squirrelmail/functions/mime.php
2001-10-08 21:47:28 +00:00

770 lines
29 KiB
PHP

<?php
/** mime.php
**
** This contains the functions necessary to detect and decode MIME
** messages.
**
** $Id$
**/
if (defined('mime_php'))
return;
define('mime_php', true);
global $debug_mime;
$debug_mime = false;
require_once('../functions/imap.php');
/** Setting up the objects that have the structure for the message **/
class msg_header {
/** msg_header contains generic variables for values that **/
/** could be in a header. **/
var $type0 = '', $type1 = '', $boundary = '', $charset = '';
var $encoding = '', $size = 0, $to = array(), $from = '', $date = '';
var $cc = array(), $bcc = array(), $reply_to = '', $subject = '';
var $id = 0, $mailbox = '', $description = '', $filename = '';
var $entity_id = 0, $message_id = 0, $name = '';
}
class message {
/** message is the object that contains messages. It is a recursive
object in that through the $entities variable, it can contain
more objects of type message. See documentation in mime.txt for
a better description of how this works.
**/
var $header = '';
var $entities = array();
function addEntity ($msg) {
$this->entities[] = $msg;
}
}
/* --------------------------------------------------------------------------------- */
/* MIME DECODING */
/* --------------------------------------------------------------------------------- */
// This function gets the structure of a message and stores it in the "message" class.
// It will return this object for use with all relevant header information and
// fully parsed into the standard "message" object format.
function mime_structure ($imap_stream, $header) {
global $debug_mime;
sqimap_messages_flag ($imap_stream, $header->id, $header->id, "Seen");
$id = $header->id;
fputs ($imap_stream, sqimap_session_id() . " FETCH $id BODYSTRUCTURE\r\n");
//
// This should use sqimap_read_data instead of reading it itself
//
$sid = sqimap_session_id();
$lsid = strlen( $sid );
$read = fgets ($imap_stream, 10000);
$bodystructure = "";
while( substr($read, 0, $lsid) <> $sid && !feof( $imap_stream ) ) {
$bodystructure .= $read;
$read = fgets ($imap_stream, 10000);
}
$read = $bodystructure;
if ($debug_mime) echo "<tt>$read</tt><br><br>\n";
// isolate the body structure and remove beginning and end parenthesis
$read = trim(substr ($read, strpos(strtolower($read), "bodystructure") + 13));
$read = trim(substr ($read, 0, -1));
$end = mime_match_parenthesis(0, $read);
while ($end == strlen($read)-1) {
$read = trim(substr ($read, 0, -1));
$read = trim(substr ($read, 1));
$end = mime_match_parenthesis(0, $read);
}
if ($debug_mime) echo "<tt>$read</tt><br><br>\n";
$msg = mime_parse_structure ($read, 0);
$msg->header = $header;
return $msg;
}
// this starts the parsing of a particular structure. It is called recursively,
// so it can be passed different structures. It returns an object of type
// $message.
// First, it checks to see if it is a multipart message. If it is, then it
// handles that as it sees is necessary. If it is just a regular entity,
// then it parses it and adds the necessary header information (by calling out
// to mime_get_elements()
function mime_parse_structure ($structure, $ent_id) {
global $debug_mime;
if ($debug_mime) echo "<font color=008800><tt>START: mime_parse_structure()</tt></font><br>\n";
$msg = new message();
if (substr($structure, 0, 1) == "(") {
$ent_id = mime_new_element_level($ent_id);
$start = $end = -1;
if ($debug_mime) echo "<br><font color=0000aa><tt>$structure</tt></font><br>";
do {
if ($debug_mime) echo "<font color=008800><tt>Found entity...</tt></font><br>";
$start = $end+1;
$end = mime_match_parenthesis ($start, $structure);
$element = substr($structure, $start+1, ($end - $start)-1);
$ent_id = mime_increment_id ($ent_id);
$newmsg = mime_parse_structure ($element, $ent_id);
$msg->addEntity ($newmsg);
} while (substr($structure, $end+1, 1) == "(");
} else {
// parse the elements
if ($debug_mime) echo "<br><font color=0000aa><tt>$structure</tt></font><br>";
$msg = mime_get_element ($structure, $msg, $ent_id);
if ($debug_mime) echo "<br>";
}
if ($debug_mime) echo "<font color=008800><tt>&nbsp;&nbsp;END: mime_parse_structure()</tt></font><br>";
return $msg;
}
// Increments the element ID. An element id can look like any of
// the following: 1, 1.2, 4.3.2.4.1, etc. This function increments
// the last number of the element id, changing 1.2 to 1.3.
function mime_increment_id ($id) {
global $debug_mime;
if (strpos($id, ".")) {
$first = substr($id, 0, strrpos($id, "."));
$last = substr($id, strrpos($id, ".")+1);
$last++;
$new = $first . "." .$last;
} else {
$new = $id + 1;
}
if ($debug_mime) echo "<b>INCREMENT: $new</b><br>";
return $new;
}
// See comment for mime_increment_id().
// This adds another level on to the entity_id changing 1.3 to 1.3.0
// NOTE: 1.3.0 is not a valid element ID. It MUST be incremented
// before it can be used. I left it this way so as not to have
// to make a special case if it is the first entity_id. It
// always increments it, and that works fine.
function mime_new_element_level ($id) {
if (!$id) $id = 0;
else $id = $id . ".0";
return $id;
}
function mime_get_element (&$structure, $msg, $ent_id) {
global $debug_mime;
$elem_num = 1;
$msg->header = new msg_header();
$msg->header->entity_id = $ent_id;
$properties = array();
while (strlen($structure) > 0) {
$structure = trim($structure);
$char = substr($structure, 0, 1);
if (strtolower(substr($structure, 0, 3)) == "nil") {
$text = "";
$structure = substr($structure, 3);
} else if ($char == "\"") {
// loop through until we find the matching quote, and return that as a string
$pos = 1;
$char = substr($structure, $pos, 1);
$text = "";
while ($char != "\"" && $pos < strlen($structure)) {
$text .= $char;
$pos++;
$char = substr($structure, $pos, 1);
}
$structure = substr($structure, strlen($text) + 2);
} else if ($char == "(") {
// comment me
$end = mime_match_parenthesis (0, $structure);
$sub = substr($structure, 1, $end-1);
$properties = mime_get_props($properties, $sub);
$structure = substr($structure, strlen($sub) + 2);
} else {
// loop through until we find a space or an end parenthesis
$pos = 0;
$char = substr($structure, $pos, 1);
$text = "";
while ($char != " " && $char != ")" && $pos < strlen($structure)) {
$text .= $char;
$pos++;
$char = substr($structure, $pos, 1);
}
$structure = substr($structure, strlen($text));
}
if ($debug_mime) echo "<tt>$elem_num : $text</tt><br>";
// This is where all the text parts get put into the header
switch ($elem_num) {
case 1:
$msg->header->type0 = strtolower($text);
if ($debug_mime) echo "<tt>type0 = ".strtolower($text)."</tt><br>";
break;
case 2:
$msg->header->type1 = strtolower($text);
if ($debug_mime) echo "<tt>type1 = ".strtolower($text)."</tt><br>";
break;
case 5:
$msg->header->description = $text;
if ($debug_mime) echo "<tt>description = $text</tt><br>";
break;
case 6:
$msg->header->encoding = strtolower($text);
if ($debug_mime) echo "<tt>encoding = ".strtolower($text)."</tt><br>";
break;
case 7:
$msg->header->size = $text;
if ($debug_mime) echo "<tt>size = $text</tt><br>";
break;
default:
if ($msg->header->type0 == "text" && $elem_num == 8) {
// This is a plain text message, so lets get the number of lines
// that it contains.
$msg->header->num_lines = $text;
if ($debug_mime) echo "<tt>num_lines = $text</tt><br>";
} else if ($msg->header->type0 == "message" && $msg->header->type1 == "rfc822" && $elem_num == 8) {
// This is an encapsulated message, so lets start all over again and
// parse this message adding it on to the existing one.
$structure = trim($structure);
if (substr($structure, 0, 1) == "(") {
$e = mime_match_parenthesis (0, $structure);
$structure = substr($structure, 0, $e);
$structure = substr($structure, 1);
$m = mime_parse_structure($structure, $msg->header->entity_id);
// the following conditional is there to correct a bug that wasn't
// incrementing the entity IDs correctly because of the special case
// that message/rfc822 is. This fixes it fine.
if (substr($structure, 1, 1) != "(")
$m->header->entity_id = mime_increment_id(mime_new_element_level($ent_id));
// Now we'll go through and reformat the results.
if ($m->entities) {
for ($i=0; $i < count($m->entities); $i++) {
$msg->addEntity($m->entities[$i]);
}
} else {
$msg->addEntity($m);
}
$structure = "";
}
}
break;
}
$elem_num++;
$text = "";
}
// loop through the additional properties and put those in the various headers
if ($msg->header->type0 != "message") {
for ($i=0; $i < count($properties); $i++) {
$msg->header->{$properties[$i]["name"]} = $properties[$i]["value"];
if ($debug_mime) echo "<tt>".$properties[$i]["name"]." = " . $properties[$i]["value"] . "</tt><br>";
}
}
return $msg;
}
// I did most of the MIME stuff yesterday (June 20, 2000), but I couldn't
// figure out how to do this part, so I decided to go to bed. I woke up
// in the morning and had a flash of insight. I went to the white-board
// and scribbled it out, then spent a bit programming it, and this is the
// result. Nothing complicated, but I think my brain was fried yesterday.
// Funny how that happens some times.
//
// This gets properties in a nested parenthesisized list. For example,
// this would get passed something like: ("attachment" ("filename" "luke.tar.gz"))
// This returns an array called $props with all paired up properties.
// It ignores the "attachment" for now, maybe that should change later
// down the road. In this case, what is returned is:
// $props[0]["name"] = "filename";
// $props[0]["value"] = "luke.tar.gz";
function mime_get_props ($props, $structure) {
global $debug_mime;
while (strlen($structure) > 0) {
$structure = trim($structure);
$char = substr($structure, 0, 1);
if ($char == "\"") {
$pos = 1;
$char = substr($structure, $pos, 1);
$tmp = "";
while ($char != "\"" && $pos < strlen($structure)) {
$tmp .= $char;
$pos++;
$char = substr($structure, $pos, 1);
}
$structure = trim(substr($structure, strlen($tmp) + 2));
$char = substr($structure, 0, 1);
if ($char == "\"") {
$pos = 1;
$char = substr($structure, $pos, 1);
$value = "";
while ($char != "\"" && $pos < strlen($structure)) {
$value .= $char;
$pos++;
$char = substr($structure, $pos, 1);
}
$structure = trim(substr($structure, strlen($tmp) + 2));
$k = count($props);
$props[$k]["name"] = strtolower($tmp);
$props[$k]["value"] = $value;
} else if ($char == "(") {
$end = mime_match_parenthesis (0, $structure);
$sub = substr($structure, 1, $end-1);
if (! isset($props))
$props = array();
$props = mime_get_props($props, $sub);
$structure = substr($structure, strlen($sub) + 2);
}
return $props;
} else if ($char == "(") {
$end = mime_match_parenthesis (0, $structure);
$sub = substr($structure, 1, $end-1);
$props = mime_get_props($props, $sub);
$structure = substr($structure, strlen($sub) + 2);
return $props;
} else {
return $props;
}
}
}
// Matches parenthesis. It will return the position of the matching
// parenthesis in $structure. For instance, if $structure was:
// ("text" "plain" ("val1name", "1") nil ... )
// x x
// then this would return 42 to match up those two.
function mime_match_parenthesis ($pos, $structure) {
$char = substr($structure, $pos, 1);
// ignore all extra characters
// If inside of a string, skip string -- Boundary IDs and other
// things can have ) in them.
if ($char != '(')
return strlen($structure);
while ($pos < strlen($structure)) {
$pos++;
$char = substr($structure, $pos, 1);
if ($char == ")") {
return $pos;
} else if ($char == '"') {
$pos ++;
while (substr($structure, $pos, 1) != '"' &&
$pos < strlen($structure)) {
if (substr($structure, $pos, 2) == '\\"')
$pos ++;
elseif (substr($structure, $pos, 2) == '\\\\')
$pos ++;
$pos ++;
}
} else if ($char == "(") {
$pos = mime_match_parenthesis ($pos, $structure);
}
}
echo "Error decoding mime structure. Report this as a bug!<br>\n";
return $pos;
}
function mime_fetch_body ($imap_stream, $id, $ent_id) {
// do a bit of error correction. If we couldn't find the entity id, just guess
// that it is the first one. That is usually the case anyway.
if (!$ent_id) $ent_id = 1;
fputs ($imap_stream, sqimap_session_id() . " FETCH $id BODY[$ent_id]\r\n");
$data = sqimap_read_data ($imap_stream, sqimap_session_id(), true, $response, $message);
$topline = array_shift($data);
while (! ereg('\\* [0-9]+ FETCH ', $topline) && $data)
$topline = array_shift($data);
$wholemessage = implode('', $data);
if (ereg('\\{([^\\}]*)\\}', $topline, $regs)) {
return substr($wholemessage, 0, $regs[1]);
}
else if (ereg('"([^"]*)"', $topline, $regs)) {
return $regs[1];
}
$str = "Body retrieval error. Please report this bug!\n" .
"Response: $response\n" .
"Message: $message\n" .
"FETCH line: $topline" .
"---------------\n$wholemessage";
foreach ($data as $d) {
$str .= htmlspecialchars($d) . "\n";
}
return $str;
}
function mime_print_body_lines ($imap_stream, $id, $ent_id, $encoding) {
// do a bit of error correction. If we couldn't find the entity id, just guess
// that it is the first one. That is usually the case anyway.
if (!$ent_id) $ent_id = 1;
// Don't kill the connection if the browser is over a dialup
// and it would take over 30 seconds to download it.
set_time_limit(0);
fputs ($imap_stream, sqimap_session_id() . " FETCH $id BODY[$ent_id]\r\n");
$cnt = 0;
$continue = true;
$read = fgets ($imap_stream,4096);
// This could be bad -- if the section has sqimap_session_id() . ' OK'
// or similar, it will kill the download.
while (!ereg("^" . sqimap_session_id() . " (OK|BAD|NO)(.*)$", $read, $regs)) {
if (trim($read) == ")==") {
$read1 = $read;
$read = fgets ($imap_stream,4096);
if (ereg("^" . sqimap_session_id() . " (OK|BAD|NO)(.*)$", $read, $regs)) {
return;
} else {
echo decodeBody($read1, $encoding) .
decodeBody($read, $encoding);
}
} else if ($cnt) {
echo decodeBody($read, $encoding);
}
$read = fgets ($imap_stream,4096);
$cnt++;
}
}
/* -[ END MIME DECODING ]----------------------------------------------------------- */
/** This is the first function called. It decides if this is a multipart
message or if it should be handled as a single entity
**/
function decodeMime ($imap_stream, &$header) {
global $username, $key, $imapServerAddress, $imapPort;
return mime_structure ($imap_stream, $header);
}
// This is here for debugging purposese. It will print out a list
// of all the entity IDs that are in the $message object.
function listEntities ($message) {
if ($message) {
if ($message->header->entity_id)
echo "<tt>" . $message->header->entity_id . " : " . $message->header->type0 . "/" . $message->header->type1 . "<br>";
for ($i = 0; $message->entities[$i]; $i++) {
$msg = listEntities($message->entities[$i], $ent_id);
if ($msg)
return $msg;
}
}
}
// returns a $message object for a particular entity id
function getEntity ($message, $ent_id) {
if ($message) {
if ($message->header->entity_id == $ent_id && strlen($ent_id) == strlen($message->header->entity_id)) {
return $message;
} else {
for ($i = 0; isset($message->entities[$i]); $i++) {
$msg = getEntity ($message->entities[$i], $ent_id);
if ($msg)
return $msg;
}
}
}
}
// figures out what entity to display and returns the $message object
// for that entity.
function findDisplayEntity ($message, $textOnly = 1)
{
global $show_html_default;
if (! $message)
return 0;
if ($message->header->type0 == "multipart" &&
$message->header->type1 == "alternative" &&
$show_html_default && ! $textOnly) {
$entity = findDisplayEntityHTML($message);
if ($entity != 0)
return $entity;
}
// Show text/plain or text/html -- the first one we find.
if ($message->header->type0 == 'text' &&
($message->header->type1 == 'plain' ||
$message->header->type1 == 'html') &&
isset($message->header->entity_id))
return $message->header->entity_id;
for ($i=0; isset($message->entities[$i]); $i++) {
$entity = findDisplayEntity($message->entities[$i], $textOnly);
if ($entity != 0)
return $entity;
}
return 0;
}
// Shows the HTML version
function findDisplayEntityHTML ($message) {
if ($message->header->type0 == 'text' &&
$message->header->type1 == 'html' &&
isset($message->header->entity_id))
return $message->header->entity_id;
for ($i = 0; isset($message->entities[$i]); $i ++) {
$entity = findDisplayEntityHTML($message->entities[$i]);
if ($entity != 0)
return $entity;
}
return 0;
}
/** This returns a parsed string called $body. That string can then
be displayed as the actual message in the HTML. It contains
everything needed, including HTML Tags, Attachments at the
bottom, etc.
**/
function formatBody($imap_stream, $message, $color, $wrap_at) {
// this if statement checks for the entity to show as the
// primary message. To add more of them, just put them in the
// order that is their priority.
global $startMessage, $username, $key, $imapServerAddress, $imapPort,
$show_html_default;
$id = $message->header->id;
$urlmailbox = urlencode($message->header->mailbox);
// Get the right entity and redefine message to be this entity
// Pass the 0 to mean that we want the 'best' viewable one
$ent_num = findDisplayEntity ($message, 0);
$body_message = getEntity($message, $ent_num);
if (($body_message->header->type0 == "text") ||
($body_message->header->type0 == "rfc822")) {
$body = mime_fetch_body ($imap_stream, $id, $ent_num);
$body = decodeBody($body, $body_message->header->encoding);
$hookResults = do_hook("message_body", $body);
$body = $hookResults[1];
// If there are other types that shouldn't be formatted, add
// them here
if ($body_message->header->type1 != "html" || ! $show_html_default) {
translateText($body, $wrap_at, $body_message->header->charset);
}
$body .= "<SMALL><CENTER><A HREF=\"../src/download.php?absolute_dl=true&passed_id=$id&passed_ent_id=$ent_num&mailbox=$urlmailbox&showHeaders=1\">". _("Download this as a file") ."</A></CENTER><BR></SMALL>";
/** Display the ATTACHMENTS: message if there's more than one part **/
$body .= "</TD></TR></TABLE>";
if (isset($message->entities[0])) {
$body .= formatAttachments ($message, $ent_num, $message->header->mailbox, $id);
}
$body .= "</TD></TR></TABLE>";
} else {
$body = formatAttachments ($message, -1, $message->header->mailbox, $id);
}
return $body;
}
// A recursive function that returns a list of attachments with links
// to where to download these attachments
function formatAttachments ($message, $ent_id, $mailbox, $id) {
global $where, $what;
global $startMessage, $color;
static $ShownHTML = 0;
$body = "";
if ($ShownHTML == 0)
{
$ShownHTML = 1;
$body .= "<TABLE WIDTH=100% CELLSPACING=0 CELLPADDING=2 BORDER=0 BGCOLOR=\"$color[0]\"><TR>\n";
$body .= "<TH ALIGN=\"left\" BGCOLOR=\"$color[9]\"><B>\n";
$body .= _("Attachments") . ':';
$body .= "</B></TH></TR><TR><TD>\n";
$body .= "<TABLE CELLSPACING=0 CELLPADDING=1 BORDER=0>\n";
$body .= formatAttachments ($message, $ent_id, $mailbox, $id);
$body .= "</TABLE></TD></TR></TABLE>";
return $body;
}
if ($message) {
if (!$message->entities) {
$type0 = strtolower($message->header->type0);
$type1 = strtolower($message->header->type1);
$name = decodeHeader($message->header->name);
if ($message->header->entity_id != $ent_id) {
$filename = decodeHeader($message->header->filename);
if (trim($filename) == "") {
if (trim($name) == "") {
$display_filename = "untitled-".$message->header->entity_id;
} else {
$display_filename = $name;
$filename = $name;
}
} else {
$display_filename = $filename;
}
$urlMailbox = urlencode($mailbox);
$ent = urlencode($message->header->entity_id);
$DefaultLink =
"../src/download.php?startMessage=$startMessage&passed_id=$id&mailbox=$urlMailbox&passed_ent_id=$ent";
if ($where && $what)
$DefaultLink .= '&where=' . urlencode($where) . '&what=' . urlencode($what);
$Links['download link']['text'] = _("download");
$Links['download link']['href'] =
"../src/download.php?absolute_dl=true&passed_id=$id&mailbox=$urlMailbox&passed_ent_id=$ent";
$ImageURL = '';
$HookResults = do_hook("attachment $type0/$type1", $Links,
$startMessage, $id, $urlMailbox, $ent, $DefaultLink,
$display_filename, $where, $what);
$Links = $HookResults[1];
$DefaultLink = $HookResults[6];
$body .= '<TR><TD>&nbsp;&nbsp;</TD><TD>';
$body .= "<A HREF=\"$DefaultLink\">$display_filename</A>&nbsp;</TD>";
$body .= '<TD><SMALL><b>' . show_readable_size($message->header->size) .
'</b>&nbsp;&nbsp;</small></TD>';
$body .= "<TD><SMALL>[ $type0/$type1 ]&nbsp;</SMALL></TD>";
$body .= '<TD><SMALL>';
if ($message->header->description)
$body .= '<b>' . htmlspecialchars($message->header->description) . '</b>';
$body .= '</SMALL></TD><TD><SMALL>&nbsp;';
$SkipSpaces = 1;
foreach ($Links as $Val)
{
if ($SkipSpaces)
{
$SkipSpaces = 0;
}
else
{
$body .= '&nbsp;&nbsp;|&nbsp;&nbsp;';
}
$body .= '<a href="' . $Val['href'] . '">' . $Val['text'] . '</a>';
}
unset($Links);
$body .= "</SMALL></TD></TR>\n";
}
return $body;
} else {
for ($i = 0; $i < count($message->entities); $i++) {
$body .= formatAttachments ($message->entities[$i], $ent_id, $mailbox, $id);
}
return $body;
}
}
}
/** this function decodes the body depending on the encoding type. **/
function decodeBody($body, $encoding) {
$body = str_replace("\r\n", "\n", $body);
$encoding = strtolower($encoding);
global $show_html_default;
if ($encoding == "quoted-printable") {
$body = quoted_printable_decode($body);
while (ereg("=\n", $body))
$body = ereg_replace ("=\n", "", $body);
} else if ($encoding == "base64") {
$body = base64_decode($body);
}
// All other encodings are returned raw.
return $body;
}
// This functions decode strings that is encoded according to
// RFC1522 (MIME Part Two: Message Header Extensions for Non-ASCII Text).
function decodeHeader ($string) {
if (eregi('=\\?([^?]+)\\?(q|b)\\?([^?]+)\\?=',
$string, $res)) {
if (ucfirst($res[2]) == "B") {
$replace = base64_decode($res[3]);
} else {
$replace = ereg_replace("_", " ", $res[3]);
// Convert lowercase Quoted Printable to uppercase for
// quoted_printable_decode to understand it.
while (ereg("(=(([0-9][abcdef])|([abcdef][0-9])|([abcdef][abcdef])))", $replace, $res)) {
$replace = str_replace($res[1], strtoupper($res[1]), $replace);
}
$replace = quoted_printable_decode($replace);
}
$replace = charset_decode ($res[1], $replace);
// Remove the name of the character set.
$string = eregi_replace ('=\\?([^?]+)\\?(q|b)\\?([^?]+)\\?=',
$replace, $string);
// In case there should be more encoding in the string: recurse
return (decodeHeader($string));
} else
return ($string);
}
// Encode a string according to RFC 1522 for use in headers if it
// contains 8-bit characters or anything that looks like it should
// be encoded.
function encodeHeader ($string) {
global $default_charset;
// Encode only if the string contains 8-bit characters or =?
$j = strlen( $string );
$l = FALSE; // Must be encoded ?
$ret = '';
for( $i=0; $i < $j; ++$i) {
switch( $string{$i} ) {
case '=':
$ret .= '=3D';
break;
case '?':
$l = TRUE;
$ret .= '=3F';
break;
case '_':
$ret .= '=5F';
break;
case ' ':
$ret .= '_';
break;
default:
$k = ord( $string{$i} );
if( $k > 126 ) {
$ret .= sprintf("=%02X", $k);
$l = TRUE;
} else
$ret .= $string{$i};
}
}
if( $l )
$string = "=?$default_charset?Q?$ret?=";
return( $string );
}
?>