^(http:\/\/www\.|https:\/\/www\.|http:\/\/|https:\/\/)?[a-z0-9]+([\-\.]{1}[a-z0-9]+)*\.[a-z]{2,5}(:[0-9]{1,5})?(\/.*)?$

现场演示:https://regex101.com/r/HUNasA/2

我已经测试了各种表达式来满足我的要求。

作为用户，我可以用以下字符串点击浏览器搜索栏:

有效的网址

https://www.google.com http://www.google.com http://google.com/ https://google.com/ www.google.com google.com https://www.google.com.ua http://www.google.com.ua http://google.com.ua https://google.com.ua/ www.google.com.ua google.com.ua https://mail.google.com http://mail.google.com mail.google.com

无效的url

http://google https://google.c 谷歌 谷歌。 .google .google.com goole.c .．.

对我来说，URL的最佳正则表达式是:

"(([\w]+:)?//)?(([\d\w]|%[a-fA-F\d]{2,2})+(:([\d\w]|%[a-fA-f\d]{2,2})+)?@)?([\d\w][-\d\w]{0,253}[\d\w]\.)+[\w]{2,4}(:[\d]+)?(/([-+_~.\d\w]|%[a-fA-f\d]{2,2})*)*(\?(&?([-+_~.\d\w]|%[a-fA-f\d]{2,2})=?)*)?(#([-+_~.\d\w]|%[a-fA-f\d]{2,2})*)?"

下面的正则表达式适用于我:

(http(s)?:\/\/.)?(ftp(s)?:\/\/.)?(www\.)?[-a-zA-Z0-9@:%._\+~#=]{0,256}\.[a-z] 
{2,6}\b([-a-zA-Z0-9@:%_\+.~#?&//=]*)

匹配:

https://google.com t.me https://t.me ftp://google.com http://sm.tj http://bro.tj t.me/rshss https:google.com www.cool.com.au http://www.cool.com.au http://www.cool.com.au/ersdfs http://www.cool.com.au/ersdfs?dfd=dfgd@s=1 http://www.cool.com:81/index.html

我一直在写一篇深入的文章，讨论使用正则表达式进行URI验证。它基于RFC3986。

正则表达式URI验证

虽然这篇文章还不完整，但我已经提出了一个PHP函数，它在验证HTTP和FTP url方面做得非常好。以下是当前版本:

// function url_valid($url) { Rev:20110423_2000
//
// Return associative array of valid URI components, or FALSE if $url is not
// RFC-3986 compliant. If the passed URL begins with: "www." or "ftp.", then
// "http://" or "ftp://" is prepended and the corrected full-url is stored in
// the return array with a key name "url". This value should be used by the caller.
//
// Return value: FALSE if $url is not valid, otherwise array of URI components:
// e.g.
// Given: "http://www.jmrware.com:80/articles?height=10&width=75#fragone"
// Array(
//    [scheme] => http
//    [authority] => www.jmrware.com:80
//    [userinfo] =>
//    [host] => www.jmrware.com
//    [IP_literal] =>
//    [IPV6address] =>
//    [ls32] =>
//    [IPvFuture] =>
//    [IPv4address] =>
//    [regname] => www.jmrware.com
//    [port] => 80
//    [path_abempty] => /articles
//    [query] => height=10&width=75
//    [fragment] => fragone
//    [url] => http://www.jmrware.com:80/articles?height=10&width=75#fragone
// )
function url_valid($url) {
    if (strpos($url, 'www.') === 0) $url = 'http://'. $url;
    if (strpos($url, 'ftp.') === 0) $url = 'ftp://'. $url;
    if (!preg_match('/# Valid absolute URI having a non-empty, valid DNS host.
        ^
        (?P<scheme>[A-Za-z][A-Za-z0-9+\-.]*):\/\/
        (?P<authority>
          (?:(?P<userinfo>(?:[A-Za-z0-9\-._~!$&\'()*+,;=:]|%[0-9A-Fa-f]{2})*)@)?
          (?P<host>
            (?P<IP_literal>
              \[
              (?:
                (?P<IPV6address>
                  (?:                                                (?:[0-9A-Fa-f]{1,4}:){6}
                  |                                                ::(?:[0-9A-Fa-f]{1,4}:){5}
                  | (?:                          [0-9A-Fa-f]{1,4})?::(?:[0-9A-Fa-f]{1,4}:){4}
                  | (?:(?:[0-9A-Fa-f]{1,4}:){0,1}[0-9A-Fa-f]{1,4})?::(?:[0-9A-Fa-f]{1,4}:){3}
                  | (?:(?:[0-9A-Fa-f]{1,4}:){0,2}[0-9A-Fa-f]{1,4})?::(?:[0-9A-Fa-f]{1,4}:){2}
                  | (?:(?:[0-9A-Fa-f]{1,4}:){0,3}[0-9A-Fa-f]{1,4})?::   [0-9A-Fa-f]{1,4}:
                  | (?:(?:[0-9A-Fa-f]{1,4}:){0,4}[0-9A-Fa-f]{1,4})?::
                  )
                  (?P<ls32>[0-9A-Fa-f]{1,4}:[0-9A-Fa-f]{1,4}
                  | (?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}
                       (?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)
                  )
                |   (?:(?:[0-9A-Fa-f]{1,4}:){0,5}[0-9A-Fa-f]{1,4})?::   [0-9A-Fa-f]{1,4}
                |   (?:(?:[0-9A-Fa-f]{1,4}:){0,6}[0-9A-Fa-f]{1,4})?::
                )
              | (?P<IPvFuture>[Vv][0-9A-Fa-f]+\.[A-Za-z0-9\-._~!$&\'()*+,;=:]+)
              )
              \]
            )
          | (?P<IPv4address>(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}
                               (?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?))
          | (?P<regname>(?:[A-Za-z0-9\-._~!$&\'()*+,;=]|%[0-9A-Fa-f]{2})+)
          )
          (?::(?P<port>[0-9]*))?
        )
        (?P<path_abempty>(?:\/(?:[A-Za-z0-9\-._~!$&\'()*+,;=:@]|%[0-9A-Fa-f]{2})*)*)
        (?:\?(?P<query>       (?:[A-Za-z0-9\-._~!$&\'()*+,;=:@\\/?]|%[0-9A-Fa-f]{2})*))?
        (?:\#(?P<fragment>    (?:[A-Za-z0-9\-._~!$&\'()*+,;=:@\\/?]|%[0-9A-Fa-f]{2})*))?
        $
        /mx', $url, $m)) return FALSE;
    switch ($m['scheme']) {
    case 'https':
    case 'http':
        if ($m['userinfo']) return FALSE; // HTTP scheme does not allow userinfo.
        break;
    case 'ftps':
    case 'ftp':
        break;
    default:
        return FALSE;   // Unrecognized URI scheme. Default to FALSE.
    }
    // Validate host name conforms to DNS "dot-separated-parts".
    if ($m['regname']) { // If host regname specified, check for DNS conformance.
        if (!preg_match('/# HTTP DNS host name.
            ^                      # Anchor to beginning of string.
            (?!.{256})             # Overall host length is less than 256 chars.
            (?:                    # Group dot separated host part alternatives.
              [A-Za-z0-9]\.        # Either a single alphanum followed by dot
            |                      # or... part has more than one char (63 chars max).
              [A-Za-z0-9]          # Part first char is alphanum (no dash).
              [A-Za-z0-9\-]{0,61}  # Internal chars are alphanum plus dash.
              [A-Za-z0-9]          # Part last char is alphanum (no dash).
              \.                   # Each part followed by literal dot.
            )*                     # Zero or more parts before top level domain.
            (?:                    # Explicitly specify top level domains.
              com|edu|gov|int|mil|net|org|biz|
              info|name|pro|aero|coop|museum|
              asia|cat|jobs|mobi|tel|travel|
              [A-Za-z]{2})         # Country codes are exactly two alpha chars.
              \.?                  # Top level domain can end in a dot.
            $                      # Anchor to end of string.
            /ix', $m['host'])) return FALSE;
    }
    $m['url'] = $url;
    for ($i = 0; isset($m[$i]); ++$i) unset($m[$i]);
    return $m; // return TRUE == array of useful named $matches plus the valid $url.
}

这个函数使用了两个正则表达式;一个用于匹配有效通用uri的子集(具有非空主机的绝对uri)，另一个用于验证DNS“点分隔部分”主机名。虽然这个函数目前只验证HTTP和FTP方案，但它的结构使它可以很容易地扩展以处理其他方案。

有趣的是，上面的答案都不能满足我的需要，所以我想我可以提供我的解决方案。我需要做到以下几点:

匹配http(s)://www.google.com, http://google.com, www.google.com和google.com 匹配Github降价风格的链接，如[谷歌](http://www.google.com) 匹配所有可能的域名扩展名，比如。com，或。io，或。guru等。基本上长度在2-6个字符之间 将所有内容分成适当的组，以便我可以根据需要访问每个部分。

解决办法是这样的:

/^(\[[A-z0-9 _]*\]\()?((?:(http|https):\/\/)?(?:[\w-]+\.)+[a-z]{2,6})(\))?$

这就满足了上述所有要求。如果需要，你可以选择添加ftp和file功能:

/^(\[[A-z0-9 _]*\]\()?((?:(http|https|ftp|file):\/\/)?(?:[\w-]+\.)+[a-z]{2,6})(\))?$

Mathias Bynens有一篇关于大量正则表达式的最佳比较的很棒的文章:寻找完美的URL验证正则表达式

最好的一个帖子有点长，但它几乎可以匹配任何你可以扔给它的东西。

JavaScript版本

/^(?:(?:(?:https?|ftp):)?\/\/)(?:\S+(?::\S*)?@)?(?:(?!(?:10|127)(?:\.\d{1,3}){3})(?!(?:169\.254|192\.168)(?:\.\d{1,3}){2})(?!172\.(?:1[6-9]|2\d|3[0-1])(?:\.\d{1,3}){2})(?:[1-9]\d?|1\d\d|2[01]\d|22[0-3])(?:\.(?:1?\d{1,2}|2[0-4]\d|25[0-5])){2}(?:\.(?:[1-9]\d?|1\d\d|2[0-4]\d|25[0-4]))|(?:(?:[a-z0-9\u00a1-\uffff][a-z0-9\u00a1-\uffff_-]{0,62})?[a-z0-9\u00a1-\uffff]\.)+(?:[a-z\u00a1-\uffff]{2,}\.?))(?::\d{2,5})?(?:[/?#]\S*)?$/i

PHP版本(使用%符号作为分隔符)

%^(?:(?:(?:https?|ftp):)?\/\/)(?:\S+(?::\S*)?@)?(?:(?!(?:10|127)(?:\.\d{1,3}){3})(?!(?:169\.254|192\.168)(?:\.\d{1,3}){2})(?!172\.(?:1[6-9]|2\d|3[0-1])(?:\.\d{1,3}){2})(?:[1-9]\d?|1\d\d|2[01]\d|22[0-3])(?:\.(?:1?\d{1,2}|2[0-4]\d|25[0-5])){2}(?:\.(?:[1-9]\d?|1\d\d|2[0-4]\d|25[0-4]))|(?:(?:[a-z0-9\x{00a1}-\x{ffff}][a-z0-9\x{00a1}-\x{ffff}_-]{0,62})?[a-z0-9\x{00a1}-\x{ffff}]\.)+(?:[a-z\x{00a1}-\x{ffff}]{2,}\.?))(?::\d{2,5})?(?:[/?#]\S*)?$%iuS