用于URL验证的PHP正则表达式，filter_var的权限太高 [英] PHP regex for url validation, filter_var is too permisive
问题描述
首先让我们根据我的要求定义一个"URL".
First lets define a "URL" according to my requirements.
可选的唯一协议是http://和https://
然后是一个强制性域名，例如stackoverflow.com
then a mandatory domain name like stackoverflow.com
然后选择其余的url组件(path，query，hash，...)
then optionally the rest of url components (path, query, hash, ...)
根据我的要求供参考的有效和无效网址列表
For reference a list of valid and invalid url's according to my requirements
- stackoverflow.com
- stackoverflow.com/questions/ask
- https://stackoverflow.com/questions/ask
- stackoverflow.com
- stackoverflow.com/questions/ask
- https://stackoverflow.com/questions/ask
- http://www.amazon.com/Computers-Internet-Books/b/ref=bhp_bb0309A_comint2?ie=UTF8&node=5&pf_rd_m=ATVPDKIKX0DER&pf_rd_s=browse&pf_rd_r=0AH7GM29WF81Q72VPFDH&pf_rd_t=101&pf_rd_p=1273387142&pf_rd_i=283155
amazon.com/Computers-Internet-Books/b/ref=bhp_bb0309A_comint2?ie=UTF8&node=5&pf_rd_m=ATVPDKIKX0DER&pf_rd_s=browse&pf_rd_r=0AH7GM29WF81Q72VPFDH&pf_rd_t=101&pf_rd_p=1273387142&pf_rd_i=283155
http://test-site.com (filter_var拒绝！！！带有破折号的域名)
http://test-site.com (filter_var reject this!!! I have domain names with dashes )
- http://www (php filter_var允许这样做，是的，我知道这是
valid网址) - http://www..des (php filter_var允许这样做)
- 域名中不允许包含任何字符的任何URL
- http://www (php filter_var allow this, yes i know is a
validurl) - http://www..des (php filter_var allow this)
- Any url with not allowed characters in the domain name
为了完整性，这是我的php版本:5.3.2-1ubuntu4.2
For completeness here is my php version: 5.3.2-1ubuntu4.2
推荐答案
作为起点，您可以使用它用于JS ，但是转换起来很容易它可用于PHP preg_match.
As a starting point you can use this one, it's for JS, but it's easy to convert it to work for PHP preg_match.
/^(https?\://)?(www\.)?([a-z0-9]([a-z0-9]|(\-[a-z0-9]))*\.)+[a-z]+$/i
对于PHP，这应该可以使用:
For PHP should work this one:
$reg = '@^(https?\://)?(www\.)?([a-z0-9]([a-z0-9]|(\-[a-z0-9]))*\.)+[a-z]+$@i';
此正则表达式始终仅验证域部分，但是您可以对此进行处理或在第一个斜杠'/'(在"://"之后)拆分网址，并分别验证域部分和休息.
This regexp anyway validates only the domain part, but you can work on this or split the url at the 1st slash '/' (after "://") and validate separately the domain part and the rest.
BTW:它将同时验证"http://www.domain.com.com"，但这不是错误，因为子域url可能类似于:"http://www.subdomain.domain.com"并且有效！而且几乎没有方法(或至少没有操作上简便的方法)使用正则表达式来验证正确的域tld ，因为您必须像这样将所有可能的域tld逐一内联到正则表达式中:
BTW: It would validate also "http://www.domain.com.com" but this is not an error because a subdomain url could be like: "http://www.subdomain.domain.com" and it's valid! And there is almost no way (or at least no operatively easy way) to validate for proper domain tld with a regex because you would have to write inline into your regex all possible domain tlds ONE BY ONE like this:
/^(https?\://)?(www\.)?([a-z0-9]([a-z0-9]|(\-[a-z0-9]))*\.)+(com|it|net|uk|de)$/i
(例如，最后一个仅验证以.com/.net/.de/.it/.co.uk结尾的域). 新TLD总是会出现，因此您必须调整正则表达式，每当一个新TLD出现时，这都是令人头疼的事！
(this last one for instance would validate only domain ending with .com/.net/.de/.it/.co.uk). New tlds always come out, so you would have to adjust you regex everytimne a new tld comes out, that's a pain in the neck!
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