validation max_length, min_length in codeigniter

Question

I am getting an error when trying to set custom validation messages in CodeIgniter for the min_length and max_length validation constraints.

These are my validation rules:

$this->form_validation->set_rules('username', 'Username', 'required|xss_clean|min_length[6]|max_length[10]');
$this->form_validation->set_rules('password', 'Password', 'required|min_length[8]|max_length[20]';

These are my custom validation message:

$this->form_validation->set_message('min_length[3]', '%s: the minimum of characters is three');
$this->form_validation->set_message('max_length[20]', '%s:the maximum of characters is 20');

In my example we have two fields, but I have many fields with different minimum and maximum length values. They all have a specific constraint validations. This messages doesn't work. The message appears by default. Thanks for your help.

Answer 1

When using set_message, you can't specify the lengths (both min and max) the way that you have done. You can either set a general message for min_length and max_length like:

$this->form_validation->set_message('min_length', 'The value you have entered for %s is too short');
$this->form_validation->set_message('max_length', 'The value you have entered for %s is too long');

Otherwise, you will have to utilise CodeIgniter's callback feature and set up a custom validation function which would look something like this (for the minimum length!!).

public function custom_min_length($str, $val) {
    if (preg_match("/[^0-9]/", $val)) {
        return FALSE;
    }
    if (function_exists('mb_strlen')) {
        if(mb_strlen($str) < $val) {
            $this->form_validation->set_message('custom_min_length', '%s: The Minimum Number Of Characters Is ' . $val);
            return FALSE;
        } else {
            return TRUE;
        }
    }
    if(strlen($str) < $val) {
        $this->form_validation->set_message('custom_min_length', '%s: The Minimum Number Of Characters Is ' . $val);
        return FALSE;
    } else {
        return TRUE;
    }
}

You would set your validation rule like this:

$this->form_validation->set_rules('username', 'Username', 'callback_custom_min_length[6]|required|xss_clean');

Notice the callback_ prefix on the custom_min_length rule. This replaces, and is used instead of the usual min_length CI function.

Hope that helps...I'll leave you figure out how to do the custom_max_length function :)