preg_match trailing slash in url

I want to make sure that a visitor is exactly at the homepage of the site. Is this correct to match if the url is:

• www.site.com
• www.site.com/

• www.site.com/index.php

  preg_match("/^(www.)?(".$host.")(\/)?(index.php)?$/", $url, $matches)
  

It doesn't seem too formally开发者_开发问答 correct to separate the last two matches like this, but it works Plus is there any browser that doesn't "redirect" a www.site.com to www.site.com/?

Close. I would go with this instead:

preg_match("/^(?:www\.)?(?:".$host.")(?:\/(?:index\.php)?)?(?:\?.*)?$/", $url, $matches)

The differences here are:

• Escaping . characters meant as literal dots (a dot normally means "any character except \n or \r" in regular expressions).
• Requiring a / before index.php, if index.php is present.
• Optionally allowing GET parameters (the \?.* part).
• Non-capturing groups, since you don't seem interested in going through the captures.

Other than that, it looks good to me.