(PHP 5 >= 5.4.0, PHP 7, PHP 8)
header_register_callback — Call a header function
Registers a function that will be called when PHP starts sending output.
The callback
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
Function called just before the headers are sent. It gets no parameters and the return value is ignored.
Beispiel #1 header_register_callback() 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";
?>
Das oben gezeigte Beispiel erzeugt eine ähnliche Ausgabe wie:
Content-Type: text/plain a
header_register_callback() is executed just as the headers are about to be sent out, so any output from this function can break output.
Hinweis:
Header sind nur dann zugänglich und werden nur dann gesendet, wenn die genutzte SAPI sie unterstützt.