php - 电子邮件主题分隔符中的重音词 - 我该如何阻止它？

Question

我们有一个自定义的 php 电子邮件营销应用程序，还有一个有趣的问题:如果邮件的主题行包含带重音的单词，它会“吞掉”它与下一个单词之间的空格。一个例子:短语

Ángel Ríos escucha y soprende

(至少通过 gmail 和 lotus notes)显示为

ÁngelRíos escucha y soprende

消息源中的特定行显示:

主题:=?ISO-8859-1?Q?=C1ngel?= =?ISO-8859-1?Q?R=EDos?= escucha y sorprende

(半完整标题):

Delivered-To: me@gmail.com
Received: {elided}
Return-Path: <return@path>
Received: {elided}
Received: (qmail 23734 invoked by uid 48); 18 Aug 2009 13:51:14 -0000
Date: 18 Aug 2009 13:51:14 -0000
To: "Adriano" <me@gmail.com>
Subject: =?ISO-8859-1?Q?=C1ngel?= =?ISO-8859-1?Q?R=EDos?= escucha y sorprende
MIME-Version: 1.0
From: {elided}
X-Mailer: PHP
X-Lista: 1290
X-ID: 48163
Content-Type: text/html; charset="ISO-8859-1"
Content-Transfer-Encoding: quoted-printable
Message-ID: <kokrte.rpq06m@example.com>

编辑:

该应用程序使用旧版本的 Html Mime Mail 来准备邮件，我会尝试升级到较新的版本。无论如何，这是对主题进行编码的函数:

/**
 * Function to encode a header if necessary
 * according to RFC2047
 */
function _encodeHeader($input, $charset = 'ISO-8859-1')
{
    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;
}

这是对主题进行编码的代码:

if (!empty($this->headers['Subject'])) {
    $subject = $this->_encodeHeader($this->headers['Subject'],
                                    $this->build_params['head_charset']);
    unset($this->headers['Subject']);
}

总结

问题是，事实上，在上述情况下，程序并未对空间进行编码。 The accepted answer解决了我的问题，经过轻微修改(在该答案的评论中提到)，因为安装的 PHP 版本不支持特定的实现细节。

最终答案

虽然接受的答案确实解决了问题，但我们发现它与数千封电子邮件相结合，正在吞噬服务器上的所有可用内存。查看了这个邮件框架原开发者的网站，发现功能已经更新为:

function _encodeHeader($input, $charset = 'ISO-8859-1') {
        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, $replacement , $input);
        }
        if (!empty($matches[1])) {
            $input = str_replace(' ', '=20', $input);
            $input = '=?' . $charset .  '?Q?' .$input . '?=';
        }
        return $input;
    }

巧妙地解决了问题并保持在内存限制之下。

Answer 1

您还需要对中间的空格进行编码(请参阅 RFC 2047 ):

(=?ISO-8859-1?Q?a?= =?ISO-8859-1?Q?b?=)     (ab)

White space between adjacent 'encoded-word's is not displayed.

[…]

(=?ISO-8859-1?Q?a_b?=)                      (a b)

In order to cause a SPACE to be displayed within a portion of encoded text, the SPACE MUST be encoded as part of the 'encoded-word'.

(=?ISO-8859-1?Q?a?= =?ISO-8859-2?Q?_b?=)    (a b)

In order to cause a SPACE to be displayed between two strings of encoded text, the SPACE MAY be encoded as part of one of the 'encoded-word's.

所以应该这样做:

Subject: =?ISO-8859-1?Q?=C1ngel=20R=EDos?= escucha y sorprende

---

编辑 试试这个功能:

function _encodeHeader($str, $charset='ISO-8859-1')
{
    $words = preg_split('/(\s+)/', $str, -1, PREG_SPLIT_NO_EMPTY | PREG_SPLIT_DELIM_CAPTURE);
    $func = create_function('$match', 'return $match[0] === " " ? "_" : sprintf("=%02X", ord($match[0]));');
    $encoded = false;
    foreach ($words as $key => &$word) {
        if (!ctype_space($word)) {
            $tmp = preg_replace_callback('/[^\x21-\x3C\x3E-\x5E\x60-\x7E]/', $func, $word);
            if ($tmp !== $word) {
                if (!$encoded) {
                    $word = '=?'.$charset.'?Q?'.$tmp;
                } else {
                    $word = $tmp;
                    if ($key > 0) {
                        $words[$key-1] = preg_replace_callback('/[^\x21-\x3C\x3E-\x5E\x60-\x7E]/', $func, $words[$key-1]);
                    }
                }
                $encoded = true;
            } else {
                if ($encoded) {
                    $words[$key-2] .= '?=';
                }
                $encoded = false;
            }
        }
    }
    if ($encoded) {
        $words[$key] .= '?=';
    }
    return implode('', $words);
}