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