Undefined index HTTP_HOST even though it is checked

Question

Here\'s the code:

if (isset($_SERVER[\'HTTP_HOST\']) === TRUE) {
  $host = $_SERVER[\'HTTP_HOST\'];
}

How is it possible to get an \"Undefined

Answer 1

An bad implemented browser can omit send que host header information, try this example:

telnet myphpserver.com 80
> GET / 

in this case $_SERVER['HTTP_HOST'] not have assigned value, in this case u can use $_SERVER['SERVER_NAME'] but only if $_SERVER['HTTP_HOST'] is empty, because no is the same.