header_register_callback

header_register_callback

Call a header function

bool **header_register_callback** callable $callback

Registers a function that will be called when PHP starts sending output.

The is executed just after PHP prepares all headers to be sent, and before any other output is sent, creating a window to manipulate the outgoing headers before being sent. callback

callbackFunction called just before the headers are sent. It gets no parameters and the return value is ignored.

return.success

Voorbeeld: example

<?php

header('Content-Type: text/plain');
header('X-Test: foo');

function foo() {
 foreach (headers_list() as $header) {
   if (strpos($header, 'X-Powered-By:') !== false) {
     header_remove('X-Powered-By');
   }
   header_remove('X-Test');
 }
}

$result = header_register_callback('foo');
echo "a";
?>

Content-Type: text/plain

a

is executed just as the

headers are about to be sent out, so any output from this function can break output. header_register_callback

headers_list``header_remove``header