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'.$ver.'.css').' /><![endif]');
 167                 }
 168         }
 169
 170         common_element('script', array('type' => 'text/javascript',
 171                                                                    'src' => common_path('js/jquery.min.js')),
 172                                    ' ');
 173
 174         if ($callable) {
 175                 if ($data) {
 176                         call_user_func($callable, $data);
 177                 } else {
 178                         call_user_func($callable);
 179                 }
 180         }
 181         common_element_end('head');
 182         common_element_start('body');
 183         common_element_start('div', array('id' => 'wrap'));
 184         common_element_start('div', array('id' => 'header'));
 185         common_nav_menu();
 186         if ((is_string($config['site']['logo']) && (strlen($config['site']['logo']) > 0))
 187                 || file_exists(theme_file('logo.png')))
 188         {
 189                 common_element_start('a', array('href' => common_local_url('public')));
 190                 common_element('img', array('src' => ($config['site']['logo']) ?
 191                                                                         ($config['site']['logo']) : theme_path('logo.png'),
 192                                                                         'alt' => $config['site']['name'],
 193                                                                         'id' => 'logo'));
 194                 common_element_end('a');
 195         } else {
 196                 common_element('p', array('id' => 'branding'), $config['site']['name']);
 197         }
 198
 199         common_element('h1', 'pagetitle', $pagetitle);
 200
 201         if ($headercall) {
 202                 if ($data) {
 203                         call_user_func($headercall, $data);
 204                 } else {
 205                         call_user_func($headercall);
 206                 }
 207         }
 208         common_element_end('div');
 209         common_element_start('div', array('id' => 'content'));
 210 }
 211
 212 function common_show_footer() {
 213         global $xw, $config;
 214         common_element_end('div'); # content div
 215         common_foot_menu();
 216         common_element_start('div', array('id' => 'footer'));
 217         common_element_start('p', 'laconica');
 218         common_text(_t('This site is running the '));
 219         common_element('a', array('class' => 'software',
 220                                                           href => 'http://laconi.ca/'),
 221                                    'Laconica');
 222         common_text(_t('microblogging tool, version ' . LACONICA_VERSION . ', available under the '));
 223         common_element('a', array(href => 'http://www.fsf.org/licensing/licenses/agpl-3.0.html'),
 224                                    'GNU Affero General Public License');
 225         common_text(_t('.'));
 226         common_element_end('p');
 227         common_element('img', array('id' => 'cc',
 228                                                                 'src' => $config['license']['image'],
 229                                                                 'alt' => $config['license']['title']));
 230         common_element_start('p');
 231         common_text(_t('Unless otherwise specified, contents of this site are copyright by the contributors and available under the '));
 232         common_element('a', array('class' => 'license',
 233                                                           'rel' => 'license',
 234                                                           href => $config['license']['url']),
 235                                    $config['license']['title']);
 236         common_text(_t('. Contributors should be attributed by full name or nickname.'));
 237         common_element_end('p');
 238         common_element_end('div');
 239         common_element_end('div');
 240         common_element_end('body');
 241         common_element_end('html');
 242         common_end_xml();
 243 }
 244
 245 function common_text($txt) {
 246         global $xw;
 247         $xw->text($txt);
 248 }
 249
 250 function common_raw($xml) {
 251         global $xw;
 252         $xw->writeRaw($xml);
 253 }
 254
 255 function common_nav_menu() {
 256         $user = common_current_user();
 257         common_element_start('ul', array('id' => 'nav'));
 258         if ($user) {
 259                 common_menu_item(common_local_url('all', array('nickname' => $user->nickname)),
 260                                                  _t('Home'));
 261         }
 262         common_menu_item(common_local_url('public'), _t('Public'));
 263         common_menu_item(common_local_url('doc', array('title' => 'help')),
 264                                          _t('Help'));
 265         if ($user) {
 266                 common_menu_item(common_local_url('profilesettings'),
 267                                                  _t('Settings'));
 268                 common_menu_item(common_local_url('logout'),
 269                                                  _t('Logout'));
 270         } else {
 271                 common_menu_item(common_local_url('login'), _t('Login'));
 272                 common_menu_item(common_local_url('register'), _t('Register'));
 273                 common_menu_item(common_local_url('openidlogin'), _t('OpenID'));
 274         }
 275         common_element_end('ul');
 276 }
 277
 278 function common_foot_menu() {
 279         common_element_start('ul', array('id' => 'nav_sub'));
 280         common_menu_item(common_local_url('doc', array('title' => 'about')),
 281                                          _t('About'));
 282         common_menu_item(common_local_url('doc', array('title' => 'privacy')),
 283                                          _t('Privacy'));
 284         common_menu_item(common_local_url('doc', array('title' => 'source')),
 285                                          _t('Source'));
 286         common_element_end('ul');
 287 }
 288
 289 function common_menu_item($url, $text, $title=NULL, $is_selected=false) {
 290         $lattrs = array();
 291         if ($is_selected) {
 292                 $lattrs['class'] = 'current';
 293         }
 294         common_element_start('li', $lattrs);
 295         $attrs['href'] = $url;
 296         if ($title) {
 297                 $attrs['title'] = $title;
 298         }
 299         common_element('a', $attrs, $text);
 300         common_element_end('li');
 301 }
 302
 303 function common_input($id, $label, $value=NULL,$instructions=NULL) {
 304         common_element_start('p');
 305         common_element('label', array('for' => $id), $label);
 306         $attrs = array('name' => $id,
 307                                    'type' => 'text',
 308                                    'id' => $id);
 309         if ($value) {
 310                 $attrs['value'] = htmlspecialchars($value);
 311         }
 312         common_element('input', $attrs);
 313         if ($instructions) {
 314                 common_element('span', 'input_instructions', $instructions);
 315         }
 316         common_element_end('p');
 317 }
 318
 319 function common_hidden($id, $value) {
 320         common_element('input', array('name' => $id,
 321                                                                   'type' => 'hidden',
 322                                                                   'id' => $id,
 323                                                                   'value' => $value));
 324 }
 325
 326 function common_password($id, $label, $instructions=NULL) {
 327         common_element_start('p');
 328         common_element('label', array('for' => $id), $label);
 329         $attrs = array('name' => $id,
 330                                    'type' => 'password',
 331                                    'id' => $id);
 332         common_element('input', $attrs);
 333         if ($instructions) {
 334                 common_element('span', 'input_instructions', $instructions);
 335         }
 336         common_element_end('p');
 337 }
 338
 339 function common_submit($id, $label) {
 340         global $xw;
 341         common_element_start('p');
 342         common_element('input', array('type' => 'submit',
 343                                                                   'id' => $id,
 344                                                                   'name' => $id,
 345                                                                   'class' => 'submit',
 346                                                                   'value' => $label));
 347         common_element_end('p');
 348 }
 349
 350 function common_textarea($id, $label, $content=NULL, $instructions=NULL) {
 351         common_element_start('p');
 352         common_element('label', array('for' => $id), $label);
 353         common_element('textarea', array('rows' => 3,
 354                                                                          'cols' => 40,
 355                                                                          'name' => $id,
 356                                                                          'id' => $id),
 357                                    ($content) ? $content : ' ');
 358         if ($instructions) {
 359                 common_element('span', 'input_instructions', $instructions);
 360         }
 361         common_element_end('p');
 362 }
 363
 364 # salted, hashed passwords are stored in the DB
 365
 366 function common_munge_password($id, $password) {
 367         return md5($id . $password);
 368 }
 369
 370 # check if a username exists and has matching password
 371 function common_check_user($nickname, $password) {
 372         $user = User::staticGet('nickname', $nickname);
 373         if (is_null($user)) {
 374                 return false;
 375         } else {
 376                 return (0 == strcmp(common_munge_password($password, $user->id),
 377                                                         $user->password));
 378         }
 379 }
 380
 381 # is the current user logged in?
 382 function common_logged_in() {
 383         return (!is_null(common_current_user()));
 384 }
 385
 386 function common_have_session() {
 387         return (0 != strcmp(session_id(), ''));
 388 }
 389
 390 function common_ensure_session() {
 391         if (!common_have_session()) {
 392                 @session_start();
 393         }
 394 }
 395
 396 function common_set_user($nickname) {
 397         if (is_null($nickname) && common_have_session()) {
 398                 unset($_SESSION['userid']);
 399                 return true;
 400         } else {
 401                 $user = User::staticGet('nickname', $nickname);
 402                 if ($user) {
 403                         common_ensure_session();
 404                         $_SESSION['userid'] = $user->id;
 405                         return true;
 406                 } else {
 407                         return false;
 408                 }
 409         }
 410         return false;
 411 }
 412
 413 # who is the current user?
 414 function common_current_user() {
 415         static $user = NULL; # FIXME: global memcached
 416         if (is_null($user)) {
 417                 common_ensure_session();
 418                 $id = $_SESSION['userid'];
 419                 if ($id) {
 420                         $user = User::staticGet($id);
 421                 }
 422         }
 423         return $user;
 424 }
 425
 426 # get canonical version of nickname for comparison
 427 function common_canonical_nickname($nickname) {
 428         # XXX: UTF-8 canonicalization (like combining chars)
 429         return strtolower($nickname);
 430 }
 431
 432 # get canonical version of email for comparison
 433 function common_canonical_email($email) {
 434         # XXX: canonicalize UTF-8
 435         # XXX: lcase the domain part
 436         return $email;
 437 }
 438
 439 define('URL_REGEX', '^|[ \t\r\n])((ftp|http|https|gopher|mailto|news|nntp|telnet|wais|file|prospero|aim|webcal):(([A-Za-z0-9$_.+!*(),;/?:@&~=-])|%[A-Fa-f0-9]{2}){2,}(#([a-zA-Z0-9][a-zA-Z0-9$_.+!*(),;/?:@&~=%-]*))?([A-Za-z0-9$_+!*();/?:~-]))');
 440
 441 function common_render_content($text, $notice) {
 442         $r = htmlspecialchars($text);
 443         $id = $notice->profile_id;
 444         $r = preg_replace('@https?://\S+@', '<a href="\0" class="extlink">\0</a>', $r);
 445         $r = preg_replace('/(^|\b)@([\w-]+)($|\b)/e', "'\\1@'.common_at_link($id, '\\2').'\\3'", $r);
 446         # XXX: # tags
 447         # XXX: machine tags
 448         return $r;
 449 }
 450
 451 function common_at_link($sender_id, $nickname) {
 452         # Try to find profiles this profile is subscribed to that have this nickname
 453         $recipient = new Profile();
 454         # XXX: chokety and bad
 455         $recipient->whereAdd('EXISTS (SELECT subscribed from subscription where subscriber = '.$sender_id.' and subscribed = id)', 'AND');
 456         $recipient->whereAdd('nickname = "' . trim($nickname) . '"', 'AND');
 457         if ($recipient->find(TRUE)) {
 458                 return '<a href="'.htmlspecialchars($recipient->profileurl).'" class="atlink tolistenee">'.$nickname.'</a>';
 459         }
 460         # Try to find profiles that listen to this profile and that have this nickname
 461         $recipient = new Profile();
 462         # XXX: chokety and bad
 463         $recipient->whereAdd('EXISTS (SELECT subscriber from subscription where subscribed = '.$sender_id.' and subscriber = id)', 'AND');
 464         $recipient->whereAdd('nickname = "' . trim($nickname) . '"', 'AND');
 465         if ($recipient->find(TRUE)) {
 466                 return '<a href="'.htmlspecialchars($recipient->profileurl).'" class="atlink tolistener">'.$nickname.'</a>';
 467         }
 468         # If this is a local user, try to find a local user with that nickname.
 469         $sender = User::staticGet($sender_id);
 470         if ($sender) {
 471                 $recipient_user = User::staticGet('nickname', $nickname);
 472                 if ($recipient_user) {
 473                         $recipient = $recipient->getProfile();
 474                         return '<a href="'.htmlspecialchars($recipient->profileurl).'" class="atlink usertouser">'.$nickname.'</a>';
 475                 }
 476         }
 477         # Otherwise, no links. @messages from local users to remote users,
 478         # or from remote users to other remote users, are just
 479         # outside our ability to make intelligent guesses about
 480         return $nickname;
 481 }
 482
 483 // where should the avatar go for this user?
 484
 485 function common_avatar_filename($id, $extension, $size=NULL, $extra=NULL) {
 486         global $config;
 487
 488         if ($size) {
 489                 return $id . '-' . $size . (($extra) ? ('-' . $extra) : '') . $extension;
 490         } else {
 491                 return $id . '-original' . (($extra) ? ('-' . $extra) : '') . $extension;
 492         }
 493 }
 494
 495 function common_avatar_path($filename) {
 496         global $config;
 497         return INSTALLDIR . '/avatar/' . $filename;
 498 }
 499
 500 function common_avatar_url($filename) {
 501         return common_path('avatar/'.$filename);
 502 }
 503
 504 function common_default_avatar($size) {
 505         static $sizenames = array(AVATAR_PROFILE_SIZE => 'profile',
 506                                                           AVATAR_STREAM_SIZE => 'stream',
 507                                                           AVATAR_MINI_SIZE => 'mini');
 508         return theme_path('default-avatar-'.$sizenames[$size].'.png');
 509 }
 510
 511 function common_local_url($action, $args=NULL) {
 512         global $config;
 513         if ($config['site']['fancy']) {
 514                 return common_fancy_url($action, $args);
 515         } else {
 516                 return common_simple_url($action, $args);
 517         }
 518 }
 519
 520 function common_fancy_url($action, $args=NULL) {
 521         switch (strtolower($action)) {
 522          case 'public':
 523                 if ($args && $args['page']) {
 524                         return common_path('?page=' . $args['page']);
 525                 } else {
 526                         return common_path('');
 527                 }
 528          case 'publicrss':
 529                 return common_path('rss');
 530          case 'doc':
 531                 return common_path('doc/'.$args['title']);
 532          case 'login':
 533          case 'logout':
 534          case 'register':
 535          case 'subscribe':
 536          case 'unsubscribe':
 537                 return common_path('main/'.$action);
 538          case 'openidlogin':
 539                 return common_path('main/openid');
 540          case 'avatar':
 541          case 'password':
 542                 return common_path('settings/'.$action);
 543          case 'profilesettings':
 544                 return common_path('settings/profile');
 545          case 'openidsettings':
 546                 return common_path('settings/openid');
 547          case 'newnotice':
 548                 return common_path('notice/new');
 549          case 'shownotice':
 550                 return common_path('notice/'.$args['notice']);
 551          case 'xrds':
 552          case 'foaf':
 553                 return common_path($args['nickname'].'/'.$action);
 554          case 'subscriptions':
 555          case 'subscribed':
 556          case 'all':
 557                 if ($args && $args['page']) {
 558                         return common_path($args['nickname'].'/'.$action.'?page=' . $args['page']);
 559                 } else {
 560                         return common_path($args['nickname'].'/'.$action);
 561                 }
 562          case 'allrss':
 563                 return common_path($args['nickname'].'/all/rss');
 564          case 'userrss':
 565                 return common_path($args['nickname'].'/rss');
 566          case 'showstream':
 567                 if ($args && $args['page']) {
 568                         return common_path($args['nickname'].'?page=' . $args['page']);
 569                 } else {
 570                         return common_path($args['nickname']);
 571                 }
 572          default:
 573                 return common_simple_url($action, $args);
 574         }
 575 }
 576
 577 function common_simple_url($action, $args=NULL) {
 578         global $config;
 579         /* XXX: pretty URLs */
 580         $extra = '';
 581         if ($args) {
 582                 foreach ($args as $key => $value) {
 583                         $extra .= "&${key}=${value}";
 584                 }
 585         }
 586         return common_path("index.php?action=${action}${extra}");
 587 }
 588
 589 function common_path($relative) {
 590         global $config;
 591         $pathpart = ($config['site']['path']) ? $config['site']['path']."/" : '';
 592         return "http://".$config['site']['server'].'/'.$pathpart.$relative;
 593 }
 594
 595 function common_date_string($dt) {
 596         // XXX: do some sexy date formatting
 597         // return date(DATE_RFC822, $dt);
 598         return $dt;
 599 }
 600
 601 function common_date_w3dtf($dt) {
 602         $t = strtotime($dt);
 603         return date(DATE_W3C, $t);
 604 }
 605
 606 function common_redirect($url, $code=307) {
 607         static $status = array(301 => "Moved Permanently",
 608                                                    302 => "Found",
 609                                                    303 => "See Other",
 610                                                    307 => "Temporary Redirect");
 611         header("Status: ${code} $status[$code]");
 612         header("Location: $url");
 613         common_element('a', array('href' => $url), $url);
 614 }
 615
 616 function common_broadcast_notice($notice, $remote=false) {
 617         // XXX: optionally use a queue system like http://code.google.com/p/microapps/wiki/NQDQ
 618         if (!$remote) {
 619                 # Make sure we have the OMB stuff
 620                 require_once(INSTALLDIR.'/lib/omb.php');
 621                 omb_broadcast_remote_subscribers($notice);
 622         }
 623         // XXX: broadcast notices to Jabber
 624         // XXX: broadcast notices to SMS
 625         // XXX: broadcast notices to other IM
 626         return true;
 627 }
 628
 629 function common_broadcast_profile($profile) {
 630         // XXX: optionally use a queue system like http://code.google.com/p/microapps/wiki/NQDQ
 631         require_once(INSTALLDIR.'/lib/omb.php');
 632         omb_broadcast_profile($profile);
 633         // XXX: Other broadcasts...?
 634         return true;
 635 }
 636
 637 function common_profile_url($nickname) {
 638         return common_local_url('showstream', array('nickname' => $nickname));
 639 }
 640
 641 # Don't call if nobody's logged in
 642
 643 function common_notice_form() {
 644         $user = common_current_user();
 645         assert(!is_null($user));
 646         common_element_start('form', array('id' => 'status_form',
 647                                                                            'method' => 'POST',
 648                                                                            'action' => common_local_url('newnotice')));
 649         common_element_start('p');
 650         common_element('label', array('for' => 'status_update',
 651                                                                   'id' => 'status_label'),
 652                                    _t('What\'s up, ').$user->nickname.'?');
 653         common_element('textarea', array('id' => 'status_textarea',
 654                                                                          'name' => 'status_textarea'),
 655                                    ' ');
 656         common_element('input', array('id' => 'status_submit',
 657                                                                   'name' => 'status_submit',
 658                                                                   'type' => 'submit',
 659                                                                   'value' => _t('Send')));
 660         common_element_end('p');
 661         common_element_end('form');
 662 }
 663
 664 function common_mint_tag($extra) {
 665         global $config;
 666         return
 667           'tag:'.$config['tag']['authority'].','.
 668           $config['tag']['date'].':'.$config['tag']['prefix'].$extra;
 669 }
 670
 671 # Should make up a reasonable root URL
 672
 673 function common_root_url() {
 674         return common_path('');
 675 }
 676
 677 # returns $bytes bytes of random data as a hexadecimal string
 678 # "good" here is a goal and not a guarantee
 679
 680 function common_good_rand($bytes) {
 681         # XXX: use random.org...?
 682         if (file_exists('/dev/urandom')) {
 683                 return common_urandom($bytes);
 684         } else { # FIXME: this is probably not good enough
 685                 return common_mtrand($bytes);
 686         }
 687 }
 688
 689 function common_urandom($bytes) {
 690         $h = fopen('/dev/urandom', 'rb');
 691         # should not block
 692         $src = fread($h, $bytes);
 693         fclose($h);
 694         $enc = '';
 695         for ($i = 0; $i < $bytes; $i++) {
 696                 $enc .= sprintf("%02x", (ord($src[$i])));
 697         }
 698         return $enc;
 699 }
 700
 701 function common_mtrand($bytes) {
 702         $enc = '';
 703         for ($i = 0; $i < $bytes; $i++) {
 704                 $enc .= sprintf("%02x", mt_rand(0, 255));
 705         }
 706         return $enc;
 707 }
 708
 709 function common_set_returnto($url) {
 710         common_ensure_session();
 711         $_SESSION['returnto'] = $url;
 712 }
 713
 714 function common_get_returnto() {
 715         common_ensure_session();
 716         return $_SESSION['returnto'];
 717 }
 718
 719 function common_timestamp() {
 720         return date('YmdHis');
 721 }
 722
 723 // XXX: set up gettext
 724
 725 function _t($str) {
 726         return $str;
 727 }
 728
 729 function common_ensure_syslog() {
 730         static $initialized = false;
 731         if (!$initialized) {
 732                 global $config;
 733                 define_syslog_variables();
 734                 openlog($config['syslog']['appname'], 0, LOG_USER);
 735                 $initialized = true;
 736         }
 737 }
 738
 739 function common_log($priority, $msg, $filename=NULL) {
 740         common_ensure_syslog();
 741         syslog($priority, $msg);
 742 }
 743
 744 function common_debug($msg, $filename=NULL) {
 745         if ($filename) {
 746                 common_log(LOG_DEBUG, basename($filename).' - '.$msg);
 747         } else {
 748                 common_log(LOG_DEBUG, $msg);
 749         }
 750 }
 751
 752 function common_valid_http_url($url) {
 753         return Validate::uri($url, array('allowed_schemes' => array('http', 'https')));
 754 }
 755
 756 function common_valid_tag($tag) {
 757         if (preg_match('/^tag:(.*?),(\d{4}(-\d{2}(-\d{2})?)?):(.*)$/', $tag, $matches)) {
 758                 return (Validate::email($matches[1]) ||
 759                                 preg_match('/^([\w-\.]+)$/', $matches[1]));
 760         }
 761         return false;
 762 }
 763
 764 # Does a little before-after block for next/prev page
 765
 766 function common_pagination($have_before, $have_after, $page, $action, $args=NULL) {
 767
 768         if ($have_before || $have_after) {
 769                 common_element_start('div', array('id' => 'pagination'));
 770                 common_element_start('ul', array('id' => 'nav_pagination'));
 771         }
 772
 773         if ($have_before) {
 774                 $pargs = array('page' => $page-1);
 775                 $newargs = ($args) ? array_merge($args,$pargs) : $pargs;
 776
 777                 common_element_start('li', 'before');
 778                 common_element('a', array('href' => common_local_url($action, $newargs)),
 779                                            _t('« After'));
 780                 common_element_end('li');
 781         }
 782
 783         if ($have_after) {
 784                 $pargs = array('page' => $page+1);
 785                 $newargs = ($args) ? array_merge($args,$pargs) : $pargs;
 786                 common_element_start('li', 'after');
 787                 common_element('a', array('href' => common_local_url($action, $newargs)),
 788                                                    _t('Before »'));
 789                 common_element_end('li');
 790         }
 791
 792         if ($have_before || $have_after) {
 793                 common_element_end('ul');
 794                 common_element_end('div');
 795         }
 796 }
 797
 798 /* Following functions are copied from MediaWiki GlobalFunctions.php
 799  * and written by Evan Prodromou. */
 800
 801 function common_accept_to_prefs($accept, $def = '*/*') {
 802         # No arg means accept anything (per HTTP spec)
 803         if(!$accept) {
 804                 return array($def => 1);
 805         }
 806
 807         $prefs = array();
 808
 809         $parts = explode(',', $accept);
 810
 811         foreach($parts as $part) {
 812                 # FIXME: doesn't deal with params like 'text/html; level=1'
 813                 @list($value, $qpart) = explode(';', $part);
 814                 $match = array();
 815                 if(!isset($qpart)) {
 816                         $prefs[$value] = 1;
 817                 } elseif(preg_match('/q\s*=\s*(\d*\.\d+)/', $qpart, $match)) {
 818                         $prefs[$value] = $match[1];
 819                 }
 820         }
 821
 822         return $prefs;
 823 }
 824
 825 function common_mime_type_match($type, $avail) {
 826         if(array_key_exists($type, $avail)) {
 827                 return $type;
 828         } else {
 829                 $parts = explode('/', $type);
 830                 if(array_key_exists($parts[0] . '/*', $avail)) {
 831                         return $parts[0] . '/*';
 832                 } elseif(array_key_exists('*/*', $avail)) {
 833                         return '*/*';
 834                 } else {
 835                         return NULL;
 836                 }
 837         }
 838 }
 839
 840 function common_negotiate_type($cprefs, $sprefs) {
 841         $combine = array();
 842
 843         foreach(array_keys($sprefs) as $type) {
 844                 $parts = explode('/', $type);
 845                 if($parts[1] != '*') {
 846                         $ckey = common_mime_type_match($type, $cprefs);
 847                         if($ckey) {
 848                                 $combine[$type] = $sprefs[$type] * $cprefs[$ckey];
 849                         }
 850                 }
 851         }
 852
 853         foreach(array_keys($cprefs) as $type) {
 854                 $parts = explode('/', $type);
 855                 if($parts[1] != '*' && !array_key_exists($type, $sprefs)) {
 856                         $skey = common_mime_type_match($type, $sprefs);
 857                         if($skey) {
 858                                 $combine[$type] = $sprefs[$skey] * $cprefs[$type];
 859                         }
 860                 }
 861         }
 862
 863         $bestq = 0;
 864         $besttype = NULL;
 865
 866         foreach(array_keys($combine) as $type) {
 867                 if($combine[$type] > $bestq) {
 868                         $besttype = $type;
 869                         $bestq = $combine[$type];
 870                 }
 871         }
 872
 873         return $besttype;
 874 }
 875
 876 function common_config($main, $sub) {
 877         global $config;
 878         return $config[$main][$sub];
 879 }