乐在其中

Headers list – Jump straight to:
301 moved permanently
302 moved temporarily
404 page not found
Service not available
CSS
Javascript
Images(JPEG,BMP,PNG)
PDF
Force browsers not to cache pages
Download dialog
AuthenticationPHP is not limited to outputting html. PHP can output images, pdf, javascript files, etc. Browsers determine what type of content is by analyzing the headers sent. In this tutorial I will present you with some examples of how to send headers. To send PHP header use the function header(). You must call this function before any output. Use the function headers_sent() to check whether the headers have been sent and output started.

301 moved permanently (redirect):
<?php
header('HTTP/1.1 301 Moved Permanently');
header('Location: http://www.example.com');
die();
?>

302 moved temporarily(redirect):
<?php
header('Location: http://www.example.com');
die();
?>

404 Page Not Found:
<?php
header('HTTP/1.1 404 Not Found');
?>

Service not avaliable:
<?php
header('HTTP/1.1 503 Service Temporarily Unavailable');
header('Status: 503 Service Temporarily Unavailable');
header('Retry-After: 60');
?>

CSS:
<?php
header('Content-Type: text/css');
?>

Javascript header:
<?php
header('Content-Type: application/javascript');
?>

Images:
For JPEG(jpg):
<?php
header('Content-Type: image/jpeg');
?>
For PNG:
<?php
header('Content-Type: image/png');
?>
For BMP:
<?php
header('Content-Type: image/bmp');
?>

PDF (output pdf with php):
<?php
header('Content-Type: application/pdf');
echo file_get_contents('filename.pdf');
?>

Cache (force browsers not to cache files):
<?php
header('Expires: Sat, 26 Jul 1997 05:00:00 GMT');
header('Cache-Control: no-store, no-cache, must-revalidate');
header('Cache-Control: pre-check=0, post-check=0, max-age=0');
header ('Pragma: no-cache');
?>

Download dialog:
<?php
header('Content-Disposition: attachment; filename=' . urlencode($f));
header('Content-Type: application/force-download');
header('Content-Type: application/octet-stream');
header('Content-Type: application/download');
header('Content-Description: File Transfer');
header('Content-Length: ' . filesize($f));
echo file_get_contents($f);
?>

Authentication (force the browser to pop up a Username/Password input window) – only available when PHP is running as an Apache module:
<?php
if (!isset($_SERVER['PHP_AUTH_USER'])) {
header('WWW-Authenticate: Basic realm="The Realm"');
header('HTTP/1.0 401 Unauthorized');
echo 'If cancel is pressed this text shows';
die();
} else {
//always escape your data//
$user='user';
$pass='pass';
if($_SERVER['PHP_AUTH_USER']==$user && $_SERVER['PHP_AUTH_PW']==$pass){
echo 'Authorized';
}
}
?>