如何检查给定的字符串是否是有效的URL地址?
我对正则表达式的知识是基本的，不允许我从我已经在网上看到的数百个正则表达式中进行选择。
当前回答
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:
/^(\[[A-z0-9 _]*\]\()?((?:(http|https|ftp|file):\/\/)?(?:[\w-]+\.)+[a-z]{2,6})(\))?$
其他回答
这是一个相当老的线程，现在的问题要求一个基于正则表达式的URL验证器。我在寻找完全相同的东西时也碰到了这条线。虽然很可能编写一个真正全面的正则表达式来验证url。我最终选择了另一种方法——使用PHP的parse_url函数。
如果url无法解析，则返回布尔false。否则，它返回方案、主机和其他信息。这对于一个全面的URL检查本身可能还不够，但是可以深入到进一步的分析中。如果目的仅仅是捕捉拼写错误、无效方案等。这完全足够了!
关于眼睑问题，他的回答是“这是基于我对URI规范的阅读。”谢谢眼睑，你的是我寻求的完美的解决方案，因为它是基于URI规范!出色的工作。：）
我不得不做了两个修改。第一个在PHP (v5.2.10)中使用preg_match()函数使regexp正确匹配IP地址url的方法。
我不得不在管道周围的“IP Address”上方的行中添加一组括号:
)|((\d|[1-9]\d|1\d{2}|2[0-4][0-9]|25[0-5])\.){3}(?#
不知道为什么。
我还将顶级域名的最小长度从3个字母减少到2个字母，以支持.co。英国和类似国家。
最后的代码:
/^(https?|ftp):\/\/(?# protocol
)(([a-z0-9$_\.\+!\*\'\(\),;\?&=-]|%[0-9a-f]{2})+(?# username
)(:([a-z0-9$_\.\+!\*\'\(\),;\?&=-]|%[0-9a-f]{2})+)?(?# password
)@)?(?# auth requires @
)((([a-z0-9]\.|[a-z0-9][a-z0-9-]*[a-z0-9]\.)*(?# domain segments AND
)[a-z][a-z0-9-]*[a-z0-9](?# top level domain OR
)|((\d|[1-9]\d|1\d{2}|2[0-4][0-9]|25[0-5])\.){3}(?#
)(\d|[1-9]\d|1\d{2}|2[0-4][0-9]|25[0-5])(?# IP address
))(:\d+)?(?# port
))(((\/+([a-z0-9$_\.\+!\*\'\(\),;:@&=-]|%[0-9a-f]{2})*)*(?# path
)(\?([a-z0-9$_\.\+!\*\'\(\),;:@&=-]|%[0-9a-f]{2})*)(?# query string
)?)?)?(?# path and query string optional
)(#([a-z0-9$_\.\+!\*\'\(\),;:@&=-]|%[0-9a-f]{2})*)?(?# fragment
)$/i
这个修改后的版本没有根据URI规范进行检查，所以我不能保证它的合规性，它被修改为处理本地网络环境中的URL和两位tld以及其他类型的Web URL，并在我使用的PHP设置中更好地工作。
作为PHP代码:
define('URL_FORMAT',
'/^(https?):\/\/'. // protocol
'(([a-z0-9$_\.\+!\*\'\(\),;\?&=-]|%[0-9a-f]{2})+'. // username
'(:([a-z0-9$_\.\+!\*\'\(\),;\?&=-]|%[0-9a-f]{2})+)?'. // password
'@)?(?#'. // auth requires @
')((([a-z0-9]\.|[a-z0-9][a-z0-9-]*[a-z0-9]\.)*'. // domain segments AND
'[a-z][a-z0-9-]*[a-z0-9]'. // top level domain OR
'|((\d|[1-9]\d|1\d{2}|2[0-4][0-9]|25[0-5])\.){3}'.
'(\d|[1-9]\d|1\d{2}|2[0-4][0-9]|25[0-5])'. // IP address
')(:\d+)?'. // port
')(((\/+([a-z0-9$_\.\+!\*\'\(\),;:@&=-]|%[0-9a-f]{2})*)*'. // path
'(\?([a-z0-9$_\.\+!\*\'\(\),;:@&=-]|%[0-9a-f]{2})*)'. // query string
'?)?)?'. // path and query string optional
'(#([a-z0-9$_\.\+!\*\'\(\),;:@&=-]|%[0-9a-f]{2})*)?'. // fragment
'$/i');
下面是一个PHP测试程序，它使用正则表达式验证各种url:
<?php
define('URL_FORMAT',
'/^(https?):\/\/'. // protocol
'(([a-z0-9$_\.\+!\*\'\(\),;\?&=-]|%[0-9a-f]{2})+'. // username
'(:([a-z0-9$_\.\+!\*\'\(\),;\?&=-]|%[0-9a-f]{2})+)?'. // password
'@)?(?#'. // auth requires @
')((([a-z0-9]\.|[a-z0-9][a-z0-9-]*[a-z0-9]\.)*'. // domain segments AND
'[a-z][a-z0-9-]*[a-z0-9]'. // top level domain OR
'|((\d|[1-9]\d|1\d{2}|2[0-4][0-9]|25[0-5])\.){3}'.
'(\d|[1-9]\d|1\d{2}|2[0-4][0-9]|25[0-5])'. // IP address
')(:\d+)?'. // port
')(((\/+([a-z0-9$_\.\+!\*\'\(\),;:@&=-]|%[0-9a-f]{2})*)*'. // path
'(\?([a-z0-9$_\.\+!\*\'\(\),;:@&=-]|%[0-9a-f]{2})*)'. // query string
'?)?)?'. // path and query string optional
'(#([a-z0-9$_\.\+!\*\'\(\),;:@&=-]|%[0-9a-f]{2})*)?'. // fragment
'$/i');
/**
* Verify the syntax of the given URL.
*
* @access public
* @param $url The URL to verify.
* @return boolean
*/
function is_valid_url($url) {
if (str_starts_with(strtolower($url), 'http://localhost')) {
return true;
}
return preg_match(URL_FORMAT, $url);
}
/**
* String starts with something
*
* This function will return true only if input string starts with
* niddle
*
* @param string $string Input string
* @param string $niddle Needle string
* @return boolean
*/
function str_starts_with($string, $niddle) {
return substr($string, 0, strlen($niddle)) == $niddle;
}
/**
* Test a URL for validity and count results.
* @param url url
* @param expected expected result (true or false)
*/
$numtests = 0;
$passed = 0;
function test_url($url, $expected) {
global $numtests, $passed;
$numtests++;
$valid = is_valid_url($url);
echo "URL Valid?: " . ($valid?"yes":"no") . " for URL: $url. Expected: ".($expected?"yes":"no").". ";
if($valid == $expected) {
echo "PASS\n"; $passed++;
} else {
echo "FAIL\n";
}
}
echo "URL Tests:\n\n";
test_url("http://localserver/projects/public/assets/javascript/widgets/UserBoxMenu/widget.css", true);
test_url("http://www.google.com", true);
test_url("http://www.google.co.uk/projects/my%20folder/test.php", true);
test_url("https://myserver.localdomain", true);
test_url("http://192.168.1.120/projects/index.php", true);
test_url("http://192.168.1.1/projects/index.php", true);
test_url("http://projectpier-server.localdomain/projects/public/assets/javascript/widgets/UserBoxMenu/widget.css", true);
test_url("https://2.4.168.19/project-pier?c=test&a=b", true);
test_url("https://localhost/a/b/c/test.php?c=controller&arg1=20&arg2=20", true);
test_url("http://user:password@localhost/a/b/c/test.php?c=controller&arg1=20&arg2=20", true);
echo "\n$passed out of $numtests tests passed.\n\n";
?>
再次感谢regex的虚实!
function validateURL(textval) {
var urlregex = new RegExp(
"^(http|https|ftp)\://[a-zA-Z0-9\-\.]+\.[a-zA-Z]{2,3}(:[a-zA-Z0-9]*)?/?([a-zA-Z0-9\-\._\?\,\'/\\\+&%\$#\=~])*$");
return urlregex.test(textval);
}
匹配 http://www.asdah.com/~joe | ftp://ftp.asdah.co.uk:2828/asdah%20asdah.gif | https://asdah.gov/asdh-ah.as
这个很适合我。(https ? | ftp): / / (www \ d ? | [a-zA-Z0-9] +) ? \ [a-zA-Z0-9。 -]+(\:|\.)([ a-zA-Z0-9) + | (\ d +)?)([/?:].*)?
感谢@eyelidlessness提供了非常彻底(尽管很长)的基于RFC的正则表达式。
然而，对于那些使用EICMAScript / JavaScript / Apps Script的人来说，它不起作用。以下是他的答案的精确副本，可以与这些问题一起工作(以及一个代码片段，例如-整洁的新功能!):
regEx_valid_URL = /^[a-z](?:[-a-z0-9\+\.])*:(?:\/\/(?:(?:%[0-9a-f][0-9a-f]|[-a-z0-9\._~\uA0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF\u10000-\u1FFFD\u20000-\u2FFFD\u30000-\u3FFFD\u40000-\u4FFFD\u50000-\u5FFFD\u60000-\u6FFFD\u70000-\u7FFFD\u80000-\u8FFFD\u90000-\u9FFFD\uA0000-\uAFFFD\uB0000-\uBFFFD\uC0000-\uCFFFD\uD0000-\uDFFFD\uE1000-\uEFFFD!\$&'\(\)\*\+,;=:])*@)?(?:\[(?:(?:(?:[0-9a-f]{1,4}:){6}(?:[0-9a-f]{1,4}:[0-9a-f]{1,4}|(?:[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])(?:\.(?:[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])){3})|::(?:[0-9a-f]{1,4}:){5}(?:[0-9a-f]{1,4}:[0-9a-f]{1,4}|(?:[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])(?:\.(?:[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])){3})|(?:[0-9a-f]{1,4})?::(?:[0-9a-f]{1,4}:){4}(?:[0-9a-f]{1,4}:[0-9a-f]{1,4}|(?:[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])(?:\.(?:[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])){3})|(?:(?:[0-9a-f]{1,4}:){0,1}[0-9a-f]{1,4})?::(?:[0-9a-f]{1,4}:){3}(?:[0-9a-f]{1,4}:[0-9a-f]{1,4}|(?:[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])(?:\.(?:[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])){3})|(?:(?:[0-9a-f]{1,4}:){0,2}[0-9a-f]{1,4})?::(?:[0-9a-f]{1,4}:){2}(?:[0-9a-f]{1,4}:[0-9a-f]{1,4}|(?:[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])(?:\.(?:[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])){3})|(?:(?:[0-9a-f]{1,4}:){0,3}[0-9a-f]{1,4})?::[0-9a-f]{1,4}:(?:[0-9a-f]{1,4}:[0-9a-f]{1,4}|(?:[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])(?:\.(?:[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])){3})|(?:(?:[0-9a-f]{1,4}:){0,4}[0-9a-f]{1,4})?::(?:[0-9a-f]{1,4}:[0-9a-f]{1,4}|(?:[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])(?:\.(?:[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])){3})|(?:(?:[0-9a-f]{1,4}:){0,5}[0-9a-f]{1,4})?::[0-9a-f]{1,4}|(?:(?:[0-9a-f]{1,4}:){0,6}[0-9a-f]{1,4})?::)|v[0-9a-f]+\.[-a-z0-9\._~!\$&'\(\)\*\+,;=:]+)\]|(?:[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])(?:\.(?:[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])){3}|(?:%[0-9a-f][0-9a-f]|[-a-z0-9\._~\uA0}-\uD7FF}\uF900-\uFDCF}\uFDF0}-\uFFEF}\u10000-\u1FFFD\u20000-\u2FFFD\u30000-\u3FFFD\u40000-\u4FFFD\u50000-\u5FFFD\u60000-\u6FFFD\u70000-\u7FFFD\u80000-\u8FFFD\u90000-\u9FFFD\uA0000-\uAFFFD\uB0000-\uBFFFD\uC0000-\uCFFFD\uD0000-\uDFFFD\uE1000-\uEFFFD!\$&'\(\)\*\+,;=])*)(?::[0-9]*)?(?:\/(?:(?:%[0-9a-f][0-9a-f]|[-a-z0-9\._~\uA0}-\uD7FF}\uF900-\uFDCF}\uFDF0}-\uFFEF}\u10000-\u1FFFD\u20000-\u2FFFD\u30000-\u3FFFD\u40000-\u4FFFD\u50000-\u5FFFD\u60000-\u6FFFD\u70000-\u7FFFD\u80000-\u8FFFD\u90000-\u9FFFD\uA0000-\uAFFFD\uB0000-\uBFFFD\uC0000-\uCFFFD\uD0000-\uDFFFD\uE1000-\uEFFFD!\$&'\(\)\*\+,;=:@]))*)*|\/(?:(?:(?:(?:%[0-9a-f][0-9a-f]|[-a-z0-9\._~\uA0}-\uD7FF}\uF900-\uFDCF}\uFDF0}-\uFFEF}\u10000-\u1FFFD\u20000-\u2FFFD\u30000-\u3FFFD\u40000-\u4FFFD\u50000-\u5FFFD\u60000-\u6FFFD\u70000-\u7FFFD\u80000-\u8FFFD\u90000-\u9FFFD\uA0000-\uAFFFD\uB0000-\uBFFFD\uC0000-\uCFFFD\uD0000-\uDFFFD\uE1000-\uEFFFD!\$&'\(\)\*\+,;=:@]))+)(?:\/(?:(?:%[0-9a-f][0-9a-f]|[-a-z0-9\._~\uA0}-\uD7FF}\uF900-\uFDCF}\uFDF0}-\uFFEF}\u10000-\u1FFFD\u20000-\u2FFFD\u30000-\u3FFFD\u40000-\u4FFFD\u50000-\u5FFFD\u60000-\u6FFFD\u70000-\u7FFFD\u80000-\u8FFFD\u90000-\u9FFFD\uA0000-\uAFFFD\uB0000-\uBFFFD\uC0000-\uCFFFD\uD0000-\uDFFFD\uE1000-\uEFFFD!\$&'\(\)\*\+,;=:@]))*)*)?|(?:(?:(?:%[0-9a-f][0-9a-f]|[-a-z0-9\._~\uA0}-\uD7FF}\uF900-\uFDCF}\uFDF0}-\uFFEF}\u10000-\u1FFFD\u20000-\u2FFFD\u30000-\u3FFFD\u40000-\u4FFFD\u50000-\u5FFFD\u60000-\u6FFFD\u70000-\u7FFFD\u80000-\u8FFFD\u90000-\u9FFFD\uA0000-\uAFFFD\uB0000-\uBFFFD\uC0000-\uCFFFD\uD0000-\uDFFFD\uE1000-\uEFFFD!\$&'\(\)\*\+,;=:@]))+)(?:\/(?:(?:%[0-9a-f][0-9a-f]|[-a-z0-9\._~\uA0}-\uD7FF}\uF900-\uFDCF}\uFDF0}-\uFFEF}\u10000-\u1FFFD\u20000-\u2FFFD\u30000-\u3FFFD\u40000-\u4FFFD\u50000-\u5FFFD\u60000-\u6FFFD\u70000-\u7FFFD\u80000-\u8FFFD\u90000-\u9FFFD\uA0000-\uAFFFD\uB0000-\uBFFFD\uC0000-\uCFFFD\uD0000-\uDFFFD\uE1000-\uEFFFD!\$&'\(\)\*\+,;=:@]))*)*|(?!(?:%[0-9a-f][0-9a-f]|[-a-z0-9\._~\uA0}-\uD7FF}\uF900-\uFDCF}\uFDF0}-\uFFEF}\u10000-\u1FFFD\u20000-\u2FFFD\u30000-\u3FFFD\u40000-\u4FFFD\u50000-\u5FFFD\u60000-\u6FFFD\u70000-\u7FFFD\u80000-\u8FFFD\u90000-\u9FFFD\uA0000-\uAFFFD\uB0000-\uBFFFD\uC0000-\uCFFFD\uD0000-\uDFFFD\uE1000-\uEFFFD!\$&'\(\)\*\+,;=:@])))(?:\?(?:(?:%[0-9a-f][0-9a-f]|[-a-z0-9\._~\uA0}-\uD7FF}\uF900-\uFDCF}\uFDF0}-\uFFEF}\u10000-\u1FFFD\u20000-\u2FFFD\u30000-\u3FFFD\u40000-\u4FFFD\u50000-\u5FFFD\u60000-\u6FFFD\u70000-\u7FFFD\u80000-\u8FFFD\u90000-\u9FFFD\uA0000-\uAFFFD\uB0000-\uBFFFD\uC0000-\uCFFFD\uD0000-\uDFFFD\uE1000-\uEFFFD!\$&'\(\)\*\+,;=:@])|[\uE000-\uF8FF}\uF0000-\uFFFFD\u100000-\u10FFFD\/\?])*)?(?:\#(?:(?:%[0-9a-f][0-9a-f]|[-a-z0-9\._~\uA0}-\uD7FF}\uF900-\uFDCF}\uFDF0}-\uFFEF}\u10000-\u1FFFD\u20000-\u2FFFD\u30000-\u3FFFD\u40000-\u4FFFD\u50000-\u5FFFD\u60000-\u6FFFD\u70000-\u7FFFD\u80000-\u8FFFD\u90000-\u9FFFD\uA0000-\uAFFFD\uB0000-\uBFFFD\uC0000-\uCFFFD\uD0000-\uDFFFD\uE1000-\uEFFFD!\$&'\(\)\*\+,;=:@])|[\/\?])*)?$/i; checkedURL = RegExp(regEx_valid_URL).exec('gopher://example.somewhere.university/'); if (checkedURL != null) { console.log('The URL ' + checkedURL + ' is valid'); }
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