Code Critique - validUsername

[premiso]

Hello,

 

I am just looking to see if this is the best way to check a valid username. The requirements I want are in the comment. Any suggestions would be great, thanks!

 

<?php
$userArray = array("username", "test1234testsetset", "test-test-3est455test", "#dfdf45-sfdsf", "'sdfsdf+__", "good_username", 
				"bad_username%", "bad123", "good12", "goodgood1234", "goodbad1234", "bad1234", "bad123ba4", "b1c2v3b4n5m6", "toolongofausernameok", "sh", "sht", "bad cause spaces", "bad12345b", "good_but-bad", "gooduser", "frost", "david", "creative210", "12345321");

foreach ($userArray as $user) {
if (!validUsername($user)) {
	echo "BAD: " . $user . "<Br />";
}else {
	echo "GOOD: " . $user . "<br />";
}
}					

/**
* Checks if a username is valid
*
* Takes in a string of username. If the username is valid
* which means that there are no special characters, it has
* at least 1 letter, the start of it does not start with a number
* and the length is between 4 and 15. And it does not have more than
* 4 numbers in it. For every number there must be at least 2 
* letters.
**/
function validUsername($user) {
// first check the length. No need to continue if the length, or first is wrong.
$firstNum = substr($user, 0, 1);
if ((strlen($user) < 4 || strlen($user) > 15) || is_numeric($firstNum)) 
	return false;

$checkNum = preg_replace('/([a-z])*/i', "", $user);
if (strlen($checkNum) > 4 || (strlen($checkNum) > 0 && (strlen($user) - strlen($checkNum)) < (strlen($checkNum) * 2)))
	return false;

preg_match('/(^[a-z0-9]*)/i', $user, $matches);
if ($matches[1] != $user) 
	return false;

return true;
}
?>

 

I think it is pretty efficient as is, but yea since I am new the regex part just wanted to check.

 

Thanks!

[MadTechie]

Heres an example with error messages to make it more use friendsly

 

<?php
$Username = "test"; 
//Must have atleast 1 number

$Username = "1test"; 
//Must Start with a letter

$Username = "test1"; 
//Username: test1 is Okay

$Username = "tes"; 
//Must Start with a letter 
//Must have atleast 1 number
//Must have twice as many letters to numbers

$Username = "te12";
//Must have twice as many letters to numbers

$Username = "te12fghdsgfhsdgfsd gfhdsgfhdsgfhsdgfhgdsfjgsdfhsdfgsdhj";
//Must have twice as many letters to numbers

$Username = "test 12";
//Must NOT contain special chars
//Must have twice as many letters to numbers


$error = array();

$letters = strlen(preg_replace('/\d/i', '', $Username));
$numbers = strlen(preg_replace('/[a-z]/i', '', $Username));
$total = $numbers+$letters;
if ($Username != preg_replace('/[^\da-z]/i', '', $Username))
{
$error[] = "Must NOT contain special chars";
}

if (!preg_match('/^[a-z]\w{3}/i', $Username))
{
$error[] = "Must Start with a letter";
}
if($numbers > 4)
{
$error[] = "Must have less than 4 numbers";
}
if( $numbers < 1)
{
$error[] = "Must have atleast 1 number";
}
if( ($numbers*2) > $letters)
{
$error[] = "Must have twice as many letters to numbers";
}

if( $total > 15 || $total < 4) 
{
$error[] = "Must have twice as many letters to numbers";
}
if(count($error)>0)
{
echo implode($error, "<br>");
}else{
echo "Username: $Username is Okay";
}

?>

 

Hope this helps