includes/AjaxResponse.php

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