includes/AjaxResponse.php

   1 <?php
   2 /**
   3  * Response handler for Ajax requests.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup Ajax
  22  */
  23
  24 /**
  25  * Handle responses for Ajax requests (send headers, print
  26  * content, that sort of thing)
  27  *
  28  * @ingroup Ajax
  29  */
  30 class AjaxResponse {
  31
  32         /**
  33          * Number of seconds to get the response cached by a proxy
  34          * @var int $mCacheDuration
  35          */
  36         private $mCacheDuration;
  37
  38         /**
  39          * HTTP header Content-Type
  40          * @var string $mContentType
  41          */
  42         private $mContentType;
  43
  44         /**
  45          * Disables output. Can be set by calling $AjaxResponse->disable()
  46          * @var bool $mDisabled
  47          */
  48         private $mDisabled;
  49
  50         /**
  51          * Date for the HTTP header Last-modified
  52          * @var string|false $mLastModified
  53          */
  54         private $mLastModified;
  55
  56         /**
  57          * HTTP response code
  58          * @var string $mResponseCode
  59          */
  60         private $mResponseCode;
  61
  62         /**
  63          * HTTP Vary header
  64          * @var string $mVary
  65          */
  66         private $mVary;
  67
  68         /**
  69          * Content of our HTTP response
  70          * @var string $mText
  71          */
  72         private $mText;
  73
  74         /**
  75          * @param $text string|null
  76          */
  77         function __construct( $text = null ) {
  78                 $this->mCacheDuration = null;
  79                 $this->mVary = null;
  80
  81                 $this->mDisabled = false;
  82                 $this->mText = '';
  83                 $this->mResponseCode = '200 OK';
  84                 $this->mLastModified = false;
  85                 $this->mContentType = 'application/x-wiki';
  86
  87                 if ( $text ) {
  88                         $this->addText( $text );
  89                 }
  90         }
  91
  92         /**
  93          * Set the number of seconds to get the response cached by a proxy
  94          * @param $duration int
  95          */
  96         function setCacheDuration( $duration ) {
  97                 $this->mCacheDuration = $duration;
  98         }
  99
 100         /**
 101          * Set the HTTP Vary header
 102          * @param $vary string
 103          */
 104         function setVary( $vary ) {
 105                 $this->mVary = $vary;
 106         }
 107
 108         /**
 109          * Set the HTTP response code
 110          * @param $code string
 111          */
 112         function setResponseCode( $code ) {
 113                 $this->mResponseCode = $code;
 114         }
 115
 116         /**
 117          * Set the HTTP header Content-Type
 118          * @param $type string
 119          */
 120         function setContentType( $type ) {
 121                 $this->mContentType = $type;
 122         }
 123
 124         /**
 125          * Disable output.
 126          */
 127         function disable() {
 128                 $this->mDisabled = true;
 129         }
 130
 131         /**
 132          * Add content to the response
 133          * @param $text string
 134          */
 135         function addText( $text ) {
 136                 if ( ! $this->mDisabled && $text ) {
 137                         $this->mText .= $text;
 138                 }
 139         }
 140
 141         /**
 142          * Output text
 143          */
 144         function printText() {
 145                 if ( ! $this->mDisabled ) {
 146                         print $this->mText;
 147                 }
 148         }
 149
 150         /**
 151          * Construct the header and output it
 152          */
 153         function sendHeaders() {
 154                 global $wgUseSquid, $wgUseESI;
 155
 156                 if ( $this->mResponseCode ) {
 157                         $n = preg_replace( '/^ *(\d+)/', '\1', $this->mResponseCode );
 158                         header( "Status: " . $this->mResponseCode, true, (int)$n );
 159                 }
 160
 161                 header ( "Content-Type: " . $this->mContentType );
 162
 163                 if ( $this->mLastModified ) {
 164                         header ( "Last-Modified: " . $this->mLastModified );
 165                 } else {
 166                         header ( "Last-Modified: " . gmdate( "D, d M Y H:i:s" ) . " GMT" );
 167                 }
 168
 169                 if ( $this->mCacheDuration ) {
 170                         # If squid caches are configured, tell them to cache the response,
 171                         # and tell the client to always check with the squid. Otherwise,
 172                         # tell the client to use a cached copy, without a way to purge it.
 173
 174                         if ( $wgUseSquid ) {
 175                                 # Expect explicite purge of the proxy cache, but require end user agents
 176                                 # to revalidate against the proxy on each visit.
 177                                 # Surrogate-Control controls our Squid, Cache-Control downstream caches
 178
 179                                 if ( $wgUseESI ) {
 180                                         header( 'Surrogate-Control: max-age=' . $this->mCacheDuration . ', content="ESI/1.0"' );
 181                                         header( 'Cache-Control: s-maxage=0, must-revalidate, max-age=0' );
 182                                 } else {
 183                                         header( 'Cache-Control: s-maxage=' . $this->mCacheDuration . ', must-revalidate, max-age=0' );
 184                                 }
 185
 186                         } else {
 187
 188                                 # Let the client do the caching. Cache is not purged.
 189                                 header ( "Expires: " . gmdate( "D, d M Y H:i:s", time() + $this->mCacheDuration ) . " GMT" );
 190                                 header ( "Cache-Control: s-maxage={$this->mCacheDuration},public,max-age={$this->mCacheDuration}" );
 191                         }
 192
 193                 } else {
 194                         # always expired, always modified
 195                         header ( "Expires: Mon, 26 Jul 1997 05:00:00 GMT" );    // Date in the past
 196                         header ( "Cache-Control: no-cache, must-revalidate" );  // HTTP/1.1
 197                         header ( "Pragma: no-cache" );                          // HTTP/1.0
 198                 }
 199
 200                 if ( $this->mVary ) {
 201                         header ( "Vary: " . $this->mVary );
 202                 }
 203         }
 204
 205         /**
 206          * checkLastModified tells the client to use the client-cached response if
 207          * possible. If sucessful, the AjaxResponse is disabled so that
 208          * any future call to AjaxResponse::printText() have no effect.
 209          *
 210          * @param $timestamp string
 211          * @return bool Returns true if the response code was set to 304 Not Modified.
 212          */
 213         function checkLastModified ( $timestamp ) {
 214                 global $wgCachePages, $wgCacheEpoch, $wgUser;
 215                 $fname = 'AjaxResponse::checkLastModified';
 216
 217                 if ( !$timestamp || $timestamp == '19700101000000' ) {
 218                         wfDebug( "$fname: CACHE DISABLED, NO TIMESTAMP\n" );
 219                         return false;
 220                 }
 221
 222                 if ( !$wgCachePages ) {
 223                         wfDebug( "$fname: CACHE DISABLED\n", false );
 224                         return false;
 225                 }
 226
 227                 if ( $wgUser->getOption( 'nocache' ) ) {
 228                         wfDebug( "$fname: USER DISABLED CACHE\n", false );
 229                         return false;
 230                 }
 231
 232                 $timestamp = wfTimestamp( TS_MW, $timestamp );
 233                 $lastmod = wfTimestamp( TS_RFC2822, max( $timestamp, $wgUser->getTouched(), $wgCacheEpoch ) );
 234
 235                 if ( !empty( $_SERVER['HTTP_IF_MODIFIED_SINCE'] ) ) {
 236                         # IE sends sizes after the date like this:
 237                         # Wed, 20 Aug 2003 06:51:19 GMT; length=5202
 238                         # this breaks strtotime().
 239                         $modsince = preg_replace( '/;.*$/', '', $_SERVER["HTTP_IF_MODIFIED_SINCE"] );
 240                         $modsinceTime = strtotime( $modsince );
 241                         $ismodsince = wfTimestamp( TS_MW, $modsinceTime ? $modsinceTime : 1 );
 242                         wfDebug( "$fname: -- client send If-Modified-Since: " . $modsince . "\n", false );
 243                         wfDebug( "$fname: --  we might send Last-Modified : $lastmod\n", false );
 244
 245                         if ( ( $ismodsince >= $timestamp ) && $wgUser->validateCache( $ismodsince ) && $ismodsince >= $wgCacheEpoch ) {
 246                                 ini_set( 'zlib.output_compression', 0 );
 247                                 $this->setResponseCode( "304 Not Modified" );
 248                                 $this->disable();
 249                                 $this->mLastModified = $lastmod;
 250
 251                                 wfDebug( "$fname: CACHED client: $ismodsince ; user: {$wgUser->getTouched()} ; page: $timestamp ; site $wgCacheEpoch\n", false );
 252
 253                                 return true;
 254                         } else {
 255                                 wfDebug( "$fname: READY  client: $ismodsince ; user: {$wgUser->getTouched()} ; page: $timestamp ; site $wgCacheEpoch\n", false );
 256                                 $this->mLastModified = $lastmod;
 257                         }
 258                 } else {
 259                         wfDebug( "$fname: client did not send If-Modified-Since header\n", false );
 260                         $this->mLastModified = $lastmod;
 261                 }
 262                 return false;
 263         }
 264
 265         /**
 266          * @param $mckey string
 267          * @param $touched int
 268          * @return bool
 269          */
 270         function loadFromMemcached( $mckey, $touched ) {
 271                 global $wgMemc;
 272
 273                 if ( !$touched ) {
 274                         return false;
 275                 }
 276
 277                 $mcvalue = $wgMemc->get( $mckey );
 278                 if ( $mcvalue ) {
 279                         # Check to see if the value has been invalidated
 280                         if ( $touched <= $mcvalue['timestamp'] ) {
 281                                 wfDebug( "Got $mckey from cache\n" );
 282                                 $this->mText = $mcvalue['value'];
 283
 284                                 return true;
 285                         } else {
 286                                 wfDebug( "$mckey has expired\n" );
 287                         }
 288                 }
 289
 290                 return false;
 291         }
 292
 293         /**
 294          * @param $mckey string
 295          * @param $expiry int
 296          * @return bool
 297          */
 298         function storeInMemcached( $mckey, $expiry = 86400 ) {
 299                 global $wgMemc;
 300
 301                 $wgMemc->set( $mckey,
 302                         array(
 303                                 'timestamp' => wfTimestampNow(),
 304                                 'value' => $this->mText
 305                         ), $expiry
 306                 );
 307
 308                 return true;
 309         }
 310 }