mb_encode_mimeheader

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

mb_encode_mimeheaderEncode string for MIME header

Beschreibung

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

Encodes a given string string by the MIME header encoding scheme.

Parameter-Liste

string

The string being encoded. Its encoding should be same as mb_internal_encoding().

charset

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

transfer_encoding

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.

newline

newline 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.

indent

Indentation of the first line (number of characters in the header before string).

Rückgabewerte

A converted version of the string represented in ASCII.

Changelog

Version Beschreibung
8.0.0 charset and transfer_encoding are nullable now.

Beispiele

Beispiel #1 mb_encode_mimeheader() example

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

Das oben gezeigte Beispiel erzeugt folgende Ausgabe:

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

Anmerkungen

Hinweis:

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.

Siehe auch

add a note

User Contributed Notes 10 notes

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8
stormflyCUT at hyh dot pl
17 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').
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1
nigrez at nius dot waw dot pl
17 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.

<?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;
}

?>
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2
gullevek at gullevek dot org
20 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:

$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
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1
tokul at users dot sourceforge dot net
15 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
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1
gullevek at gullevek dot org
17 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.

<?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;
}

?>
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1
Anonymous
14 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:

<?php
// 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));
}
else
$Out .= $Chr;
}
return
$Out;
}
?>
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0
paravoid
17 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);
$offset++;
} while (strlen($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;
}
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0
chappy at citromail dot hu
17 years ago
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
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-1
iwakura at junx dot org
18 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) {
$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
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-2
mortoray at ecircle-ag dot com
18 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.

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
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