includes/AjaxResponse.php

   1 <?php
   2 /**
   3  * @file
   4  * @ingroup Ajax
   5  */
   6
   7 if ( !defined( 'MEDIAWIKI' ) ) {
   8         die( 1 );
   9 }
  10
  11 /**
  12  * Handle responses for Ajax requests (send headers, print
  13  * content, that sort of thing)
  14  *
  15  * @ingroup Ajax
  16  */
  17 class AjaxResponse {
  18         /** Number of seconds to get the response cached by a proxy */
  19         private $mCacheDuration;
  20
  21         /** HTTP header Content-Type */
  22         private $mContentType;
  23
  24         /** Disables output. Can be set by calling $AjaxResponse->disable() */
  25         private $mDisabled;
  26
  27         /** Date for the HTTP header Last-modified */
  28         private $mLastModified;
  29
  30         /** HTTP response code */
  31         private $mResponseCode;
  32
  33         /** HTTP Vary header */
  34         private $mVary;
  35
  36         /** Content of our HTTP response */
  37         private $mText;
  38
  39         function __construct( $text = null ) {
  40                 $this->mCacheDuration = null;
  41                 $this->mVary = null;
  42
  43                 $this->mDisabled = false;
  44                 $this->mText = '';
  45                 $this->mResponseCode = '200 OK';
  46                 $this->mLastModified = false;
  47                 $this->mContentType = 'application/x-wiki';
  48
  49                 if ( $text ) {
  50                         $this->addText( $text );
  51                 }
  52         }
  53
  54         function setCacheDuration( $duration ) {
  55                 $this->mCacheDuration = $duration;
  56         }
  57
  58         function setVary( $vary ) {
  59                 $this->mVary = $vary;
  60         }
  61
  62         function setResponseCode( $code ) {
  63                 $this->mResponseCode = $code;
  64         }
  65
  66         function setContentType( $type ) {
  67                 $this->mContentType = $type;
  68         }
  69
  70         function disable() {
  71                 $this->mDisabled = true;
  72         }
  73
  74         /** Add content to the response */
  75         function addText( $text ) {
  76                 if ( ! $this->mDisabled && $text ) {
  77                         $this->mText .= $text;
  78                 }
  79         }
  80
  81         /** Output text */
  82         function printText() {
  83                 if ( ! $this->mDisabled ) {
  84                         print $this->mText;
  85                 }
  86         }
  87
  88         /** Construct the header and output it */
  89         function sendHeaders() {
  90                 global $wgUseSquid, $wgUseESI;
  91
  92                 if ( $this->mResponseCode ) {
  93                         $n = preg_replace( '/^ *(\d+)/', '\1', $this->mResponseCode );
  94                         header( "Status: " . $this->mResponseCode, true, (int)$n );
  95                 }
  96
  97                 header ( "Content-Type: " . $this->mContentType );
  98
  99                 if ( $this->mLastModified ) {
 100                         header ( "Last-Modified: " . $this->mLastModified );
 101                 } else {
 102                         header ( "Last-Modified: " . gmdate( "D, d M Y H:i:s" ) . " GMT" );
 103                 }
 104
 105                 if ( $this->mCacheDuration ) {
 106                         # If squid caches are configured, tell them to cache the response,
 107                         # and tell the client to always check with the squid. Otherwise,
 108                         # tell the client to use a cached copy, without a way to purge it.
 109
 110                         if ( $wgUseSquid ) {
 111                                 # Expect explicite purge of the proxy cache, but require end user agents
 112                                 # to revalidate against the proxy on each visit.
 113                                 # Surrogate-Control controls our Squid, Cache-Control downstream caches
 114
 115                                 if ( $wgUseESI ) {
 116                                         header( 'Surrogate-Control: max-age=' . $this->mCacheDuration . ', content="ESI/1.0"' );
 117                                         header( 'Cache-Control: s-maxage=0, must-revalidate, max-age=0' );
 118                                 } else {
 119                                         header( 'Cache-Control: s-maxage=' . $this->mCacheDuration . ', must-revalidate, max-age=0' );
 120                                 }
 121
 122                         } else {
 123
 124                                 # Let the client do the caching. Cache is not purged.
 125                                 header ( "Expires: " . gmdate( "D, d M Y H:i:s", time() + $this->mCacheDuration ) . " GMT" );
 126                                 header ( "Cache-Control: s-max-age={$this->mCacheDuration},public,max-age={$this->mCacheDuration}" );
 127                         }
 128
 129                 } else {
 130                         # always expired, always modified
 131                         header ( "Expires: Mon, 26 Jul 1997 05:00:00 GMT" );    // Date in the past
 132                         header ( "Cache-Control: no-cache, must-revalidate" );  // HTTP/1.1
 133                         header ( "Pragma: no-cache" );                          // HTTP/1.0
 134                 }
 135
 136                 if ( $this->mVary ) {
 137                         header ( "Vary: " . $this->mVary );
 138                 }
 139         }
 140
 141         /**
 142          * checkLastModified tells the client to use the client-cached response if
 143          * possible. If sucessful, the AjaxResponse is disabled so that
 144          * any future call to AjaxResponse::printText() have no effect. The method
 145          * returns true iff the response code was set to 304 Not Modified.
 146          */
 147         function checkLastModified ( $timestamp ) {
 148                 global $wgCachePages, $wgCacheEpoch, $wgUser;
 149                 $fname = 'AjaxResponse::checkLastModified';
 150
 151                 if ( !$timestamp || $timestamp == '19700101000000' ) {
 152                         wfDebug( "$fname: CACHE DISABLED, NO TIMESTAMP\n" );
 153                         return;
 154                 }
 155
 156                 if ( !$wgCachePages ) {
 157                         wfDebug( "$fname: CACHE DISABLED\n", false );
 158                         return;
 159                 }
 160
 161                 if ( $wgUser->getOption( 'nocache' ) ) {
 162                         wfDebug( "$fname: USER DISABLED CACHE\n", false );
 163                         return;
 164                 }
 165
 166                 $timestamp = wfTimestamp( TS_MW, $timestamp );
 167                 $lastmod = wfTimestamp( TS_RFC2822, max( $timestamp, $wgUser->mTouched, $wgCacheEpoch ) );
 168
 169                 if ( !empty( $_SERVER['HTTP_IF_MODIFIED_SINCE'] ) ) {
 170                         # IE sends sizes after the date like this:
 171                         # Wed, 20 Aug 2003 06:51:19 GMT; length=5202
 172                         # this breaks strtotime().
 173                         $modsince = preg_replace( '/;.*$/', '', $_SERVER["HTTP_IF_MODIFIED_SINCE"] );
 174                         $modsinceTime = strtotime( $modsince );
 175                         $ismodsince = wfTimestamp( TS_MW, $modsinceTime ? $modsinceTime : 1 );
 176                         wfDebug( "$fname: -- client send If-Modified-Since: " . $modsince . "\n", false );
 177                         wfDebug( "$fname: --  we might send Last-Modified : $lastmod\n", false );
 178
 179                         if ( ( $ismodsince >= $timestamp ) && $wgUser->validateCache( $ismodsince ) && $ismodsince >= $wgCacheEpoch ) {
 180                                 ini_set( 'zlib.output_compression', 0 );
 181                                 $this->setResponseCode( "304 Not Modified" );
 182                                 $this->disable();
 183                                 $this->mLastModified = $lastmod;
 184
 185                                 wfDebug( "$fname: CACHED client: $ismodsince ; user: $wgUser->mTouched ; page: $timestamp ; site $wgCacheEpoch\n", false );
 186
 187                                 return true;
 188                         } else {
 189                                 wfDebug( "$fname: READY  client: $ismodsince ; user: $wgUser->mTouched ; page: $timestamp ; site $wgCacheEpoch\n", false );
 190                                 $this->mLastModified = $lastmod;
 191                         }
 192                 } else {
 193                         wfDebug( "$fname: client did not send If-Modified-Since header\n", false );
 194                         $this->mLastModified = $lastmod;
 195                 }
 196         }
 197
 198         function loadFromMemcached( $mckey, $touched ) {
 199                 global $wgMemc;
 200
 201                 if ( !$touched ) {
 202                         return false;
 203                 }
 204
 205                 $mcvalue = $wgMemc->get( $mckey );
 206                 if ( $mcvalue ) {
 207                         # Check to see if the value has been invalidated
 208                         if ( $touched <= $mcvalue['timestamp'] ) {
 209                                 wfDebug( "Got $mckey from cache\n" );
 210                                 $this->mText = $mcvalue['value'];
 211
 212                                 return true;
 213                         } else {
 214                                 wfDebug( "$mckey has expired\n" );
 215                         }
 216                 }
 217
 218                 return false;
 219         }
 220
 221         function storeInMemcached( $mckey, $expiry = 86400 ) {
 222                 global $wgMemc;
 223
 224                 $wgMemc->set( $mckey,
 225                         array(
 226                                 'timestamp' => wfTimestampNow(),
 227                                 'value' => $this->mText
 228                         ), $expiry
 229                 );
 230
 231                 return true;
 232         }
 233 }