class/deliver/Deliver.class.php

   1 <?php
   2 /**
   3  * Deliver.class.php
   4  *
   5  * Copyright (c) 1999-2004 The SquirrelMail Project Team
   6  * Licensed under the GNU GPL. For full terms see the file COPYING.
   7  *
   8  * This contains all the functions needed to send messages through
   9  * a delivery backend.
  10  *
  11  * $Id$
  12  *
  13  * @author  Marc Groot Koerkamp
  14  * @package squirrelmail
  15  */
  16
  17 /**
  18  * Deliver Class - called to actually deliver the message
  19  *
  20  * This class is called by compose.php and other code that needs
  21  * to send messages.  All delivery functionality should be centralized
  22  * in this class.
  23  *
  24  * Do not place UI code in this class, as UI code should be placed in templates
  25  * going forward.
  26  *
  27  * @author  Marc Groot Koerkamp
  28  * @package squirrelmail
  29  */
  30 class Deliver {
  31
  32     /**
  33      * function mail - send the message parts to the SMTP stream
  34      *
  35      * @param Message  $message  Message class to send
  36      * @param resource $stream   file handle to the SMTP stream
  37      *
  38      * @return integer $raw_length
  39      */
  40     function mail($message, $stream=false) {
  41         $rfc822_header = $message->rfc822_header;
  42         if (count($message->entities)) {
  43             $boundary = $this->mimeBoundary();
  44             $rfc822_header->content_type->properties['boundary']='"'.$boundary.'"';
  45         } else {
  46             $boundary='';
  47         }
  48         $raw_length = 0;
  49         $reply_rfc822_header = (isset($message->reply_rfc822_header)
  50                              ? $message->reply_rfc822_header : '');
  51         $header = $this->prepareRFC822_Header($rfc822_header, $reply_rfc822_header, $raw_length);
  52
  53         if ($stream) {
  54             $this->preWriteToStream($header);
  55             $this->writeToStream($stream, $header);
  56         }
  57         $this->writeBody($message, $stream, $raw_length, $boundary);
  58         return $raw_length;
  59     }
  60
  61     /**
  62      * function writeBody - generate and write the mime boundaries around each part to the stream
  63      *
  64      * Recursively formats and writes the MIME boundaries of the $message
  65      * to the output stream.
  66      *
  67      * @param Message   $message      Message object to transform
  68      * @param resource  $stream       SMTP output stream
  69      * @param integer  &$length_raw   raw length of the message (part)
  70      *                                as returned by mail fn
  71      * @param string    $boundary     custom boundary to call, usually for subparts
  72      *
  73      * @return void
  74      */
  75     function writeBody($message, $stream, &$length_raw, $boundary='') {
  76         // calculate boundary in case of multidimensional mime structures
  77         if ($boundary && $message->entity_id && count($message->entities)) {
  78             if (strpos($boundary,'_part_')) {
  79                 $boundary = substr($boundary,0,strpos($boundary,'_part_'));
  80             }
  81             $boundary_new = $boundary . '_part_'.$message->entity_id;
  82         } else {
  83             $boundary_new = $boundary;
  84         }
  85         if ($boundary && !$message->rfc822_header) {
  86             $s = '--'.$boundary."\r\n";
  87             $s .= $this->prepareMIME_Header($message, $boundary_new);
  88             $length_raw += strlen($s);
  89             if ($stream) {
  90                 $this->preWriteToStream($s);
  91                 $this->writeToStream($stream, $s);
  92             }
  93         }
  94         $this->writeBodyPart($message, $stream, $length_raw);
  95
  96         $last = false;
  97         for ($i=0, $entCount=count($message->entities);$i<$entCount;$i++) {
  98             $msg = $this->writeBody($message->entities[$i], $stream, $length_raw, $boundary_new);
  99             if ($i == $entCount-1) $last = true;
 100         }
 101         if ($boundary && $last) {
 102             $s = "--".$boundary_new."--\r\n\r\n";
 103             $length_raw += strlen($s);
 104             if ($stream) {
 105                 $this->preWriteToStream($s);
 106                 $this->writeToStream($stream, $s);
 107             }
 108         }
 109     }
 110
 111     /**
 112      * function writeBodyPart - write each individual mimepart
 113      *
 114      * Recursively called by WriteBody to write each mime part to the SMTP stream
 115      *
 116      * @param Message   $message      Message object to transform
 117      * @param resource  $stream       SMTP output stream
 118      * @param integer  &$length       length of the message part
 119      *                                as returned by mail fn
 120      *
 121      * @return void
 122      */
 123     function writeBodyPart($message, $stream, &$length) {
 124         if ($message->mime_header) {
 125             $type0 = $message->mime_header->type0;
 126         } else {
 127             $type0 = $message->rfc822_header->content_type->type0;
 128         }
 129
 130         $body_part_trailing = $last = '';
 131         switch ($type0)
 132         {
 133         case 'text':
 134         case 'message':
 135             if ($message->body_part) {
 136                 $body_part = $message->body_part;
 137                 $length += $this->clean_crlf($body_part);
 138                 if ($stream) {
 139                     $this->preWriteToStream($body_part);
 140                     $this->writeToStream($stream, $body_part);
 141                 }
 142                 $last = $body_part;
 143             } elseif ($message->att_local_name) {
 144                 $filename = $message->att_local_name;
 145                 $file = fopen ($filename, 'rb');
 146                 while ($body_part = fgets($file, 4096)) {
 147                     $length += $this->clean_crlf($body_part);
 148                     if ($stream) {
 149                         $this->preWriteToStream($body_part);
 150                         $this->writeToStream($stream, $body_part);
 151                     }
 152                     $last = $body_part;
 153                 }
 154                 fclose($file);
 155             }
 156             break;
 157         default:
 158             if ($message->body_part) {
 159                 $body_part = $message->body_part;
 160                 $length += $this->clean_crlf($body_part);
 161                 if ($stream) {
 162                     $this->writeToStream($stream, $body_part);
 163                 }
 164             } elseif ($message->att_local_name) {
 165                 $filename = $message->att_local_name;
 166                 $file = fopen ($filename, 'rb');
 167                 $encoded = '';
 168                 while ($tmp = fread($file, 570)) {
 169                    $body_part = chunk_split(base64_encode($tmp));
 170                     $length += $this->clean_crlf($body_part);
 171                     if ($stream) {
 172                         $this->writeToStream($stream, $body_part);
 173                     }
 174                 }
 175                 fclose($file);
 176             }
 177             break;
 178         }
 179         $body_part_trailing = '';
 180         if ($last && substr($last,-1) != "\n") {
 181             $body_part_trailing = "\r\n";
 182         }
 183         if ($body_part_trailing) {
 184             $length += strlen($body_part_trailing);
 185             if ($stream) {
 186                 $this->preWriteToStream($body_part_trailing);
 187                 $this->writeToStream($stream, $body_part_trailing);
 188             }
 189         }
 190     }
 191
 192     /**
 193      * function clean_crlf - change linefeeds and newlines to legal characters
 194      *
 195      * The SMTP format only allows CRLF as line terminators.
 196      * This function replaces illegal teminators with the correct terminator.
 197      *
 198      * @param string &$s string to clean linefeeds on
 199      *
 200      * @return void
 201      */
 202     function clean_crlf(&$s) {
 203         $s = str_replace("\r\n", "\n", $s);
 204         $s = str_replace("\r", "\n", $s);
 205         $s = str_replace("\n", "\r\n", $s);
 206         return strlen($s);
 207     }
 208
 209     /**
 210      * function strip_crlf - strip linefeeds and newlines from a string
 211      *
 212      * The SMTP format only allows CRLF as line terminators.
 213      * This function strips all line terminators from the string.
 214      *
 215      * @param string &$s string to clean linefeeds on
 216      *
 217      * @return void
 218      */
 219     function strip_crlf(&$s) {
 220         $s = str_replace("\r\n ", '', $s);
 221         $s = str_replace("\r", '', $s);
 222         $s = str_replace("\n", '', $s);
 223     }
 224
 225     /**
 226      * function preWriteToStream - reserved for extended functionality
 227      *
 228      * This function is not yet implemented.
 229      * Reserved for extended functionality.
 230      *
 231      * @param string &$s string to operate on
 232      *
 233      * @return void
 234      */
 235     function preWriteToStream(&$s) {
 236     }
 237
 238     /**
 239      * function writeToStream - write data to the SMTP stream
 240      *
 241      * @param resource $stream  SMTP output stream
 242      * @param string   $data    string with data to send to the SMTP stream
 243      *
 244      * @return void
 245      */
 246     function writeToStream($stream, $data) {
 247         fputs($stream, $data);
 248     }
 249
 250     /**
 251      * function initStream - reserved for extended functionality
 252      *
 253      * This function is not yet implemented.
 254      * Reserved for extended functionality.
 255      *
 256      * @param Message $message  Message object
 257      * @param string  $host     host name or IP to connect to
 258      * @param string  $user     username to log into the SMTP server with
 259      * @param string  $pass     password to log into the SMTP server with
 260      * @param integer $length
 261      *
 262      * @return handle $stream file handle resource to SMTP stream
 263      */
 264     function initStream($message, $length=0, $host='', $port='', $user='', $pass='') {
 265         return $stream;
 266     }
 267
 268     /**
 269      * function getBCC - reserved for extended functionality
 270      *
 271      * This function is not yet implemented.
 272      * Reserved for extended functionality.
 273      *
 274      */
 275     function getBCC() {
 276         return false;
 277     }
 278
 279     /**
 280      * function prepareMIME_Header - creates the mime header
 281      *
 282      * @param Message $message  Message object to act on
 283      * @param string  $boundary mime boundary from fn MimeBoundary
 284      *
 285      * @return string $header properly formatted mime header
 286      */
 287     function prepareMIME_Header($message, $boundary) {
 288         $mime_header = $message->mime_header;
 289         $rn="\r\n";
 290         $header = array();
 291
 292         $contenttype = 'Content-Type: '. $mime_header->type0 .'/'.
 293                         $mime_header->type1;
 294         if (count($message->entities)) {
 295             $contenttype .= ";\r\n " . 'boundary="'.$boundary.'"';
 296         }
 297         if (isset($mime_header->parameters['name'])) {
 298             $contenttype .= '; name="'.
 299             encodeHeader($mime_header->parameters['name']). '"';
 300         }
 301         if (isset($mime_header->parameters['charset'])) {
 302             $charset = $mime_header->parameters['charset'];
 303             $contenttype .= '; charset="'.
 304             encodeHeader($charset). '"';
 305         }
 306
 307         $header[] = $contenttype . $rn;
 308         if ($mime_header->description) {
 309             $header[] .= 'Content-Description: ' . $mime_header->description . $rn;
 310         }
 311         if ($mime_header->encoding) {
 312             $encoding = $mime_header->encoding;
 313             $header[] .= 'Content-Transfer-Encoding: ' . $mime_header->encoding . $rn;
 314         } else {
 315             if ($mime_header->type0 == 'text' || $mime_header->type0 == 'message') {
 316                 $header[] .= 'Content-Transfer-Encoding: 8bit' .  $rn;
 317             } else {
 318                 $header[] .= 'Content-Transfer-Encoding: base64' .  $rn;
 319             }
 320         }
 321         if ($mime_header->id) {
 322             $header[] .= 'Content-ID: ' . $mime_header->id . $rn;
 323         }
 324         if ($mime_header->disposition) {
 325             $disposition = $mime_header->disposition;
 326             $contentdisp = 'Content-Disposition: ' . $disposition->name;
 327             if ($disposition->getProperty('filename')) {
 328                 $contentdisp .= '; filename="'.
 329                 encodeHeader($disposition->getProperty('filename')). '"';
 330             }
 331             $header[] = $contentdisp . $rn;
 332         }
 333         if ($mime_header->md5) {
 334             $header[] .= 'Content-MD5: ' . $mime_header->md5 . $rn;
 335         }
 336         if ($mime_header->language) {
 337             $header[] .= 'Content-Language: ' . $mime_header->language . $rn;
 338         }
 339
 340         $cnt = count($header);
 341         $hdr_s = '';
 342         for ($i = 0 ; $i < $cnt ; $i++)    {
 343             $hdr_s .= $this->foldLine($header[$i], 78,str_pad('',4));
 344         }
 345         $header = $hdr_s;
 346         $header .= $rn; /* One blank line to separate mimeheader and body-entity */
 347         return $header;
 348     }
 349
 350     /**
 351      * function prepareRFC822_Header - prepares the RFC822 header string from Rfc822Header object(s)
 352      *
 353      * This function takes the Rfc822Header object(s) and formats them
 354      * into the RFC822Header string to send to the SMTP server as part
 355      * of the SMTP message.
 356      *
 357      * @param Rfc822Header  $rfc822_header
 358      * @param Rfc822Header  $reply_rfc822_header
 359      * @param integer      &$raw_length length of the message
 360      *
 361      * @return string $header
 362      */
 363     function prepareRFC822_Header($rfc822_header, $reply_rfc822_header, &$raw_length) {
 364         global $domain, $version, $username;
 365
 366         /* if server var SERVER_NAME not available, use $domain */
 367         if(!sqGetGlobalVar('SERVER_NAME', $SERVER_NAME, SQ_SERVER)) {
 368             $SERVER_NAME = $domain;
 369         }
 370
 371         sqGetGlobalVar('REMOTE_ADDR', $REMOTE_ADDR, SQ_SERVER);
 372         sqGetGlobalVar('REMOTE_PORT', $REMOTE_PORT, SQ_SERVER);
 373         sqGetGlobalVar('REMOTE_HOST', $REMOTE_HOST, SQ_SERVER);
 374         sqGetGlobalVar('HTTP_VIA',    $HTTP_VIA,    SQ_SERVER);
 375         sqGetGlobalVar('HTTP_X_FORWARDED_FOR', $HTTP_X_FORWARDED_FOR, SQ_SERVER);
 376
 377         $rn = "\r\n";
 378
 379         /* This creates an RFC 822 date */
 380         $date = date('D, j M Y H:i:s ', mktime()) . $this->timezone();
 381         /* Create a message-id */
 382         $message_id = '<' . $REMOTE_PORT . '.' . $REMOTE_ADDR . '.';
 383         $message_id .= time() . '.squirrel@' . $REMOTE_ADDR .'>';
 384         /* Make an RFC822 Received: line */
 385         if (isset($REMOTE_HOST)) {
 386             $received_from = "$REMOTE_HOST ([$REMOTE_ADDR])";
 387         } else {
 388             $received_from = $REMOTE_ADDR;
 389         }
 390         if (isset($HTTP_VIA) || isset ($HTTP_X_FORWARDED_FOR)) {
 391             if (!isset($HTTP_X_FORWARDED_FOR) || $HTTP_X_FORWARDED_FOR == '') {
 392                 $HTTP_X_FORWARDED_FOR = 'unknown';
 393             }
 394             $received_from .= " (proxying for $HTTP_X_FORWARDED_FOR)";
 395         }
 396         $header = array();
 397         $header[] = "Received: from $received_from" . $rn;
 398         $header[] = "        (SquirrelMail authenticated user $username);" . $rn;
 399         $header[] = "        by $SERVER_NAME with HTTP;" . $rn;
 400         $header[] = "        $date" . $rn;
 401         /* Insert the rest of the header fields */
 402         $header[] = 'Message-ID: '. $message_id . $rn;
 403         if ($reply_rfc822_header->message_id) {
 404             $rep_message_id = $reply_rfc822_header->message_id;
 405         //        $this->strip_crlf($message_id);
 406             $header[] = 'In-Reply-To: '.$rep_message_id . $rn;
 407             $references = $this->calculate_references($reply_rfc822_header);
 408             $header[] = 'References: '.$references . $rn;
 409         }
 410         $header[] = "Date: $date" . $rn;
 411         $header[] = 'Subject: '.encodeHeader($rfc822_header->subject) . $rn;
 412         $header[] = 'From: '. $rfc822_header->getAddr_s('from',',',true) . $rn;
 413         /* RFC2822 if from contains more then 1 address */
 414         if (count($rfc822_header->from) > 1) {
 415             $header[] = 'Sender: '. $rfc822_header->getAddr_s('sender',',',true) . $rn;
 416         }
 417         if (count($rfc822_header->to)) {
 418             $header[] = 'To: '. $rfc822_header->getAddr_s('to',',',true) . $rn;
 419         }
 420         if (count($rfc822_header->cc)) {
 421             $header[] = 'Cc: '. $rfc822_header->getAddr_s('cc',',',true) . $rn;
 422         }
 423         if (count($rfc822_header->reply_to)) {
 424             $header[] = 'Reply-To: '. $rfc822_header->getAddr_s('reply_to',',',true) . $rn;
 425         }
 426         /* Sendmail should return true. Default = false */
 427         $bcc = $this->getBcc();
 428         if (count($rfc822_header->bcc)) {
 429             $s = 'Bcc: '. $rfc822_header->getAddr_s('bcc',',',true) . $rn;
 430             if (!$bcc) {
 431                 $s = $this->foldLine($s, 78, str_pad('',4));
 432                 $raw_length += strlen($s);
 433             } else {
 434                 $header[] = $s;
 435             }
 436         }
 437         /* Identify SquirrelMail */
 438         $header[] = 'User-Agent: SquirrelMail/' . $version . $rn;
 439         /* Do the MIME-stuff */
 440         $header[] = 'MIME-Version: 1.0' . $rn;
 441         $contenttype = 'Content-Type: '. $rfc822_header->content_type->type0 .'/'.
 442                                          $rfc822_header->content_type->type1;
 443         if (count($rfc822_header->content_type->properties)) {
 444             foreach ($rfc822_header->content_type->properties as $k => $v) {
 445                 if ($k && $v) {
 446                     $contenttype .= ';' .$k.'='.$v;
 447                 }
 448             }
 449         }
 450         $header[] = $contenttype . $rn;
 451         if ($encoding = $rfc822_header->encoding) {
 452             $header[] .= 'Content-Transfer-Encoding: ' . $encoding .  $rn;
 453         }
 454         if ($rfc822_header->dnt) {
 455             $dnt = $rfc822_header->getAddr_s('dnt');
 456             /* Pegasus Mail */
 457             $header[] = 'X-Confirm-Reading-To: '.$dnt. $rn;
 458             /* RFC 2298 */
 459             $header[] = 'Disposition-Notification-To: '.$dnt. $rn;
 460         }
 461         if ($rfc822_header->priority) {
 462             $prio = $rfc822_header->priority;
 463             $header[] = 'X-Priority: '. $prio. $rn;
 464             switch($prio)
 465             {
 466             case 1: $header[] = 'Importance: High'. $rn; break;
 467             case 3: $header[] = 'Importance: Normal'. $rn; break;
 468             case 5: $header[] = 'Importance: Low'. $rn; break;
 469             default: break;
 470             }
 471         }
 472         /* Insert headers from the $more_headers array */
 473         if(count($rfc822_header->more_headers)) {
 474             reset($rfc822_header->more_headers);
 475             foreach ($rfc822_header->more_headers as $k => $v) {
 476                 $header[] = $k.': '.$v .$rn;
 477             }
 478         }
 479         $cnt = count($header);
 480         $hdr_s = '';
 481
 482         for ($i = 0 ; $i < $cnt ; $i++) {
 483             $sKey = substr($header[$i],0,strpos($header[$i],':'));
 484             switch ($sKey)
 485             {
 486             case 'Message-ID':
 487             case 'In-Reply_To':
 488                 $hdr_s .= $header[$i];
 489                 break;
 490             case 'References':
 491                 $sRefs = substr($header[$i],12);
 492                 $aRefs = explode(' ',$sRefs);
 493                 $sLine = 'References:';
 494                 foreach ($aRefs as $sReference) {
 495                     if (strlen($sLine)+strlen($sReference) >76) {
 496                         $hdr_s .= $sLine;
 497                         $sLine = $rn . '    ' . $sReference;
 498                     } else {
 499                         $sLine .= ' '. $sReference;
 500                     }
 501                 }
 502                 $hdr_s .= $sLine;
 503                 break;
 504             default: $hdr_s .= $this->foldLine($header[$i], 78, str_pad('',4)); break;
 505             }
 506         }
 507         $header = $hdr_s;
 508         $header .= $rn; /* One blank line to separate header and body */
 509         $raw_length += strlen($header);
 510         return $header;
 511     }
 512
 513     /**
 514      * function foldLine - for cleanly folding of headerlines
 515      *
 516      * @param   string  $line
 517      * @param   integer $length length to fold the line at
 518      * @param   string  $pre    prefix the line with...
 519      *
 520      * @return string   $line folded line with trailing CRLF
 521      */
 522     function foldLine($line, $length, $pre='') {
 523         $line = substr($line,0, -2);
 524         $length -= 2; /* do not fold between \r and \n */
 525         $cnt = strlen($line);
 526         if ($cnt > $length) { /* try folding */
 527             $fold_string = "\r\n " . $pre;
 528             $bFirstFold = false;
 529             $aFoldLine = array();
 530             while (strlen($line) > $length) {
 531                 $fold = false;
 532                 /* handle encoded parts */
 533                 if (preg_match('/(=\?([^?]*)\?(Q|B)\?([^?]*)\?=)(\s+|.*)/Ui',$line,$regs)) {
 534                     $fold_tmp = $regs[1];
 535                     if (!trim($regs[5])) {
 536                         $fold_tmp .= $regs[5];
 537                     }
 538                     $iPosEnc = strpos($line,$fold_tmp);
 539                     $iLengthEnc = strlen($fold_tmp);
 540                     $iPosEncEnd = $iPosEnc+$iLengthEnc;
 541                     if ($iPosEnc < $length && (($iPosEncEnd) > $length)) {
 542                         $fold = true;
 543                         /* fold just before the start of the encoded string */
 544                         if ($iPosEnc) {
 545                             $aFoldLine[] = substr($line,0,$iPosEnc);
 546                         }
 547                         $line = substr($line,$iPosEnc);
 548                         if (!$bFirstFold) {
 549                             $bFirstFold = true;
 550                             $length -= strlen($fold_string);
 551                         }
 552                         if ($iLengthEnc > $length) { /* place the encoded
 553                             string on a separate line and do not fold inside it*/
 554                             /* minimize foldstring */
 555                             $fold_string = "\r\n ";
 556                             $aFoldLine[] = substr($line,0,$iLengthEnc);
 557                             $line = substr($line,$iLengthEnc);
 558                         }
 559                     } else if ($iPosEnc < $length) { /* the encoded string fits into the foldlength */
 560                         /*remainder */
 561                         $sLineRem = substr($line,$iPosEncEnd,$length - $iPosEncEnd);
 562                         if (preg_match('/^(=\?([^?]*)\?(Q|B)\?([^?]*)\?=)(.*)/Ui',$sLineRem) || !preg_match('/[=,;\s]/',$sLineRem)) {
 563                             /*impossible to fold clean in the next part -> fold after the enc string */
 564                             $aFoldLine[] = substr($line,0,$iPosEncEnd);
 565                             $line = substr($line,$iPosEncEnd);
 566                             $fold = true;
 567                             if (!$bFirstFold) {
 568                                 $bFirstFold = true;
 569                                 $length -= strlen($fold_string);
 570                             }
 571                         }
 572                     }
 573                 }
 574                 if (!$fold) {
 575                     $line_tmp = substr($line,0,$length);
 576                     $iFoldPos = false;
 577                     /* try to fold at logical places */
 578                     switch (true)
 579                     {
 580                     case ($iFoldPos = strrpos($line_tmp,',')): break;
 581                     case ($iFoldPos = strrpos($line_tmp,';')): break;
 582                     case ($iFoldPos = strrpos($line_tmp,' ')): break;
 583                     case ($iFoldPos = strrpos($line_tmp,'=')): break;
 584                     default: break;
 585                     }
 586
 587                     if (!$iFoldPos) { /* clean folding didn't work */
 588                         $iFoldPos = $length;
 589                     }
 590                     $aFoldLine[] = substr($line,0,$iFoldPos+1);
 591                     $line = substr($line,$iFoldPos+1);
 592                     if (!$bFirstFold) {
 593                         $bFirstFold = true;
 594                         $length -= strlen($fold_string);
 595                     }
 596                 }
 597             }
 598             /*$reconstruct the line */
 599             if ($line) {
 600                 $aFoldLine[] = $line;
 601             }
 602             $line = implode($fold_string,$aFoldLine);
 603         }
 604         return $line."\r\n";
 605     }
 606
 607     /**
 608      * function mimeBoundary - calculates the mime boundary to use
 609      *
 610      * This function will generate a random mime boundary base part
 611      * for the message if the boundary has not already been set.
 612      *
 613      * @return string $mimeBoundaryString random mime boundary string
 614      */
 615     function mimeBoundary () {
 616         static $mimeBoundaryString;
 617
 618         if ( !isset( $mimeBoundaryString ) ||
 619             $mimeBoundaryString == '') {
 620             $mimeBoundaryString = '----=_' . date( 'YmdHis' ) . '_' .
 621             mt_rand( 10000, 99999 );
 622         }
 623         return $mimeBoundaryString;
 624     }
 625
 626     /**
 627      * function timezone - Time offset for correct timezone
 628      *
 629      * @return string $result with timezone and offset
 630      */
 631     function timezone () {
 632         global $invert_time;
 633
 634         $diff_second = date('Z');
 635         if ($invert_time) {
 636             $diff_second = - $diff_second;
 637         }
 638         if ($diff_second > 0) {
 639             $sign = '+';
 640         } else {
 641             $sign = '-';
 642         }
 643         $diff_second = abs($diff_second);
 644         $diff_hour = floor ($diff_second / 3600);
 645         $diff_minute = floor (($diff_second-3600*$diff_hour) / 60);
 646         $zonename = '('.strftime('%Z').')';
 647         $result = sprintf ("%s%02d%02d %s", $sign, $diff_hour, $diff_minute,
 648                        $zonename);
 649         return ($result);
 650     }
 651
 652     /**
 653      * function calculate_references - calculate correct Referer string
 654      *
 655      * @param   Rfc822Header $hdr    message header to calculate from
 656      *
 657      * @return  string       $refer  concatenated and trimmed Referer string
 658      */
 659     function calculate_references($hdr) {
 660         $refer = $hdr->references;
 661         $message_id = $hdr->message_id;
 662         $in_reply_to = $hdr->in_reply_to;
 663         if (strlen($refer) > 2) {
 664             $refer .= ' ' . $message_id;
 665         } else {
 666             if ($in_reply_to) {
 667                 $refer .= $in_reply_to . ' ' . $message_id;
 668             } else {
 669                 $refer .= $message_id;
 670             }
 671         }
 672         trim($refer);
 673         return $refer;
 674     }
 675 }
 676 ?>