class/deliver/Deliver.class.php

   1 <?php
   2 /**
   3  * Deliver.class.php
   4  *
   5  * Copyright (c) 1999-2005 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  * @version $Id$
  12  * @author  Marc Groot Koerkamp
  13  * @package squirrelmail
  14  */
  15
  16 /**
  17  * Deliver Class - called to actually deliver the message
  18  *
  19  * This class is called by compose.php and other code that needs
  20  * to send messages.  All delivery functionality should be centralized
  21  * in this class.
  22  *
  23  * Do not place UI code in this class, as UI code should be placed in templates
  24  * going forward.
  25  *
  26  * @author  Marc Groot Koerkamp
  27  * @package squirrelmail
  28  */
  29 class Deliver {
  30
  31     /**
  32      * function mail - send the message parts to the SMTP stream
  33      *
  34      * @param Message  $message  Message class to send
  35      * @param resource $stream   file handle to the SMTP stream
  36      *
  37      * @return integer $raw_length
  38      */
  39     function mail($message, $stream=false) {
  40         $rfc822_header = $message->rfc822_header;
  41         if (count($message->entities)) {
  42             $boundary = $this->mimeBoundary();
  43             $rfc822_header->content_type->properties['boundary']='"'.$boundary.'"';
  44         } else {
  45             $boundary='';
  46         }
  47         $raw_length = 0;
  48         $reply_rfc822_header = (isset($message->reply_rfc822_header)
  49                              ? $message->reply_rfc822_header : '');
  50         $header = $this->prepareRFC822_Header($rfc822_header, $reply_rfc822_header, $raw_length);
  51
  52         if ($stream) {
  53             $this->preWriteToStream($header);
  54             $this->writeToStream($stream, $header);
  55         }
  56         $this->writeBody($message, $stream, $raw_length, $boundary);
  57         return $raw_length;
  58     }
  59
  60     /**
  61      * function writeBody - generate and write the mime boundaries around each part to the stream
  62      *
  63      * Recursively formats and writes the MIME boundaries of the $message
  64      * to the output stream.
  65      *
  66      * @param Message   $message      Message object to transform
  67      * @param resource  $stream       SMTP output stream
  68      * @param integer  &$length_raw   raw length of the message (part)
  69      *                                as returned by mail fn
  70      * @param string    $boundary     custom boundary to call, usually for subparts
  71      *
  72      * @return void
  73      */
  74     function writeBody($message, $stream, &$length_raw, $boundary='') {
  75         // calculate boundary in case of multidimensional mime structures
  76         if ($boundary && $message->entity_id && count($message->entities)) {
  77             if (strpos($boundary,'_part_')) {
  78                 $boundary = substr($boundary,0,strpos($boundary,'_part_'));
  79             }
  80             $boundary_new = $boundary . '_part_'.$message->entity_id;
  81         } else {
  82             $boundary_new = $boundary;
  83         }
  84         if ($boundary && !$message->rfc822_header) {
  85             $s = '--'.$boundary."\r\n";
  86             $s .= $this->prepareMIME_Header($message, $boundary_new);
  87             $length_raw += strlen($s);
  88             if ($stream) {
  89                 $this->preWriteToStream($s);
  90                 $this->writeToStream($stream, $s);
  91             }
  92         }
  93         $this->writeBodyPart($message, $stream, $length_raw);
  94
  95         $last = false;
  96         for ($i=0, $entCount=count($message->entities);$i<$entCount;$i++) {
  97             $msg = $this->writeBody($message->entities[$i], $stream, $length_raw, $boundary_new);
  98             if ($i == $entCount-1) $last = true;
  99         }
 100         if ($boundary && $last) {
 101             $s = "--".$boundary_new."--\r\n\r\n";
 102             $length_raw += strlen($s);
 103             if ($stream) {
 104                 $this->preWriteToStream($s);
 105                 $this->writeToStream($stream, $s);
 106             }
 107         }
 108     }
 109
 110     /**
 111      * function writeBodyPart - write each individual mimepart
 112      *
 113      * Recursively called by WriteBody to write each mime part to the SMTP stream
 114      *
 115      * @param Message   $message      Message object to transform
 116      * @param resource  $stream       SMTP output stream
 117      * @param integer  &$length       length of the message part
 118      *                                as returned by mail fn
 119      *
 120      * @return void
 121      */
 122     function writeBodyPart($message, $stream, &$length) {
 123         if ($message->mime_header) {
 124             $type0 = $message->mime_header->type0;
 125         } else {
 126             $type0 = $message->rfc822_header->content_type->type0;
 127         }
 128
 129         $body_part_trailing = $last = '';
 130         switch ($type0)
 131         {
 132         case 'text':
 133         case 'message':
 134             if ($message->body_part) {
 135                 $body_part = $message->body_part;
 136                 // remove NUL characters
 137                 $body_part = str_replace("\0",'',$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                 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             $contenttype .= ';' . 'boundary="'.$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             $header[] = 'Content-Transfer-Encoding: ' . $mime_header->encoding . $rn;
 313         } else {
 314             if ($mime_header->type0 == 'text' || $mime_header->type0 == 'message') {
 315                 $header[] = 'Content-Transfer-Encoding: 8bit' .  $rn;
 316             } else {
 317                 $header[] = 'Content-Transfer-Encoding: base64' .  $rn;
 318             }
 319         }
 320         if ($mime_header->id) {
 321             $header[] = 'Content-ID: ' . $mime_header->id . $rn;
 322         }
 323         if ($mime_header->disposition) {
 324             $disposition = $mime_header->disposition;
 325             $contentdisp = 'Content-Disposition: ' . $disposition->name;
 326             if ($disposition->getProperty('filename')) {
 327                 $contentdisp .= '; filename="'.
 328                 encodeHeader($disposition->getProperty('filename')). '"';
 329             }
 330             $header[] = $contentdisp . $rn;
 331         }
 332         if ($mime_header->md5) {
 333             $header[] = 'Content-MD5: ' . $mime_header->md5 . $rn;
 334         }
 335         if ($mime_header->language) {
 336             $header[] = 'Content-Language: ' . $mime_header->language . $rn;
 337         }
 338
 339         $cnt = count($header);
 340         $hdr_s = '';
 341         for ($i = 0 ; $i < $cnt ; $i++)    {
 342             $hdr_s .= $this->foldLine($header[$i], 78,str_pad('',4));
 343         }
 344         $header = $hdr_s;
 345         $header .= $rn; /* One blank line to separate mimeheader and body-entity */
 346         return $header;
 347     }
 348
 349     /**
 350      * function prepareRFC822_Header - prepares the RFC822 header string from Rfc822Header object(s)
 351      *
 352      * This function takes the Rfc822Header object(s) and formats them
 353      * into the RFC822Header string to send to the SMTP server as part
 354      * of the SMTP message.
 355      *
 356      * @param Rfc822Header  $rfc822_header
 357      * @param Rfc822Header  $reply_rfc822_header
 358      * @param integer      &$raw_length length of the message
 359      *
 360      * @return string $header
 361      */
 362     function prepareRFC822_Header($rfc822_header, $reply_rfc822_header, &$raw_length) {
 363         global $domain, $version, $username, $skip_SM_header;
 364
 365         /* if server var SERVER_NAME not available, use $domain */
 366         if(!sqGetGlobalVar('SERVER_NAME', $SERVER_NAME, SQ_SERVER)) {
 367             $SERVER_NAME = $domain;
 368         }
 369
 370         sqGetGlobalVar('REMOTE_ADDR', $REMOTE_ADDR, SQ_SERVER);
 371         sqGetGlobalVar('REMOTE_PORT', $REMOTE_PORT, SQ_SERVER);
 372         sqGetGlobalVar('REMOTE_HOST', $REMOTE_HOST, SQ_SERVER);
 373         sqGetGlobalVar('HTTP_VIA',    $HTTP_VIA,    SQ_SERVER);
 374         sqGetGlobalVar('HTTP_X_FORWARDED_FOR', $HTTP_X_FORWARDED_FOR, SQ_SERVER);
 375
 376         $rn = "\r\n";
 377
 378         /* This creates an RFC 822 date */
 379         $date = date('D, j M Y H:i:s ', mktime()) . $this->timezone();
 380         /* Create a message-id */
 381         $message_id = '<' . $REMOTE_PORT . '.' . $REMOTE_ADDR . '.';
 382         $message_id .= time() . '.squirrel@' . $SERVER_NAME .'>';
 383         /* Make an RFC822 Received: line */
 384         if (isset($REMOTE_HOST)) {
 385             $received_from = "$REMOTE_HOST ([$REMOTE_ADDR])";
 386         } else {
 387             $received_from = $REMOTE_ADDR;
 388         }
 389         if (isset($HTTP_VIA) || isset ($HTTP_X_FORWARDED_FOR)) {
 390             if (!isset($HTTP_X_FORWARDED_FOR) || $HTTP_X_FORWARDED_FOR == '') {
 391                 $HTTP_X_FORWARDED_FOR = 'unknown';
 392             }
 393             $received_from .= " (proxying for $HTTP_X_FORWARDED_FOR)";
 394         }
 395         $header = array();
 396         if ( !isset($skip_SM_header) || !$skip_SM_header )
 397         {
 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         }
 403         /* Insert the rest of the header fields */
 404         $header[] = 'Message-ID: '. $message_id . $rn;
 405         if ($reply_rfc822_header->message_id) {
 406             $rep_message_id = $reply_rfc822_header->message_id;
 407         //        $this->strip_crlf($message_id);
 408             $header[] = 'In-Reply-To: '.$rep_message_id . $rn;
 409             $references = $this->calculate_references($reply_rfc822_header);
 410             $header[] = 'References: '.$references . $rn;
 411         }
 412         $header[] = "Date: $date" . $rn;
 413         $header[] = 'Subject: '.encodeHeader($rfc822_header->subject) . $rn;
 414         $header[] = 'From: '. $rfc822_header->getAddr_s('from',",$rn ",true) . $rn;
 415
 416         // folding address list [From|To|Cc|Bcc] happens by using ",$rn<space>" as delimiter
 417         // Do not use foldLine for that.
 418
 419         // RFC2822 if from contains more then 1 address
 420         if (count($rfc822_header->from) > 1) {
 421             $header[] = 'Sender: '. $rfc822_header->getAddr_s('sender',',',true) . $rn;
 422         }
 423         if (count($rfc822_header->to)) {
 424             $header[] = 'To: '. $rfc822_header->getAddr_s('to',",$rn ",true) . $rn;
 425         }
 426         if (count($rfc822_header->cc)) {
 427             $header[] = 'Cc: '. $rfc822_header->getAddr_s('cc',",$rn ",true) . $rn;
 428         }
 429         if (count($rfc822_header->reply_to)) {
 430             $header[] = 'Reply-To: '. $rfc822_header->getAddr_s('reply_to',',',true) . $rn;
 431         }
 432         /* Sendmail should return true. Default = false */
 433         $bcc = $this->getBcc();
 434         if (count($rfc822_header->bcc)) {
 435             $s = 'Bcc: '. $rfc822_header->getAddr_s('bcc',",$rn ",true) . $rn;
 436             if (!$bcc) {
 437                 $raw_length += strlen($s);
 438             } else {
 439                 $header[] = $s;
 440             }
 441         }
 442         /* Identify SquirrelMail */
 443         $header[] = 'User-Agent: SquirrelMail/' . $version . $rn;
 444         /* Do the MIME-stuff */
 445         $header[] = 'MIME-Version: 1.0' . $rn;
 446         $contenttype = 'Content-Type: '. $rfc822_header->content_type->type0 .'/'.
 447                                          $rfc822_header->content_type->type1;
 448         if (count($rfc822_header->content_type->properties)) {
 449             foreach ($rfc822_header->content_type->properties as $k => $v) {
 450                 if ($k && $v) {
 451                     $contenttype .= ';' .$k.'='.$v;
 452                 }
 453             }
 454         }
 455         $header[] = $contenttype . $rn;
 456         if ($encoding = $rfc822_header->encoding) {
 457             $header[] = 'Content-Transfer-Encoding: ' . $encoding .  $rn;
 458         }
 459         if ($rfc822_header->dnt) {
 460             $dnt = $rfc822_header->getAddr_s('dnt');
 461             /* Pegasus Mail */
 462             $header[] = 'X-Confirm-Reading-To: '.$dnt. $rn;
 463             /* RFC 2298 */
 464             $header[] = 'Disposition-Notification-To: '.$dnt. $rn;
 465         }
 466         if ($rfc822_header->priority) {
 467             switch($rfc822_header->priority)
 468             {
 469             case 1:
 470                 $header[] = 'X-Priority: 1 (Highest)'.$rn;
 471                 $header[] = 'Importance: High'. $rn; break;
 472             case 5:
 473                 $header[] = 'X-Priority: 5 (Lowest)'.$rn;
 474                 $header[] = 'Importance: Low'. $rn; break;
 475             default: break;
 476             }
 477         }
 478         /* Insert headers from the $more_headers array */
 479         if(count($rfc822_header->more_headers)) {
 480             reset($rfc822_header->more_headers);
 481             foreach ($rfc822_header->more_headers as $k => $v) {
 482                 $header[] = $k.': '.$v .$rn;
 483             }
 484         }
 485         $cnt = count($header);
 486         $hdr_s = '';
 487
 488         for ($i = 0 ; $i < $cnt ; $i++) {
 489             $sKey = substr($header[$i],0,strpos($header[$i],':'));
 490             switch ($sKey)
 491             {
 492             case 'Message-ID':
 493             case 'In-Reply_To':
 494                 $hdr_s .= $header[$i];
 495                 break;
 496             case 'References':
 497                 $sRefs = substr($header[$i],12);
 498                 $aRefs = explode(' ',$sRefs);
 499                 $sLine = 'References:';
 500                 foreach ($aRefs as $sReference) {
 501                     if (strlen($sLine)+strlen($sReference) >76) {
 502                         $hdr_s .= $sLine;
 503                         $sLine = $rn . '    ' . $sReference;
 504                     } else {
 505                         $sLine .= ' '. $sReference;
 506                     }
 507                 }
 508                 $hdr_s .= $sLine;
 509                 break;
 510             case 'To':
 511             case 'Cc':
 512             case 'Bcc':
 513             case 'From':
 514                 $hdr_s .= $header[$i];
 515                 break;
 516             default: $hdr_s .= $this->foldLine($header[$i], 78, str_pad('',4)); break;
 517             }
 518         }
 519         $header = $hdr_s;
 520         $header .= $rn; /* One blank line to separate header and body */
 521         $raw_length += strlen($header);
 522         return $header;
 523     }
 524
 525     /**
 526      * function foldLine - for cleanly folding of headerlines
 527      *
 528      * @param   string  $line
 529      * @param   integer $length length to fold the line at
 530      * @param   string  $pre    prefix the line with...
 531      *
 532      * @return string   $line folded line with trailing CRLF
 533      */
 534     function foldLine($line, $length, $pre='') {
 535         $line = substr($line,0, -2);
 536         $length -= 2; /* do not fold between \r and \n */
 537         $cnt = strlen($line);
 538         if ($cnt > $length) { /* try folding */
 539             $fold_string = "\r\n " . $pre;
 540             $bFirstFold = false;
 541             $aFoldLine = array();
 542             while (strlen($line) > $length) {
 543                 $fold = false;
 544                 /* handle encoded parts */
 545                 if (preg_match('/(=\?([^?]*)\?(Q|B)\?([^?]*)\?=)(\s+|.*)/Ui',$line,$regs)) {
 546                     $fold_tmp = $regs[1];
 547                     if (!trim($regs[5])) {
 548                         $fold_tmp .= $regs[5];
 549                     }
 550                     $iPosEnc = strpos($line,$fold_tmp);
 551                     $iLengthEnc = strlen($fold_tmp);
 552                     $iPosEncEnd = $iPosEnc+$iLengthEnc;
 553                     if ($iPosEnc < $length && (($iPosEncEnd) > $length)) {
 554                         $fold = true;
 555                         /* fold just before the start of the encoded string */
 556                         if ($iPosEnc) {
 557                             $aFoldLine[] = substr($line,0,$iPosEnc);
 558                         }
 559                         $line = substr($line,$iPosEnc);
 560                         if (!$bFirstFold) {
 561                             $bFirstFold = true;
 562                             $length -= strlen($fold_string);
 563                         }
 564                         if ($iLengthEnc > $length) { /* place the encoded
 565                             string on a separate line and do not fold inside it*/
 566                             /* minimize foldstring */
 567                             $fold_string = "\r\n ";
 568                             $aFoldLine[] = substr($line,0,$iLengthEnc);
 569                             $line = substr($line,$iLengthEnc);
 570                         }
 571                     } else if ($iPosEnc < $length) { /* the encoded string fits into the foldlength */
 572                         /*remainder */
 573                         $sLineRem = substr($line,$iPosEncEnd,$length - $iPosEncEnd);
 574                         if (preg_match('/^(=\?([^?]*)\?(Q|B)\?([^?]*)\?=)(.*)/Ui',$sLineRem) || !preg_match('/[=,;\s]/',$sLineRem)) {
 575                             /*impossible to fold clean in the next part -> fold after the enc string */
 576                             $aFoldLine[] = substr($line,0,$iPosEncEnd);
 577                             $line = substr($line,$iPosEncEnd);
 578                             $fold = true;
 579                             if (!$bFirstFold) {
 580                                 $bFirstFold = true;
 581                                 $length -= strlen($fold_string);
 582                             }
 583                         }
 584                     }
 585                 }
 586                 if (!$fold) {
 587                     $line_tmp = substr($line,0,$length);
 588                     $iFoldPos = false;
 589                     /* try to fold at logical places */
 590                     switch (true)
 591                     {
 592                     case ($iFoldPos = strrpos($line_tmp,',')): break;
 593                     case ($iFoldPos = strrpos($line_tmp,';')): break;
 594                     case ($iFoldPos = strrpos($line_tmp,' ')): break;
 595                     case ($iFoldPos = strrpos($line_tmp,'=')): break;
 596                     default: break;
 597                     }
 598
 599                     if (!$iFoldPos) { /* clean folding didn't work */
 600                         $iFoldPos = $length;
 601                     }
 602                     $aFoldLine[] = substr($line,0,$iFoldPos+1);
 603                     $line = substr($line,$iFoldPos+1);
 604                     if (!$bFirstFold) {
 605                         $bFirstFold = true;
 606                         $length -= strlen($fold_string);
 607                     }
 608                 }
 609             }
 610             /*$reconstruct the line */
 611             if ($line) {
 612                 $aFoldLine[] = $line;
 613             }
 614             $line = implode($fold_string,$aFoldLine);
 615         }
 616         return $line."\r\n";
 617     }
 618
 619     /**
 620      * function mimeBoundary - calculates the mime boundary to use
 621      *
 622      * This function will generate a random mime boundary base part
 623      * for the message if the boundary has not already been set.
 624      *
 625      * @return string $mimeBoundaryString random mime boundary string
 626      */
 627     function mimeBoundary () {
 628         static $mimeBoundaryString;
 629
 630         if ( !isset( $mimeBoundaryString ) ||
 631             $mimeBoundaryString == '') {
 632             $mimeBoundaryString = '----=_' . date( 'YmdHis' ) . '_' .
 633             mt_rand( 10000, 99999 );
 634         }
 635         return $mimeBoundaryString;
 636     }
 637
 638     /**
 639      * function timezone - Time offset for correct timezone
 640      *
 641      * @return string $result with timezone and offset
 642      */
 643     function timezone () {
 644         global $invert_time;
 645
 646         $diff_second = date('Z');
 647         if ($invert_time) {
 648             $diff_second = - $diff_second;
 649         }
 650         if ($diff_second > 0) {
 651             $sign = '+';
 652         } else {
 653             $sign = '-';
 654         }
 655         $diff_second = abs($diff_second);
 656         $diff_hour = floor ($diff_second / 3600);
 657         $diff_minute = floor (($diff_second-3600*$diff_hour) / 60);
 658         $zonename = '('.strftime('%Z').')';
 659         $result = sprintf ("%s%02d%02d %s", $sign, $diff_hour, $diff_minute,
 660                        $zonename);
 661         return ($result);
 662     }
 663
 664     /**
 665      * function calculate_references - calculate correct Referer string
 666      *
 667      * @param   Rfc822Header $hdr    message header to calculate from
 668      *
 669      * @return  string       $refer  concatenated and trimmed Referer string
 670      */
 671     function calculate_references($hdr) {
 672         $refer = $hdr->references;
 673         $message_id = $hdr->message_id;
 674         $in_reply_to = $hdr->in_reply_to;
 675         if (strlen($refer) > 2) {
 676             $refer .= ' ' . $message_id;
 677         } else {
 678             if ($in_reply_to) {
 679                 $refer .= $in_reply_to . ' ' . $message_id;
 680             } else {
 681                 $refer .= $message_id;
 682             }
 683         }
 684         trim($refer);
 685         return $refer;
 686     }
 687 }
 688 ?>