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         if (common_logged_in()) {
 173                 common_notice_form();
 174         }
 175         common_element_end('div');
 176         common_element_start('div', array('id' => 'content'));
 177         if (common_logged_in()) {
 178                 common_views_menu();
 179         }
 180 }
 181
 182 function common_show_footer() {
 183         global $xw, $config;
 184         common_element_end('div'); # content div
 185         common_foot_menu();
 186         common_element_start('div', 'footer');
 187         common_license_block();
 188         common_element_end('div');
 189         common_element_end('div');
 190         common_element_end('body');
 191         common_element_end('html');
 192         common_end_xml();
 193 }
 194
 195 function common_text($txt) {
 196         global $xw;
 197         $xw->text($txt);
 198 }
 199
 200 function common_raw($xml) {
 201         global $xw;
 202         $xw->writeRaw($xml);
 203 }
 204
 205 function common_license_block() {
 206         global $config, $xw;
 207         common_element_start('p', 'license');
 208         common_element_start('a', array('class' => 'license',
 209                                                                         'rel' => 'license',
 210                                                                         href => $config['license']['url']));
 211         common_element('img', array('class' => 'license',
 212                                                                 'src' => $config['license']['image'],
 213                                                                 'alt' => $config['license']['title']));
 214         common_element_end('a');
 215         common_text(_t('Unless otherwise specified, contents of this site are copyright by the contributors and available under the '));
 216         common_element('a', array('class' => 'license',
 217                                                           'rel' => 'license',
 218                                                           href => $config['license']['url']),
 219                                    $config['license']['title']);
 220         common_text(_t('. Contributors should be attributed by full name or nickname.'));
 221         common_element_end('p');
 222 }
 223
 224 function common_nav_menu() {
 225         $user = common_current_user();
 226         common_element_start('ul', array('id' => 'nav'));
 227         common_menu_item(common_local_url('public'), _t('Public'));
 228         if ($user) {
 229                 common_menu_item(common_local_url('profilesettings'),
 230                                                  _t('Settings'));
 231                 common_menu_item(common_local_url('logout'),
 232                                                  _t('Logout'));
 233         } else {
 234                 common_menu_item(common_local_url('login'), _t('Login'));
 235                 common_menu_item(common_local_url('register'), _t('Register'));
 236         }
 237         common_element_end('ul');
 238 }
 239
 240 function common_views_menu() {
 241         common_element_start('ul', array('id' => 'nav_views'));
 242         common_menu_item(common_local_url('all', array('nickname' =>
 243                                                                                                    $user->nickname)),
 244                                          _t('Home'));
 245         common_menu_item(common_local_url('showstream', array('nickname' =>
 246                                                                                                                   $user->nickname)),
 247                                          _t('Profile'),  $user->fullname || $user->nickname);
 248         common_element_end('ul');
 249 }
 250
 251 function common_foot_menu() {
 252         common_element_start('ul', array('id' => 'nav_sub'));
 253         common_menu_item(common_local_url('doc', array('title' => 'about')),
 254                                          _t('About'));
 255         common_menu_item(common_local_url('doc', array('title' => 'help')),
 256                                          _t('Help'));
 257         common_menu_item(common_local_url('doc', array('title' => 'privacy')),
 258                                          _t('Privacy'));
 259         common_menu_item(common_local_url('doc', array('title' => 'source')),
 260                                          _t('Source'));
 261         common_element_end('ul');
 262 }
 263
 264 function common_menu_item($url, $text, $title=NULL) {
 265         $attrs['href'] = $url;
 266         if ($title) {
 267                 $attrs['title'] = $title;
 268         }
 269         common_element_start('li', 'menuitem');
 270         common_element('a', $attrs, $text);
 271         common_element_end('li');
 272 }
 273
 274 function common_input($id, $label, $value=NULL) {
 275         common_element_start('p');
 276         common_element('label', array('for' => $id), $label);
 277         $attrs = array('name' => $id,
 278                                    'type' => 'text',
 279                                    'id' => $id);
 280         if ($value) {
 281                 $attrs['value'] = htmlspecialchars($value);
 282         }
 283         common_element('input', $attrs);
 284         common_element_end('p');
 285 }
 286
 287 function common_hidden($id, $value) {
 288         common_element('input', array('name' => $id,
 289                                                                   'type' => 'hidden',
 290                                                                   'id' => $id,
 291                                                                   'value' => $value));
 292 }
 293
 294 function common_password($id, $label) {
 295         common_element_start('p');
 296         common_element('label', array('for' => $id), $label);
 297         $attrs = array('name' => $id,
 298                                    'type' => 'password',
 299                                    'id' => $id);
 300         common_element('input', $attrs);
 301         common_element_end('p');
 302 }
 303
 304 function common_submit($id, $label) {
 305         global $xw;
 306         common_element_start('p');
 307         common_element_start('label', array('for' => $id));
 308         $xw->writeRaw('&nbsp;');
 309         common_element_end('label');
 310         common_element('input', array('type' => 'submit',
 311                                                                   'id' => $id,
 312                                                                   'name' => $id,
 313                                                                   'value' => $label,
 314                                                                   'class' => 'button'));
 315         common_element_end('p');
 316 }
 317
 318 function common_textarea($id, $label, $content=NULL) {
 319         common_element_start('p');
 320         common_element('label', array('for' => $id), $label);
 321         common_element('textarea', array('rows' => 3,
 322                                                                          'cols' => 40,
 323                                                                          'name' => $id,
 324                                                                          'id' => $id,
 325                                                                          'class' => 'width50'),
 326                                    ($content) ? $content : ' ');
 327         common_element_end('p');
 328 }
 329
 330 # salted, hashed passwords are stored in the DB
 331
 332 function common_munge_password($id, $password) {
 333         return md5($id . $password);
 334 }
 335
 336 # check if a username exists and has matching password
 337 function common_check_user($nickname, $password) {
 338         $user = User::staticGet('nickname', $nickname);
 339         if (is_null($user)) {
 340                 return false;
 341         } else {
 342                 return (0 == strcmp(common_munge_password($password, $user->id),
 343                                                         $user->password));
 344         }
 345 }
 346
 347 # is the current user logged in?
 348 function common_logged_in() {
 349         return (!is_null(common_current_user()));
 350 }
 351
 352 function common_have_session() {
 353         return (0 != strcmp(session_id(), ''));
 354 }
 355
 356 function common_ensure_session() {
 357         if (!common_have_session()) {
 358                 @session_start();
 359         }
 360 }
 361
 362 function common_set_user($nickname) {
 363         if (is_null($nickname) && common_have_session()) {
 364                 unset($_SESSION['userid']);
 365                 return true;
 366         } else {
 367                 $user = User::staticGet('nickname', $nickname);
 368                 if ($user) {
 369                         common_ensure_session();
 370                         $_SESSION['userid'] = $user->id;
 371                         return true;
 372                 } else {
 373                         return false;
 374                 }
 375         }
 376         return false;
 377 }
 378
 379 # who is the current user?
 380 function common_current_user() {
 381         static $user = NULL; # FIXME: global memcached
 382         if (is_null($user)) {
 383                 common_ensure_session();
 384                 $id = $_SESSION['userid'];
 385                 if ($id) {
 386                         $user = User::staticGet($id);
 387                 }
 388         }
 389         return $user;
 390 }
 391
 392 # get canonical version of nickname for comparison
 393 function common_canonical_nickname($nickname) {
 394         # XXX: UTF-8 canonicalization (like combining chars)
 395         return $nickname;
 396 }
 397
 398 # get canonical version of email for comparison
 399 function common_canonical_email($email) {
 400         # XXX: canonicalize UTF-8
 401         # XXX: lcase the domain part
 402         return $email;
 403 }
 404
 405 define('URL_REGEX', '^|[ \t\r\n])((ftp|http|https|gopher|mailto|news|nntp|telnet|wais|file|prospero|aim|webcal):(([A-Za-z0-9$_.+!*(),;/?:@&~=-])|%[A-Fa-f0-9]{2}){2,}(#([a-zA-Z0-9][a-zA-Z0-9$_.+!*(),;/?:@&~=%-]*))?([A-Za-z0-9$_+!*();/?:~-]))');
 406
 407 function common_render_content($text, $notice) {
 408         $r = htmlspecialchars($text);
 409         $id = $notice->profile_id;
 410         $r = preg_replace('@https?://\S+@', '<a href="\0" class="extlink">\0</a>', $r);
 411         $r = preg_replace('/(^|\b)@([\w-]+)($|\b)/e', "'\\1@'.common_at_link($id, '\\2').'\\3'", $r);
 412         # XXX: # tags
 413         # XXX: machine tags
 414         return $r;
 415 }
 416
 417 function common_at_link($sender_id, $nickname) {
 418         # Try to find profiles this profile is subscribed to that have this nickname
 419         $recipient = new Profile();
 420         # XXX: chokety and bad
 421         $recipient->whereAdd('EXISTS (SELECT subscribed from subscription where subscriber = '.$sender_id.' and subscribed = id)', 'AND');
 422         $recipient->whereAdd('nickname = "' . trim($nickname) . '"', 'AND');
 423         if ($recipient->find(TRUE)) {
 424                 return '<a href="'.htmlspecialchars($recipient->profileurl).'" class="atlink tolistenee">'.$nickname.'</a>';
 425         }
 426         # Try to find profiles that listen to this profile and that have this nickname
 427         $recipient = new Profile();
 428         # XXX: chokety and bad
 429         $recipient->whereAdd('EXISTS (SELECT subscriber from subscription where subscribed = '.$sender_id.' and subscriber = id)', 'AND');
 430         $recipient->whereAdd('nickname = "' . trim($nickname) . '"', 'AND');
 431         if ($recipient->find(TRUE)) {
 432                 return '<a href="'.htmlspecialchars($recipient->profileurl).'" class="atlink tolistener">'.$nickname.'</a>';
 433         }
 434         # If this is a local user, try to find a local user with that nickname.
 435         $sender = User::staticGet($sender_id);
 436         if ($sender) {
 437                 $recipient_user = User::staticGet('nickname', $nickname);
 438                 if ($recipient_user) {
 439                         $recipient = $recipient->getProfile();
 440                         return '<a href="'.htmlspecialchars($recipient->profileurl).'" class="atlink usertouser">'.$nickname.'</a>';
 441                 }
 442         }
 443         # Otherwise, no links. @messages from local users to remote users,
 444         # or from remote users to other remote users, are just
 445         # outside our ability to make intelligent guesses about
 446         return $nickname;
 447 }
 448
 449 // where should the avatar go for this user?
 450
 451 function common_avatar_filename($id, $extension, $size=NULL, $extra=NULL) {
 452         global $config;
 453
 454         if ($size) {
 455                 return $id . '-' . $size . (($extra) ? ('-' . $extra) : '') . $extension;
 456         } else {
 457                 return $id . '-original' . (($extra) ? ('-' . $extra) : '') . $extension;
 458         }
 459 }
 460
 461 function common_avatar_path($filename) {
 462         global $config;
 463         return INSTALLDIR . '/avatar/' . $filename;
 464 }
 465
 466 function common_avatar_url($filename) {
 467         return common_path('avatar/'.$filename);
 468 }
 469
 470 function common_default_avatar($size) {
 471         static $sizenames = array(AVATAR_PROFILE_SIZE => 'profile',
 472                                                           AVATAR_STREAM_SIZE => 'stream',
 473                                                           AVATAR_MINI_SIZE => 'mini');
 474         global $config;
 475
 476         return common_path($config['avatar']['default'][$sizenames[$size]]);
 477 }
 478
 479 function common_local_url($action, $args=NULL) {
 480         global $config;
 481         if ($config['site']['fancy']) {
 482                 return common_fancy_url($action, $args);
 483         } else {
 484                 return common_simple_url($action, $args);
 485         }
 486 }
 487
 488 function common_fancy_url($action, $args=NULL) {
 489         switch (strtolower($action)) {
 490          case 'public':
 491                 return common_path('');
 492          case 'publicrss':
 493                 return common_path('rss');
 494          case 'doc':
 495                 return common_path('doc/'.$args['title']);
 496          case 'login':
 497          case 'logout':
 498          case 'register':
 499          case 'subscribe':
 500          case 'unsubscribe':
 501                 return common_path('main/'.$action);
 502          case 'avatar':
 503          case 'password':
 504                 return common_path('settings/'.$action);
 505          case 'profilesettings':
 506                 return common_path('settings/profile');
 507          case 'newnotice':
 508                 return common_path('notice/new');
 509          case 'shownotice':
 510                 return common_path('notice/'.$args['notice']);
 511          case 'subscriptions':
 512          case 'subscribed':
 513          case 'xrds':
 514          case 'all':
 515          case 'foaf':
 516                 return common_path($args['nickname'].'/'.$action);
 517          case 'allrss':
 518                 return common_path($args['nickname'].'/all/rss');
 519          case 'userrss':
 520                 return common_path($args['nickname'].'/rss');
 521          case 'showstream':
 522                 return common_path($args['nickname']);
 523          default:
 524                 return common_simple_url($action, $args);
 525         }
 526 }
 527
 528 function common_simple_url($action, $args=NULL) {
 529         global $config;
 530         /* XXX: pretty URLs */
 531         $extra = '';
 532         if ($args) {
 533                 foreach ($args as $key => $value) {
 534                         $extra .= "&${key}=${value}";
 535                 }
 536         }
 537         return common_path("index.php?action=${action}${extra}");
 538 }
 539
 540 function common_path($relative) {
 541         global $config;
 542         $pathpart = ($config['site']['path']) ? $config['site']['path']."/" : '';
 543         return "http://".$config['site']['server'].'/'.$pathpart.$relative;
 544 }
 545
 546 function common_date_string($dt) {
 547         // XXX: do some sexy date formatting
 548         // return date(DATE_RFC822, $dt);
 549         return $dt;
 550 }
 551
 552 function common_date_w3dtf($dt) {
 553         $t = strtotime($dt);
 554         return date(DATE_W3C, $t);
 555 }
 556
 557 function common_redirect($url, $code=307) {
 558         static $status = array(301 => "Moved Permanently",
 559                                                    302 => "Found",
 560                                                    303 => "See Other",
 561                                                    307 => "Temporary Redirect");
 562         header("Status: ${code} $status[$code]");
 563         header("Location: $url");
 564         common_element('a', array('href' => $url), $url);
 565 }
 566
 567 function common_broadcast_notice($notice, $remote=false) {
 568         // XXX: optionally use a queue system like http://code.google.com/p/microapps/wiki/NQDQ
 569         if (!$remote) {
 570                 # Make sure we have the OMB stuff
 571                 require_once(INSTALLDIR.'/lib/omb.php');
 572                 omb_broadcast_remote_subscribers($notice);
 573         }
 574         // XXX: broadcast notices to Jabber
 575         // XXX: broadcast notices to SMS
 576         // XXX: broadcast notices to other IM
 577         return true;
 578 }
 579
 580
 581 function common_profile_url($nickname) {
 582         return common_local_url('showstream', array('nickname' => $nickname));
 583 }
 584
 585 # Don't call if nobody's logged in
 586
 587 function common_notice_form() {
 588         $user = common_current_user();
 589         assert(!is_null($user));
 590         common_element_start('form', array('id' => 'status_form',
 591                                                                            'method' => 'POST',
 592                                                                            'action' => common_local_url('newnotice')));
 593         common_element('label', array('for' => 'status_update',
 594                                                                   'id' => 'status_label'),
 595                                    _t('What\'s up, ').$user->nickname.'?');
 596         common_element('textarea', 'status_textarea');
 597         common_element('input', array('id' => 'status_submit',
 598                                                                   'type' => 'submit',
 599                                                                   'value' => _t('Send')));
 600         common_element_end('form');
 601 }
 602
 603 function common_mint_tag($extra) {
 604         global $config;
 605         return
 606           'tag:'.$config['tag']['authority'].','.
 607           $config['tag']['date'].':'.$config['tag']['prefix'].$extra;
 608 }
 609
 610 # Should make up a reasonable root URL
 611
 612 function common_root_url() {
 613         return common_path('');
 614 }
 615
 616 # returns $bytes bytes of random data as a hexadecimal string
 617 # "good" here is a goal and not a guarantee
 618
 619 function common_good_rand($bytes) {
 620         # XXX: use random.org...?
 621         if (file_exists('/dev/urandom')) {
 622                 return common_urandom($bytes);
 623         } else { # FIXME: this is probably not good enough
 624                 return common_mtrand($bytes);
 625         }
 626 }
 627
 628 function common_urandom($bytes) {
 629         $h = fopen('/dev/urandom', 'rb');
 630         # should not block
 631         $src = fread($h, $bytes);
 632         fclose($h);
 633         $enc = '';
 634         for ($i = 0; $i < $bytes; $i++) {
 635                 $enc .= sprintf("%02x", (ord($src[$i])));
 636         }
 637         return $enc;
 638 }
 639
 640 function common_mtrand($bytes) {
 641         $enc = '';
 642         for ($i = 0; $i < $bytes; $i++) {
 643                 $enc .= sprintf("%02x", mt_rand(0, 255));
 644         }
 645         return $enc;
 646 }
 647
 648 function common_set_returnto($url) {
 649         common_ensure_session();
 650         $_SESSION['returnto'] = $url;
 651 }
 652
 653 function common_get_returnto() {
 654         common_ensure_session();
 655         return $_SESSION['returnto'];
 656 }
 657
 658 function common_timestamp() {
 659         return date('YmdHis');
 660 }
 661
 662 // XXX: set up gettext
 663
 664 function _t($str) {
 665         return $str;
 666 }
 667
 668 function common_ensure_syslog() {
 669         static $initialized = false;
 670         if (!$initialized) {
 671                 global $config;
 672                 define_syslog_variables();
 673                 openlog($config['syslog']['appname'], 0, LOG_USER);
 674                 $initialized = true;
 675         }
 676 }
 677
 678 function common_log($priority, $msg, $filename=NULL) {
 679         common_ensure_syslog();
 680         syslog($priority, $msg);
 681 }
 682
 683 function common_debug($msg, $filename=NULL) {
 684         if ($filename) {
 685                 common_log(LOG_DEBUG, basename($filename).' - '.$msg);
 686         } else {
 687                 common_log(LOG_DEBUG, $msg);
 688         }
 689 }
 690
 691 function common_valid_http_url($url) {
 692         return Validate::uri($url, array('allowed_schemes' => array('http', 'https')));
 693 }
 694
 695 function common_valid_tag($tag) {
 696         if (preg_match('/^tag:(.*?),(\d{4}(-\d{2}(-\d{2})?)?):(.*)$/', $tag, $matches)) {
 697                 return (Validate::email($matches[1]) ||
 698                                 preg_match('/^([\w-\.]+)$/', $matches[1]));
 699         }
 700         return false;
 701 }
 702
 703 # Does a little before-after block for next/prev page
 704
 705 function common_pagination($have_before, $have_after, $page, $action, $args=NULL) {
 706
 707         if ($have_before || $have_after) {
 708                 common_element_start('div', array('id' => 'pagination'));
 709                 common_element_start('ul', array('id' => 'nav_pagination'));
 710         }
 711
 712         if ($have_before) {
 713                 $pargs = array('page' => $page-1);
 714                 $newargs = ($args) ? array_merge($args,$pargs) : $pargs;
 715
 716                 common_element_start('li', 'before');
 717                 common_element('a', array('href' => common_local_url($action, $newargs)),
 718                                            _t('« Before'));
 719                 common_element_end('li');
 720         }
 721
 722         if ($have_after) {
 723                 $pargs = array('page' => $page+1);
 724                 $newargs = ($args) ? array_merge($args,$pargs) : $pargs;
 725                 common_element_start('li', 'after');
 726                 common_element('a', array('href' => common_local_url($action, $newargs)),
 727                                                    _t('After »'));
 728                 common_element_end('li');
 729         }
 730
 731         if ($have_before || $have_after) {
 732                 common_element_end('ul');
 733                 common_element_end('div');
 734         }
 735 }