class/deliver/Deliver.class.php

   1 <?php
   2 /**
   3  * Deliver.class.php
   4  *
   5  * Copyright (c) 1999-2003 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 /**
  19  * Deliver Class - called to actually deliver the message
  20  *
  21  * This class is called by compose.php and other code that needs
  22  * to send messages.  All delivery functionality should be centralized
  23  * in this class.
  24  *
  25  * Do not place UI code in this class, as UI code should be placed in templates
  26  * going forward.
  27  *
  28  * @author  Marc Groot Koerkamp
  29  * @package squirrelmail
  30  */
  31 class Deliver {
  32
  33     /**
  34      * function mail - send the message parts to the SMTP stream
  35      *
  36      * @param Message  $message  Message class to send
  37      * @param resource $stream   file handle to the SMTP stream
  38      *
  39      * @return integer $raw_length
  40      */
  41     function mail($message, $stream=false) {
  42         $rfc822_header = $message->rfc822_header;
  43         if (count($message->entities)) {
  44             $boundary = $this->mimeBoundary();
  45             $rfc822_header->content_type->properties['boundary']='"'.$boundary.'"';
  46         } else {
  47             $boundary='';
  48         }
  49         $raw_length = 0;
  50         $reply_rfc822_header = (isset($message->reply_rfc822_header)
  51                              ? $message->reply_rfc822_header : '');
  52         $header = $this->prepareRFC822_Header($rfc822_header, $reply_rfc822_header, $raw_length);
  53
  54         if ($stream) {
  55             $this->preWriteToStream($header);
  56             $this->writeToStream($stream, $header);
  57         }
  58         $this->writeBody($message, $stream, $raw_length, $boundary);
  59         return $raw_length;
  60     }
  61
  62     /**
  63      * function writeBody - generate and write the mime boundaries around each part to the stream
  64      *
  65      * Recursively formats and writes the MIME boundaries of the $message
  66      * to the output stream.
  67      *
  68      * @param Message   $message      Message object to transform
  69      * @param resource  $stream       SMTP output stream
  70      * @param integer  &$length_raw   raw length of the message (part)
  71      *                                as returned by mail fn
  72      * @param string    $boundary     custom boundary to call, usually for subparts
  73      *
  74      * @return void
  75      */
  76     function writeBody($message, $stream, &$length_raw, $boundary='') {
  77         // calculate boundary in case of multidimensional mime structures
  78         if ($boundary && $message->entity_id && count($message->entities)) {
  79             if (strpos($boundary,'_part_')) {
  80                 $boundary = substr($boundary,0,strpos($boundary,'_part_'));
  81             }
  82             $boundary_new = $boundary . '_part_'.$message->entity_id;
  83         } else {
  84             $boundary_new = $boundary;
  85         }
  86         if ($boundary && !$message->rfc822_header) {
  87             $s = '--'.$boundary."\r\n";
  88             $s .= $this->prepareMIME_Header($message, $boundary_new);
  89             $length_raw += strlen($s);
  90             if ($stream) {
  91                 $this->preWriteToStream($s);
  92                 $this->writeToStream($stream, $s);
  93             }
  94         }
  95         $this->writeBodyPart($message, $stream, $length_raw);
  96
  97         $last = false;
  98         for ($i=0, $entCount=count($message->entities);$i<$entCount;$i++) {
  99             $msg = $this->writeBody($message->entities[$i], $stream, $length_raw, $boundary_new);
 100             if ($i == $entCount-1) $last = true;
 101         }
 102         if ($boundary && $last) {
 103             $s = "--".$boundary_new."--\r\n\r\n";
 104             $length_raw += strlen($s);
 105             if ($stream) {
 106                 $this->preWriteToStream($s);
 107                 $this->writeToStream($stream, $s);
 108             }
 109         }
 110     }
 111
 112     /**
 113      * function writeBodyPart - write each individual mimepart
 114      *
 115      * Recursively called by WriteBody to write each mime part to the SMTP stream
 116      *
 117      * @param Message   $message      Message object to transform
 118      * @param resource  $stream       SMTP output stream
 119      * @param integer  &$length       length of the message part
 120      *                                as returned by mail fn
 121      *
 122      * @return void
 123      */
 124     function writeBodyPart($message, $stream, &$length) {
 125         if ($message->mime_header) {
 126             $type0 = $message->mime_header->type0;
 127         } else {
 128             $type0 = $message->rfc822_header->content_type->type0;
 129         }
 130
 131         $body_part_trailing = $last = '';
 132         switch ($type0)
 133         {
 134         case 'text':
 135         case 'message':
 136             if ($message->body_part) {
 137                 $body_part = $message->body_part;
 138                 $length += $this->clean_crlf($body_part);
 139                 if ($stream) {
 140                     $this->preWriteToStream($body_part);
 141                     $this->writeToStream($stream, $body_part);
 142                 }
 143                 $last = $body_part;
 144             } elseif ($message->att_local_name) {
 145                 $filename = $message->att_local_name;
 146                 $file = fopen ($filename, 'rb');
 147                 while ($body_part = fgets($file, 4096)) {
 148                     $length += $this->clean_crlf($body_part);
 149                     if ($stream) {
 150                         $this->preWriteToStream($body_part);
 151                         $this->writeToStream($stream, $body_part);
 152                     }
 153                     $last = $body_part;
 154                 }
 155                 fclose($file);
 156             }
 157             break;
 158         default:
 159             if ($message->body_part) {
 160                 $body_part = $message->body_part;
 161                 $length += $this->clean_crlf($body_part);
 162                 if ($stream) {
 163                     $this->writeToStream($stream, $body_part);
 164                 }
 165             } elseif ($message->att_local_name) {
 166                 $filename = $message->att_local_name;
 167                 $file = fopen ($filename, 'rb');
 168                 $encoded = '';
 169                 while ($tmp = fread($file, 570)) {
 170                    $body_part = chunk_split(base64_encode($tmp));
 171                     $length += $this->clean_crlf($body_part);
 172                     if ($stream) {
 173                         $this->writeToStream($stream, $body_part);
 174                     }
 175                 }
 176                 fclose($file);
 177             }
 178             break;
 179         }
 180         $body_part_trailing = '';
 181         if ($last && substr($last,-1) != "\n") {
 182             $body_part_trailing = "\r\n";
 183         }
 184         if ($body_part_trailing) {
 185             $length += strlen($body_part_trailing);
 186             if ($stream) {
 187                 $this->preWriteToStream($body_part_trailing);
 188                 $this->writeToStream($stream, $body_part_trailing);
 189             }
 190         }
 191     }
 192
 193     /**
 194      * function clean_crlf - change linefeeds and newlines to legal characters
 195      *
 196      * The SMTP format only allows CRLF as line terminators.
 197      * This function replaces illegal teminators with the correct terminator.
 198      *
 199      * @param string &$s string to clean linefeeds on
 200      *
 201      * @return void
 202      */
 203     function clean_crlf(&$s) {
 204         $s = str_replace("\r\n", "\n", $s);
 205         $s = str_replace("\r", "\n", $s);
 206         $s = str_replace("\n", "\r\n", $s);
 207         return strlen($s);
 208     }
 209
 210     /**
 211      * function strip_crlf - strip linefeeds and newlines from a string
 212      *
 213      * The SMTP format only allows CRLF as line terminators.
 214      * This function strips all line terminators from the string.
 215      *
 216      * @param string &$s string to clean linefeeds on
 217      *
 218      * @return void
 219      */
 220     function strip_crlf(&$s) {
 221         $s = str_replace("\r\n ", '', $s);
 222         $s = str_replace("\r", '', $s);
 223         $s = str_replace("\n", '', $s);
 224     }
 225
 226     /**
 227      * function preWriteToStream - reserved for extended functionality
 228      *
 229      * This function is not yet implemented.
 230      * Reserved for extended functionality.
 231      *
 232      * @param string &$s string to operate on
 233      *
 234      * @return void
 235      */
 236     function preWriteToStream(&$s) {
 237     }
 238
 239     /**
 240      * function writeToStream - write data to the SMTP stream
 241      *
 242      * @param resource $stream  SMTP output stream
 243      * @param string   $data    string with data to send to the SMTP stream
 244      *
 245      * @return void
 246      */
 247     function writeToStream($stream, $data) {
 248         fputs($stream, $data);
 249     }
 250
 251     /**
 252      * function initStream - reserved for extended functionality
 253      *
 254      * This function is not yet implemented.
 255      * Reserved for extended functionality.
 256      *
 257      * @param Message $message  Message object
 258      * @param string  $host     host name or IP to connect to
 259      * @param string  $user     username to log into the SMTP server with
 260      * @param string  $pass     password to log into the SMTP server with
 261      * @param integer $length
 262      *
 263      * @return handle $stream file handle resource to SMTP stream
 264      */
 265     function initStream($message, $length=0, $host='', $port='', $user='', $pass='') {
 266         return $stream;
 267     }
 268
 269     /**
 270      * function getBCC - reserved for extended functionality
 271      *
 272      * This function is not yet implemented.
 273      * Reserved for extended functionality.
 274      *
 275      */
 276     function getBCC() {
 277         return false;
 278     }
 279
 280     /**
 281      * function prepareMIME_Header - creates the mime header
 282      *
 283      * @param Message $message  Message object to act on
 284      * @param string  $boundary mime boundary from fn MimeBoundary
 285      *
 286      * @return string $header properly formatted mime header
 287      */
 288     function prepareMIME_Header($message, $boundary) {
 289         $mime_header = $message->mime_header;
 290         $rn="\r\n";
 291         $header = array();
 292
 293         $contenttype = 'Content-Type: '. $mime_header->type0 .'/'.
 294                         $mime_header->type1;
 295         if (count($message->entities)) {
 296             $contenttype .= ";\r\n " . 'boundary="'.$boundary.'"';
 297         }
 298         if (isset($mime_header->parameters['name'])) {
 299             $contenttype .= '; name="'.
 300             encodeHeader($mime_header->parameters['name']). '"';
 301         }
 302         if (isset($mime_header->parameters['charset'])) {
 303             $charset = $mime_header->parameters['charset'];
 304             $contenttype .= '; charset="'.
 305             encodeHeader($charset). '"';
 306         }
 307
 308         $header[] = $contenttype . $rn;
 309         if ($mime_header->description) {
 310             $header[] .= 'Content-Description: ' . $mime_header->description . $rn;
 311         }
 312         if ($mime_header->encoding) {
 313             $encoding = $mime_header->encoding;
 314             $header[] .= 'Content-Transfer-Encoding: ' . $mime_header->encoding . $rn;
 315         } else {
 316             if ($mime_header->type0 == 'text' || $mime_header->type0 == 'message') {
 317                 $header[] .= 'Content-Transfer-Encoding: 8bit' .  $rn;
 318             } else {
 319                 $header[] .= 'Content-Transfer-Encoding: base64' .  $rn;
 320             }
 321         }
 322         if ($mime_header->id) {
 323             $header[] .= 'Content-ID: ' . $mime_header->id . $rn;
 324         }
 325         if ($mime_header->disposition) {
 326             $disposition = $mime_header->disposition;
 327             $contentdisp = 'Content-Disposition: ' . $disposition->name;
 328             if ($disposition->getProperty('filename')) {
 329                 $contentdisp .= '; filename="'.
 330                 encodeHeader($disposition->getProperty('filename')). '"';
 331             }
 332             $header[] = $contentdisp . $rn;
 333         }
 334         if ($mime_header->md5) {
 335             $header[] .= 'Content-MD5: ' . $mime_header->md5 . $rn;
 336         }
 337         if ($mime_header->language) {
 338             $header[] .= 'Content-Language: ' . $mime_header->language . $rn;
 339         }
 340
 341         $cnt = count($header);
 342         $hdr_s = '';
 343         for ($i = 0 ; $i < $cnt ; $i++)    {
 344             $hdr_s .= $this->foldLine($header[$i], 78,str_pad('',4));
 345         }
 346         $header = $hdr_s;
 347         $header .= $rn; /* One blank line to separate mimeheader and body-entity */
 348         return $header;
 349     }
 350
 351     /**
 352      * function prepareRFC822_Header - prepares the RFC822 header string from Rfc822Header object(s)
 353      *
 354      * This function takes the Rfc822Header object(s) and formats them
 355      * into the RFC822Header string to send to the SMTP server as part
 356      * of the SMTP message.
 357      *
 358      * @param Rfc822Header  $rfc822_header
 359      * @param Rfc822Header  $reply_rfc822_header
 360      * @param integer      &$raw_length length of the message
 361      *
 362      * @return string $header
 363      */
 364     function prepareRFC822_Header($rfc822_header, $reply_rfc822_header, &$raw_length) {
 365         global $domain, $version, $username;
 366
 367         /* if server var SERVER_NAME not available, use $domain */
 368         if(!sqGetGlobalVar('SERVER_NAME', $SERVER_NAME, SQ_SERVER)) {
 369             $SERVER_NAME = $domain;
 370         }
 371
 372         sqGetGlobalVar('REMOTE_ADDR', $REMOTE_ADDR, SQ_SERVER);
 373         sqGetGlobalVar('REMOTE_PORT', $REMOTE_PORT, SQ_SERVER);
 374         sqGetGlobalVar('REMOTE_HOST', $REMOTE_HOST, SQ_SERVER);
 375         sqGetGlobalVar('HTTP_VIA',    $HTTP_VIA,    SQ_SERVER);
 376         sqGetGlobalVar('HTTP_X_FORWARDED_FOR', $HTTP_X_FORWARDED_FOR, SQ_SERVER);
 377
 378         $rn = "\r\n";
 379
 380         /* This creates an RFC 822 date */
 381         $date = date('D, j M Y H:i:s ', mktime()) . $this->timezone();
 382         /* Create a message-id */
 383         $message_id = '<' . $REMOTE_PORT . '.' . $REMOTE_ADDR . '.';
 384         $message_id .= time() . '.squirrel@' . $REMOTE_ADDR .'>';
 385         /* Make an RFC822 Received: line */
 386         if (isset($REMOTE_HOST)) {
 387             $received_from = "$REMOTE_HOST ([$REMOTE_ADDR])";
 388         } else {
 389             $received_from = $REMOTE_ADDR;
 390         }
 391         if (isset($HTTP_VIA) || isset ($HTTP_X_FORWARDED_FOR)) {
 392             if (!isset($HTTP_X_FORWARDED_FOR) || $HTTP_X_FORWARDED_FOR == '') {
 393                 $HTTP_X_FORWARDED_FOR = 'unknown';
 394             }
 395             $received_from .= " (proxying for $HTTP_X_FORWARDED_FOR)";
 396         }
 397         $header = array();
 398         $header[] = "Received: from $received_from" . $rn;
 399         $header[] = "        (SquirrelMail authenticated user $username);" . $rn;
 400         $header[] = "        by $SERVER_NAME with HTTP;" . $rn;
 401         $header[] = "        $date" . $rn;
 402         /* Insert the rest of the header fields */
 403         $header[] = 'Message-ID: '. $message_id . $rn;
 404         if ($reply_rfc822_header->message_id) {
 405             $rep_message_id = $reply_rfc822_header->message_id;
 406         //        $this->strip_crlf($message_id);
 407             $header[] = 'In-Reply-To: '.$rep_message_id . $rn;
 408             $references = $this->calculate_references($reply_rfc822_header);
 409             $header[] = 'References: '.$references . $rn;
 410         }
 411         $header[] = "Date: $date" . $rn;
 412         $header[] = 'Subject: '.encodeHeader($rfc822_header->subject) . $rn;
 413         $header[] = 'From: '. $rfc822_header->getAddr_s('from',',',true) . $rn;
 414         /* RFC2822 if from contains more then 1 address */
 415         if (count($rfc822_header->from) > 1) {
 416             $header[] = 'Sender: '. $rfc822_header->getAddr_s('sender',',',true) . $rn;
 417         }
 418         if (count($rfc822_header->to)) {
 419             $header[] = 'To: '. $rfc822_header->getAddr_s('to',',',true) . $rn;
 420         }
 421         if (count($rfc822_header->cc)) {
 422             $header[] = 'Cc: '. $rfc822_header->getAddr_s('cc',',',true) . $rn;
 423         }
 424         if (count($rfc822_header->reply_to)) {
 425             $header[] = 'Reply-To: '. $rfc822_header->getAddr_s('reply_to',',',true) . $rn;
 426         }
 427         /* Sendmail should return true. Default = false */
 428         $bcc = $this->getBcc();
 429         if (count($rfc822_header->bcc)) {
 430             $s = 'Bcc: '. $rfc822_header->getAddr_s('bcc',',',true) . $rn;
 431             if (!$bcc) {
 432                 $s = $this->foldLine($s, 78, str_pad('',4));
 433                 $raw_length += strlen($s);
 434             } else {
 435                 $header[] = $s;
 436             }
 437         }
 438         /* Identify SquirrelMail */
 439         $header[] = 'User-Agent: SquirrelMail/' . $version . $rn;
 440         // Spamassassin complains about no X-Mailer in combination with X-Priority
 441         $header[] = 'X-Mailer: SquirrelMail/' . $version . $rn;
 442         /* Do the MIME-stuff */
 443         $header[] = 'MIME-Version: 1.0' . $rn;
 444         $contenttype = 'Content-Type: '. $rfc822_header->content_type->type0 .'/'.
 445                                          $rfc822_header->content_type->type1;
 446         if (count($rfc822_header->content_type->properties)) {
 447             foreach ($rfc822_header->content_type->properties as $k => $v) {
 448                 if ($k && $v) {
 449                     $contenttype .= ';' .$k.'='.$v;
 450                 }
 451             }
 452         }
 453         $header[] = $contenttype . $rn;
 454         if ($encoding = $rfc822_header->encoding) {
 455             $header[] .= 'Content-Transfer-Encoding: ' . $encoding .  $rn;
 456         }
 457         if ($rfc822_header->dnt) {
 458             $dnt = $rfc822_header->getAddr_s('dnt');
 459             /* Pegasus Mail */
 460             $header[] = 'X-Confirm-Reading-To: '.$dnt. $rn;
 461             /* RFC 2298 */
 462             $header[] = 'Disposition-Notification-To: '.$dnt. $rn;
 463         }
 464         if ($rfc822_header->priority) {
 465             $prio = $rfc822_header->priority;
 466             $header[] = 'X-Priority: '. $prio. $rn;
 467             switch($prio)
 468             {
 469             case 1: $header[] = 'Importance: High'. $rn; break;
 470             case 3: $header[] = 'Importance: Normal'. $rn; break;
 471             case 5: $header[] = 'Importance: Low'. $rn; break;
 472             default: break;
 473             }
 474         }
 475         /* Insert headers from the $more_headers array */
 476         if(count($rfc822_header->more_headers)) {
 477             reset($rfc822_header->more_headers);
 478             foreach ($rfc822_header->more_headers as $k => $v) {
 479                 $header[] = $k.': '.$v .$rn;
 480             }
 481         }
 482         $cnt = count($header);
 483         $hdr_s = '';
 484
 485         for ($i = 0 ; $i < $cnt ; $i++) {
 486             $sKey = substr($header[$i],0,strpos($header[$i],':'));
 487             switch ($sKey)
 488             {
 489             case 'Message-ID':
 490             case 'In-Reply_To':
 491                 $hdr_s .= $header[$i];
 492                 break;
 493             case 'References':
 494                 $sRefs = substr($header[$i],12);
 495                 $aRefs = explode(' ',$sRefs);
 496                 $sLine = 'References:';
 497                 foreach ($aRefs as $sReference) {
 498                     if (strlen($sLine)+strlen($sReference) >76) {
 499                         $hdr_s .= $sLine;
 500                         $sLine = $rn . '    ' . $sReference;
 501                     } else {
 502                         $sLine .= ' '. $sReference;
 503                     }
 504                 }
 505                 $hdr_s .= $sLine;
 506                 break;
 507             default: $hdr_s .= $this->foldLine($header[$i], 78, str_pad('',4)); break;
 508             }
 509         }
 510         $header = $hdr_s;
 511         $header .= $rn; /* One blank line to separate header and body */
 512         $raw_length += strlen($header);
 513         return $header;
 514     }
 515
 516     /**
 517      * function foldLine - for cleanly folding of headerlines
 518      *
 519      * @param   string  $line
 520      * @param   integer $length length to fold the line at
 521      * @param   string  $pre    prefix the line with...
 522      *
 523      * @return string   $line folded line with trailing CRLF
 524      */
 525     function foldLine($line, $length, $pre='') {
 526         $line = substr($line,0, -2);
 527         $length -= 2; /* do not fold between \r and \n */
 528         $cnt = strlen($line);
 529         if ($cnt > $length) { /* try folding */
 530             $fold_string = "\r\n " . $pre;
 531             $bFirstFold = false;
 532             $aFoldLine = array();
 533             while (strlen($line) > $length) {
 534                 $fold = false;
 535                 /* handle encoded parts */
 536                 if (preg_match('/(=\?([^?]*)\?(Q|B)\?([^?]*)\?=)(\s+|.*)/Ui',$line,$regs)) {
 537                     $fold_tmp = $regs[1];
 538                     if (!trim($regs[5])) {
 539                         $fold_tmp .= $regs[5];
 540                     }
 541                     $iPosEnc = strpos($line,$fold_tmp);
 542                     $iLengthEnc = strlen($fold_tmp);
 543                     $iPosEncEnd = $iPosEnc+$iLengthEnc;
 544                     if ($iPosEnc < $length && (($iPosEncEnd) > $length)) {
 545                         $fold = true;
 546                         /* fold just before the start of the encoded string */
 547                         if ($iPosEnc) {
 548                             $aFoldLine[] = substr($line,0,$iPosEnc);
 549                         }
 550                         $line = substr($line,$iPosEnc);
 551                         if (!$bFirstFold) {
 552                             $bFirstFold = true;
 553                             $length -= strlen($fold_string);
 554                         }
 555                         if ($iLengthEnc > $length) { /* place the encoded
 556                             string on a separate line and do not fold inside it*/
 557                             /* minimize foldstring */
 558                             $fold_string = "\r\n ";
 559                             $aFoldLine[] = substr($line,0,$iLengthEnc);
 560                             $line = substr($line,$iLengthEnc);
 561                         }
 562                     } else if ($iPosEnc < $length) { /* the encoded string fits into the foldlength */
 563                         /*remainder */
 564                         $sLineRem = substr($line,$iPosEncEnd,$length - $iPosEncEnd);
 565                         if (preg_match('/^(=\?([^?]*)\?(Q|B)\?([^?]*)\?=)(.*)/Ui',$sLineRem) || !preg_match('/[=,;\s]/',$sLineRem)) {
 566                             /*impossible to fold clean in the next part -> fold after the enc string */
 567                             $aFoldLine[] = substr($line,0,$iPosEncEnd);
 568                             $line = substr($line,$iPosEncEnd);
 569                             $fold = true;
 570                             if (!$bFirstFold) {
 571                                 $bFirstFold = true;
 572                                 $length -= strlen($fold_string);
 573                             }
 574                         }
 575                     }
 576                 }
 577                 if (!$fold) {
 578                     $line_tmp = substr($line,0,$length);
 579                     $iFoldPos = false;
 580                     /* try to fold at logical places */
 581                     switch (true)
 582                     {
 583                     case ($iFoldPos = strrpos($line_tmp,',')): break;
 584                     case ($iFoldPos = strrpos($line_tmp,';')): break;
 585                     case ($iFoldPos = strrpos($line_tmp,' ')): break;
 586                     case ($iFoldPos = strrpos($line_tmp,'=')): break;
 587                     default: break;
 588                     }
 589
 590                     if (!$iFoldPos) { /* clean folding didn't work */
 591                         $iFoldPos = $length;
 592                     }
 593                     $aFoldLine[] = substr($line,0,$iFoldPos+1);
 594                     $line = substr($line,$iFoldPos+1);
 595                     if (!$bFirstFold) {
 596                         $bFirstFold = true;
 597                         $length -= strlen($fold_string);
 598                     }
 599                 }
 600             }
 601             /*$reconstruct the line */
 602             if ($line) {
 603                 $aFoldLine[] = $line;
 604             }
 605             $line = implode($fold_string,$aFoldLine);
 606         }
 607         return $line."\r\n";
 608     }
 609
 610     /**
 611      * function mimeBoundary - calculates the mime boundary to use
 612      *
 613      * This function will generate a random mime boundary base part
 614      * for the message if the boundary has not already been set.
 615      *
 616      * @return string $mimeBoundaryString random mime boundary string
 617      */
 618     function mimeBoundary () {
 619         static $mimeBoundaryString;
 620
 621         if ( !isset( $mimeBoundaryString ) ||
 622             $mimeBoundaryString == '') {
 623             $mimeBoundaryString = '----=_' . date( 'YmdHis' ) . '_' .
 624             mt_rand( 10000, 99999 );
 625         }
 626         return $mimeBoundaryString;
 627     }
 628
 629     /**
 630      * function timezone - Time offset for correct timezone
 631      *
 632      * @return string $result with timezone and offset
 633      */
 634     function timezone () {
 635         global $invert_time;
 636
 637         $diff_second = date('Z');
 638         if ($invert_time) {
 639             $diff_second = - $diff_second;
 640         }
 641         if ($diff_second > 0) {
 642             $sign = '+';
 643         } else {
 644             $sign = '-';
 645         }
 646         $diff_second = abs($diff_second);
 647         $diff_hour = floor ($diff_second / 3600);
 648         $diff_minute = floor (($diff_second-3600*$diff_hour) / 60);
 649         $zonename = '('.strftime('%Z').')';
 650         $result = sprintf ("%s%02d%02d %s", $sign, $diff_hour, $diff_minute,
 651                        $zonename);
 652         return ($result);
 653     }
 654
 655     /**
 656      * function calculate_references - calculate correct Referer string
 657      *
 658      * @param   Rfc822Header $hdr    message header to calculate from
 659      *
 660      * @return  string       $refer  concatenated and trimmed Referer string
 661      */
 662     function calculate_references($hdr) {
 663         $refer = $hdr->references;
 664         $message_id = $hdr->message_id;
 665         $in_reply_to = $hdr->in_reply_to;
 666         if (strlen($refer) > 2) {
 667             $refer .= ' ' . $message_id;
 668         } else {
 669             if ($in_reply_to) {
 670                 $refer .= $in_reply_to . ' ' . $message_id;
 671             } else {
 672                 $refer .= $message_id;
 673             }
 674         }
 675         trim($refer);
 676         return $refer;
 677     }
 678 }
 679 ?>