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header_register_callback

(PHP 5 >= 5.4.0, PHP 7, PHP 8)

header_register_callback — Call a header function

Beschreibung

header_register_callback(callable $callback): bool

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.

Parameter-Liste

callback

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

Rückgabewerte

Gibt bei Erfolg true zurück. Bei einem Fehler wird false zurückgegeben.

Beispiele

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

Anmerkungen

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.

Siehe auch