(PHP 4 >= 4.0.6, PHP 5, PHP 7, PHP 8)

mb_encode_mimeheaderEncode une chaîne pour un en-tête MIME


    string $string,
    ?string $charset = null,
    ?string $transfer_encoding = null,
    string $newline = "\r\n",
    int $indent = 0
): string

Encode une chaîne de caractères string donnée en un en-tête MIME.

Liste de paramètres


La chaîne de caractères à encoder. Son encodage devrait être identique à mb_internal_encoding().


charset est le nom de l'encodage utilisé par la chaîne string. La valeur par défaut est déterminée par les paramètres courants du NLS (mbstring.language).


transfer_encoding est l'encodage de transfert. Il peut être "B" (Base64) ou "Q" (Quoted-Printable). Par défaut, c'est "B".


newline spécifie les fins de lignes (EOF : end-of-line) utilisées par mb_encode_mimeheader() pour formater la chaîne (une » RFC définie la longueur d'une chaîne à partir de laquelle on doit ajouter une fin de ligne. La longueur courante est 74 caractères). La valeur par défaut est "\r\n" (CRLF).


Indentation de la première ligne (nombre de caractères dans l'en-tête avant string).

Valeurs de retour

Une version convertie de la chaîne de caractères en ASCII.


Version Description
8.0.0 charset et transfer_encoding sont désormais nullable.


Exemple #1 Exemple avec mb_encode_mimeheader()

"太郎"// kanji
$mbox "kru";
$doma "gtinn.mon";
$addr '"' addcslashes(mb_encode_mimeheader($name"UTF-7""Q"), '"') . '" <' $mbox "@" $doma ">";

L'exemple ci-dessus va afficher :

"=?UTF-7?Q?+WSqQzg-?=" <kru@gtinn.mon>



Cette fonction n'est pas conçue pour couper les lignes en milieu de mots. Ce comportement peut ajouter des espaces non désirées dans un mot de la chaîne originale.

Voir aussi

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User Contributed Notes 10 notes

stormflyCUT at hyh dot pl
16 years ago
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').
gullevek at gullevek dot org
19 years ago
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:

$split=36; // after 36 single bytes characters, if then comes MB, it is broken
while ($pos<mb_strlen($string,$encoding))
  $_string.=(($_string)?' ':'').mb_encode_mimeheader($output,$encoding);

is not the best, but it works
tokul at users dot sourceforge dot net
14 years ago
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
gullevek at gullevek dot org
16 years ago
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.


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 .= "\r\n";
$_string .= $_string_encoded;
$string = $_string;

nigrez at nius dot waw dot pl
16 years ago
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.


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

$length = mb_strlen($string)) {
$encoded .= "=?$encoding?B?"
. base64_encode(mb_substr($string,0,24,$encoding))

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


13 years ago
I could not find a PHP function to MIME encode the name for a n email address.

Input   = "Karl Müller<kmueller@gmx.de>"
Output = "Karl%20M%FCller<kmueller@gmx.de>"

I wrote it on my own:

// required to encode names in email addresses   
// replace " " with "%20"
// replace "ü" with "%FC"
// replace "%" with "%25"      etc....
// Use "%" as Delimiter for MIME
// Use "=" as Delimiter for Quoted Printable
// Input string must be UTF8 encoded
public static function EncodeMime($Text, $Delimiter)
$Text = utf8_decode($Text);
$Len  = strlen($Text);
$Out  = "";
    for (
$i=0; $i<$Len; $i++)
$Chr = substr($Text, $i, 1);
$Asc = ord($Chr);

        if (
$Asc > 0x255) // Unicode not allowed
$Out .= "?";
        else if (
$Chr == " " || $Chr == $Delimiter || $Asc > 127)
$Out .= $Delimiter . strtoupper(bin2hex($Chr));
$Out .= $Chr;
16 years ago
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);
        } 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;
chappy at citromail dot hu
16 years ago
In countries where there's non-us ASCII, it's a very good example, for sending mail:

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
16 years ago
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) {
                $mode = 1;
                $string_array[$row] = NULL;
        } else {                                // multibyte
            if ($mode != 2) {
                $mode = 2;
                $string_array[$row] = NULL;
        $string_array[$row] .= $word;
    //echo "<pre>";
    //echo "</pre>";
    foreach ($string_array as $key => $value) {
        $value = mb_convert_encoding($value, $encoding);
        $string_array[$key] = mb_encode_mimeheader($value, $encoding);
    //echo "<pre>";
    //echo "</pre>";
    return implode("", $string_array);

is not the best, but it works
mortoray at ecircle-ag dot com
17 years ago
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.


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
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