Regular Expression Sanitize (PHP)

Question

I would like to sanitize a string in to a URL so this is what I basically need.

1. Everything must be removed except alphanumeric characters and spaces and dashed.
2. Spaces should be converter into dashes.

Eg.

This, is the URL!

must return

this-is-the-url

Answer 1

function slug($z){
    $z = strtolower($z);
    $z = preg_replace('/[^a-z0-9 -]+/', '', $z);
    $z = str_replace(' ', '-', $z);
    return trim($z, '-');
}

Answer 2

All previous asnwers deal with url, but in case some one will need to sanitize string for login (e.g.) and keep it as text, here is you go:

function sanitizeText($str) {
    $withSpecCharacters = htmlspecialchars($str);
    $splitted_str = str_split($str);
    $result = '';
    foreach ($splitted_str as $letter){
        if (strpos($withSpecCharacters, $letter) !== false) {
            $result .= $letter;
        }
    }
    return $result;
}

echo sanitizeText('ОРРииыфвсси ajvnsakjvnHB "&nvsp;\n" <script>alert()</script>');
//ОРРииыфвсси ajvnsakjvnHB &nvsp;\n scriptalert()/script
//No injections possible, all info at max keeped

Answer 3

First strip unwanted characters

$new_string = preg_replace("/[^a-zA-Z0-9\s]/", "", $string);

Then changes spaces for unserscores

$url = preg_replace('/\s/', '-', $new_string);

Finally encode it ready for use

$new_url = urlencode($url);

Answer 4

This will do it in a Unix shell (I just tried it on my MacOS):

$ tr -cs A-Za-z '-' < infile.txt > outfile.txt

I got the idea from a blog post on More Shell, Less Egg

Answer 5

Try This

 function clean($string) {
       $string = str_replace(' ', '-', $string); // Replaces all spaces with hyphens.
       $string = preg_replace('/[^A-Za-z0-9\-]/', '', $string); // Removes special chars.

       return preg_replace('/-+/', '-', $string); // Replaces multiple hyphens with single one.
    }

Usage:

echo clean('a|"bc!@£de^&$f g');

Will output: abcdef-g

source : https://stackoverflow.com/a/14114419/2439715