Last updated: Sun, 25 Nov 2007

mb_encode_mimeheader

(PHP 4 >= 4.0.6, PHP 5)

mb_encode_mimeheader — Encode string for MIME header

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string mb_encode_mimeheader ( string $str [, string $charset [, string $transfer_encoding [, string $linefeed [, int $indent ]]]] )

mb_encode_mimeheader() encodes a given string str by the MIME header encoding scheme. Returns a converted version of the string represented in ASCII.

charset specifies the name of the character set in which str is represented in. The default value is determined by the current NLS setting (mbstring.language).

transfer_encoding specifies the scheme of MIME encoding. It should be either "B" (Base64) or "Q" (Quoted-Printable). Falls back to "B" if not given.

linefeed specifies the EOL (end-of-line) marker with which mb_encode_mimeheader() performs line-folding (a » RFC term, the act of breaking a line longer than a certain length into multiple lines. The length is currently hard-coded to 74 characters). Falls back to "\r\n" (CRLF) if not given.

Example#1 mb_encode_mimeheader() example


<?php
$name = ""; // kanji
$mbox = "kru";
$doma = "gtinn.mon";
$addr = mb_encode_mimeheader($name, "UTF-7", "Q") . " <" . $mbox . "@" . $doma . ">";
echo $addr;
?>

Note: This function isn't designed to break lines at higher-level contextual break points (word boundaries, etc.). This behaviour may clutter up the original string with unexpected spaces.

The indent was added as of PHP 5.

See also mb_decode_mimeheader().

mb_encode_numericentity

mb_detect_order

Last updated: Sun, 25 Nov 2007

add a note User Contributed Notes
mb_encode_mimeheader

tokul at users dot sourceforge dot net
30-Mar-2008 05:26


mb_encode_mimeheader() depends on correct mbstring.internal_encoding setting. It tries to convert $str from internal encoding to $charset. If you ignore mbstring internal encoding, function might encode strings incorrectly even when $str character set matches $charset

chappy at citromail dot hu
05-Jun-2006 04:33


I found a bad function. 



<?php

function encodeHeader($input, $charset = 'ISO-8859-2')

{

    preg_match_all('/(\\w*[\\x80-\\xFF]+\\w*)/', $input, $matches);

    foreach ($matches[1] as $value) {

        $replacement = preg_replace('/([\\x80-\\xFF])/e', '"=" . strtoupper(dechex(ord("\\1")))', $value);

        $input = str_replace($value, '=?' . $charset . '?Q?' . $replacement . '?=', $input);

    }

    return $input;

}

?>



This function should be used:



<?php

function encodeHeader($input, $charset = 'ISO-8859-2')

{

    $m=preg_match_all('/(\w*[\x80-\xFF]+\w*)/', $input, $matches);

    if($m)$input=mb_encode_mimeheader($input,$charset, 'Q');

    return $input;

}

?>

stormflyCUT at hyh dot pl
05-May-2006 04:41


Some solution for using national chars and have problem with UTF-8 for example in mail subject. Before you use mb_encode_mimeheader with UTF-8 set mb_internal_encoding('UTF-8').

paravoid
01-Jan-2006 05:58


If mb_ version doesn't work for you in MIME-B mode:



function encode_mimeheader($string, $charset=null, $linefeed="\r\n") {

    if (!$charset)

        $charset = mb_internal_encoding();



    $start = "=?$charset?B?";

    $end = "?=";

    $encoded = '';



    /* Each line must have length <= 75, including $start and $end */

    $length = 75 - strlen($start) - strlen($end);

    /* Average multi-byte ratio */

    $ratio = mb_strlen($string, $charset) / strlen($string);

    /* Base64 has a 4:3 ratio */

    $magic = $avglength = floor(3 * $length * $ratio / 4);



    for ($i=0; $i <= mb_strlen($string, $charset); $i+=$magic) {

        $magic = $avglength;

        $offset = 0;

        /* Recalculate magic for each line to be 100% sure */

        do {

            $magic -= $offset;

            $chunk = mb_substr($string, $i, $magic, $charset);

            $chunk = base64_encode($chunk);

            $offset++;

        } while (strlen($chunk) > $length);

        if ($chunk)

            $encoded .= ' '.$start.$chunk.$end.$linefeed;

    }

    /* Chomp the first space and the last linefeed */

    $encoded = substr($encoded, 1, -strlen($linefeed));



    return $encoded;

}

nigrez at nius dot waw dot pl
13-Dec-2005 03:42


True, function is broken (PHP5.1, encoding from UTF-8 with pl_PL charset). Below is about 15% faster version of proposed _mb_mime_encode. Also it has header more like othe mb_* functions and doesn't trigger any errors/warnings/notices.



<?php



function mb_mime_header($string, $encoding=null, $linefeed="\r\n") {

  if(!$encoding) $encoding = mb_internal_encoding();

  $encoded = '';



  while($length = mb_strlen($string)) {

    $encoded .= "=?$encoding?B?"

             . base64_encode(mb_substr($string,0,24,$encoding))

             . "?=$linefeed";



    $string = mb_substr($string,24,$length,$encoding);

  }



  return $encoded;

}



?>

gullevek at gullevek dot org
06-Nov-2005 05:29


My first post was around 2003, and still the mb_mime_header is broken. It is *NOT* usable with longer subjects, and mostly unusable with anything else than japanese.



iwakura at junx dot org is also not working for me, it produces also some gargabe.



I updated my old function (the one I posted 2003) and I tested it with overlong subjects in UTF-8, ISO-2022-JP (japanese), GB2312 (simplified chinese) and EUC-KR (korean) and I got readable results in thunderbird, mail.app, outlook, etc.



<?php



function _mb_mime_encode($string, $encoding)

{

    $pos = 0;

    // after 36 single bytes characters if then comes MB, it is broken

    // but I trimmed it down to 24, to stay 100% < 76 chars per line

    $split = 24;

    while ($pos < mb_strlen($string, $encoding))

    {

        $output = mb_strimwidth($string, $pos, $split, "", $encoding);

        $pos += mb_strlen($output, $encoding);

        $_string_encoded = "=?".$encoding."?B?".base64_encode($output)."?=";

        if ($_string)

            $_string .= "\r\n";

        $_string .= $_string_encoded;

    }

    $string = $_string;

    return $string;

}



?>

chappy at citromail dot hu
28-Oct-2005 11:14


In countries where there's non-us ASCII, it's a very good example, for sending mail:



mb_internal_encoding('iso-8859-2');

setlocale(LC_CTYPE, 'hu_HU');



function encode($str,$charset){

    $str=mb_encode_mimeheader(trim($str),$charset, 'Q', "\n\t");

    return $str;

}



print encode('the text with spec. chars: &#337; &#368; &#336; &#369;, �','iso-8859-2');



It creates a 7bit string

iwakura at junx dot org
15-Sep-2005 11:35


i think mb_encode_mimeheader still have bug. here is sample code:



function mb_encode_mimeheader2($string, $encoding = "ISO-2022-JP") {

    $string_array = array();

    $pos = 0;

    $row = 0;

    $mode = 0;

    

    while ($pos < mb_strlen($string)) {

        $word = mb_strimwidth($string, $pos, 1);

        if (!$word) {

            $word = mb_strimwidth($string, $pos, 2);

        }

        if (mb_ereg_match("[ -~]", $word)) {    // ascii

            if ($mode != 1) {

                $row++;

                $mode = 1;

                $string_array[$row] = NULL;

            }

        } else {                                // multibyte

            if ($mode != 2) {

                $row++;

                $mode = 2;

                $string_array[$row] = NULL;

            }

        }

        $string_array[$row] .= $word;

        $pos++;

    }

    

    //echo "<pre>";

    //print_r($string_array);

    //echo "</pre>";

    

    foreach ($string_array as $key => $value) {

        $value = mb_convert_encoding($value, $encoding);

        $string_array[$key] = mb_encode_mimeheader($value, $encoding);

    }

    

    //echo "<pre>";

    //print_r($string_array);

    //echo "</pre>";

    

    return implode("", $string_array);

}



is not the best, but it works

mortoray at ecircle-ag dot com
15-Mar-2005 01:19


At least for Q encoding, this function is unsafe and does not encode correctly. Raw characters which appear as RFC2047 sequences are simply left as is.



Ex:



mb_encode_mimeheader( '=?iso-8859-1?q?this=20is=20some=20text?=' );



returns '=?iso-8859-1?q?this=20is=20some=20text?='



The exact same string, which is obviously not the encoding for the source string.  That is, mb_encode_mimeheader does not do any type of escaping.



That is, the following condition is not always true:

    mb_decode_mimeheader( mb_encode_mimeheader( $text ) ) == $text

gullevek at gullevek dot org
30-Jul-2003 12:02


Read this FIRST: http://bugs.php.net/bug.php?id=23192 because mb_encode_mimeheaders is BUGGY!



a work around for the multibyte broken error for too long subjects for ISO-2022-JP:



$pos=0;

$split=36; // after 36 single bytes characters, if then comes MB, it is broken

while ($pos<mb_strlen($string,$encoding))

{

  $output=mb_strimwidth($string,$pos,$split,"",$encoding);

  $pos+=mb_strlen($output,$encoding);

  $_string.=(($_string)?' ':'').mb_encode_mimeheader($output,$encoding);

}

$string=$_string;



is not the best, but it works

masataka
12-Apr-2003 07:46


second parameter 'charset' is character encoding name, but default must be UTF-8 on PHP4.3.1.

add a note

mb_encode_numericentity

mb_detect_order

Last updated: Sun, 25 Nov 2007