Make sure username contains only: A-Z, a-z, ., _, -, 0-9 (no comma) PHP

Question

Possible Duplicate:
regular expression for letters, numbers and - _

I am creating a signup form in PHP and need to ensure that user's usernames don't contain unwanted characters. Is there anyway I can create a function that returns true for A-Z a-z 0-9 - . _.

Also I do not want the user's emails to be from yahoo as for some reason they reject the confirmation emails sent. Along with __FILTER_VALIDATE_EMAIL__what would I need to add?

PS: is there anything wrong with the characters I have mentioned above? I have noted that gmail doesn't allow -_ only . and YouTube only alpha-numeric characters.

please allow me to chose what ever user-name i want,not arbitrarily restrict me. Thanks. — , Oct 09 '12 at 20:41
@MuqMan I want all sites to stop imposing meaningless restrictions. — , Oct 09 '12 at 20:47
@mario, its not a duplicate because i want a . as well ;) and I __never__ found that post! — user115422, Oct 09 '12 at 20:51
@MuqMan: That happens to be included. If you couldn't be bothered to make such a trivial addition, then you're wrong on Stackoverflow. And there many more duplicates. Objectively too little search effort. — mario, Oct 09 '12 at 20:54
@mario im sure you can tell that i am not too frequent to SO, also i _did_ google it, plus I don't know the rules of prey_match! Sorry if this seems against your terms! — user115422, Oct 09 '12 at 20:58

Sam · Accepted Answer · 2012-10-11T18:41:16.983

8

Edited to use \w instead of a-zA-Z0-9_

if(preg_match("/[^\w-.]/", $user)){
    // invalid character
}
if(!filter_var($email, FILTER_VALIDATE_EMAIL) || strstr($email,'@yahoo.com')) {
    // either invalid email, or it contains in @yahoo.com
}

edited Oct 11 '12 at 18:41

answered Oct 09 '12 at 20:46

Sam

20,096
2
45
71

1

Could be shortened to `[^\w.-]`. – Madara's Ghost Oct 09 '12 at 20:51
1

wait i also do want the _ ? would that work and does \w extend to numbers? w sounds like it represents words – user115422 Oct 09 '12 at 21:00
\w finds [a-z][A-Z][0-9] and the underscore [_]. You can replace the first line with `if(preg_match("/[^\w-.?]/", $user)){` – Sam Oct 09 '12 at 21:02
`and added '?' to valid username character` what does that mean? Thanks anyway. I've marked your answer as answer! It helps a lot! – user115422 Oct 09 '12 at 23:48
I thought your original comment said you wanted the ? allowed also. Nevermind. – Sam Oct 11 '12 at 18:41

circusdei · Answer 2 · 2012-10-09T20:47:35.430

2

if(preg_match("/[^-A-Za-z0-9._ ]/", $userName)){
    // there are one or more of the forbidden characters (the set of which is unknown)
}

edited Oct 09 '12 at 20:47

answered Oct 09 '12 at 20:41

circusdei

1,967
12
28

wait $email will be $user for me right? $email needs to be escaped from @yahoo.com – user115422 Oct 09 '12 at 20:42
@zerkms - wouldn't that eval to false? Question was for eval to true if chars are present. – circusdei Oct 09 '12 at 20:43
@zerkms um where does the `^` go? – user115422 Oct 09 '12 at 20:43
@circusdei: please test your code on any invalid input, say ` a` (spaces followed by `a` char) – zerkms Oct 09 '12 at 20:45

score 2 · Answer 3 · answered Oct 09 '12 at 20:51

<?php

    // The validator class

    class Validator
    {
        public function isValidUsername($username)
        {
            if(preg_match('/^[a-zA-Z0-9_\-\.]+$/', $username)) {
                return true;    
            }
            return false;
        }

        public function isYahooMail($mail) {
            if(preg_match('/^[a-zA-Z0-9_\-\.]+@yahoo.com$/', $mail)) {
                return true;    
            }
            return false;
        }
    }

    // The way to use this class

    $username = "otporan_123";
    $email = "otporan@gmail.com";

    $badUsername = "otporan*bad";
    $yahooEmail = "otporan@yahoo.com";

    $validator = new Validator();

    var_export($validator->isValidUsername($username));
    echo "<br />";

    var_export($validator->isValidUsername($badUsername));
    echo "<br />";

    var_export($validator->isYahooMail($email));
    echo "<br />";

    var_export($validator->isYahooMail($yahooEmail));
    echo "<br />";  

?>

This code would return: true false false true

This is a class, but you can see whats going on in methods and write your own functions if you like procedural code :)

Hope this helps!

great! I'll try it out! Looks like you're introducing me to classes and OOP ;) — user115422, Oct 09 '12 at 20:53
I wanted to mark both as answers but right now i am not doing OOP much :) srry not to give you the full points but I still plus1d your answer (not google plus ;)) — user115422, Oct 09 '12 at 23:47

score -1 · Answer 4 · answered Oct 09 '12 at 20:44

-1

if (!preg_match('/\w\-/', $username) {
    //throw error 
}

answered Oct 09 '12 at 20:44

chmeliuk

1,060
9
8

This matches any word-char followed by a hyphen. Clearly not desired. – John Dvorak Oct 09 '12 at 20:45
I appreciate the effort but like they said, it doesn't work. :( – user115422 Oct 09 '12 at 20:50

Make sure username contains only: A-Z, a-z, ., _, -, 0-9 (no comma) PHP

4 Answers4