Forcing a URL field to not have “http://www.” using regex

Question

I need to validate a URL field for an input field that deals with a finicky API that will accept URL strings in a very certain format - no www's and no http's attached to the start of the string, or it breaks. A javascript handler grabs the data from the validation.php file. I have everything working except for one field.

---

So, for example I want

example.com/example

and

example.com

to pass validation, but I want

http://example.com/example

and

http://www.example.com/example

and any variation including any derivation of http:// or www. to not validate.

---

The regex I have below currently allows any type of URL including http and www. I want it to ONLY allow the above type of URL string, but not sure how to go about this.

    // API URL VALIDATION
    if ($formfield == "api_url") {
        if (!preg_match("/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0-9+&@#\/%?=~_|!:,.;]*[-a-z0-9+&@#\/%=~_|]/i", $value)) {
            echo "Please enter your URL without the http://www part attached" 
        } else {
            echo "<span>Valid</span>";
        }

}

Any ideas?

Answer 1

You can use this simple negative lookahead based regex in preg_match :

~^(?!https?://)(?!www\.).+$~i

RegEx Demo

Answer 2

您可以尝试“不匹配”以http或www开头的主题：

if(!preg_match('/^((http|ftp)s?:\/\/)?(www\.).+?/', $value))

Answer 3

You can do it with .htaccess mod rewrite rule. But in your case it looks like you need to validate a input field so it doesn't apply to all cases. Here is function which will allow/dis-allow such protocols in the url.

function remove_protocol($url) {
   $filter_protocol = array('http://', 'https://', 'http://www');
   foreach($filter_protocol as $d) {
      if(strpos($url, $d) === 0) {
         return str_replace($d, '', $url);
      }
   }
   return $url;
}

in the $filter_protocol array you can keep on defining protocols not to allow in urls for instance ftp://