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) {
 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 . " - " . $config['site']['name']);
 144         common_element('link', array('rel' => 'stylesheet',
 145                                                                  'type' => 'text/css',
 146                                                                  'href' => common_path('theme/default/style/html.css'),
 147                                                                  'media' => 'screen, projection, tv'));
 148         common_element('link', array('rel' => 'stylesheet',
 149                                                                  'type' => 'text/css',
 150                                                                  'href' => common_path('theme/default/style/layout.css'),
 151                                                                  'media' => 'screen, projection, tv'));
 152         common_element('link', array('rel' => 'stylesheet',
 153                                                                  'type' => 'text/css',
 154                                                                  'href' => common_path('theme/default/style/print.css'),
 155                                                                  'media' => 'print'));
 156         if ($callable) {
 157                 if ($data) {
 158                         call_user_func($callable, $data);
 159                 } else {
 160                         call_user_func($callable);
 161                 }
 162         }
 163         common_element_end('head');
 164         common_element_start('body');
 165         common_element_start('div', array('id' => 'wrapper'));
 166         common_element_start('div', array('id' => 'content'));
 167         common_element_start('div', array('id' => 'header'));
 168         common_element('h1', 'title', $pagetitle);
 169         common_element('h2', 'subtitle', $config['site']['name']);
 170         common_element_end('div');
 171         common_head_menu();
 172         common_element_start('div', array('id' => 'page'));
 173 }
 174
 175 function common_show_footer() {
 176         global $xw, $config;
 177         common_element_start('div', 'footer');
 178         common_foot_menu();
 179         common_license_block();
 180         common_element_end('div');
 181         common_element_end('div');
 182         common_element_end('div');
 183         common_element_end('div');
 184         common_element_end('body');
 185         common_element_end('html');
 186         common_end_xml();
 187 }
 188
 189 function common_text($txt) {
 190         global $xw;
 191         $xw->text($txt);
 192 }
 193
 194 function common_raw($xml) {
 195         global $xw;
 196         $xw->writeRaw($xml);
 197 }
 198
 199 function common_license_block() {
 200         global $config, $xw;
 201         common_element_start('p', 'license greenBg');
 202         common_element_start('span', 'floatLeft width25');
 203         common_element_start('a', array('class' => 'license',
 204                                                                         'rel' => 'license',
 205                                                                         href => $config['license']['url']));
 206         common_element('img', array('class' => 'license',
 207                                                                 'src' => $config['license']['image'],
 208                                                                 'alt' => $config['license']['title']));
 209         common_element_end('a');
 210         common_element_end('span');
 211         common_element_start('span', 'floatRight width75');
 212         common_text(_t('Unless otherwise specified, contents of this site are copyright by the contributors and available under the '));
 213         common_element('a', array('class' => 'license',
 214                                                           'rel' => 'license',
 215                                                           href => $config['license']['url']),
 216                                    $config['license']['title']);
 217         common_text(_t('. Contributors should be attributed by full name or nickname.'));
 218         common_element_end('span');
 219         common_element_end('p');
 220 }
 221
 222 function common_head_menu() {
 223         $user = common_current_user();
 224         common_element_start('ul', array('id' => 'menu', 'class' => ($user) ? 'five' : 'three'));
 225         common_menu_item(common_local_url('public'), _t('Public'));
 226         if ($user) {
 227                 common_menu_item(common_local_url('all', array('nickname' =>
 228                                                                                                            $user->nickname)),
 229                                                  _t('Home'));
 230                 common_menu_item(common_local_url('showstream', array('nickname' =>
 231                                                                                                                           $user->nickname)),
 232                                                  _t('Profile'),  $user->fullname || $user->nickname);
 233                 common_menu_item(common_local_url('profilesettings'),
 234                                                  _t('Settings'));
 235                 common_menu_item(common_local_url('logout'),
 236                                                  _t('Logout'));
 237         } else {
 238                 common_menu_item(common_local_url('login'),
 239                                                  _t('Login'));
 240                 common_menu_item(common_local_url('register'),
 241                                                  _t('Register'));
 242         }
 243         common_element_end('ul');
 244 }
 245
 246 function common_foot_menu() {
 247         common_element_start('ul', 'footmenu menuish');
 248         common_menu_item(common_local_url('doc', array('title' => 'about')),
 249                                          _t('About'));
 250         common_menu_item(common_local_url('doc', array('title' => 'help')),
 251                                          _t('Help'));
 252         common_menu_item(common_local_url('doc', array('title' => 'privacy')),
 253                                          _t('Privacy'));
 254         common_menu_item(common_local_url('doc', array('title' => 'source')),
 255                                          _t('Source'));
 256         common_element_end('ul');
 257 }
 258
 259 function common_menu_item($url, $text, $title=NULL) {
 260         $attrs['href'] = $url;
 261         if ($title) {
 262                 $attrs['title'] = $title;
 263         }
 264         common_element_start('li', 'menuitem');
 265         common_element('a', $attrs, $text);
 266         common_element_end('li');
 267 }
 268
 269 function common_input($id, $label, $value=NULL) {
 270         common_element_start('p');
 271         common_element('label', array('for' => $id), $label);
 272         $attrs = array('name' => $id,
 273                                    'type' => 'text',
 274                                    'id' => $id);
 275         if ($value) {
 276                 $attrs['value'] = htmlspecialchars($value);
 277         }
 278         common_element('input', $attrs);
 279         common_element_end('p');
 280 }
 281
 282 function common_hidden($id, $value) {
 283         common_element('input', array('name' => $id,
 284                                                                   'type' => 'hidden',
 285                                                                   'id' => $id,
 286                                                                   'value' => $value));
 287 }
 288
 289 function common_password($id, $label) {
 290         common_element_start('p');
 291         common_element('label', array('for' => $id), $label);
 292         $attrs = array('name' => $id,
 293                                    'type' => 'password',
 294                                    'id' => $id);
 295         common_element('input', $attrs);
 296         common_element_end('p');
 297 }
 298
 299 function common_submit($id, $label) {
 300         global $xw;
 301         common_element_start('p');
 302         common_element_start('label', array('for' => $id));
 303         $xw->writeRaw('&nbsp;');
 304         common_element_end('label');
 305         common_element('input', array('type' => 'submit',
 306                                                                   'id' => $id,
 307                                                                   'name' => $id,
 308                                                                   'value' => $label,
 309                                                                   'class' => 'button'));
 310         common_element_end('p');
 311 }
 312
 313 function common_textarea($id, $label, $content=NULL) {
 314         common_element_start('p');
 315         common_element('label', array('for' => $id), $label);
 316         common_element('textarea', array('rows' => 3,
 317                                                                          'cols' => 40,
 318                                                                          'name' => $id,
 319                                                                          'id' => $id,
 320                                                                          'class' => 'width50'),
 321                                    ($content) ? $content : ' ');
 322         common_element_end('p');
 323 }
 324
 325 # salted, hashed passwords are stored in the DB
 326
 327 function common_munge_password($id, $password) {
 328         return md5($id . $password);
 329 }
 330
 331 # check if a username exists and has matching password
 332 function common_check_user($nickname, $password) {
 333         $user = User::staticGet('nickname', $nickname);
 334         if (is_null($user)) {
 335                 return false;
 336         } else {
 337                 return (0 == strcmp(common_munge_password($password, $user->id),
 338                                                         $user->password));
 339         }
 340 }
 341
 342 # is the current user logged in?
 343 function common_logged_in() {
 344         return (!is_null(common_current_user()));
 345 }
 346
 347 function common_have_session() {
 348         return (0 != strcmp(session_id(), ''));
 349 }
 350
 351 function common_ensure_session() {
 352         if (!common_have_session()) {
 353                 @session_start();
 354         }
 355 }
 356
 357 function common_set_user($nickname) {
 358         if (is_null($nickname) && common_have_session()) {
 359                 unset($_SESSION['userid']);
 360                 return true;
 361         } else {
 362                 $user = User::staticGet('nickname', $nickname);
 363                 if ($user) {
 364                         common_ensure_session();
 365                         $_SESSION['userid'] = $user->id;
 366                         return true;
 367                 } else {
 368                         return false;
 369                 }
 370         }
 371         return false;
 372 }
 373
 374 # who is the current user?
 375 function common_current_user() {
 376         static $user = NULL; # FIXME: global memcached
 377         if (is_null($user)) {
 378                 common_ensure_session();
 379                 $id = $_SESSION['userid'];
 380                 if ($id) {
 381                         $user = User::staticGet($id);
 382                 }
 383         }
 384         return $user;
 385 }
 386
 387 # get canonical version of nickname for comparison
 388 function common_canonical_nickname($nickname) {
 389         # XXX: UTF-8 canonicalization (like combining chars)
 390         return $nickname;
 391 }
 392
 393 # get canonical version of email for comparison
 394 function common_canonical_email($email) {
 395         # XXX: canonicalize UTF-8
 396         # XXX: lcase the domain part
 397         return $email;
 398 }
 399
 400 define('URL_REGEX', '^|[ \t\r\n])((ftp|http|https|gopher|mailto|news|nntp|telnet|wais|file|prospero|aim|webcal):(([A-Za-z0-9$_.+!*(),;/?:@&~=-])|%[A-Fa-f0-9]{2}){2,}(#([a-zA-Z0-9][a-zA-Z0-9$_.+!*(),;/?:@&~=%-]*))?([A-Za-z0-9$_+!*();/?:~-]))');
 401
 402 function common_render_content($text, $notice) {
 403         $r = htmlspecialchars($text);
 404         $id = $notice->profile_id;
 405         $r = preg_replace('@https?://\S+@', '<a href="\0" class="extlink">\0</a>', $r);
 406         $r = preg_replace('/(^|\b)@([\w-]+)($|\b)/e', "'\\1@'.common_at_link($id, '\\2').'\\3'", $r);
 407         # XXX: # tags
 408         # XXX: machine tags
 409         return $r;
 410 }
 411
 412 function common_at_link($sender_id, $nickname) {
 413         # Try to find profiles this profile is subscribed to that have this nickname
 414         $recipient = new Profile();
 415         # XXX: chokety and bad
 416         $recipient->whereAdd('EXISTS (SELECT subscribed from subscription where subscriber = '.$sender_id.' and subscribed = id)', 'AND');
 417         $recipient->whereAdd('nickname = "' . trim($nickname) . '"', 'AND');
 418         if ($recipient->find(TRUE)) {
 419                 return '<a href="'.htmlspecialchars($recipient->profileurl).'" class="atlink tolistenee">'.$nickname.'</a>';
 420         }
 421         # Try to find profiles that listen to this profile and that have this nickname
 422         $recipient = new Profile();
 423         # XXX: chokety and bad
 424         $recipient->whereAdd('EXISTS (SELECT subscriber from subscription where subscribed = '.$sender_id.' and subscriber = id)', 'AND');
 425         $recipient->whereAdd('nickname = "' . trim($nickname) . '"', 'AND');
 426         if ($recipient->find(TRUE)) {
 427                 return '<a href="'.htmlspecialchars($recipient->profileurl).'" class="atlink tolistener">'.$nickname.'</a>';
 428         }
 429         # If this is a local user, try to find a local user with that nickname.
 430         $sender = User::staticGet($sender_id);
 431         if ($sender) {
 432                 $recipient_user = User::staticGet('nickname', $nickname);
 433                 if ($recipient_user) {
 434                         $recipient = $recipient->getProfile();
 435                         return '<a href="'.htmlspecialchars($recipient->profileurl).'" class="atlink usertouser">'.$nickname.'</a>';
 436                 }
 437         }
 438         # Otherwise, no links. @messages from local users to remote users,
 439         # or from remote users to other remote users, are just
 440         # outside our ability to make intelligent guesses about
 441         return $nickname;
 442 }
 443
 444 // where should the avatar go for this user?
 445
 446 function common_avatar_filename($id, $extension, $size=NULL, $extra=NULL) {
 447         global $config;
 448
 449         if ($size) {
 450                 return $id . '-' . $size . (($extra) ? ('-' . $extra) : '') . $extension;
 451         } else {
 452                 return $id . '-original' . (($extra) ? ('-' . $extra) : '') . $extension;
 453         }
 454 }
 455
 456 function common_avatar_path($filename) {
 457         global $config;
 458         return INSTALLDIR . '/avatar/' . $filename;
 459 }
 460
 461 function common_avatar_url($filename) {
 462         return common_path('avatar/'.$filename);
 463 }
 464
 465 function common_default_avatar($size) {
 466         static $sizenames = array(AVATAR_PROFILE_SIZE => 'profile',
 467                                                           AVATAR_STREAM_SIZE => 'stream',
 468                                                           AVATAR_MINI_SIZE => 'mini');
 469         global $config;
 470
 471         return common_path($config['avatar']['default'][$sizenames[$size]]);
 472 }
 473
 474 function common_local_url($action, $args=NULL) {
 475         global $config;
 476         if ($config['site']['fancy']) {
 477                 return common_fancy_url($action, $args);
 478         } else {
 479                 return common_simple_url($action, $args);
 480         }
 481 }
 482
 483 function common_fancy_url($action, $args=NULL) {
 484         switch (strtolower($action)) {
 485          default:
 486                 return common_simple_url($action, $args);
 487         }
 488 }
 489
 490 function common_simple_url($action, $args=NULL) {
 491         global $config;
 492         /* XXX: pretty URLs */
 493         $extra = '';
 494         if ($args) {
 495                 foreach ($args as $key => $value) {
 496                         $extra .= "&${key}=${value}";
 497                 }
 498         }
 499         return common_path("index.php?action=${action}${extra}");
 500 }
 501
 502 function common_path($relative) {
 503         global $config;
 504         $pathpart = ($config['site']['path']) ? $config['site']['path']."/" : '';
 505         return "http://".$config['site']['server'].'/'.$pathpart.$relative;
 506 }
 507
 508 function common_date_string($dt) {
 509         // XXX: do some sexy date formatting
 510         // return date(DATE_RFC822, $dt);
 511         return $dt;
 512 }
 513
 514 function common_date_w3dtf($dt) {
 515         $t = strtotime($dt);
 516         return date(DATE_W3C, $t);
 517 }
 518
 519 function common_redirect($url, $code=307) {
 520         static $status = array(301 => "Moved Permanently",
 521                                                    302 => "Found",
 522                                                    303 => "See Other",
 523                                                    307 => "Temporary Redirect");
 524         header("Status: ${code} $status[$code]");
 525         header("Location: $url");
 526         common_element('a', array('href' => $url), $url);
 527 }
 528
 529 function common_broadcast_notice($notice, $remote=false) {
 530         // XXX: optionally use a queue system like http://code.google.com/p/microapps/wiki/NQDQ
 531         if (!$remote) {
 532                 common_broadcast_remote_subscribers($notice);
 533         }
 534         // XXX: broadcast notices to Jabber
 535         // XXX: broadcast notices to SMS
 536         // XXX: broadcast notices to other IM
 537         return true;
 538 }
 539
 540 function common_broadcast_remote_subscribers($notice) {
 541         # First, get remote users subscribed to this profile
 542         $sub = new Subscription();
 543         $sub->subscribed = $notice->profile_id;
 544         $rp = new Remote_profile();
 545         $sub->addJoin($rp, 'INNER', NULL, 'subscriber');
 546         if ($sub->find()) {
 547                 $posted = array();
 548                 while ($sub->fetch()) {
 549                         if (!$posted[$rp->postnoticeurl]) {
 550                                 if (common_post_notice($notice, $rp, $sub)) {
 551                                         $posted[$rp->postnoticeurl] = TRUE;
 552                                 }
 553                         }
 554                 }
 555         }
 556 }
 557
 558 function common_post_notice($notice, $remote_profile, $subscription) {
 559         global $config; # for license URL
 560         $user = User::staticGet('id', $notice->profile_id);
 561         $con = omb_oauth_consumer();
 562         $token = new OAuthToken($subscription->token, $subscription->secret);
 563         $url = $remote_profile->postnoticeurl;
 564         $parsed = parse_url($url);
 565         $params = array();
 566         parse_str($parsed['query'], $params);
 567         $req = OAuthRequest::from_consumer_and_token($con, $token,
 568                                                                                                  "POST", $url, $params);
 569         $req->set_parameter('omb_version', OMB_VERSION_01);
 570         $req->set_parameter('omb_listenee', $user->uri);
 571         $req->set_parameter('omb_notice', $notice->uri);
 572         $req->set_parameter('omb_notice_content', $notice->content);
 573         $req->set_parameter('omb_notice_url', common_local_url('shownotice',
 574                                                                                                                    array('notice' =>
 575                                                                                                                                  $notice->id)));
 576         $req->set_parameter('omb_notice_license', $config['license']['url']);
 577         $req->sign_request(omb_hmac_sha1(), $con, $tok);
 578
 579         # We re-use this tool's fetcher, since it's pretty good
 580
 581         $fetcher = Auth_Yadis_Yadis::getHTTPFetcher();
 582
 583         $result = $fetcher->post($req->get_normalized_http_url(),
 584                                                          $req->to_postdata());
 585
 586         if ($result->status == 403) { # not authorized, don't send again
 587                 $subscription->delete();
 588                 return false;
 589         } else if ($result->status != 200) {
 590                 return false;
 591         } else { # success!
 592                 parse_str($result->body, $return);
 593                 if ($return['omb_version'] == OMB_VERSION_01) {
 594                         return true;
 595                 } else {
 596                         return false;
 597                 }
 598         }
 599 }
 600
 601 function common_profile_url($nickname) {
 602         return common_local_url('showstream', array('nickname' => $nickname));
 603 }
 604
 605 function common_notice_form() {
 606         common_element_start('form', array('id' => 'newnotice', 'method' => 'POST',
 607                                                                            'action' => common_local_url('newnotice')));
 608         common_textarea('noticecontent', _t('What\'s up?'));
 609         common_submit('submit', _t('Send'));
 610         common_element_end('form');
 611 }
 612
 613 function common_mint_tag($extra) {
 614         global $config;
 615         return
 616           'tag:'.$config['tag']['authority'].','.
 617           $config['tag']['date'].':'.$config['tag']['prefix'].$extra;
 618 }
 619
 620 # Should make up a reasonable root URL
 621
 622 function common_root_url() {
 623         return common_path('');
 624 }
 625
 626 # returns $bytes bytes of random data as a hexadecimal string
 627 # "good" here is a goal and not a guarantee
 628
 629 function common_good_rand($bytes) {
 630         # XXX: use random.org...?
 631         if (file_exists('/dev/urandom')) {
 632                 return common_urandom($bytes);
 633         } else { # FIXME: this is probably not good enough
 634                 return common_mtrand($bytes);
 635         }
 636 }
 637
 638 function common_urandom($bytes) {
 639         $h = fopen('/dev/urandom', 'rb');
 640         # should not block
 641         $src = fread($h, $bytes);
 642         fclose($h);
 643         $enc = '';
 644         for ($i = 0; $i < $bytes; $i++) {
 645                 $enc .= sprintf("%02x", (ord($src[$i])));
 646         }
 647         return $enc;
 648 }
 649
 650 function common_mtrand($bytes) {
 651         $enc = '';
 652         for ($i = 0; $i < $bytes; $i++) {
 653                 $enc .= sprintf("%02x", mt_rand(0, 255));
 654         }
 655         return $enc;
 656 }
 657
 658 function common_set_returnto($url) {
 659         common_ensure_session();
 660         $_SESSION['returnto'] = $url;
 661 }
 662
 663 function common_get_returnto() {
 664         common_ensure_session();
 665         return $_SESSION['returnto'];
 666 }
 667
 668 function common_timestamp() {
 669         return date('YmdHis');
 670 }
 671
 672 // XXX: set up gettext
 673
 674 function _t($str) {
 675         return $str;
 676 }
 677
 678 function common_ensure_syslog() {
 679         static $initialized = false;
 680         if (!$initialized) {
 681                 global $config;
 682                 define_syslog_variables();
 683                 openlog($config['syslog']['appname'], 0, LOG_USER);
 684                 $initialized = true;
 685         }
 686 }
 687
 688 function common_log($priority, $msg, $filename=NULL) {
 689         common_ensure_syslog();
 690         syslog($priority, $msg);
 691 }
 692
 693 function common_debug($msg, $filename=NULL) {
 694         if ($filename) {
 695                 common_log(LOG_DEBUG, basename($filename).' - '.$msg);
 696         } else {
 697                 common_log(LOG_DEBUG, $msg);
 698         }
 699 }
 700
 701 function common_valid_http_url($url) {
 702         return Validate::uri($url, array('allowed_schemes' => array('http', 'https')));
 703 }
 704
 705 function common_valid_tag($tag) {
 706         if (preg_match('/^tag:(.*?),(\d{4}(-\d{2}(-\d{2})?)?):(.*)$/', $tag, $matches)) {
 707                 return (Validate::email($matches[1]) ||
 708                                 preg_match('/^([\w-\.]+)$/', $matches[1]));
 709         }
 710         return false;
 711 }