regular expression for validating url with sub-domain

问题

preg_match('/^(http:\\/\/)?(.+)\.MYDOMAIN\.com(.*)/', $url, $match)

This is my regex to validate a URL that must have a sub-domain, but if someone uses www instead of sub-domain it also gets validated. For example:

• http://shoes.en.MYDOMAIN.com/ This must pass

• http://www.MYDOMAIN.com/ This must fail

How can I edit my regex to fail if the sub-domain is www?

回答1:

I think you can do it with a negative lookahead assertion: (?!www\.) which being placed after the protocol check, checks if there is not a www. following the start or protocol.

/^(http:\\\/\/)?(?!www\.)(.+)\.MYDOMAIN\.com(.*)/.test("www.MYDOMAIN.com")

回答2:

try this one: tested a litle, seems to be working

preg_match('/^(http:\\/\/)?([^(www)]+)\.MYDOMAIN\.com(.*)/', $url, $match);

回答3:

How about first validate the domain using your current solution then check for www using a second expression:

(\.www\.|http:\/\/www\.|^www\.)

来源：https://stackoverflow.com/questions/10118536/regular-expression-for-validating-url-with-sub-domain