Note that this function only registers a single callback as of php 5.4. The most recent callback set is the one that will be executed, they will not be executed in order like with register_shutdown_function(), just overwritten.
Here is my test:
<?php
$i = $j = 0;
header_register_callback(function() use(&$i){ $i+=2; });
header_register_callback(function() use(&$i){ $i+=3; });
register_shutdown_function(function() use(&$j){ $j+=2; });
register_shutdown_function(function() use(&$j){ $j+=3; });
register_shutdown_function(function() use(&$j){ var_dump($j); });
while(!headers_sent()) { echo "<!-- ... flushing ... -->"; }
var_dump(headers_sent(), $i);
exit;
?>
Results:
headers_sent() - true
$i = 3
$j = 5
header_register_callback
(PHP 5 >= 5.4.0, PHP 7, PHP 8)
header_register_callback — Call a header function
Descrizione
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.
Elenco dei parametri
-
callback -
Function called just before the headers are sent. It gets no parameters and the return value is ignored.
Valori restituiti
Restituisce true in caso di successo, false in caso di fallimento.
Esempi
Example #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";
?>Il precedente esempio visualizzerà qualcosa simile a:
Content-Type: text/plain a
Note
header_register_callback() is executed just as the headers are about to be sent out, so any output from this function can break output.
Nota:
Gli header sono accessibili (e emessi nell'output) quando è in uso un SAPI che li supporta.
Vedere anche:
- headers_list() - Returns a list of response headers sent (or ready to send)
- header_remove() - Remove previously set headers
- header() - Send a raw HTTP header
add a note
User Contributed Notes 1 note
matt@kafene ¶
11 years ago
