PHP 5.5.16 is released

mb_encode_mimeheader

(PHP 4 >= 4.0.6, PHP 5)

mb_encode_mimeheader为 MIME 头编码字符串

说明

string mb_encode_mimeheader ( string $str [, string $charset = mb_internal_encoding() [, string $transfer_encoding = "B" [, string $linefeed = "\r\n" [, int $indent = 0 ]]]] )

按 MIME 头编码方案将指定的字符串 str 进行编码。

参数

str

要编码的 string

charset

charset 指定了 str 的字符集名。 其默认值由当前的 NLS 设置(mbstring.language)来确定。 mb_internal_encoding() 应当设置为同样的编码。

transfer_encoding

transfer_encoding 指定了 MIME 的编码方案。 它可以是 "B"(Base64)也可以是 "Q"(Quoted-Printable)。 如果未设置,将回退为 "B"

linefeed

linefeed 指定了 EOL(行尾)标记,使 mb_encode_mimeheader() 执行了一个换行(» RFC 文档中规定,超过长度的一行将换成多行,当前该长度硬式编码为 74 个字符)。 如果没有设定,则回退为 "\r\n" (CRLF)。

indent

首行缩进(header 里 str 前的字符数目)。

返回值

转换后的字符串版本以 ASCII 形式表达。

更新日志

版本 说明
5.0.0 增加了 indent 参数。

范例

Example #1 mb_encode_mimeheader() 例子

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

注释

Note:

这个函数没有设计成据更高级上下文的中断点来换行(单词边界等)。 这个特性将导致意外的空格可能会让原始字符串看上去很乱。

参见

add a note add a note

User Contributed Notes 12 notes

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3
Anonymous
5 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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2
gullevek at gullevek dot org
11 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
6 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
stormflyCUT at hyh dot pl
8 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
chappy at citromail dot hu
8 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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0
chappy at citromail dot hu
8 years ago
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;
}
?>
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0
paravoid
8 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
nigrez at nius dot waw dot pl
8 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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0
iwakura at junx dot org
8 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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0
mortoray at ecircle-ag dot com
9 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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-1
gullevek at gullevek dot org
8 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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-2
masataka
11 years ago
second parameter 'charset' is character encoding name, but default must be UTF-8 on PHP4.3.1.
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