PHP security detection code snippet (share)_PHP tutorial

/**
* html conversion output (only escape ' " to keep Html running normally)
* @param $param
* @return string
*/
 function htmlEscape($param) {
    return trim(htmlspecialchars($param, ENT_QUOTES));
 }

  /**
* Whether it is an array (while checking whether there is a value in the array)
* @param $params
* @return boolean
*/
 function isArray($params) {
     return (!is_array($params) || !count($params)) ? false : true;
 }

 /**
* Whether the variable exists in the array (parameter tolerance, whether the string exists in the array)
* @param $param
* @param $params
* @return boolean
*/
 function inArray($param, $params) {
    return (!in_array((string)$param, (array)$params)) ? false : true;
 }

 /**
* Universal multi-type mixed escape function
* @param $var
* @param $strip
* @param $isArray
* @return mixture
*/
 function sqlEscape($var, $strip = true, $isArray = false) {
    if (is_array($var)) {
        if (!$isArray) return " '' ";
        foreach ($var as $key => $value) {
            $var[$key] = trim(S::sqlEscape($value, $strip));
        }
        return $var;
    } elseif (is_numeric($var)) {
         return " '" . $var . "' ";
    } else {
        return " '" . addslashes($strip ? stripslashes($var) : $var) . "' ";
    }
}

     /**
* Get server variables
* @param $keys
* @return string
*/
     function getServer($keys) {
         $server = array();
         $array = (array) $keys;
         foreach ($array as $key) {
             $server[$key] = NULL;
             if (isset($_SERVER[$key])) {
                 $server[$key] = str_replace(array('<','>','"',"'",'%3C','%3E','%22','%27','%3c','%3e'), '', $_SERVER[$key]);
             }
         }
         return is_array($keys) ? $server : $server[$keys];
     }

     /**
                                                                             */     function slashes(&$array) {
         if (is_array($array)) {             foreach ($array as $key => $value) {
                 if (is_array($value)) {
                     S::slashes($array[$key]);
                 } else {
                     $array[$key] = addslashes($value);
                 }
             }
         }
     }

     /**
                                                                                           */
     function escapeDir($dir) {
         $dir = str_replace(array("'",'#','=','`','$','%','&',';'), '', $dir);
         return rtrim(preg_replace('/(/){2,}|(\){1,}/', '/', $dir), '/');
     }
     /**
                                                                                              */     function escapeChar($mixed, $isint = false, $istrim = false) {
         if (is_array($mixed)) {             foreach ($mixed as $key => $value) {
                 $mixed[$key] = S::escapeChar($value, $isint, $istrim);
             }
         } elseif ($isint) {
             $mixed = (int) $mixed;
         } elseif (!is_numeric($mixed) && ($istrim ? $mixed = trim($mixed) : $mixed) && $mixed) {
             $mixed = S::escapeStr($mixed);
         }
         return $mixed;
     }
     /**

* Character conversion

* @param $string
* @return string
*/
     function escapeStr($string) {
         $string = str_replace(array("