552ec41814
Use name constants instead of string literals in calls to Config::get and ServiceOptions::get, when referring to core configuration variables. This protects against typos and makes the decumentation and schema declaration of the config settings discoverable. This is the first batch, only touching files directly under /includes/ Change-Id: I7252e636c7c86d950d9257b33491af492c6dd5eb
226 lines
7 KiB
PHP
226 lines
7 KiB
PHP
<?php
|
|
/**
|
|
* Functions to be used with PHP's output buffer.
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation; either version 2 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License along
|
|
* with this program; if not, write to the Free Software Foundation, Inc.,
|
|
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
|
|
* http://www.gnu.org/copyleft/gpl.html
|
|
*
|
|
* @file
|
|
*/
|
|
|
|
namespace MediaWiki;
|
|
|
|
use MediaWiki\Logger\LoggerFactory;
|
|
|
|
/**
|
|
* @since 1.31
|
|
*/
|
|
class OutputHandler {
|
|
/**
|
|
* Standard output handler for use with ob_start.
|
|
*
|
|
* Output buffers using this method should only be started from MW_SETUP_CALLBACK,
|
|
* and only if there are no parent output buffers.
|
|
*
|
|
* @param string $s Web response output
|
|
* @param int $phase Flags indicating the reason for the call
|
|
* @return string
|
|
*/
|
|
public static function handle( $s, $phase ) {
|
|
$config = MediaWikiServices::getInstance()->getMainConfig();
|
|
$disableOutputCompression = $config->get( MainConfigNames::DisableOutputCompression );
|
|
$mangleFlashPolicy = $config->get( MainConfigNames::MangleFlashPolicy );
|
|
// Don't send headers if output is being discarded (T278579)
|
|
if ( ( $phase & PHP_OUTPUT_HANDLER_CLEAN ) === PHP_OUTPUT_HANDLER_CLEAN ) {
|
|
$logger = LoggerFactory::getInstance( 'output' );
|
|
$logger->debug( __METHOD__ . " entrypoint={entry}; size={size}; phase=$phase", [
|
|
'entry' => MW_ENTRY_POINT,
|
|
'size' => strlen( $s ),
|
|
] );
|
|
|
|
return $s;
|
|
}
|
|
|
|
if ( $mangleFlashPolicy ) {
|
|
$s = self::mangleFlashPolicy( $s );
|
|
}
|
|
|
|
// Check if a compression output buffer is already enabled via php.ini. Such
|
|
// buffers exists at the start of the request and are reflected by ob_get_level().
|
|
$phpHandlesCompression = (
|
|
ini_get( 'output_handler' ) === 'ob_gzhandler' ||
|
|
ini_get( 'zlib.output_handler' ) === 'ob_gzhandler' ||
|
|
!in_array(
|
|
strtolower( ini_get( 'zlib.output_compression' ) ),
|
|
[ '', 'off', '0' ]
|
|
)
|
|
);
|
|
|
|
if (
|
|
// Compression is not already handled by an internal PHP buffer
|
|
!$phpHandlesCompression &&
|
|
// Compression is not disabled by the application entry point
|
|
!defined( 'MW_NO_OUTPUT_COMPRESSION' ) &&
|
|
// Compression is not disabled by site configuration
|
|
!$disableOutputCompression
|
|
) {
|
|
$s = self::handleGzip( $s );
|
|
}
|
|
|
|
if (
|
|
// Response body length does not depend on internal PHP compression buffer
|
|
!$phpHandlesCompression &&
|
|
// Response body length does not depend on mangling by a custom buffer
|
|
!ini_get( 'output_handler' ) &&
|
|
!ini_get( 'zlib.output_handler' )
|
|
) {
|
|
self::emitContentLength( strlen( $s ) );
|
|
}
|
|
|
|
return $s;
|
|
}
|
|
|
|
/**
|
|
* Get the "file extension" that some client apps will estimate from
|
|
* the currently-requested URL.
|
|
*
|
|
* This isn't a WebRequest method, because we need it before the class loads.
|
|
* @todo As of 2018, this actually runs after autoloader in Setup.php, so
|
|
* WebRequest seems like a good place for this.
|
|
*
|
|
* @return string
|
|
*/
|
|
private static function findUriExtension() {
|
|
// @todo FIXME: this sort of dupes some code in WebRequest::getRequestUrl()
|
|
if ( isset( $_SERVER['REQUEST_URI'] ) ) {
|
|
// Strip the query string...
|
|
$path = explode( '?', $_SERVER['REQUEST_URI'], 2 )[0];
|
|
} elseif ( isset( $_SERVER['SCRIPT_NAME'] ) ) {
|
|
// Probably IIS. QUERY_STRING appears separately.
|
|
$path = $_SERVER['SCRIPT_NAME'];
|
|
} else {
|
|
// Can't get the path from the server? :(
|
|
return '';
|
|
}
|
|
|
|
$period = strrpos( $path, '.' );
|
|
if ( $period !== false ) {
|
|
return strtolower( substr( $path, $period ) );
|
|
}
|
|
return '';
|
|
}
|
|
|
|
/**
|
|
* Handler that compresses data with gzip if allowed by the Accept header.
|
|
*
|
|
* Unlike ob_gzhandler, it works for HEAD requests too. This assumes that the application
|
|
* processes them as normal GET request and that the webserver is tasked with stripping out
|
|
* the response body before sending the response the client.
|
|
*
|
|
* @param string $s Web response output
|
|
* @return string
|
|
*/
|
|
private static function handleGzip( $s ) {
|
|
if ( !function_exists( 'gzencode' ) ) {
|
|
wfDebug( __METHOD__ . "() skipping compression (gzencode unavailable)" );
|
|
return $s;
|
|
}
|
|
if ( headers_sent() ) {
|
|
wfDebug( __METHOD__ . "() skipping compression (headers already sent)" );
|
|
return $s;
|
|
}
|
|
|
|
$ext = self::findUriExtension();
|
|
if ( $ext == '.gz' || $ext == '.tgz' ) {
|
|
// Don't do gzip compression if the URL path ends in .gz or .tgz
|
|
// This confuses Safari and triggers a download of the page,
|
|
// even though it's pretty clearly labeled as viewable HTML.
|
|
// Bad Safari! Bad!
|
|
return $s;
|
|
}
|
|
|
|
if ( $s === '' ) {
|
|
// Do not gzip empty HTTP responses since that would not only bloat the body
|
|
// length, but it would result in invalid HTTP responses when the HTTP status code
|
|
// is one that must not be accompanied by a body (e.g. "204 No Content").
|
|
return $s;
|
|
}
|
|
|
|
if ( wfClientAcceptsGzip() ) {
|
|
wfDebug( __METHOD__ . "() is compressing output" );
|
|
header( 'Content-Encoding: gzip' );
|
|
$s = gzencode( $s, 6 );
|
|
}
|
|
|
|
// Set vary header if it hasn't been set already
|
|
$headers = headers_list();
|
|
$foundVary = false;
|
|
foreach ( $headers as $header ) {
|
|
$headerName = strtolower( substr( $header, 0, 5 ) );
|
|
if ( $headerName == 'vary:' ) {
|
|
$foundVary = true;
|
|
break;
|
|
}
|
|
}
|
|
if ( !$foundVary ) {
|
|
header( 'Vary: Accept-Encoding' );
|
|
}
|
|
return $s;
|
|
}
|
|
|
|
/**
|
|
* Mangle flash policy tags which open up the site to XSS attacks.
|
|
*
|
|
* @param string $s Web response output
|
|
* @return string
|
|
*/
|
|
private static function mangleFlashPolicy( $s ) {
|
|
# Avoid weird excessive memory usage in PCRE on big articles
|
|
if ( preg_match( '/\<\s*cross-domain-policy(?=\s|\>)/i', $s ) ) {
|
|
return preg_replace( '/\<(\s*)(cross-domain-policy(?=\s|\>))/i', '<$1NOT-$2', $s );
|
|
} else {
|
|
return $s;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Set the Content-Length header if possible
|
|
*
|
|
* This sets Content-Length for the following cases:
|
|
* - When the response body is meaningful (HTTP 200/404).
|
|
* - On any HTTP 1.0 request response. This improves cooperation with certain CDNs.
|
|
*
|
|
* This assumes that HEAD requests are processed as GET requests by MediaWiki and that
|
|
* the webserver is tasked with stripping out the body.
|
|
*
|
|
* Setting Content-Length can prevent clients from getting stuck waiting on PHP to finish
|
|
* while deferred updates are running.
|
|
*
|
|
* @param int $length
|
|
*/
|
|
private static function emitContentLength( $length ) {
|
|
if ( headers_sent() ) {
|
|
wfDebug( __METHOD__ . "() headers already sent" );
|
|
return;
|
|
}
|
|
|
|
if (
|
|
in_array( http_response_code(), [ 200, 404 ], true ) ||
|
|
( $_SERVER['SERVER_PROTOCOL'] ?? null ) === 'HTTP/1.0'
|
|
) {
|
|
header( "Content-Length: $length" );
|
|
}
|
|
}
|
|
}
|