functions/mime.php

   1 <?php
   2    /** mime.php
   3     **
   4     ** This contains the functions necessary to detect and decode MIME
   5     ** messages.
   6     **
   7     **/
   8
   9    $debug_mime = false;
  10    $mime_php = true;
  11
  12    if (!isset($i18n_php))
  13       include "../functions/i18n.php";
  14    if (!isset($imap_php))
  15       include "../functions/imap.php";
  16    if (!isset($config_php))
  17       include "../config/config.php";
  18
  19
  20    /** Setting up the objects that have the structure for the message **/
  21
  22    class msg_header {
  23       /** msg_header contains generic variables for values that **/
  24       /** could be in a header.                                 **/
  25
  26       var $type0, $type1, $boundary, $charset, $encoding;
  27       var $to, $from, $date, $cc, $bcc, $reply_to, $subject;
  28       var $id, $mailbox, $description;
  29       var $entity_id, $message_id, $charset;
  30    }
  31
  32    class message {
  33       /** message is the object that contains messages.  It is a recursive
  34           object in that through the $entities variable, it can contain
  35           more objects of type message.  See documentation in mime.txt for
  36           a better description of how this works.
  37        **/
  38       var $header;
  39       var $entities;
  40
  41       function addEntity ($msg) {
  42          $this->entities[count($this->entities)] = $msg;
  43       }
  44    }
  45
  46
  47
  48    /* --------------------------------------------------------------------------------- */
  49    /* MIME DECODING                                                                     */
  50    /* --------------------------------------------------------------------------------- */
  51
  52    // This function gets the structure of a message and stores it in the "message" class.
  53    // It will return this object for use with all relevant header information and
  54    // fully parsed into the standard "message" object format.
  55    function mime_structure ($imap_stream, $header) {
  56       global $debug_mime;
  57       sqimap_messages_flag ($imap_stream, $header->id, $header->id, "Seen");
  58
  59       $id = $header->id;
  60       fputs ($imap_stream, "a001 FETCH $id BODYSTRUCTURE\r\n");
  61       $read = fgets ($imap_stream, 10000);
  62       $endline = fgets($imap_stream, 1024);
  63       $read = strtolower($read);
  64
  65       if ($debug_mime) echo "<tt>$read</tt><br><br>";
  66       // isolate the body structure and remove beginning and end parenthesis
  67       $read = trim(substr ($read, strpos($read, "bodystructure") + 13));
  68       $read = trim(substr ($read, 0, -1));
  69       $end = mime_match_parenthesis(0, $read);
  70       while ($end == strlen($read)-1) {
  71          $read = trim(substr ($read, 0, -1));
  72          $read = trim(substr ($read, 1));
  73          $end = mime_match_parenthesis(0, $read);
  74       }
  75
  76       if ($debug_mime) echo "<tt>$read</tt><br><br>";
  77
  78       $msg = mime_parse_structure ($read, 0);
  79       $msg->header = $header;
  80       return $msg;
  81    }
  82
  83    // this starts the parsing of a particular structure.  It is called recursively,
  84    // so it can be passed different structures.  It returns an object of type
  85    // $message.
  86    // First, it checks to see if it is a multipart message.  If it is, then it
  87    // handles that as it sees is necessary.  If it is just a regular entity,
  88    // then it parses it and adds the necessary header information (by calling out
  89    // to mime_get_elements()
  90    function mime_parse_structure ($structure, $ent_id) {
  91       global $debug_mime;
  92       if ($debug_mime) echo "<font color=008800><tt>START: mime_parse_structure()</tt></font><br>";
  93       $msg = new message();
  94       if (substr($structure, 0, 1) == "(") {
  95          $ent_id = mime_new_element_level($ent_id);
  96          $start = $end = -1;
  97          if ($debug_mime) echo "<br><font color=0000aa><tt>$structure</tt></font><br>";
  98          do {
  99             if ($debug_mime) echo "<font color=008800><tt>Found entity...</tt></font><br>";
 100             $start = $end+1;
 101             $end = mime_match_parenthesis ($start, $structure);
 102
 103             $element = substr($structure, $start+1, ($end - $start)-1);
 104             $ent_id = mime_increment_id ($ent_id);
 105             $newmsg = mime_parse_structure ($element, $ent_id);
 106             $msg->addEntity ($newmsg);
 107          } while (substr($structure, $end+1, 1) == "(");
 108       } else {
 109          // parse the elements
 110          if ($debug_mime) echo "<br><font color=0000aa><tt>$structure</tt></font><br>";
 111          $msg = mime_get_element (&$structure, $msg, $ent_id);
 112          if ($debug_mime) echo "<br>";
 113       }
 114       return $msg;
 115       if ($debug_mime) echo "<font color=008800><tt>&nbsp;&nbsp;END: mime_parse_structure()</tt></font><br>";
 116    }
 117
 118    // Increments the element ID.  An element id can look like any of
 119    // the following:  1, 1.2, 4.3.2.4.1, etc.  This function increments
 120    // the last number of the element id, changing 1.2 to 1.3.
 121    function mime_increment_id ($id) {
 122       global $debug_mime;
 123       if (strpos($id, ".")) {
 124          $first = substr($id, 0, strrpos($id, "."));
 125          $last = substr($id, strrpos($id, ".")+1);
 126          $last++;
 127          $new = $first . "." .$last;
 128       } else {
 129          $new = $id + 1;
 130       }
 131       if ($debug_mime) echo "<b>INCREMENT: $new</b><br>";
 132       return $new;
 133    }
 134
 135    // See comment for mime_increment_id().
 136    // This adds another level on to the entity_id changing 1.3 to 1.3.0
 137    // NOTE:  1.3.0 is not a valid element ID.  It MUST be incremented
 138    //        before it can be used.  I left it this way so as not to have
 139    //        to make a special case if it is the first entity_id.  It
 140    //        always increments it, and that works fine.
 141    function mime_new_element_level ($id) {
 142       if (!$id) $id = 0;
 143       else      $id = $id . ".0";
 144
 145       return $id;
 146    }
 147
 148    function mime_get_element (&$structure, $msg, $ent_id) {
 149       global $debug_mime;
 150       $elem_num = 1;
 151       $msg->header = new msg_header();
 152       $msg->header->entity_id = $ent_id;
 153
 154       while (strlen($structure) > 0) {
 155          $structure = trim($structure);
 156          $char = substr($structure, 0, 1);
 157
 158          if (substr($structure, 0, 3) == "nil") {
 159             $text = "";
 160             $structure = substr($structure, 3);
 161          } else if ($char == "\"") {
 162             // loop through until we find the matching quote, and return that as a string
 163             $pos = 1;
 164             $char = substr($structure, $pos, 1);
 165             while ($char != "\"" && $pos < strlen($structure)) {
 166                $text .= $char;
 167                $pos++;
 168                $char = substr($structure, $pos, 1);
 169             }
 170             $structure = substr($structure, strlen($text) + 2);
 171          } else if ($char == "(") {
 172             // comment me
 173             $end = mime_match_parenthesis (0, $structure);
 174             $sub = substr($structure, 1, $end-1);
 175             $properties = mime_get_props($properties, $sub);
 176             $structure = substr($structure, strlen($sub) + 2);
 177          } else {
 178             // loop through until we find a space or an end parenthesis
 179             $pos = 0;
 180             $char = substr($structure, $pos, 1);
 181             while ($char != " " && $char != ")" && $pos < strlen($structure)) {
 182                $text .= $char;
 183                $pos++;
 184                $char = substr($structure, $pos, 1);
 185             }
 186             $structure = substr($structure, strlen($text));
 187          }
 188          if ($debug_mime) echo "<tt>$elem_num : $text</tt><br>";
 189
 190          // This is where all the text parts get put into the header
 191          switch ($elem_num) {
 192             case 1:
 193                $msg->header->type0 = $text;
 194                if ($debug_mime) echo "<tt>type0 = $text</tt><br>";
 195                break;
 196             case 2:
 197                $msg->header->type1 = $text;
 198                if ($debug_mime) echo "<tt>type1 = $text</tt><br>";
 199                break;
 200             case 5:
 201                $msg->header->description = $text;
 202                if ($debug_mime) echo "<tt>description = $text</tt><br>";
 203                break;
 204             case 6:
 205                $msg->header->encoding = $text;
 206                if ($debug_mime) echo "<tt>encoding = $text</tt><br>";
 207                break;
 208             case 7:
 209                $msg->header->size = $text;
 210                if ($debug_mime) echo "<tt>size = $text</tt><br>";
 211                break;
 212             default:
 213                if ($msg->header->type0 == "text" && $elem_num == 8) {
 214                   // This is a plain text message, so lets get the number of lines
 215                   // that it contains.
 216                   $msg->header->num_lines = $text;
 217                   if ($debug_mime) echo "<tt>num_lines = $text</tt><br>";
 218
 219                } else if ($msg->header->type0 == "message" && $msg->header->type1 == "rfc822" && $elem_num == 8) {
 220                   // This is an encapsulated message, so lets start all over again and
 221                   // parse this message adding it on to the existing one.
 222                   $structure = trim($structure);
 223                   if (substr($structure, 0, 1) == "(") {
 224                      $e = mime_match_parenthesis (0, $structure);
 225                      $structure = substr($structure, 0, $e);
 226                      $structure = substr($structure, 1);
 227                      $m = mime_parse_structure($structure, $msg->header->entity_id);
 228
 229                      // the following conditional is there to correct a bug that wasn't
 230                      // incrementing the entity IDs correctly because of the special case
 231                      // that message/rfc822 is.  This fixes it fine.
 232                      if (substr($structure, 1, 1) != "(")
 233                         $m->header->entity_id = mime_increment_id(mime_new_element_level($ent_id));
 234
 235                      // Now we'll go through and reformat the results.
 236                      if ($m->entities) {
 237                         for ($i=0; $i < count($m->entities); $i++) {
 238                            $msg->addEntity($m->entities[$i]);
 239                         }
 240                      } else {
 241                         $msg->addEntity($m);
 242                      }
 243                      $structure = "";
 244                   }
 245                }
 246                break;
 247          }
 248          $elem_num++;
 249          $text = "";
 250       }
 251       // loop through the additional properties and put those in the various headers
 252       if ($msg->header->type0 != "message") {
 253          for ($i=0; $i < count($properties); $i++) {
 254             $msg->header->{$properties[$i]["name"]} = $properties[$i]["value"];
 255             if ($debug_mime) echo "<tt>".$properties[$i]["name"]." = " . $properties[$i]["value"] . "</tt><br>";
 256          }
 257       }
 258
 259       return $msg;
 260    }
 261
 262    // I did most of the MIME stuff yesterday (June 20, 2000), but I couldn't
 263    // figure out how to do this part, so I decided to go to bed.  I woke up
 264    // in the morning and had a flash of insight.  I went to the white-board
 265    // and scribbled it out, then spent a bit programming it, and this is the
 266    // result.  Nothing complicated, but I think my brain was fried yesterday.
 267    // Funny how that happens some times.
 268    //
 269    // This gets properties in a nested parenthesisized list.  For example,
 270    // this would get passed something like:  ("attachment" ("filename" "luke.tar.gz"))
 271    // This returns an array called $props with all paired up properties.
 272    // It ignores the "attachment" for now, maybe that should change later
 273    // down the road.  In this case, what is returned is:
 274    //    $props[0]["name"] = "filename";
 275    //    $props[0]["value"] = "luke.tar.gz";
 276    function mime_get_props ($props, $structure) {
 277       global $debug_mime;
 278       while (strlen($structure) > 0) {
 279          $structure = trim($structure);
 280          $char = substr($structure, 0, 1);
 281
 282          if ($char == "\"") {
 283             $pos = 1;
 284             $char = substr($structure, $pos, 1);
 285             while ($char != "\"" && $pos < strlen($structure)) {
 286                $tmp .= $char;
 287                $pos++;
 288                $char = substr($structure, $pos, 1);
 289             }
 290             $structure = trim(substr($structure, strlen($tmp) + 2));
 291             $char = substr($structure, 0, 1);
 292
 293             if ($char == "\"") {
 294                $pos = 1;
 295                $char = substr($structure, $pos, 1);
 296                while ($char != "\"" && $pos < strlen($structure)) {
 297                   $value .= $char;
 298                   $pos++;
 299                   $char = substr($structure, $pos, 1);
 300                }
 301                $structure = trim(substr($structure, strlen($tmp) + 2));
 302
 303                $k = count($props);
 304                $props[$k]["name"] = $tmp;
 305                $props[$k]["value"] = $value;
 306             } else if ($char == "(") {
 307                $end = mime_match_parenthesis (0, $structure);
 308                $sub = substr($structure, 1, $end-1);
 309                $props = mime_get_props($props, $sub);
 310                $structure = substr($structure, strlen($sub) + 2);
 311             }
 312             return $props;
 313          } else if ($char == "(") {
 314             $end = mime_match_parenthesis (0, $structure);
 315             $sub = substr($structure, 1, $end-1);
 316             $props = mime_get_props($props, $sub);
 317             $structure = substr($structure, strlen($sub) + 2);
 318             return $props;
 319          } else {
 320             return $props;
 321          }
 322       }
 323    }
 324
 325    //  Matches parenthesis.  It will return the position of the matching
 326    //  parenthesis in $structure.  For instance, if $structure was:
 327    //     ("text" "plain" ("val1name", "1") nil ... )
 328    //     x                                         x
 329    //  then this would return 42 to match up those two.
 330    function mime_match_parenthesis ($pos, $structure) {
 331       $char = substr($structure, $pos, 1);
 332
 333       // ignore all extra characters
 334       while ($pos < strlen($structure)) {
 335          $pos++;
 336          $char = substr($structure, $pos, 1);
 337          if ($char == ")") {
 338             return $pos;
 339          } else if ($char == "(") {
 340             $pos = mime_match_parenthesis ($pos, $structure);
 341          }
 342       }
 343    }
 344
 345    function mime_fetch_body ($imap_stream, $id, $ent_id) {
 346       // do a bit of error correction.  If we couldn't find the entity id, just guess
 347       // that it is the first one.  That is usually the case anyway.
 348       if (!$ent_id) $ent_id = 1;
 349
 350       fputs ($imap_stream, "a001 FETCH $id BODY[$ent_id]\r\n");
 351       $topline = fgets ($imap_stream, 1024);
 352       $size = substr ($topline, strpos($topline, "{")+1);
 353       $size = substr ($size, 0, strpos($size, "}"));
 354       $read = fread ($imap_stream, $size);
 355       return $read;
 356    }
 357
 358    /* -[ END MIME DECODING ]----------------------------------------------------------- */
 359
 360
 361
 362    /** This is the first function called.  It decides if this is a multipart
 363        message or if it should be handled as a single entity
 364     **/
 365    function decodeMime ($imap_stream, $body, $header) {
 366       global $username, $key, $imapServerAddress, $imapPort;
 367       return mime_structure ($imap_stream, $header);
 368    }
 369
 370    // This is here for debugging purposese.  It will print out a list
 371    // of all the entity IDs that are in the $message object.
 372    function listEntities ($message) {
 373       if ($message) {
 374          if ($message->header->entity_id)
 375          echo "<tt>" . $message->header->entity_id . " : " . $message->header->type0 . "/" . $message->header->type1 . "<br>";
 376          for ($i = 0; $message->entities[$i]; $i++) {
 377             $msg = listEntities($message->entities[$i], $ent_id);
 378             if ($msg)
 379                return $msg;
 380          }
 381       }
 382    }
 383
 384    // returns a $message object for a particular entity id
 385    function getEntity ($message, $ent_id) {
 386       if ($message) {
 387          if ($message->header->entity_id == $ent_id && strlen($ent_id) == strlen($message->header->entity_id)) {
 388             return $message;
 389          } else {
 390             for ($i = 0; $message->entities[$i]; $i++) {
 391                $msg = getEntity ($message->entities[$i], $ent_id);
 392                if ($msg)
 393                   return $msg;
 394             }
 395          }
 396       }
 397    }
 398
 399    // figures out what entity to display and returns the $message object
 400    // for that entity.
 401    function findDisplayEntity ($message) {
 402       if ($message) {
 403          if ($message->header->type0 == "text") {
 404             if ($message->header->type1 == "plain" ||
 405                 $message->header->type1 == "html") {
 406                return $message->header->entity_id;
 407             }
 408          } else {
 409             for ($i=0; $message->entities[$i]; $i++) {
 410                return findDisplayEntity($message->entities[$i]);
 411             }
 412          }
 413       }
 414    }
 415
 416    /** This returns a parsed string called $body. That string can then
 417        be displayed as the actual message in the HTML. It contains
 418        everything needed, including HTML Tags, Attachments at the
 419        bottom, etc.
 420     **/
 421    function formatBody($imap_stream, $message, $color, $wrap_at) {
 422       // this if statement checks for the entity to show as the
 423       // primary message. To add more of them, just put them in the
 424       // order that is their priority.
 425       global $username, $key, $imapServerAddress, $imapPort;
 426
 427       $id = $message->header->id;
 428       $urlmailbox = urlencode($message->header->mailbox);
 429
 430       // Get the right entity and redefine message to be this entity
 431       $ent_num = findDisplayEntity ($message);
 432       $body_message = getEntity($message, $ent_num);
 433
 434       $body = mime_fetch_body ($imap_stream, $id, $ent_num);
 435       $body = decodeBody($body, $body_message->header->encoding);
 436
 437       // If there are other types that shouldn't be formatted, add
 438       // them here
 439       if ($message->header->type1 != "html") {
 440          $body = translateText($body, $wrap_at, $body_message->header->charset);
 441       }
 442
 443       $body .= "<SMALL><CENTER><A HREF=\"../src/download.php?absolute_dl=true&passed_id=$id&passed_ent_id=$ent_num&mailbox=$urlmailbox\">". _("Download this as a file") ."</A></CENTER><BR></SMALL>";
 444
 445       /** Display the ATTACHMENTS: message if there's more than one part **/
 446       if ($message->entities) {
 447          $body .= "<TABLE WIDTH=100% CELLSPACING=0 CELLPADDING=4 BORDER=0><TR><TD BGCOLOR=\"$color[0]\">";
 448          $body .= "<TT><B>ATTACHMENTS:</B></TT>";
 449          $body .= "</TD></TR><TR><TD BGCOLOR=\"$color[0]\">";
 450          $num = 0;
 451
 452          /** make this recurisve at some point **/
 453          $body .= formatAttachments ($message, $ent_num, $message->header->mailbox, $id);
 454          $body .= "</TD></TR></TABLE>";
 455       }
 456       return $body;
 457    }
 458
 459    // A recursive function that returns a list of attachments with links
 460    // to where to download these attachments
 461    function formatAttachments ($message, $ent_id, $mailbox, $id) {
 462       if ($message) {
 463          if (!$message->entities) {
 464             $type0 = strtolower($message->header->type0);
 465             $type1 = strtolower($message->header->type1);
 466
 467             if ($message->header->entity_id != $ent_id) {
 468                $filename = decodeHeader($message->header->filename);
 469                if (trim($filename) == "") {
 470                   $display_filename = "untitled-".$message->header->entity_id;
 471                } else {
 472                   $display_filename = $filename;
 473                }
 474
 475                $urlMailbox = urlencode($mailbox);
 476                $ent = urlencode($message->header->entity_id);
 477                $body .= "<TT>&nbsp;&nbsp;&nbsp;<A HREF=\"../src/download.php?passed_id=$id&mailbox=$urlMailbox&passed_ent_id=$ent\">" . $display_filename . "</A>&nbsp;&nbsp;(TYPE: $type0/$type1)";
 478                if ($message->header->description)
 479                   $body .= "&nbsp;&nbsp;<b>" . htmlspecialchars($message->header->description)."</b>";
 480                $body .= "&nbsp;(<a href=\"../src/download.php?absolute_dl=true&passed_id=$id&mailbox=$urlMailbox&passed_ent_id=$ent\">"._("download")."</a>)\n";
 481                $body .= "</TT><BR>";
 482                $num++;
 483             }
 484             return $body;
 485          } else {
 486             for ($i = 0; $i < count($message->entities); $i++) {
 487                $body .= formatAttachments ($message->entities[$i], $ent_id, $mailbox, $id);
 488             }
 489             return $body;
 490          }
 491       }
 492    }
 493
 494
 495    /** this function decodes the body depending on the encoding type. **/
 496    function decodeBody($body, $encoding) {
 497       $body = str_replace("\r\n", "\n", $body);
 498       $encoding = strtolower($encoding);
 499
 500       if ($encoding == "quoted-printable") {
 501          $body = quoted_printable_decode($body);
 502
 503          while (ereg("=\n", $body))
 504             $body = ereg_replace ("=\n", "", $body);
 505       } else if ($encoding == "base64") {
 506          $body = base64_decode($body);
 507       }
 508
 509       // All other encodings are returned raw.
 510       return $body;
 511    }
 512
 513
 514    // This functions decode strings that is encoded according to
 515    // RFC1522 (MIME Part Two: Message Header Extensions for Non-ASCII Text).
 516    function decodeHeader ($string) {
 517       if (eregi('=\?([^?]+)\?(q|b)\?([^?]+)\?=',
 518                 $string, $res)) {
 519          if (ucfirst($res[2]) == "B") {
 520             $replace = base64_decode($res[3]);
 521          } else {
 522             $replace = ereg_replace("_", " ", $res[3]);
 523             $replace = quoted_printable_decode($replace);
 524          }
 525
 526          $replace = charset_decode ($res[1], $replace);
 527
 528          $string = eregi_replace
 529             ('=\?([^?]+)\?(q|b)\?([^?]+)\?=',
 530              $replace, $string);
 531          // In case there should be more encoding in the string: recurse
 532          return (decodeHeader($string));
 533       } else
 534          return ($string);
 535    }
 536
 537    // Encode a string according to RFC 1522 for use in headers if it
 538    // contains 8-bit characters or anything that looks like it should
 539    // be encoded.
 540    function encodeHeader ($string) {
 541       global $default_charset;
 542
 543       // Encode only if the string contains 8-bit characters or =?
 544       if (ereg("([\200-\377])|=\\?", $string)) {
 545          $newstring = "=?$default_charset?Q?";
 546
 547          // First the special characters
 548          $string = str_replace("=", "=3D", $string);
 549          $string = str_replace("?", "=3F", $string);
 550          $string = str_replace("_", "=5F", $string);
 551          $string = str_replace(" ", "_", $string);
 552
 553
 554          while (ereg("([\200-\377])", $string, $regs)) {
 555             $replace = $regs[1];
 556             $insert = "=" . strtoupper(bin2hex($replace));
 557             $string = str_replace($replace, $insert, $string);
 558          }
 559
 560          $newstring = "=?$default_charset?Q?".$string."?=";
 561
 562          return $newstring;
 563       }
 564
 565       return $string;
 566    }
 567
 568 ?>