message too long - maximum is 140 characters, you sent %d'), $len));
+                return;
+            }
+        }
+
+        if (!$other) {
+            $channel->error($this->user, _('No such user.'));
+            return;
+        } else if (!$this->user->mutuallySubscribed($other)) {
+            $channel->error($this->user, _('You can\'t send a message to this user.'));
+            return;
+        } else if ($this->user->id == $other->id) {
+            $channel->error($this->user, _('Don\'t send a message to yourself; just say it to yourself quietly instead.'));
+            return;
+        }
+        $message = Message::saveNew($this->user->id, $other->id, $this->text, $channel->source());
+        if ($message) {
+            $channel->output($this->user, sprintf(_('Direct message to %s sent'), $this->other));
+        } else {
+            $channel->error($this->user, _('Error sending direct message.'));
+        }
+    }
+}
+
+class GetCommand extends Command
+{
+
+    var $other = null;
+
+    function __construct($user, $other)
+    {
+        parent::__construct($user);
+        $this->other = $other;
+    }
+
+    function execute($channel)
+    {
+        $target_nickname = common_canonical_nickname($this->other);
+
+        $target =
+          common_relative_profile($this->user, $target_nickname);
+
+        if (!$target) {
+            $channel->error($this->user, _('No such user.'));
+            return;
+        }
+        $notice = $target->getCurrentNotice();
+        if (!$notice) {
+            $channel->error($this->user, _('User has no last notice'));
+            return;
+        }
+        $notice_content = $notice->content;
+
+        $channel->output($this->user, $target_nickname . ": " . $notice_content);
+    }
+}
+
+class SubCommand extends Command
+{
+
+    var $other = null;
+
+    function __construct($user, $other)
+    {
+        parent::__construct($user);
+        $this->other = $other;
+    }
+
+    function execute($channel)
+    {
+
+        if (!$this->other) {
+            $channel->error($this->user, _('Specify the name of the user to subscribe to'));
+            return;
+        }
+
+        $result = subs_subscribe_user($this->user, $this->other);
+
+        if ($result == 'true') {
+            $channel->output($this->user, sprintf(_('Subscribed to %s'), $this->other));
+        } else {
+            $channel->error($this->user, $result);
+        }
+    }
+}
+
+class UnsubCommand extends Command
+{
+
+    var $other = null;
+
+    function __construct($user, $other)
+    {
+        parent::__construct($user);
+        $this->other = $other;
+    }
+
+    function execute($channel)
+    {
+        if(!$this->other) {
+            $channel->error($this->user, _('Specify the name of the user to unsubscribe from'));
+            return;
+        }
+
+        $result=subs_unsubscribe_user($this->user, $this->other);
+
+        if ($result) {
+            $channel->output($this->user, sprintf(_('Unsubscribed from %s'), $this->other));
+        } else {
+            $channel->error($this->user, $result);
+        }
+    }
+}
+
+class OffCommand extends Command
+{
+    var $other = null;
+    function __construct($user, $other=null)
+    {
+        parent::__construct($user);
+        $this->other = $other;
+    }
+    function execute($channel)
+    {
+        if ($other) {
+            $channel->error($this->user, _("Command not yet implemented."));
+        } else {
+            if ($channel->off($this->user)) {
+                $channel->output($this->user, _('Notification off.'));
+            } else {
+                $channel->error($this->user, _('Can\'t turn off notification.'));
+            }
+        }
+    }
+}
+
+class OnCommand extends Command
+{
+    var $other = null;
+    function __construct($user, $other=null)
+    {
+        parent::__construct($user);
+        $this->other = $other;
+    }
+
+    function execute($channel)
+    {
+        if ($other) {
+            $channel->error($this->user, _("Command not yet implemented."));
+        } else {
+            if ($channel->on($this->user)) {
+                $channel->output($this->user, _('Notification on.'));
+            } else {
+                $channel->error($this->user, _('Can\'t turn on notification.'));
+            }
+        }
+    }
+}
+
+class HelpCommand extends Command
+{
+    function execute($channel)
+    {
+        $channel->output($this->user,
+                         _("Commands:\n".
+                           "on - turn on notifications\n".
+                           "off - turn off notifications\n".
+                           "help - show this help\n".
+                           "follow <nickname> - subscribe to user\n".
+                           "leave <nickname> - unsubscribe from user\n".
+                           "d <nickname> <text> - direct message to user\n".
+                           "get <nickname> - get last notice from user\n".
+                           "whois <nickname> - get profile info on user\n".
+                           "fav <nickname> - add user's last notice as a 'fave'\n".
+                           "stats - get your stats\n".
+                           "stop - same as 'off'\n".
+                           "quit - same as 'off'\n".
+                           "sub <nickname> - same as 'follow'\n".
+                           "unsub <nickname> - same as 'leave'\n".
+                           "last <nickname> - same as 'get'\n".
+                           "on <nickname> - not yet implemented.\n".
+                           "off <nickname> - not yet implemented.\n".
+                           "nudge <nickname> - not yet implemented.\n".
+                           "invite <phone number> - not yet implemented.\n".
+                           "track <word> - not yet implemented.\n".
+                           "untrack <word> - not yet implemented.\n".
+                           "track off - not yet implemented.\n".
+                           "untrack all - not yet implemented.\n".
+                           "tracks - not yet implemented.\n".
+                           "tracking - not yet implemented.\n"));
+    }
+}
diff --git a/lib/commandinterpreter.php b/lib/commandinterpreter.php
new file mode 100644
index 000000000..49c733c03
--- /dev/null
+++ b/lib/commandinterpreter.php
@@ -0,0 +1,197 @@
+<?php
+/*
+ * Laconica - a distributed open-source microblogging tool
+ * Copyright (C) 2008, Controlez-Vous, Inc.
+ *
+ * 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/>.
+ */
+
+if (!defined('LACONICA')) { exit(1); }
+
+require_once INSTALLDIR.'/lib/command.php';
+
+class CommandInterpreter
+{
+    function handle_command($user, $text)
+    {
+        # XXX: localise
+
+        $text = preg_replace('/\s+/', ' ', trim($text));
+        list($cmd, $arg) = explode(' ', $text, 2);
+
+        # We try to support all the same commands as Twitter, see
+        # http://getsatisfaction.com/twitter/topics/what_are_the_twitter_commands
+        # There are a few compatibility commands from earlier versions of
+        # Laconica
+
+        switch(strtolower($cmd)) {
+         case 'help':
+            if ($arg) {
+                return null;
+            }
+            return new HelpCommand($user);
+         case 'on':
+            if ($arg) {
+                list($other, $extra) = explode(' ', $arg, 2);
+                if ($extra) {
+                    return null;
+                } else {
+                    return new OnCommand($user, $other);
+                }
+            } else {
+                return new OnCommand($user);
+            }
+         case 'off':
+            if ($arg) {
+                list($other, $extra) = explode(' ', $arg, 2);
+                if ($extra) {
+                    return null;
+                } else {
+                    return new OffCommand($user, $other);
+                }
+            } else {
+                return new OffCommand($user);
+            }
+         case 'stop':
+         case 'quit':
+            if ($arg) {
+                return null;
+            } else {
+                return new OffCommand($user);
+            }
+         case 'follow':
+         case 'sub':
+            if (!$arg) {
+                return null;
+            }
+            list($other, $extra) = explode(' ', $arg, 2);
+            if ($extra) {
+                return null;
+            } else {
+                return new SubCommand($user, $other);
+            }
+         case 'leave':
+         case 'unsub':
+            if (!$arg) {
+                return null;
+            }
+            list($other, $extra) = explode(' ', $arg, 2);
+            if ($extra) {
+                return null;
+            } else {
+                return new UnsubCommand($user, $other);
+            }
+         case 'get':
+         case 'last':
+            if (!$arg) {
+                return null;
+            }
+            list($other, $extra) = explode(' ', $arg, 2);
+            if ($extra) {
+                return null;
+            } else {
+                return new GetCommand($user, $other);
+            }
+         case 'd':
+         case 'dm':
+            if (!$arg) {
+                return null;
+            }
+            list($other, $extra) = explode(' ', $arg, 2);
+            if (!$extra) {
+                return null;
+            } else {
+                return new MessageCommand($user, $other, $extra);
+            }
+         case 'whois':
+            if (!$arg) {
+                return null;
+            }
+            list($other, $extra) = explode(' ', $arg, 2);
+            if ($extra) {
+                return null;
+            } else {
+                return new WhoisCommand($user, $other);
+            }
+         case 'fav':
+            if (!$arg) {
+                return null;
+            }
+            list($other, $extra) = explode(' ', $arg, 2);
+            if ($extra) {
+                return null;
+            } else {
+                return new FavCommand($user, $other);
+            }
+         case 'nudge':
+            if (!$arg) {
+                return null;
+            }
+            list($other, $extra) = explode(' ', $arg, 2);
+            if ($extra) {
+                return null;
+            } else {
+                return new NudgeCommand($user, $other);
+            }
+         case 'stats':
+            if ($arg) {
+                return null;
+            }
+            return new StatsCommand($user);
+         case 'invite':
+            if (!$arg) {
+                return null;
+            }
+            list($other, $extra) = explode(' ', $arg, 2);
+            if ($extra) {
+                return null;
+            } else {
+                return new InviteCommand($user, $other);
+            }
+         case 'track':
+            if (!$arg) {
+                return null;
+            }
+            list($word, $extra) = explode(' ', $arg, 2);
+            if ($extra) {
+                return null;
+            } else if ($word == 'off') {
+                return new TrackOffCommand($user);
+            } else {
+                return new TrackCommand($user, $word);
+            }
+         case 'untrack':
+            if (!$arg) {
+                return null;
+            }
+            list($word, $extra) = explode(' ', $arg, 2);
+            if ($extra) {
+                return null;
+            } else if ($word == 'all') {
+                return new TrackOffCommand($user);
+            } else {
+                return new UntrackCommand($user, $word);
+            }
+         case 'tracks':
+         case 'tracking':
+            if ($arg) {
+                return null;
+            }
+            return new TrackingCommand($user);
+         default:
+            return false;
+        }
+    }
+}
+
diff --git a/lib/htmloutputter.php b/lib/htmloutputter.php
index 45e61d2fc..06603ac05 100644
--- a/lib/htmloutputter.php
+++ b/lib/htmloutputter.php
@@ -101,9 +101,8 @@ class HTMLOutputter extends XMLOutputter
             $type = common_negotiate_type($cp, $sp);
 
             if (!$type) {
-                common_user_error(_('This page is not available in a '.
-                                    'media type you accept'), 406);
-                exit(0);
+                throw new ClientException(_('This page is not available in a '.
+                                            'media type you accept'), 406);
             }
         }
 
diff --git a/lib/util.php b/lib/util.php
index c0c980111..37c941cdb 100644
--- a/lib/util.php
+++ b/lib/util.php
@@ -394,20 +394,20 @@ function common_render_text($text)
 
 function common_replace_urls_callback($text, $callback) {
     // Start off with a regex
-    $regex = '#
-    (?:
-        (?:
-            (?:https?|ftps?|mms|rtsp|gopher|news|nntp|telnet|wais|file|prospero|webcal|xmpp|irc)://
-            |
-            (?:mailto|aim|tel):
-        )
-        [^.\s]+\.[^\s]+
-        |
-        (?:[^.\s/:]+\.)+
-        (?:museum|travel|[a-z]{2,4})
-        (?:[:/][^\s]*)?
-    )
-    #ix';
+    $regex = '#'.
+    '(?:'.
+        '(?:'.
+            '(?:https?|ftps?|mms|rtsp|gopher|news|nntp|telnet|wais|file|prospero|webcal|xmpp|irc)://'.
+            '|'.
+            '(?:mailto|aim|tel):'.
+        ')'.
+        '[^.\s]+\.[^\s]+'.
+        '|'.
+        '(?:[^.\s/:]+\.)+'.
+        '(?:museum|travel|[a-z]{2,4})'.
+        '(?:[:/][^\s]*)?'.
+    ')'.
+    '#ix';
     preg_match_all($regex, $text, $matches);
 
     // Then clean up what the regex left behind
@@ -472,16 +472,19 @@ function common_replace_urls_callback($text, $callback) {
 }
 
 function common_linkify($url) {
+    // It comes in special'd, so we unspecial it before passing to the stringifying
+    // functions
+    $url = htmlspecialchars_decode($url);
     $display = $url;
-    $url = (!preg_match('#^([a-z]+://|(mailto|aim|tel):)#i', $url)) ? 'http://'.$url:$url;
+    $url = (!preg_match('#^([a-z]+://|(mailto|aim|tel):)#i', $url)) ? 'http://'.$url : $url;
+
+    $attrs = array('href' => $url, 'rel' => 'external');
 
     if ($longurl = common_longurl($url)) {
-        $longurl = htmlentities($longurl, ENT_QUOTES, 'UTF-8');
-        $title = "title=\"$longurl\"";
+        $attrs['title'] = $longurl;
     }
-    else $title = '';
 
-    return "<a href=\"$url\" $title rel=\"external\">$display</a>";
+    return XMLStringer::estring('a', $attrs, $display);
 }
 
 function common_longurl($short_url)
@@ -582,7 +585,13 @@ function common_tag_link($tag)
 {
     $canonical = common_canonical_tag($tag);
     $url = common_local_url('tag', array('tag' => $canonical));
-    return '<span class="tag"><a href="' . htmlspecialchars($url) . '" rel="tag">' . htmlspecialchars($tag) . '</a></span>';
+    $xs = new XMLStringer();
+    $xs->elementStart('span', 'tag');
+    $xs->element('a', array('href' => $url,
+                            'rel' => 'tag'),
+                 $tag);
+    $xs->elementEnd();
+    return $xs->getString();
 }
 
 function common_canonical_tag($tag)
@@ -600,7 +609,14 @@ function common_at_link($sender_id, $nickname)
     $sender = Profile::staticGet($sender_id);
     $recipient = common_relative_profile($sender, common_canonical_nickname($nickname));
     if ($recipient) {
-        return '<span class="vcard"><a href="'.htmlspecialchars($recipient->profileurl).'" class="url"><span class="fn nickname">'.$nickname.'</span></a></span>';
+        $xs = new XMLStringer(false);
+        $xs->elementStart('span', 'vcard');
+        $xs->elementStart('a', array('href' => $recipient->profileurl,
+                                     'class' => 'url'));
+        $xs->element('span', 'fn nickname', $nickname);
+        $xs->elementEnd('a');
+        $xs->elementEnd('span');
+        return $xs->getString();
     } else {
         return $nickname;
     }
@@ -611,7 +627,14 @@ function common_group_link($sender_id, $nickname)
     $sender = Profile::staticGet($sender_id);
     $group = User_group::staticGet('nickname', common_canonical_nickname($nickname));
     if ($group && $sender->isMember($group)) {
-        return '<span class="vcard"><a href="'.htmlspecialchars($group->permalink()).'" class="url"><span class="fn nickname">'.$nickname.'</span></a></span>';
+        $xs = new XMLStringer();
+        $xs->elementStart('span', 'vcard');
+        $xs->elementStart('a', array('href' => $group->permalink(),
+                                     'class' => 'url'));
+        $xs->element('span', 'fn nickname', $nickname);
+        $xs->elementEnd('a');
+        $xs->elementEnd('span');
+        return $xs->getString();
     } else {
         return $nickname;
     }
@@ -628,7 +651,13 @@ function common_at_hash_link($sender_id, $tag)
         $url = common_local_url('subscriptions',
                                 array('nickname' => $user->nickname,
                                       'tag' => $tag));
-        return '<span class="tag"><a href="'.htmlspecialchars($url).'" rel="tag">'.$tag.'</a></span>';
+        $xs = new XMLStringer();
+        $xs->elementStart('span', 'tag');
+        $xs->element('a', array('href' => $url,
+                                'rel' => $tag),
+                     $tag);
+        $xs->elementEnd('span');
+        return $xs->getString();
     } else {
         return $tag;
     }
diff --git a/lib/xmlstringer.php b/lib/xmlstringer.php
new file mode 100644
index 000000000..951b13b67
--- /dev/null
+++ b/lib/xmlstringer.php
@@ -0,0 +1,68 @@
+<?php
+/**
+ * Laconica, the distributed open-source microblogging tool
+ *
+ * Generator for in-memory XML
+ *
+ * PHP version 5
+ *
+ * LICENCE: This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * @category  Output
+ * @package   Laconica
+ * @author    Evan Prodromou <evan@controlyourself.ca>
+ * @copyright 2009 Control Yourself, Inc.
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      http://laconi.ca/
+ */
+
+if (!defined('LACONICA')) {
+    exit(1);
+}
+
+/**
+ * Create in-memory XML
+ *
+ * @category Output
+ * @package  Laconica
+ * @author   Evan Prodromou <evan@controlyourself.ca>
+ * @license  http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link     http://laconi.ca/
+ * @see      Action
+ * @see      HTMLOutputter
+ */
+
+class XMLStringer extends XMLOutputter
+{
+    function __construct($indent=false)
+    {
+        $this->xw = new XMLWriter();
+        $this->xw->openMemory();
+        $this->xw->setIndent($indent);
+    }
+
+    function getString()
+    {
+        return $this->xw->outputMemory();
+    }
+
+    // utility for quickly creating XML-strings
+
+    static function estring($tag, $attrs=null, $content=null)
+    {
+        $xs = new XMLStringer();
+        $xs->element($tag, $attrs, $content);
+        return $xs->getString();
+    }
+}
\ No newline at end of file