Control Form Input?

[justlukeyou]

I have a number of Forms which I want to control the input, for example prevent people from using numbers or ensure that people use specific characters.

 

For example "Your password must contain a capital letter and at least one number".

 

Does anyone know what code I should use to do this. 

[betterphp]

regular expressions can do this so preg_match() or the ctype function ctype_alnum()

[justlukeyou]

Thanks, I am using pregmatch, can you advise how I block characters such as $1) etc and limit the number of characters.

 

For example: "Your Username must not exceed 15 characters"

 

  if(preg_match("/[a-zA-Z0-9]/", $membername) == 0 && !$error) {

[betterphp]

you might want to and the start ^ and end $ of the string.

 

if (preg_match("/^[a-zA-Z0-9]+$/", $membername) == 0 && !$error) {

 

that way it will only pass this test if the whole string consists of nothing but those characters.

 

for the length thing, strlen() can tell you the length of the string.

[justlukeyou]

Thanks,

 

How do I execute strlen(), do I use it in a preg match to issue an error message

 

if(preg_match($membername= 'abcdef'; echo strlen($str); //15 == 0 && !$error) {
        $error = "The username must contain no more than 15 characters.";

[betterphp]

erm, no

 

you do it as a separate condition

 

if (strlen($str) > 15){
    echo 'username too long AHHHHH';
}

 

[justlukeyou]

Brilliant thanks,  I have this but I want spit out as error which I am currently doing with lots of other errors.  I have $error set in a table which controls the font so it would be handy if I could continue to use it..

 

if (strlen($membername) > 15) && !$error) {    
$error = "The username must not exceed 15 characters.";
    }

 

I have this working:

 

if((!isset($password2) || empty($password2)) && !$error) {
        $error = "You need to enter your password twice.";
    }

[betterphp]

that looks fine, although there is no need to check !$error all the time... you can just do

 

if (strlen($membername) > 15){
    $error = 'The username must not exceed 15 characters.';
}else if (empty($password2)){
    $error = 'You need to enter your password twice.';
}

 

and so on for all of the conditions.