lib/util.php

   1 <?php
   2 /*
   3  * Laconica - a distributed open-source microblogging tool
   4  * Copyright (C) 2008, Controlez-Vous, Inc.
   5  *
   6  * This program is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU Affero General Public License as published by
   8  * the Free Software Foundation, either version 3 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU Affero General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Affero General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 /* XXX: break up into separate modules (HTTP, HTML, user, files) */
  21
  22 # Show a server error
  23
  24 function common_server_error($msg, $code=500) {
  25         static $status = array(500 => 'Internal Server Error',
  26                                                    501 => 'Not Implemented',
  27                                                    502 => 'Bad Gateway',
  28                                                    503 => 'Service Unavailable',
  29                                                    504 => 'Gateway Timeout',
  30                                                    505 => 'HTTP Version Not Supported');
  31
  32         if (!array_key_exists($code, $status)) {
  33                 $code = 500;
  34         }
  35
  36         $status_string = $status[$code];
  37
  38         header('HTTP/1.1 '.$code.' '.$status_string);
  39         header('Content-type: text/plain');
  40
  41         print $msg;
  42         print "\n";
  43         exit();
  44 }
  45
  46 # Show a user error
  47 function common_user_error($msg, $code=400) {
  48         static $status = array(400 => 'Bad Request',
  49                                                    401 => 'Unauthorized',
  50                                                    402 => 'Payment Required',
  51                                                    403 => 'Forbidden',
  52                                                    404 => 'Not Found',
  53                                                    405 => 'Method Not Allowed',
  54                                                    406 => 'Not Acceptable',
  55                                                    407 => 'Proxy Authentication Required',
  56                                                    408 => 'Request Timeout',
  57                                                    409 => 'Conflict',
  58                                                    410 => 'Gone',
  59                                                    411 => 'Length Required',
  60                                                    412 => 'Precondition Failed',
  61                                                    413 => 'Request Entity Too Large',
  62                                                    414 => 'Request-URI Too Long',
  63                                                    415 => 'Unsupported Media Type',
  64                                                    416 => 'Requested Range Not Satisfiable',
  65                                                    417 => 'Expectation Failed');
  66
  67         if (!array_key_exists($code, $status)) {
  68                 $code = 400;
  69         }
  70
  71         $status_string = $status[$code];
  72
  73         header('HTTP/1.1 '.$code.' '.$status_string);
  74
  75         common_show_header('Error');
  76         common_element('div', array('class' => 'error'), $msg);
  77         common_show_footer();
  78 }
  79
  80 $xw = null;
  81
  82 # Start an HTML element
  83 function common_element_start($tag, $attrs=NULL) {
  84         global $xw;
  85         $xw->startElement($tag);
  86         if (is_array($attrs)) {
  87                 foreach ($attrs as $name => $value) {
  88                         $xw->writeAttribute($name, $value);
  89                 }
  90         } else if (is_string($attrs)) {
  91                 $xw->writeAttribute('class', $attrs);
  92         }
  93 }
  94
  95 function common_element_end($tag) {
  96         global $xw;
  97         $xw->endElement();
  98 }
  99
 100 function common_element($tag, $attrs=NULL, $content=NULL) {
 101     common_element_start($tag, $attrs);
 102         if ($content) {
 103                 global $xw;
 104                 $xw->text($content);
 105         }
 106         common_element_end($tag);
 107 }
 108
 109 function common_start_xml($doc=NULL, $public=NULL, $system=NULL) {
 110         global $xw;
 111         $xw = new XMLWriter();
 112         $xw->openURI('php://output');
 113         $xw->setIndent(true);
 114         $xw->startDocument('1.0', 'UTF-8');
 115         if ($doc) {
 116                 $xw->writeDTD($doc, $public, $system);
 117         }
 118 }
 119
 120 function common_end_xml() {
 121         global $xw;
 122         $xw->endDocument();
 123         $xw->flush();
 124 }
 125
 126 function common_show_header($pagetitle, $callable=NULL, $data=NULL, $notice=NULL) {
 127         global $config, $xw;
 128
 129         header('Content-Type: application/xhtml+xml');
 130
 131         common_start_xml('html',
 132                                          '-//W3C//DTD XHTML 1.0 Strict//EN',
 133                                          'http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd');
 134
 135         # FIXME: correct language for interface
 136
 137         common_element_start('html', array('xmlns' => 'http://www.w3.org/1999/xhtml',
 138                                                                            'xml:lang' => 'en',
 139                                                                            'lang' => 'en'));
 140
 141         common_element_start('head');
 142         common_element('title', NULL,
 143                                    $pagetitle . " - " . $config['site']['name']);
 144         common_element('link', array('rel' => 'stylesheet',
 145                                                                  'type' => 'text/css',
 146                                                                  'href' => theme_path('display.css'),
 147                                                                  'media' => 'screen, projection, tv'));
 148         foreach (array(6,7) as $ver) {
 149                 if (file_exists(theme_file('ie'.$ver.'.css'))) {
 150                         # Yes, IE people should be put in jail.
 151                         $xw->writeComment('[if lte IE '.$ver.']><link rel="stylesheet" type="text/css" '.
 152                                                           'href="'.theme_path('ie'.$ver.'.css').' /><![endif]');
 153                 }
 154         }
 155         if ($callable) {
 156                 if ($data) {
 157                         call_user_func($callable, $data);
 158                 } else {
 159                         call_user_func($callable);
 160                 }
 161         }
 162         common_element_end('head');
 163         common_element_start('body');
 164         common_element_start('div', array('id' => 'wrap'));
 165         common_element_start('div', array('id' => 'header'));
 166         common_nav_menu();
 167         common_element_start('a', array('href' => common_local_url('public')));
 168         common_element('img', array('src' => ($config['site']['logo']) ?
 169                                                                 ($config['site']['logo']) : theme_path('logo.png'),
 170                                                                 'alt' => $config['site']['name'],
 171                                                                 'id' => 'logo'));
 172         common_element_end('a');
 173         if (common_logged_in()) {
 174                 common_notice_form();
 175         }
 176         common_element_end('div');
 177         common_element_start('div', array('id' => 'content'));
 178         if (common_logged_in()) {
 179                 common_views_menu();
 180         }
 181 }
 182
 183 function common_show_footer() {
 184         global $xw, $config;
 185         common_element_end('div'); # content div
 186         common_foot_menu();
 187         common_element_start('div', 'footer');
 188         common_license_block();
 189         common_element_end('div');
 190         common_element_end('div');
 191         common_element_end('body');
 192         common_element_end('html');
 193         common_end_xml();
 194 }
 195
 196 function common_text($txt) {
 197         global $xw;
 198         $xw->text($txt);
 199 }
 200
 201 function common_raw($xml) {
 202         global $xw;
 203         $xw->writeRaw($xml);
 204 }
 205
 206 function common_license_block() {
 207         global $config, $xw;
 208         common_element_start('p', 'license');
 209         common_element_start('a', array('class' => 'license',
 210                                                                         'rel' => 'license',
 211                                                                         href => $config['license']['url']));
 212         common_element('img', array('class' => 'license',
 213                                                                 'src' => $config['license']['image'],
 214                                                                 'alt' => $config['license']['title']));
 215         common_element_end('a');
 216         common_text(_t('Unless otherwise specified, contents of this site are copyright by the contributors and available under the '));
 217         common_element('a', array('class' => 'license',
 218                                                           'rel' => 'license',
 219                                                           href => $config['license']['url']),
 220                                    $config['license']['title']);
 221         common_text(_t('. Contributors should be attributed by full name or nickname.'));
 222         common_element_end('p');
 223 }
 224
 225 function common_nav_menu() {
 226         $user = common_current_user();
 227         common_element_start('ul', array('id' => 'nav'));
 228         common_menu_item(common_local_url('public'), _t('Public'));
 229         common_menu_item(common_local_url('doc', array('title' => 'help')),
 230                                          _t('Help'));
 231         if ($user) {
 232                 common_menu_item(common_local_url('profilesettings'),
 233                                                  _t('Settings'));
 234                 common_menu_item(common_local_url('logout'),
 235                                                  _t('Logout'));
 236         } else {
 237                 common_menu_item(common_local_url('login'), _t('Login'));
 238                 common_menu_item(common_local_url('register'), _t('Register'));
 239         }
 240         common_element_end('ul');
 241 }
 242
 243 function common_views_menu() {
 244         common_element_start('ul', array('id' => 'nav_views'));
 245         common_menu_item(common_local_url('all', array('nickname' =>
 246                                                                                                    $user->nickname)),
 247                                          _t('Home'));
 248         common_menu_item(common_local_url('showstream', array('nickname' =>
 249                                                                                                                   $user->nickname)),
 250                                          _t('Profile'),  $user->fullname || $user->nickname);
 251         common_element_end('ul');
 252 }
 253
 254 function common_foot_menu() {
 255         common_element_start('ul', array('id' => 'nav_sub'));
 256         common_menu_item(common_local_url('doc', array('title' => 'about')),
 257                                          _t('About'));
 258         common_menu_item(common_local_url('doc', array('title' => 'privacy')),
 259                                          _t('Privacy'));
 260         common_menu_item(common_local_url('doc', array('title' => 'source')),
 261                                          _t('Source'));
 262         common_element_end('ul');
 263 }
 264
 265 function common_menu_item($url, $text, $title=NULL) {
 266         $attrs['href'] = $url;
 267         if ($title) {
 268                 $attrs['title'] = $title;
 269         }
 270         common_element_start('li');
 271         common_element('a', $attrs, $text);
 272         common_element_end('li');
 273 }
 274
 275 function common_input($id, $label, $value=NULL) {
 276         common_element_start('p');
 277         common_element('label', array('for' => $id), $label);
 278         $attrs = array('name' => $id,
 279                                    'type' => 'text',
 280                                    'id' => $id);
 281         if ($value) {
 282                 $attrs['value'] = htmlspecialchars($value);
 283         }
 284         common_element('input', $attrs);
 285         common_element_end('p');
 286 }
 287
 288 function common_hidden($id, $value) {
 289         common_element('input', array('name' => $id,
 290                                                                   'type' => 'hidden',
 291                                                                   'id' => $id,
 292                                                                   'value' => $value));
 293 }
 294
 295 function common_password($id, $label) {
 296         common_element_start('p');
 297         common_element('label', array('for' => $id), $label);
 298         $attrs = array('name' => $id,
 299                                    'type' => 'password',
 300                                    'id' => $id);
 301         common_element('input', $attrs);
 302         common_element_end('p');
 303 }
 304
 305 function common_submit($id, $label) {
 306         global $xw;
 307         common_element_start('p');
 308         common_element_start('label', array('for' => $id));
 309         $xw->writeRaw('&nbsp;');
 310         common_element_end('label');
 311         common_element('input', array('type' => 'submit',
 312                                                                   'id' => $id,
 313                                                                   'name' => $id,
 314                                                                   'value' => $label,
 315                                                                   'class' => 'button'));
 316         common_element_end('p');
 317 }
 318
 319 function common_textarea($id, $label, $content=NULL) {
 320         common_element_start('p');
 321         common_element('label', array('for' => $id), $label);
 322         common_element('textarea', array('rows' => 3,
 323                                                                          'cols' => 40,
 324                                                                          'name' => $id,
 325                                                                          'id' => $id,
 326                                                                          'class' => 'width50'),
 327                                    ($content) ? $content : ' ');
 328         common_element_end('p');
 329 }
 330
 331 # salted, hashed passwords are stored in the DB
 332
 333 function common_munge_password($id, $password) {
 334         return md5($id . $password);
 335 }
 336
 337 # check if a username exists and has matching password
 338 function common_check_user($nickname, $password) {
 339         $user = User::staticGet('nickname', $nickname);
 340         if (is_null($user)) {
 341                 return false;
 342         } else {
 343                 return (0 == strcmp(common_munge_password($password, $user->id),
 344                                                         $user->password));
 345         }
 346 }
 347
 348 # is the current user logged in?
 349 function common_logged_in() {
 350         return (!is_null(common_current_user()));
 351 }
 352
 353 function common_have_session() {
 354         return (0 != strcmp(session_id(), ''));
 355 }
 356
 357 function common_ensure_session() {
 358         if (!common_have_session()) {
 359                 @session_start();
 360         }
 361 }
 362
 363 function common_set_user($nickname) {
 364         if (is_null($nickname) && common_have_session()) {
 365                 unset($_SESSION['userid']);
 366                 return true;
 367         } else {
 368                 $user = User::staticGet('nickname', $nickname);
 369                 if ($user) {
 370                         common_ensure_session();
 371                         $_SESSION['userid'] = $user->id;
 372                         return true;
 373                 } else {
 374                         return false;
 375                 }
 376         }
 377         return false;
 378 }
 379
 380 # who is the current user?
 381 function common_current_user() {
 382         static $user = NULL; # FIXME: global memcached
 383         if (is_null($user)) {
 384                 common_ensure_session();
 385                 $id = $_SESSION['userid'];
 386                 if ($id) {
 387                         $user = User::staticGet($id);
 388                 }
 389         }
 390         return $user;
 391 }
 392
 393 # get canonical version of nickname for comparison
 394 function common_canonical_nickname($nickname) {
 395         # XXX: UTF-8 canonicalization (like combining chars)
 396         return $nickname;
 397 }
 398
 399 # get canonical version of email for comparison
 400 function common_canonical_email($email) {
 401         # XXX: canonicalize UTF-8
 402         # XXX: lcase the domain part
 403         return $email;
 404 }
 405
 406 define('URL_REGEX', '^|[ \t\r\n])((ftp|http|https|gopher|mailto|news|nntp|telnet|wais|file|prospero|aim|webcal):(([A-Za-z0-9$_.+!*(),;/?:@&~=-])|%[A-Fa-f0-9]{2}){2,}(#([a-zA-Z0-9][a-zA-Z0-9$_.+!*(),;/?:@&~=%-]*))?([A-Za-z0-9$_+!*();/?:~-]))');
 407
 408 function common_render_content($text, $notice) {
 409         $r = htmlspecialchars($text);
 410         $id = $notice->profile_id;
 411         $r = preg_replace('@https?://\S+@', '<a href="\0" class="extlink">\0</a>', $r);
 412         $r = preg_replace('/(^|\b)@([\w-]+)($|\b)/e', "'\\1@'.common_at_link($id, '\\2').'\\3'", $r);
 413         # XXX: # tags
 414         # XXX: machine tags
 415         return $r;
 416 }
 417
 418 function common_at_link($sender_id, $nickname) {
 419         # Try to find profiles this profile is subscribed to that have this nickname
 420         $recipient = new Profile();
 421         # XXX: chokety and bad
 422         $recipient->whereAdd('EXISTS (SELECT subscribed from subscription where subscriber = '.$sender_id.' and subscribed = id)', 'AND');
 423         $recipient->whereAdd('nickname = "' . trim($nickname) . '"', 'AND');
 424         if ($recipient->find(TRUE)) {
 425                 return '<a href="'.htmlspecialchars($recipient->profileurl).'" class="atlink tolistenee">'.$nickname.'</a>';
 426         }
 427         # Try to find profiles that listen to this profile and that have this nickname
 428         $recipient = new Profile();
 429         # XXX: chokety and bad
 430         $recipient->whereAdd('EXISTS (SELECT subscriber from subscription where subscribed = '.$sender_id.' and subscriber = id)', 'AND');
 431         $recipient->whereAdd('nickname = "' . trim($nickname) . '"', 'AND');
 432         if ($recipient->find(TRUE)) {
 433                 return '<a href="'.htmlspecialchars($recipient->profileurl).'" class="atlink tolistener">'.$nickname.'</a>';
 434         }
 435         # If this is a local user, try to find a local user with that nickname.
 436         $sender = User::staticGet($sender_id);
 437         if ($sender) {
 438                 $recipient_user = User::staticGet('nickname', $nickname);
 439                 if ($recipient_user) {
 440                         $recipient = $recipient->getProfile();
 441                         return '<a href="'.htmlspecialchars($recipient->profileurl).'" class="atlink usertouser">'.$nickname.'</a>';
 442                 }
 443         }
 444         # Otherwise, no links. @messages from local users to remote users,
 445         # or from remote users to other remote users, are just
 446         # outside our ability to make intelligent guesses about
 447         return $nickname;
 448 }
 449
 450 // where should the avatar go for this user?
 451
 452 function common_avatar_filename($id, $extension, $size=NULL, $extra=NULL) {
 453         global $config;
 454
 455         if ($size) {
 456                 return $id . '-' . $size . (($extra) ? ('-' . $extra) : '') . $extension;
 457         } else {
 458                 return $id . '-original' . (($extra) ? ('-' . $extra) : '') . $extension;
 459         }
 460 }
 461
 462 function common_avatar_path($filename) {
 463         global $config;
 464         return INSTALLDIR . '/avatar/' . $filename;
 465 }
 466
 467 function common_avatar_url($filename) {
 468         return common_path('avatar/'.$filename);
 469 }
 470
 471 function common_default_avatar($size) {
 472         static $sizenames = array(AVATAR_PROFILE_SIZE => 'profile',
 473                                                           AVATAR_STREAM_SIZE => 'stream',
 474                                                           AVATAR_MINI_SIZE => 'mini');
 475         global $config;
 476
 477         return common_path($config['avatar']['default'][$sizenames[$size]]);
 478 }
 479
 480 function common_local_url($action, $args=NULL) {
 481         global $config;
 482         if ($config['site']['fancy']) {
 483                 return common_fancy_url($action, $args);
 484         } else {
 485                 return common_simple_url($action, $args);
 486         }
 487 }
 488
 489 function common_fancy_url($action, $args=NULL) {
 490         switch (strtolower($action)) {
 491          case 'public':
 492                 return common_path('');
 493          case 'publicrss':
 494                 return common_path('rss');
 495          case 'doc':
 496                 return common_path('doc/'.$args['title']);
 497          case 'login':
 498          case 'logout':
 499          case 'register':
 500          case 'subscribe':
 501          case 'unsubscribe':
 502                 return common_path('main/'.$action);
 503          case 'avatar':
 504          case 'password':
 505                 return common_path('settings/'.$action);
 506          case 'profilesettings':
 507                 return common_path('settings/profile');
 508          case 'newnotice':
 509                 return common_path('notice/new');
 510          case 'shownotice':
 511                 return common_path('notice/'.$args['notice']);
 512          case 'subscriptions':
 513          case 'subscribed':
 514          case 'xrds':
 515          case 'all':
 516          case 'foaf':
 517                 return common_path($args['nickname'].'/'.$action);
 518          case 'allrss':
 519                 return common_path($args['nickname'].'/all/rss');
 520          case 'userrss':
 521                 return common_path($args['nickname'].'/rss');
 522          case 'showstream':
 523                 return common_path($args['nickname']);
 524          default:
 525                 return common_simple_url($action, $args);
 526         }
 527 }
 528
 529 function common_simple_url($action, $args=NULL) {
 530         global $config;
 531         /* XXX: pretty URLs */
 532         $extra = '';
 533         if ($args) {
 534                 foreach ($args as $key => $value) {
 535                         $extra .= "&${key}=${value}";
 536                 }
 537         }
 538         return common_path("index.php?action=${action}${extra}");
 539 }
 540
 541 function common_path($relative) {
 542         global $config;
 543         $pathpart = ($config['site']['path']) ? $config['site']['path']."/" : '';
 544         return "http://".$config['site']['server'].'/'.$pathpart.$relative;
 545 }
 546
 547 function common_date_string($dt) {
 548         // XXX: do some sexy date formatting
 549         // return date(DATE_RFC822, $dt);
 550         return $dt;
 551 }
 552
 553 function common_date_w3dtf($dt) {
 554         $t = strtotime($dt);
 555         return date(DATE_W3C, $t);
 556 }
 557
 558 function common_redirect($url, $code=307) {
 559         static $status = array(301 => "Moved Permanently",
 560                                                    302 => "Found",
 561                                                    303 => "See Other",
 562                                                    307 => "Temporary Redirect");
 563         header("Status: ${code} $status[$code]");
 564         header("Location: $url");
 565         common_element('a', array('href' => $url), $url);
 566 }
 567
 568 function common_broadcast_notice($notice, $remote=false) {
 569         // XXX: optionally use a queue system like http://code.google.com/p/microapps/wiki/NQDQ
 570         if (!$remote) {
 571                 # Make sure we have the OMB stuff
 572                 require_once(INSTALLDIR.'/lib/omb.php');
 573                 omb_broadcast_remote_subscribers($notice);
 574         }
 575         // XXX: broadcast notices to Jabber
 576         // XXX: broadcast notices to SMS
 577         // XXX: broadcast notices to other IM
 578         return true;
 579 }
 580
 581
 582 function common_profile_url($nickname) {
 583         return common_local_url('showstream', array('nickname' => $nickname));
 584 }
 585
 586 # Don't call if nobody's logged in
 587
 588 function common_notice_form() {
 589         $user = common_current_user();
 590         assert(!is_null($user));
 591         common_element_start('form', array('id' => 'status_form',
 592                                                                            'method' => 'POST',
 593                                                                            'action' => common_local_url('newnotice')));
 594         common_element_start('p');
 595         common_element('label', array('for' => 'status_update',
 596                                                                   'id' => 'status_label'),
 597                                    _t('What\'s up, ').$user->nickname.'?');
 598         common_element('textarea', array('id' => 'status_textarea'));
 599         common_element('input', array('id' => 'status_submit',
 600                                                                   'type' => 'submit',
 601                                                                   'value' => _t('Send')));
 602         common_element_end('p');
 603         common_element_end('form');
 604 }
 605
 606 function common_mint_tag($extra) {
 607         global $config;
 608         return
 609           'tag:'.$config['tag']['authority'].','.
 610           $config['tag']['date'].':'.$config['tag']['prefix'].$extra;
 611 }
 612
 613 # Should make up a reasonable root URL
 614
 615 function common_root_url() {
 616         return common_path('');
 617 }
 618
 619 # returns $bytes bytes of random data as a hexadecimal string
 620 # "good" here is a goal and not a guarantee
 621
 622 function common_good_rand($bytes) {
 623         # XXX: use random.org...?
 624         if (file_exists('/dev/urandom')) {
 625                 return common_urandom($bytes);
 626         } else { # FIXME: this is probably not good enough
 627                 return common_mtrand($bytes);
 628         }
 629 }
 630
 631 function common_urandom($bytes) {
 632         $h = fopen('/dev/urandom', 'rb');
 633         # should not block
 634         $src = fread($h, $bytes);
 635         fclose($h);
 636         $enc = '';
 637         for ($i = 0; $i < $bytes; $i++) {
 638                 $enc .= sprintf("%02x", (ord($src[$i])));
 639         }
 640         return $enc;
 641 }
 642
 643 function common_mtrand($bytes) {
 644         $enc = '';
 645         for ($i = 0; $i < $bytes; $i++) {
 646                 $enc .= sprintf("%02x", mt_rand(0, 255));
 647         }
 648         return $enc;
 649 }
 650
 651 function common_set_returnto($url) {
 652         common_ensure_session();
 653         $_SESSION['returnto'] = $url;
 654 }
 655
 656 function common_get_returnto() {
 657         common_ensure_session();
 658         return $_SESSION['returnto'];
 659 }
 660
 661 function common_timestamp() {
 662         return date('YmdHis');
 663 }
 664
 665 // XXX: set up gettext
 666
 667 function _t($str) {
 668         return $str;
 669 }
 670
 671 function common_ensure_syslog() {
 672         static $initialized = false;
 673         if (!$initialized) {
 674                 global $config;
 675                 define_syslog_variables();
 676                 openlog($config['syslog']['appname'], 0, LOG_USER);
 677                 $initialized = true;
 678         }
 679 }
 680
 681 function common_log($priority, $msg, $filename=NULL) {
 682         common_ensure_syslog();
 683         syslog($priority, $msg);
 684 }
 685
 686 function common_debug($msg, $filename=NULL) {
 687         if ($filename) {
 688                 common_log(LOG_DEBUG, basename($filename).' - '.$msg);
 689         } else {
 690                 common_log(LOG_DEBUG, $msg);
 691         }
 692 }
 693
 694 function common_valid_http_url($url) {
 695         return Validate::uri($url, array('allowed_schemes' => array('http', 'https')));
 696 }
 697
 698 function common_valid_tag($tag) {
 699         if (preg_match('/^tag:(.*?),(\d{4}(-\d{2}(-\d{2})?)?):(.*)$/', $tag, $matches)) {
 700                 return (Validate::email($matches[1]) ||
 701                                 preg_match('/^([\w-\.]+)$/', $matches[1]));
 702         }
 703         return false;
 704 }
 705
 706 # Does a little before-after block for next/prev page
 707
 708 function common_pagination($have_before, $have_after, $page, $action, $args=NULL) {
 709
 710         if ($have_before || $have_after) {
 711                 common_element_start('div', array('id' => 'pagination'));
 712                 common_element_start('ul', array('id' => 'nav_pagination'));
 713         }
 714
 715         if ($have_before) {
 716                 $pargs = array('page' => $page-1);
 717                 $newargs = ($args) ? array_merge($args,$pargs) : $pargs;
 718
 719                 common_element_start('li', 'before');
 720                 common_element('a', array('href' => common_local_url($action, $newargs)),
 721                                            _t('« Before'));
 722                 common_element_end('li');
 723         }
 724
 725         if ($have_after) {
 726                 $pargs = array('page' => $page+1);
 727                 $newargs = ($args) ? array_merge($args,$pargs) : $pargs;
 728                 common_element_start('li', 'after');
 729                 common_element('a', array('href' => common_local_url($action, $newargs)),
 730                                                    _t('After »'));
 731                 common_element_end('li');
 732         }
 733
 734         if ($have_before || $have_after) {
 735                 common_element_end('ul');
 736                 common_element_end('div');
 737         }
 738 }