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         $xw->flush();
 124 }
 125
 126 define('PAGE_TYPE_PREFS', 'application/xhtml+xml,text/html;q=0.7,application/xml;q=0.3,text/xml;q=0.2');
 127
 128 function common_show_header($pagetitle, $callable=NULL, $data=NULL, $headercall=NULL) {
 129         global $config, $xw;
 130
 131         $httpaccept = isset($_SERVER['HTTP_ACCEPT']) ? $_SERVER['HTTP_ACCEPT'] : NULL;
 132
 133         # XXX: allow content negotiation for RDF, RSS, or XRDS
 134
 135         $type = common_negotiate_type(common_accept_to_prefs($httpaccept),
 136                                                                   common_accept_to_prefs(PAGE_TYPE_PREFS));
 137
 138         if (!$type) {
 139                 common_client_error(_t('This page is not available in a media type you accept'), 406);
 140                 exit(0);
 141         }
 142
 143         header('Content-Type: '.$type);
 144
 145         common_start_xml('html',
 146                                          '-//W3C//DTD XHTML 1.0 Strict//EN',
 147                                          'http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd');
 148
 149         # FIXME: correct language for interface
 150
 151         common_element_start('html', array('xmlns' => 'http://www.w3.org/1999/xhtml',
 152                                                                            'xml:lang' => 'en',
 153                                                                            'lang' => 'en'));
 154
 155         common_element_start('head');
 156         common_element('title', NULL,
 157                                    $pagetitle . " - " . $config['site']['name']);
 158         common_element('link', array('rel' => 'stylesheet',
 159                                                                  'type' => 'text/css',
 160                                                                  'href' => theme_path('display.css'),
 161                                                                  'media' => 'screen, projection, tv'));
 162         foreach (array(6,7) as $ver) {
 163                 if (file_exists(theme_file('ie'.$ver.'.css'))) {
 164                         # Yes, IE people should be put in jail.
 165                         $xw->writeComment('[if lte IE '.$ver.']><link rel="stylesheet" type="text/css" '.
 166                                                           'href="'.theme_path('ie'.$ver.'.css').' /><![endif]');
 167                 }
 168         }
 169         if ($callable) {
 170                 if ($data) {
 171                         call_user_func($callable, $data);
 172                 } else {
 173                         call_user_func($callable);
 174                 }
 175         }
 176         common_element_end('head');
 177         common_element_start('body');
 178         common_element_start('div', array('id' => 'wrap'));
 179         common_element_start('div', array('id' => 'header'));
 180         common_nav_menu();
 181         common_element_start('a', array('href' => common_local_url('public')));
 182         common_element('img', array('src' => ($config['site']['logo']) ?
 183                                                                 ($config['site']['logo']) : theme_path('logo.png'),
 184                                                                 'alt' => $config['site']['name'],
 185                                                                 'id' => 'logo'));
 186         common_element_end('a');
 187         if ($headercall) {
 188                 if ($data) {
 189                         call_user_func($headercall, $data);
 190                 } else {
 191                         call_user_func($headercall);
 192                 }
 193         }
 194         common_element_end('div');
 195         common_element_start('div', array('id' => 'content'));
 196 }
 197
 198 function common_show_footer() {
 199         global $xw, $config;
 200         common_element_end('div'); # content div
 201         common_foot_menu();
 202         common_element_start('div', array('id' => 'footer'));
 203         common_element('img', array('id' => 'cc',
 204                                                                 'src' => $config['license']['image'],
 205                                                                 'alt' => $config['license']['title']));
 206         common_element_start('p');
 207         common_text(_t('Unless otherwise specified, contents of this site are copyright by the contributors and available under the '));
 208         common_element('a', array('class' => 'license',
 209                                                           'rel' => 'license',
 210                                                           href => $config['license']['url']),
 211                                    $config['license']['title']);
 212         common_text(_t('. Contributors should be attributed by full name or nickname.'));
 213         common_element_end('p');
 214         common_element_end('div');
 215         common_element_end('div');
 216         common_element_end('body');
 217         common_element_end('html');
 218         common_end_xml();
 219 }
 220
 221 function common_text($txt) {
 222         global $xw;
 223         $xw->text($txt);
 224 }
 225
 226 function common_raw($xml) {
 227         global $xw;
 228         $xw->writeRaw($xml);
 229 }
 230
 231 function common_nav_menu() {
 232         $user = common_current_user();
 233         common_element_start('ul', array('id' => 'nav'));
 234         if ($user) {
 235                 common_menu_item(common_local_url('all', array('nickname' => $user->nickname)),
 236                                                  _t('Home'));
 237         }
 238         common_menu_item(common_local_url('public'), _t('Public'));
 239         common_menu_item(common_local_url('doc', array('title' => 'help')),
 240                                          _t('Help'));
 241         if ($user) {
 242                 common_menu_item(common_local_url('profilesettings'),
 243                                                  _t('Settings'));
 244                 common_menu_item(common_local_url('logout'),
 245                                                  _t('Logout'));
 246         } else {
 247                 common_menu_item(common_local_url('login'), _t('Login'));
 248                 common_menu_item(common_local_url('register'), _t('Register'));
 249         }
 250         common_element_end('ul');
 251 }
 252
 253 function common_foot_menu() {
 254         common_element_start('ul', array('id' => 'nav_sub'));
 255         common_menu_item(common_local_url('doc', array('title' => 'about')),
 256                                          _t('About'));
 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, $is_selected=false) {
 265         $lattrs = array();
 266         if ($is_selected) {
 267                 $lattrs['class'] = 'current';
 268         }
 269         common_element_start('li', $lattrs);
 270         $attrs['href'] = $url;
 271         if ($title) {
 272                 $attrs['title'] = $title;
 273         }
 274         common_element('a', $attrs, $text);
 275         common_element_end('li');
 276 }
 277
 278 function common_input($id, $label, $value=NULL,$instructions=NULL) {
 279         common_element_start('p');
 280         common_element('label', array('for' => $id), $label);
 281         $attrs = array('name' => $id,
 282                                    'type' => 'text',
 283                                    'id' => $id);
 284         if ($value) {
 285                 $attrs['value'] = htmlspecialchars($value);
 286         }
 287         common_element('input', $attrs);
 288         if ($instructions) {
 289                 common_element('span', 'input_instructions', $instructions);
 290         }
 291         common_element_end('p');
 292 }
 293
 294 function common_hidden($id, $value) {
 295         common_element('input', array('name' => $id,
 296                                                                   'type' => 'hidden',
 297                                                                   'id' => $id,
 298                                                                   'value' => $value));
 299 }
 300
 301 function common_password($id, $label, $instructions=NULL) {
 302         common_element_start('p');
 303         common_element('label', array('for' => $id), $label);
 304         $attrs = array('name' => $id,
 305                                    'type' => 'password',
 306                                    'id' => $id);
 307         common_element('input', $attrs);
 308         if ($instructions) {
 309                 common_element('span', 'input_instructions', $instructions);
 310         }
 311         common_element_end('p');
 312 }
 313
 314 function common_submit($id, $label) {
 315         global $xw;
 316         common_element_start('p');
 317         common_element('input', array('type' => 'submit',
 318                                                                   'id' => $id,
 319                                                                   'name' => $id,
 320                                                                   'value' => $label));
 321         common_element_end('p');
 322 }
 323
 324 function common_textarea($id, $label, $content=NULL, $instructions=NULL) {
 325         common_element_start('p');
 326         common_element('label', array('for' => $id), $label);
 327         common_element('textarea', array('rows' => 3,
 328                                                                          'cols' => 40,
 329                                                                          'name' => $id,
 330                                                                          'id' => $id),
 331                                    ($content) ? $content : ' ');
 332         if ($instructions) {
 333                 common_element('span', 'input_instructions', $instructions);
 334         }
 335         common_element_end('p');
 336 }
 337
 338 # salted, hashed passwords are stored in the DB
 339
 340 function common_munge_password($id, $password) {
 341         return md5($id . $password);
 342 }
 343
 344 # check if a username exists and has matching password
 345 function common_check_user($nickname, $password) {
 346         $user = User::staticGet('nickname', $nickname);
 347         if (is_null($user)) {
 348                 return false;
 349         } else {
 350                 return (0 == strcmp(common_munge_password($password, $user->id),
 351                                                         $user->password));
 352         }
 353 }
 354
 355 # is the current user logged in?
 356 function common_logged_in() {
 357         return (!is_null(common_current_user()));
 358 }
 359
 360 function common_have_session() {
 361         return (0 != strcmp(session_id(), ''));
 362 }
 363
 364 function common_ensure_session() {
 365         if (!common_have_session()) {
 366                 @session_start();
 367         }
 368 }
 369
 370 function common_set_user($nickname) {
 371         if (is_null($nickname) && common_have_session()) {
 372                 unset($_SESSION['userid']);
 373                 return true;
 374         } else {
 375                 $user = User::staticGet('nickname', $nickname);
 376                 if ($user) {
 377                         common_ensure_session();
 378                         $_SESSION['userid'] = $user->id;
 379                         return true;
 380                 } else {
 381                         return false;
 382                 }
 383         }
 384         return false;
 385 }
 386
 387 # who is the current user?
 388 function common_current_user() {
 389         static $user = NULL; # FIXME: global memcached
 390         if (is_null($user)) {
 391                 common_ensure_session();
 392                 $id = $_SESSION['userid'];
 393                 if ($id) {
 394                         $user = User::staticGet($id);
 395                 }
 396         }
 397         return $user;
 398 }
 399
 400 # get canonical version of nickname for comparison
 401 function common_canonical_nickname($nickname) {
 402         # XXX: UTF-8 canonicalization (like combining chars)
 403         return strtolower($nickname);
 404 }
 405
 406 # get canonical version of email for comparison
 407 function common_canonical_email($email) {
 408         # XXX: canonicalize UTF-8
 409         # XXX: lcase the domain part
 410         return $email;
 411 }
 412
 413 define('URL_REGEX', '^|[ \t\r\n])((ftp|http|https|gopher|mailto|news|nntp|telnet|wais|file|prospero|aim|webcal):(([A-Za-z0-9$_.+!*(),;/?:@&~=-])|%[A-Fa-f0-9]{2}){2,}(#([a-zA-Z0-9][a-zA-Z0-9$_.+!*(),;/?:@&~=%-]*))?([A-Za-z0-9$_+!*();/?:~-]))');
 414
 415 function common_render_content($text, $notice) {
 416         $r = htmlspecialchars($text);
 417         $id = $notice->profile_id;
 418         $r = preg_replace('@https?://\S+@', '<a href="\0" class="extlink">\0</a>', $r);
 419         $r = preg_replace('/(^|\b)@([\w-]+)($|\b)/e', "'\\1@'.common_at_link($id, '\\2').'\\3'", $r);
 420         # XXX: # tags
 421         # XXX: machine tags
 422         return $r;
 423 }
 424
 425 function common_at_link($sender_id, $nickname) {
 426         # Try to find profiles this profile is subscribed to that have this nickname
 427         $recipient = new Profile();
 428         # XXX: chokety and bad
 429         $recipient->whereAdd('EXISTS (SELECT subscribed from subscription where subscriber = '.$sender_id.' and subscribed = id)', 'AND');
 430         $recipient->whereAdd('nickname = "' . trim($nickname) . '"', 'AND');
 431         if ($recipient->find(TRUE)) {
 432                 return '<a href="'.htmlspecialchars($recipient->profileurl).'" class="atlink tolistenee">'.$nickname.'</a>';
 433         }
 434         # Try to find profiles that listen to this profile and that have this nickname
 435         $recipient = new Profile();
 436         # XXX: chokety and bad
 437         $recipient->whereAdd('EXISTS (SELECT subscriber from subscription where subscribed = '.$sender_id.' and subscriber = id)', 'AND');
 438         $recipient->whereAdd('nickname = "' . trim($nickname) . '"', 'AND');
 439         if ($recipient->find(TRUE)) {
 440                 return '<a href="'.htmlspecialchars($recipient->profileurl).'" class="atlink tolistener">'.$nickname.'</a>';
 441         }
 442         # If this is a local user, try to find a local user with that nickname.
 443         $sender = User::staticGet($sender_id);
 444         if ($sender) {
 445                 $recipient_user = User::staticGet('nickname', $nickname);
 446                 if ($recipient_user) {
 447                         $recipient = $recipient->getProfile();
 448                         return '<a href="'.htmlspecialchars($recipient->profileurl).'" class="atlink usertouser">'.$nickname.'</a>';
 449                 }
 450         }
 451         # Otherwise, no links. @messages from local users to remote users,
 452         # or from remote users to other remote users, are just
 453         # outside our ability to make intelligent guesses about
 454         return $nickname;
 455 }
 456
 457 // where should the avatar go for this user?
 458
 459 function common_avatar_filename($id, $extension, $size=NULL, $extra=NULL) {
 460         global $config;
 461
 462         if ($size) {
 463                 return $id . '-' . $size . (($extra) ? ('-' . $extra) : '') . $extension;
 464         } else {
 465                 return $id . '-original' . (($extra) ? ('-' . $extra) : '') . $extension;
 466         }
 467 }
 468
 469 function common_avatar_path($filename) {
 470         global $config;
 471         return INSTALLDIR . '/avatar/' . $filename;
 472 }
 473
 474 function common_avatar_url($filename) {
 475         return common_path('avatar/'.$filename);
 476 }
 477
 478 function common_default_avatar($size) {
 479         static $sizenames = array(AVATAR_PROFILE_SIZE => 'profile',
 480                                                           AVATAR_STREAM_SIZE => 'stream',
 481                                                           AVATAR_MINI_SIZE => 'mini');
 482         return theme_path('default-avatar-'.$sizenames[$size].'.png');
 483 }
 484
 485 function common_local_url($action, $args=NULL) {
 486         global $config;
 487         if ($config['site']['fancy']) {
 488                 return common_fancy_url($action, $args);
 489         } else {
 490                 return common_simple_url($action, $args);
 491         }
 492 }
 493
 494 function common_fancy_url($action, $args=NULL) {
 495         switch (strtolower($action)) {
 496          case 'public':
 497                 return common_path('');
 498          case 'publicrss':
 499                 return common_path('rss');
 500          case 'doc':
 501                 return common_path('doc/'.$args['title']);
 502          case 'login':
 503          case 'logout':
 504          case 'register':
 505          case 'subscribe':
 506          case 'unsubscribe':
 507                 return common_path('main/'.$action);
 508          case 'avatar':
 509          case 'password':
 510                 return common_path('settings/'.$action);
 511          case 'profilesettings':
 512                 return common_path('settings/profile');
 513          case 'newnotice':
 514                 return common_path('notice/new');
 515          case 'shownotice':
 516                 return common_path('notice/'.$args['notice']);
 517          case 'subscriptions':
 518          case 'subscribed':
 519          case 'xrds':
 520          case 'all':
 521          case 'foaf':
 522                 return common_path($args['nickname'].'/'.$action);
 523          case 'allrss':
 524                 return common_path($args['nickname'].'/all/rss');
 525          case 'userrss':
 526                 return common_path($args['nickname'].'/rss');
 527          case 'showstream':
 528                 return common_path($args['nickname']);
 529          default:
 530                 return common_simple_url($action, $args);
 531         }
 532 }
 533
 534 function common_simple_url($action, $args=NULL) {
 535         global $config;
 536         /* XXX: pretty URLs */
 537         $extra = '';
 538         if ($args) {
 539                 foreach ($args as $key => $value) {
 540                         $extra .= "&${key}=${value}";
 541                 }
 542         }
 543         return common_path("index.php?action=${action}${extra}");
 544 }
 545
 546 function common_path($relative) {
 547         global $config;
 548         $pathpart = ($config['site']['path']) ? $config['site']['path']."/" : '';
 549         return "http://".$config['site']['server'].'/'.$pathpart.$relative;
 550 }
 551
 552 function common_date_string($dt) {
 553         // XXX: do some sexy date formatting
 554         // return date(DATE_RFC822, $dt);
 555         return $dt;
 556 }
 557
 558 function common_date_w3dtf($dt) {
 559         $t = strtotime($dt);
 560         return date(DATE_W3C, $t);
 561 }
 562
 563 function common_redirect($url, $code=307) {
 564         static $status = array(301 => "Moved Permanently",
 565                                                    302 => "Found",
 566                                                    303 => "See Other",
 567                                                    307 => "Temporary Redirect");
 568         header("Status: ${code} $status[$code]");
 569         header("Location: $url");
 570         common_element('a', array('href' => $url), $url);
 571 }
 572
 573 function common_broadcast_notice($notice, $remote=false) {
 574         // XXX: optionally use a queue system like http://code.google.com/p/microapps/wiki/NQDQ
 575         if (!$remote) {
 576                 # Make sure we have the OMB stuff
 577                 require_once(INSTALLDIR.'/lib/omb.php');
 578                 omb_broadcast_remote_subscribers($notice);
 579         }
 580         // XXX: broadcast notices to Jabber
 581         // XXX: broadcast notices to SMS
 582         // XXX: broadcast notices to other IM
 583         return true;
 584 }
 585
 586 function common_broadcast_profile($profile) {
 587         // XXX: optionally use a queue system like http://code.google.com/p/microapps/wiki/NQDQ
 588         require_once(INSTALLDIR.'/lib/omb.php');
 589         omb_broadcast_profile($profile);
 590         // XXX: Other broadcasts...?
 591         return true;
 592 }
 593
 594 function common_profile_url($nickname) {
 595         return common_local_url('showstream', array('nickname' => $nickname));
 596 }
 597
 598 # Don't call if nobody's logged in
 599
 600 function common_notice_form() {
 601         $user = common_current_user();
 602         assert(!is_null($user));
 603         common_element_start('form', array('id' => 'status_form',
 604                                                                            'method' => 'POST',
 605                                                                            'action' => common_local_url('newnotice')));
 606         common_element_start('p');
 607         common_element('label', array('for' => 'status_update',
 608                                                                   'id' => 'status_label'),
 609                                    _t('What\'s up, ').$user->nickname.'?');
 610         common_element('textarea', array('id' => 'status_textarea',
 611                                                                          'name' => 'status_textarea'));
 612         common_element('input', array('id' => 'status_submit',
 613                                                                   'name' => 'status_submit',
 614                                                                   'type' => 'submit',
 615                                                                   'value' => _t('Send')));
 616         common_element_end('p');
 617         common_element_end('form');
 618 }
 619
 620 function common_mint_tag($extra) {
 621         global $config;
 622         return
 623           'tag:'.$config['tag']['authority'].','.
 624           $config['tag']['date'].':'.$config['tag']['prefix'].$extra;
 625 }
 626
 627 # Should make up a reasonable root URL
 628
 629 function common_root_url() {
 630         return common_path('');
 631 }
 632
 633 # returns $bytes bytes of random data as a hexadecimal string
 634 # "good" here is a goal and not a guarantee
 635
 636 function common_good_rand($bytes) {
 637         # XXX: use random.org...?
 638         if (file_exists('/dev/urandom')) {
 639                 return common_urandom($bytes);
 640         } else { # FIXME: this is probably not good enough
 641                 return common_mtrand($bytes);
 642         }
 643 }
 644
 645 function common_urandom($bytes) {
 646         $h = fopen('/dev/urandom', 'rb');
 647         # should not block
 648         $src = fread($h, $bytes);
 649         fclose($h);
 650         $enc = '';
 651         for ($i = 0; $i < $bytes; $i++) {
 652                 $enc .= sprintf("%02x", (ord($src[$i])));
 653         }
 654         return $enc;
 655 }
 656
 657 function common_mtrand($bytes) {
 658         $enc = '';
 659         for ($i = 0; $i < $bytes; $i++) {
 660                 $enc .= sprintf("%02x", mt_rand(0, 255));
 661         }
 662         return $enc;
 663 }
 664
 665 function common_set_returnto($url) {
 666         common_ensure_session();
 667         $_SESSION['returnto'] = $url;
 668 }
 669
 670 function common_get_returnto() {
 671         common_ensure_session();
 672         return $_SESSION['returnto'];
 673 }
 674
 675 function common_timestamp() {
 676         return date('YmdHis');
 677 }
 678
 679 // XXX: set up gettext
 680
 681 function _t($str) {
 682         return $str;
 683 }
 684
 685 function common_ensure_syslog() {
 686         static $initialized = false;
 687         if (!$initialized) {
 688                 global $config;
 689                 define_syslog_variables();
 690                 openlog($config['syslog']['appname'], 0, LOG_USER);
 691                 $initialized = true;
 692         }
 693 }
 694
 695 function common_log($priority, $msg, $filename=NULL) {
 696         common_ensure_syslog();
 697         syslog($priority, $msg);
 698 }
 699
 700 function common_debug($msg, $filename=NULL) {
 701         if ($filename) {
 702                 common_log(LOG_DEBUG, basename($filename).' - '.$msg);
 703         } else {
 704                 common_log(LOG_DEBUG, $msg);
 705         }
 706 }
 707
 708 function common_valid_http_url($url) {
 709         return Validate::uri($url, array('allowed_schemes' => array('http', 'https')));
 710 }
 711
 712 function common_valid_tag($tag) {
 713         if (preg_match('/^tag:(.*?),(\d{4}(-\d{2}(-\d{2})?)?):(.*)$/', $tag, $matches)) {
 714                 return (Validate::email($matches[1]) ||
 715                                 preg_match('/^([\w-\.]+)$/', $matches[1]));
 716         }
 717         return false;
 718 }
 719
 720 # Does a little before-after block for next/prev page
 721
 722 function common_pagination($have_before, $have_after, $page, $action, $args=NULL) {
 723
 724         if ($have_before || $have_after) {
 725                 common_element_start('div', array('id' => 'pagination'));
 726                 common_element_start('ul', array('id' => 'nav_pagination'));
 727         }
 728
 729         if ($have_before) {
 730                 $pargs = array('page' => $page-1);
 731                 $newargs = ($args) ? array_merge($args,$pargs) : $pargs;
 732
 733                 common_element_start('li', 'before');
 734                 common_element('a', array('href' => common_local_url($action, $newargs)),
 735                                            _t('« Before'));
 736                 common_element_end('li');
 737         }
 738
 739         if ($have_after) {
 740                 $pargs = array('page' => $page+1);
 741                 $newargs = ($args) ? array_merge($args,$pargs) : $pargs;
 742                 common_element_start('li', 'after');
 743                 common_element('a', array('href' => common_local_url($action, $newargs)),
 744                                                    _t('After »'));
 745                 common_element_end('li');
 746         }
 747
 748         if ($have_before || $have_after) {
 749                 common_element_end('ul');
 750                 common_element_end('div');
 751         }
 752 }
 753
 754 /* Following functions are copied from MediaWiki GlobalFunctions.php
 755  * and written by Evan Prodromou. */
 756
 757 function common_accept_to_prefs($accept, $def = '*/*') {
 758         # No arg means accept anything (per HTTP spec)
 759         if(!$accept) {
 760                 return array($def => 1);
 761         }
 762
 763         $prefs = array();
 764
 765         $parts = explode(',', $accept);
 766
 767         foreach($parts as $part) {
 768                 # FIXME: doesn't deal with params like 'text/html; level=1'
 769                 @list($value, $qpart) = explode(';', $part);
 770                 $match = array();
 771                 if(!isset($qpart)) {
 772                         $prefs[$value] = 1;
 773                 } elseif(preg_match('/q\s*=\s*(\d*\.\d+)/', $qpart, $match)) {
 774                         $prefs[$value] = $match[1];
 775                 }
 776         }
 777
 778         return $prefs;
 779 }
 780
 781 function common_mime_type_match($type, $avail) {
 782         if(array_key_exists($type, $avail)) {
 783                 return $type;
 784         } else {
 785                 $parts = explode('/', $type);
 786                 if(array_key_exists($parts[0] . '/*', $avail)) {
 787                         return $parts[0] . '/*';
 788                 } elseif(array_key_exists('*/*', $avail)) {
 789                         return '*/*';
 790                 } else {
 791                         return NULL;
 792                 }
 793         }
 794 }
 795
 796 function common_negotiate_type($cprefs, $sprefs) {
 797         $combine = array();
 798
 799         foreach(array_keys($sprefs) as $type) {
 800                 $parts = explode('/', $type);
 801                 if($parts[1] != '*') {
 802                         $ckey = common_mime_type_match($type, $cprefs);
 803                         if($ckey) {
 804                                 $combine[$type] = $sprefs[$type] * $cprefs[$ckey];
 805                         }
 806                 }
 807         }
 808
 809         foreach(array_keys($cprefs) as $type) {
 810                 $parts = explode('/', $type);
 811                 if($parts[1] != '*' && !array_key_exists($type, $sprefs)) {
 812                         $skey = common_mime_type_match($type, $sprefs);
 813                         if($skey) {
 814                                 $combine[$type] = $sprefs[$skey] * $cprefs[$type];
 815                         }
 816                 }
 817         }
 818
 819         $bestq = 0;
 820         $besttype = NULL;
 821
 822         foreach(array_keys($combine) as $type) {
 823                 if($combine[$type] > $bestq) {
 824                         $besttype = $type;
 825                         $bestq = $combine[$type];
 826                 }
 827         }
 828
 829         return $besttype;
 830 }