Question

证书PEM文件包含开头和结尾，如：

-----BEGIN CERTIFICATE----- [Base64 of certificate] -----END CERTIFICATE

我只需要提取[Base64 of certificate]部分，即剥离"-----BEGIN CERTIFICATE----- "和" -----END CERTIFICATE-----"字符串，并想知道是否可以使用正则表达式完成此操作，如果是，那么是什么那个正则表达式会是什么样的？

我试过了：

-----BEGIN CERTIFICATE----- (.*) -----END CERTIFICATE-----

但是，不是给我证书的Base64，而是返回所有内容。

谢谢，吉姆

Answer 1

由于我不知道你使用的语言，我给你一个相对便携的模式（必须支持前瞻和后视）：

(?<=-----BEGIN CERTIFICATE----- )(?:\S+|\s(?!-----END CERTIFICATE-----))+(?=\s-----END CERTIFICATE-----)

结果是整个模式，因为看起来只是检查。

Answer 2

在perl：

my base64_cert_data;
if ($certbuf=~/(-+BEGIN CERTIFICATE-+)(.*?)(-+END CERTIFICATE-+)/s) {
    base64_cert_data = $2;
}

正则表达式解释：

/(-+BEGIN CERTIFICATE-+)(.*?)(-+END CERTIFICATE-+)/s

1st Capturing group (-+BEGIN CERTIFICATE-+)
    -+ matches the character - literally
        Quantifier: + Between one and unlimited times, as many times as possible, giving back as needed [greedy]
    BEGIN CERTIFICATE matches the characters BEGIN CERTIFICATE literally (case sensitive)
    -+ matches the character - literally
        Quantifier: + Between one and unlimited times, as many times as possible, giving back as needed [greedy]
2nd Capturing group (.*?)
    .*? matches any character
        Quantifier: *? Between zero and unlimited times, as few times as possible, expanding as needed [lazy]
3rd Capturing group (-+END CERTIFICATE-+)
    -+ matches the character - literally
        Quantifier: + Between one and unlimited times, as many times as possible, giving back as needed [greedy]
    END CERTIFICATE matches the characters END CERTIFICATE literally (case sensitive)
    -+ matches the character - literally
        Quantifier: + Between one and unlimited times, as many times as possible, giving back as needed [greedy]
s modifier: single line. Dot matches newline characters

Answer 3

下面是一个支持您的要求的示例perl代码。

my $Str = "-----BEGIN CERTIFICATE-----
MIIBuTCCASKgAwIBAgIQNdNhtuV5GbNHYZsf+LvM0zANBgkqhkiG9w0BAQUFADAb
MRkwFwYDVQQDExBFZGlkZXYgU21va2VUZXN0MB4XDTA4MTExMjE5NTEzNVoXDTM5
MTIzMTIzNTk1OVowGzEZMBcGA1UEAxMQRWRpZGV2IFNtb2tlVGVzdDCBnzANBgkq
hkiG9w0BAQEFAAOBjQAwgYkCgYEAm6zGzqxejwswWTNLcSsa7P8xqODspX9VQBuq
5W1RoTgQ0LNR64+7ywLjH8+wrb/lB6QV7s2SFUiWDeduVesvMJkWtZ5zzQyl3iUa
CBpT4S5AaO3/wkYQSKdI108pXH7Aue0e/ZOwgEEX1N6OaPQn7AmAB4uq1h+ffw+r
RKNHqnsCAwEAATANBgkqhkiG9w0BAQUFAAOBgQCZmj+pgRsN6HpoICawK3XXNAmi
cgfQkailX9akIjD3xSCwEQx4nG6tZjTz30u4NoSffW7pch58SxuZQDqW5NsJcQNq
Ngo/dMoqqpXdi2/0BYEcJ8pjsngrFm+fM2BnyGpXH7aWuKsWjVFGlWlF+yi8I35Q
8wFJt2Z/XGA7WWDjvw==
-----END CERTIFICATE-----";
if($Str =~ /^\W+\w+\s+\w+\W+\s(.*)\s+\W+.*$/s) {
    print "$1" . "\n\n";
} else {
    print "No\n" . "\n\n";
}

输出：
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Answer 4

base64字符集是：

[A-Za-z0-9+/\r\n]+={0,2}-这是对PEM文件（base64证书）通常使用的内容的准确描述。 =用于填充（末尾），\r\n是换行符。

将所有内容放在一起，我们得到：

"-+BEGIN\\s+.*CERTIFICATE[^-]*-+(?:\\s|\\r|\\n)+" // Header
 + "([A-Za-z0-9+/\r\n]+={0,2})"                   // Base64 text
 + "-+END\\s+.*CERTIFICATE[^-]*-+"                // Footer

如果您想与语言无关，则可以期望页眉/页脚为一个或多个-字符，后面仅是大写字母，再由一个或多个-字符组成。< / p>

正则表达式从证书PEM字符串开始和结束

4 个答案:

输出：