我发现下面的正则表达式的url，测试成功与500+ url:

/\b(?:(?:https?|ftp):\/\/)(?:\S+(?::\S*)?@)?(?:(?!10(?:\.\d{1,3}){3})(?!127(?:\.\d{1,3}){3})(?!169\.254(?:\.\d{1,3}){2})(?!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-z\x{00a1}-\x{ffff}0-9]+-?)*[a-z\x{00a1}-\x{ffff}0-9]+)(?:\.(?:[a-z\x{00a1}-\x{ffff}0-9]+-?)*[a-z\x{00a1}-\x{ffff}0-9]+)*(?:\.(?:[a-z\x{00a1}-\x{ffff}]{2,})))(?::\d{2,5})?(?:\/[^\s]*)?\b/gi

我知道这看起来很丑，但好处是它很有效。：）

regex101上581个随机url的解释和演示。

来源:在搜索完美的URL验证正则表达式

我创建了一个类似于RFC3987和其他RFC文档提供的@eyelidlessness的正则表达式(PCRE)。@eyelidlessness和我的正则表达式之间的主要区别主要是可读性和URN支持。

下面的正则表达式是一个整体(而不是与PHP混合)，所以它可以很容易地用于不同的语言(只要它们支持PCRE)

测试这个正则表达式最简单的方法是使用regex101，并使用适当的修饰符(gmx)复制粘贴下面的代码和测试字符串。

要在PHP中使用这个正则表达式，请将下面的正则表达式插入到以下代码中:

$regex = <<<'EOD'
// Put the regex here
EOD;

可以通过以下方式匹配不带方案的链路: 要匹配一个没有方案的链接(例如john.doe@gmail.com或www.google.com/pathtofile.php?query)，替换此部分:

  (?:
    (?<scheme>
      (?<urn>urn)|
      (?&d_scheme)
    )
    :
  )?

用这个:

  (?:
    (?<scheme>
      (?<urn>urn)|
      (?&d_scheme)
    )
    :
  )?

但是请注意，通过替换它，regex并不是100%可靠。 使用gmx修饰符的Regex (PCRE)用于下面的多行测试字符串

(?(DEFINE)
  # Definitions
  (?<ALPHA>[\p{L}])
  (?<DIGIT>[0-9])
  (?<HEX>[0-9a-fA-F])
  (?<NCCHAR>
    (?&UNRESERVED)|
    (?&PCT_ENCODED)|
    (?&SUB_DELIMS)|
    @
  )
  (?<PCHAR>
    (?&UNRESERVED)|
    (?&PCT_ENCODED)|
    (?&SUB_DELIMS)|
    :|
    @|
    \/
  )
  (?<UCHAR>
    (?&UNRESERVED)|
    (?&PCT_ENCODED)|
    (?&SUB_DELIMS)|
    :
  )
  (?<RCHAR>
    (?&UNRESERVED)|
    (?&PCT_ENCODED)|
    (?&SUB_DELIMS)
  )
  (?<PCT_ENCODED>%(?&HEX){2})
  (?<UNRESERVED>
    ((?&ALPHA)|(?&DIGIT)|[-._~])
  )
  (?<RESERVED>(?&GEN_DELIMS)|(?&SUB_DELIMS))
  (?<GEN_DELIMS>[:\/?#\[\]@])
  (?<SUB_DELIMS>[!$&'()*+,;=])
  # URI Parts
  (?<d_scheme>
    (?!urn)
    (?:
      (?&ALPHA)
      ((?&ALPHA)|(?&DIGIT)|[+-.])*
      (?=:)
    )
  )
  (?<d_hier_part_slashes>
    (\/{2})?
  )
  (?<d_authority>(?&d_userinfo)?)
  (?<d_userinfo>(?&UCHAR)*)
  (?<d_ipv6>
    (?![^:]*::[^:]*::[^:]*)
    (
      (
        ((?&HEX){0,4})
        :
      ){1,7}
      ((?&d_ipv4)|:|(?&HEX){1,4})
    )
  )
  (?<d_ipv4>
    ((?&octet)\.){3}
    (?&octet)
  )
  (?<octet>
    (
      25[]0-5]|
      2[0-4](?&DIGIT)|
      1(?&DIGIT){2}|
      [1-9](?&DIGIT)|
      (?&DIGIT)
    )
  )
  (?<d_reg_name>(?&RCHAR)*)
  (?<d_urn_name>(?&UCHAR)*)
  (?<d_port>(?&DIGIT)*)
  (?<d_path>
    (
      \/
      ((?&PCHAR)*)*
      (?=\?|\#|$)
    )
  )
  (?<d_query>
    (
      ((?&PCHAR)|\/|\?)*
    )?
  )
  (?<d_fragment>
    (
      ((?&PCHAR)|\/|\?)*
    )?
  )
)
^
(?<link>
  (?:
    (?<scheme>
      (?<urn>urn)|
      (?&d_scheme)
    )
    :
  )
  (?(urn)
    (?:
      (?<namespace_identifier>[0-9a-zA-Z\-]+)
      :
      (?<namespace_specific_string>(?&d_urn_name)+)
    )
    |
    (?<hier_part>
      (?<slashes>(?&d_hier_part_slashes))
      (?<authority>
        (?:
          (?<userinfo>(?&d_authority))
          @
        )?
        (?<host>
          (?<ipv4>\[?(?&d_ipv4)\]?)|
          (?<ipv6>\[(?&d_ipv6)\])|
          (?<domain>(?&d_reg_name))
        )
        (?:
          :
          (?<port>(?&d_port))
        )?
      )
      (?<path>(?&d_path))?
    )
    (?:
      \?
      (?<query>(?&d_query))
    )?
    (?:
      \#
      (?<fragment>(?&d_fragment))
    )?
  )
)
$

测试字符串

# Valid URIs
ftp://cnn.example.com&story=breaking_news@10.0.0.1/top_story.htm
ftp://ftp.is.co.za/rfc/rfc1808.txt
http://www.ietf.org/rfc/rfc2396.txt
ldap://[2001:db8::7]/c=GB?objectClass?one
mailto:John.Doe@example.com
news:comp.infosystems.www.servers.unix
tel:+1-816-555-1212
telnet://192.0.2.16:80/
urn:isbn:0451450523
urn:oid:2.16.840
urn:isan:0000-0000-9E59-0000-O-0000-0000-2
urn:oasis:names:specification:docbook:dtd:xml:4.1.2
http://localhost/test/somefile.php?query=someval&variable=value#fragment
http://[2001:db8:a0b:12f0::1]/test
ftp://username:password@domain.com/path/to/file/somefile.html?queryVariable=value#fragment
https://subdomain.domain.com/path/to/file.php?query=value#fragment
https://subdomain.example.com/path/to/file.php?query=value#fragment
mailto:john.smith(comment)@example.com
mailto:user@[2001:DB8::1]
mailto:user@[255:192:168:1]
mailto:M.Handley@cs.ucl.ac.uk
http://localhost:4433/path/to/file?query#fragment
# Note that the example below IS a valid as it does follow RFC standards
localhost:4433/path/to/file

# These work with the optional scheme group although I'd suggest making the scheme mandatory as misinterpretations can occur
john.doe@gmail.com
www.google.com/pathtofile.php?query
[192a:123::192.168.1.1]:80/path/to/file.html?query#fragment

这里有一个很好的规则，它涵盖了所有可能的情况:端口，参数等等

/(https?:\/\/(?:[a-z0-9](?:[a-z0-9-]{0,61}[a-z0-9])?\.)+[a-z0-9][a-z0-9-]{0,61}[a-z0-9])(:?\d*)\/?([a-z_\/0-9\-#.]*)\??([a-z_\/0-9\-#=&]*)/g

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

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})*)?"

这不是一个正则表达式，但完成了同样的事情(仅Javascript):

function isAValidUrl(url) {
  try {
    new URL(url);
    return true;
  } catch(e) {
    return false;
  }
}