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<?php
/**
* @file
* @ingroup Ajax
*/
if( !defined( 'MEDIAWIKI' ) ) {
die( 1 );
}
/**
* Handle responses for Ajax requests (send headers, print
* content, that sort of thing)
*
* @ingroup Ajax
*/
class AjaxResponse {
/** Number of seconds to get the response cached by a proxy */
private $mCacheDuration;
/** HTTP header Content-Type */
private $mContentType;
/** Disables output. Can be set by calling $AjaxResponse->disable() */
private $mDisabled;
/** Date for the HTTP header Last-modified */
private $mLastModified;
/** HTTP response code */
private $mResponseCode;
/** HTTP Vary header */
private $mVary;
/** Content of our HTTP response */
private $mText;
function __construct( $text = NULL ) {
$this->mCacheDuration = NULL;
$this->mVary = NULL;
$this->mDisabled = false;
$this->mText = '';
$this->mResponseCode = '200 OK';
$this->mLastModified = false;
$this->mContentType= 'text/html; charset=utf-8';
if ( $text ) {
$this->addText( $text );
}
}
function setCacheDuration( $duration ) {
$this->mCacheDuration = $duration;
}
function setVary( $vary ) {
$this->mVary = $vary;
}
function setResponseCode( $code ) {
$this->mResponseCode = $code;
}
function setContentType( $type ) {
$this->mContentType = $type;
}
function disable() {
$this->mDisabled = true;
}
/** Add content to the response */
function addText( $text ) {
if ( ! $this->mDisabled && $text ) {
$this->mText .= $text;
}
}
/** Output text */
function printText() {
if ( ! $this->mDisabled ) {
print $this->mText;
}
}
/** Construct the header and output it */
function sendHeaders() {
global $wgUseSquid, $wgUseESI;
if ( $this->mResponseCode ) {
$n = preg_replace( '/^ *(\d+)/', '\1', $this->mResponseCode );
header( "Status: " . $this->mResponseCode, true, (int)$n );
}
header ("Content-Type: " . $this->mContentType );
if ( $this->mLastModified ) {
header ("Last-Modified: " . $this->mLastModified );
}
else {
header ("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
}
if ( $this->mCacheDuration ) {
# If squid caches are configured, tell them to cache the response,
# and tell the client to always check with the squid. Otherwise,
# tell the client to use a cached copy, without a way to purge it.
if( $wgUseSquid ) {
# Expect explicite purge of the proxy cache, but require end user agents
# to revalidate against the proxy on each visit.
# Surrogate-Control controls our Squid, Cache-Control downstream caches
if ( $wgUseESI ) {
header( 'Surrogate-Control: max-age='.$this->mCacheDuration.', content="ESI/1.0"');
header( 'Cache-Control: s-maxage=0, must-revalidate, max-age=0' );
} else {
header( 'Cache-Control: s-maxage='.$this->mCacheDuration.', must-revalidate, max-age=0' );
}
} else {
# Let the client do the caching. Cache is not purged.
header ("Expires: " . gmdate( "D, d M Y H:i:s", time() + $this->mCacheDuration ) . " GMT");
header ("Cache-Control: s-max-age={$this->mCacheDuration},public,max-age={$this->mCacheDuration}");
}
} else {
# always expired, always modified
header ("Expires: Mon, 26 Jul 1997 05:00:00 GMT"); // Date in the past
header ("Cache-Control: no-cache, must-revalidate"); // HTTP/1.1
header ("Pragma: no-cache"); // HTTP/1.0
}
if ( $this->mVary ) {
header ( "Vary: " . $this->mVary );
}
}
/**
* checkLastModified tells the client to use the client-cached response if
* possible. If sucessful, the AjaxResponse is disabled so that
* any future call to AjaxResponse::printText() have no effect. The method
* returns true iff the response code was set to 304 Not Modified.
*/
function checkLastModified ( $timestamp ) {
global $wgCachePages, $wgCacheEpoch, $wgUser;
$fname = 'AjaxResponse::checkLastModified';
if ( !$timestamp || $timestamp == '19700101000000' ) {
wfDebug( "$fname: CACHE DISABLED, NO TIMESTAMP\n" );
return;
}
if( !$wgCachePages ) {
wfDebug( "$fname: CACHE DISABLED\n", false );
return;
}
if( $wgUser->getOption( 'nocache' ) ) {
wfDebug( "$fname: USER DISABLED CACHE\n", false );
return;
}
$timestamp = wfTimestamp( TS_MW, $timestamp );
$lastmod = wfTimestamp( TS_RFC2822, max( $timestamp, $wgUser->mTouched, $wgCacheEpoch ) );
if( !empty( $_SERVER['HTTP_IF_MODIFIED_SINCE'] ) ) {
# IE sends sizes after the date like this:
# Wed, 20 Aug 2003 06:51:19 GMT; length=5202
# this breaks strtotime().
$modsince = preg_replace( '/;.*$/', '', $_SERVER["HTTP_IF_MODIFIED_SINCE"] );
$modsinceTime = strtotime( $modsince );
$ismodsince = wfTimestamp( TS_MW, $modsinceTime ? $modsinceTime : 1 );
wfDebug( "$fname: -- client send If-Modified-Since: " . $modsince . "\n", false );
wfDebug( "$fname: -- we might send Last-Modified : $lastmod\n", false );
if( ($ismodsince >= $timestamp ) && $wgUser->validateCache( $ismodsince ) && $ismodsince >= $wgCacheEpoch ) {
$this->setResponseCode( "304 Not Modified" );
$this->disable();
$this->mLastModified = $lastmod;
wfDebug( "$fname: CACHED client: $ismodsince ; user: $wgUser->mTouched ; page: $timestamp ; site $wgCacheEpoch\n", false );
return true;
} else {
wfDebug( "$fname: READY client: $ismodsince ; user: $wgUser->mTouched ; page: $timestamp ; site $wgCacheEpoch\n", false );
$this->mLastModified = $lastmod;
}
} else {
wfDebug( "$fname: client did not send If-Modified-Since header\n", false );
$this->mLastModified = $lastmod;
}
}
function loadFromMemcached( $mckey, $touched ) {
global $wgMemc;
if ( !$touched ) return false;
$mcvalue = $wgMemc->get( $mckey );
if ( $mcvalue ) {
# Check to see if the value has been invalidated
if ( $touched <= $mcvalue['timestamp'] ) {
wfDebug( "Got $mckey from cache\n" );
$this->mText = $mcvalue['value'];
return true;
} else {
wfDebug( "$mckey has expired\n" );
}
}
return false;
}
function storeInMemcached( $mckey, $expiry = 86400 ) {
global $wgMemc;
$wgMemc->set( $mckey,
array(
'timestamp' => wfTimestampNow(),
'value' => $this->mText
), $expiry
);
return true;
}
}
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