header_register_callback — Call a header function

2018-01-19 14:50:17
linefo
506
最后编辑:linefo 于 2018-01-19 14:53:24

header_register_callback

(PHP 5 >= 5.4.0, PHP 7)

header_register_callbackCall a header function

说明

bool header_register_callback ( callable $callback )

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.

参数

callback

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

返回值

成功时返回 TRUE, 或者在失败时返回 FALSE

范例

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";
?>

以上例程的输出类似于:

Content-Type: text/plain

a

注释

header_register_callback() is executed just as the headers are about to be sent out, so any output from this function can break output.

Note:

数据头只会在SAPI支持时得到处理和输出。

参见