includes/HeaderCallback.php

   1 <?php
   2
   3 namespace MediaWiki;
   4
   5 class HeaderCallback {
   6         private static $headersSentException;
   7         private static $messageSent = false;
   8
   9         /**
  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
  12          * here.
  13          */
  14         public static function register() {
  15                 header_register_callback( [ __CLASS__, 'callback' ] );
  16         }
  17
  18         /**
  19          * The callback, which is called by the transport
  20          */
  21         public static function callback() {
  22                 // Prevent caching of responses with cookies (T127993)
  23                 $headers = [];
  24                 foreach ( headers_list() as $header ) {
  25                         list( $name, $value ) = explode( ':', $header, 2 );
  26                         $headers[strtolower( trim( $name ) )][] = trim( $value );
  27                 }
  28
  29                 if ( isset( $headers['set-cookie'] ) ) {
  30                         $cacheControl = isset( $headers['cache-control'] )
  31                                 ? implode( ', ', $headers['cache-control'] )
  32                                 : '';
  33
  34                         if ( !preg_match( '/(?:^|,)\s*(?:private|no-cache|no-store)\s*(?:$|,)/i',
  35                                 $cacheControl )
  36                         ) {
  37                                 header( 'Expires: Thu, 01 Jan 1970 00:00:00 GMT' );
  38                                 header( 'Cache-Control: private, max-age=0, s-maxage=0' );
  39                                 \MediaWiki\Logger\LoggerFactory::getInstance( 'cache-cookies' )->warning(
  40                                         'Cookies set on {url} with Cache-Control "{cache-control}"', [
  41                                                 'url' => \WebRequest::getGlobalRequestURL(),
  42                                                 'cookies' => $headers['set-cookie'],
  43                                                 'cache-control' => $cacheControl ?: '<not set>',
  44                                         ]
  45                                 );
  46                         }
  47                 }
  48
  49                 // Save a backtrace for logging in case it turns out that headers were sent prematurely
  50                 self::$headersSentException = new \Exception( 'Headers already sent from this point' );
  51         }
  52
  53         /**
  54          * Log a warning message if headers have already been sent. This can be
  55          * called before flushing the output.
  56          */
  57         public static function warnIfHeadersSent() {
  58                 if ( headers_sent() && !self::$messageSent ) {
  59                         self::$messageSent = true;
  60                         \MWDebug::warning( 'Headers already sent, should send headers earlier than ' .
  61                                 wfGetCaller( 3 ) );
  62                         $logger = \MediaWiki\Logger\LoggerFactory::getInstance( 'headers-sent' );
  63                         $logger->error( 'Warning: headers were already sent from the location below', [
  64                                 'exception' => self::$headersSentException,
  65                                 'detection-trace' => new \Exception( 'Detected here' ),
  66                         ] );
  67                 }
  68         }
  69 }