Help with regex to match any url but that of admin folder

问题

I am stuck with something I know must be simple but been going round in circles for a while now.

I want to create a regular expression for use with a cms routing feature using php and preg_match that matches any URL that doesn't begin with the string 'admin/' as somedomain.com/admin/ will be the admin part of the cms.

I have tried so far

preg_match('#^([^admin])+(.+)$#', 'mens-books'))

which fails as the url string 'mens-books' I am looking for is a match against the letter m in the string 'admin' so it fails.

I have tried doing it like this also:

preg_match('#^([^admin$])+(.+)$#', 'mens-books'))

as a dollar symbolises the end of string but that didn't work either.

I then did this:

preg_match('#^[?!=admin]+(.+)$#', 'mens-books'))

which returned true but only I think because the ?!= in the regex now will match anything that is beginning with a, d, m, i or n.

Is anyone able to help with this please. I am open to any suggestions.

Thankyou.

Matt

回答1:

if (substr($url, 0, 6) !== 'admin/')
{
  echo 'Yippie';
}

But to answer the regex question. When you use square brackets, you're specifying a character class. That means [admin] matches a single character that is either an a, a d an m an i or an n. If you skip the brackets, you're matching a literal string. But, as my code proofs, it is not needed to use regex at all if you need to check if a string starts with a fixed substring.

回答2:

If you want to use regular expressions, what you are looking for is something called negative lookahead, which is a zero-width assertion (it checks for the existence or lack of text without 'eating' it). It would work something like this:

^(?!admin\/)

Here are some specific preg_match examples:

preg_match('/^(?!admin\/)/', 'mens-books');        // true
preg_match('/^(?!admin\/)/', 'admin/mens-books');  // false
preg_match('/^(?!admin\/)/', 'admin-mens-books');  // true

回答3:

the brackets [] are used for any single character [admin] is a, d, m, i, or n not admin, what you probably want is (admin). So anything that begins with admin would be /^(admin).*$/ then the easiest way is to put a not in your code.

example (not a php coder so sorry in advance):

$pattern = '/^(admin)\/.*$/'
if (preg_match($pattern, $url) == 1) {
    $match = true;
} else {
    $match = false;
}

that is assuming your trying to get back a boolean

回答4:

Im not entirely sure I follow but dont you just want

preg_match('^(/)?admin(/)?.*', 'mens-books'))

eg starts either with /admin or admin

回答5:

Try ^(?!admin/).*$ but I think comparing a substring is much faster.

来源：https://stackoverflow.com/questions/6285677/help-with-regex-to-match-any-url-but-that-of-admin-folder