6 private static $headersSentException;
7 private static $messageSent = false;
10 * Register a callback to be called when headers are sent. There can only
11 * be one of these handlers active, so all relevant actions have to be in
14 public static function register() {
15 header_register_callback( [ __CLASS__
, 'callback' ] );
19 * The callback, which is called by the transport
21 public static function callback() {
22 // Prevent caching of responses with cookies (T127993)
24 foreach ( headers_list() as $header ) {
25 $header = explode( ':', $header, 2 );
27 // Note: The code below (currently) does not care about value-less headers
28 if ( isset( $header[1] ) ) {
29 $headers[ strtolower( trim( $header[0] ) ) ][] = trim( $header[1] );
33 if ( isset( $headers['set-cookie'] ) ) {
34 $cacheControl = isset( $headers['cache-control'] )
35 ?
implode( ', ', $headers['cache-control'] )
38 if ( !preg_match( '/(?:^|,)\s*(?:private|no-cache|no-store)\s*(?:$|,)/i',
41 header( 'Expires: Thu, 01 Jan 1970 00:00:00 GMT' );
42 header( 'Cache-Control: private, max-age=0, s-maxage=0' );
43 \MediaWiki\Logger\LoggerFactory
::getInstance( 'cache-cookies' )->warning(
44 'Cookies set on {url} with Cache-Control "{cache-control}"', [
45 'url' => \WebRequest
::getGlobalRequestURL(),
46 'cookies' => $headers['set-cookie'],
47 'cache-control' => $cacheControl ?
: '<not set>',
53 // Save a backtrace for logging in case it turns out that headers were sent prematurely
54 self
::$headersSentException = new \
Exception( 'Headers already sent from this point' );
58 * Log a warning message if headers have already been sent. This can be
59 * called before flushing the output.
61 public static function warnIfHeadersSent() {
62 if ( headers_sent() && !self
::$messageSent ) {
63 self
::$messageSent = true;
64 \MWDebug
::warning( 'Headers already sent, should send headers earlier than ' .
66 $logger = \MediaWiki\Logger\LoggerFactory
::getInstance( 'headers-sent' );
67 $logger->error( 'Warning: headers were already sent from the location below', [
68 'exception' => self
::$headersSentException,
69 'detection-trace' => new \
Exception( 'Detected here' ),