解码 EXIM 日志中的电子邮件主题

Question

在我的 EXIM 日志中我有这个电子邮件主题

6570616265626167717367 6061716163636563676172

如何使用 php 对其进行解码（人类可读）？

Answer 1

PHP: Strings

A string is series of characters…
…
If the string is enclosed in double-quotes ("), PHP will interpret the following escape sequences for special characters:

Escaped characters
Sequence    Meaning
…
\[0-7]{1,3} the sequence of characters matching the regular expression
            is a character in octal notation, which silently overflows
            to fit in a byte (e.g. "0" === "[=10=]0")
…
Note: Unlike the double-quoted and heredoc syntaxes, variables and escape sequences for special characters will not be expanded when they occur in single quoted strings.

以下代码片段显示了 double- 和 single- 引号字符串的示例。后者使用preg_replace_callback function转换（使用回调执行正则表达式搜索和替换）：

<?php
// octal literal (in double quotes)
$double_quoted_string = "6570616265626167717367 6061716163636563676172";
echo $double_quoted_string . PHP_EOL;

// octal literal like string (in sigle quotes)
$single_quoted_string = '6570616265626167717367 6061716163636563676172';
echo $single_quoted_string . PHP_EOL;

function tochrs($matches) {
    return chr(intval(ltrim($matches[0], '\'), 8));
};
$regex = "/\\[0-7]{3}/";
echo preg_replace_callback($regex, "tochrs", $single_quoted_string) . PHP_EOL;
?>

输出：72104296.php

Επιβεβαίωση Παραγγελίας
6570616265626167717367 6061716163636563676172
Επιβεβαίωση Παραγγελίας

解码 EXIM 日志中的电子邮件主题

decoding email subject in EXIM log

php

decode

exim