如何使用标头函数返回定义的常量

Question

I have my validation system and I want to make if something isn't ok it's return for example EMPTY but EMPTY is defined as function header.

I tried something like below but it is used all the time, not only when name and pass fields are empty. I could just write if... { header...} but i don't want like that. How to make it?

include 'errors.php';
if(empty($name) || empty($pass){
      return EMPTY;
      exit();}
in another file: errors.php
define('EMPTY', header("Location: ../index.php?error=empty"))

Answer 1

it is used all the times because when you write

define('EMPTY', header("Location: ../index.php?error=empty"));

the header function is run and its return value is assigned to the constant EMPTY. If you want to have specifical functions running on errors and you want to define them in error.php, you should have

//error.php
function got_error($cause){
    switch($cause){
         case 'EMPTY':
             header("location:../index.php?error=empty");
         break;
         case 'SHORT':
             header("location:../index.php?error=short");
         break;
         default:
              header("location:../index.php?error=unknown");
    }
   exit();
}

include 'errors.php';
if(empty($name) || empty($pass)){
    got_error('EMPTY');
}
if(strlen($pass) < 5){ //example of other error
    got_error('SHORT');
}