PHP: Generate random string

random_strgenerator.php

/**
 * Generate and return a random characters string
 *
 * Useful for generating passwords or hashes.
 * 
 * The default string returned is 8 alphanumeric characters string.
 *
 * The type of string returned can be changed with the "type" parameter.
 * Seven types are - by default - available: basic, alpha, alphanum, num, nozero, unique and md5. 
 *
 * @param   string  $type    Type of random string.  basic, alpha, alphanum, num, nozero, unique and md5.
 * @param   integer $length  Length of the string to be generated, Default: 8 characters long.
 * @return  string
 */
function random_str($type = 'alphanum', $length = 8)
{
    switch($type)
    {
        case 'basic'    : return mt_rand();
            break;
        case 'alpha'    :
        case 'alphanum' :
        case 'num'      :
        case 'nozero'   :
                $seedings             = array();
                $seedings['alpha']    = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
                $seedings['alphanum'] = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
                $seedings['num']      = '0123456789';
                $seedings['nozero']   = '123456789';
                
                $pool = $seedings[$type];
                
                $str = '';
                for ($i=0; $i < $length; $i++)
                {
                    $str .= substr($pool, mt_rand(0, strlen($pool) -1), 1);
                }
                return $str;
            break;
        case 'unique'   :
        case 'md5'      :
                    return md5(uniqid(mt_rand()));
            break;
    }
}

/*======================================================+
 Usage Example:
 ---------------
    # Generate 10 chars. alphanumeric string
    echo "Alpha-Numeric: " . random_str('alphanum', 10) . "\n<br>";
    
    # Generate 10 chars. alpha string
    echo "Alpha: " . random_str('alpha', 10) . "\n<br>";
    
    # Generate 10 chars. numeric string
    echo "Numeric: " . random_str('num', 10) . "\n<br>";
    
    # Generate 10 chars. nozero-numeric string
    echo "NoZero Numeric: " . random_str('nozero', 10) . "\n<br>";
    
    # Generate basic string
    echo "Basic: " . random_str('basic') . "\n<br>";
    
    # Generate unique string
    echo "Unique: " . random_str('unique') . "\n<br>";
    
    # Generate md5 string
    echo "Md5: " . random_str('md5') . "\n<br>";
    
+======================================================*/