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          * Number of seconds to get the response cached by a proxy
  33          * @var int $mCacheDuration
  34          */
  35         private $mCacheDuration;
  36
  37         /**
  38          * HTTP header Content-Type
  39          * @var string $mContentType
  40          */
  41         private $mContentType;
  42
  43         /**
  44          * Disables output. Can be set by calling $AjaxResponse->disable()
  45          * @var bool $mDisabled
  46          */
  47         private $mDisabled;
  48
  49         /**
  50          * Date for the HTTP header Last-modified
  51          * @var string|bool $mLastModified
  52          */
  53         private $mLastModified;
  54
  55         /**
  56          * HTTP response code
  57          * @var string $mResponseCode
  58          */
  59         private $mResponseCode;
  60
  61         /**
  62          * HTTP Vary header
  63          * @var string $mVary
  64          */
  65         private $mVary;
  66
  67         /**
  68          * Content of our HTTP response
  69          * @var string $mText
  70          */
  71         private $mText;
  72
  73         /**
  74          * @var Config
  75          */
  76         private $mConfig;
  77
  78         /**
  79          * @param string|null $text
  80          * @param Config|null $config
  81          */
  82         function __construct( $text = null, Config $config = null ) {
  83                 $this->mCacheDuration = null;
  84                 $this->mVary = null;
  85                 $this->mConfig = $config ?: ConfigFactory::getDefaultInstance()->makeConfig( 'main' );
  86
  87                 $this->mDisabled = false;
  88                 $this->mText = '';
  89                 $this->mResponseCode = 200;
  90                 $this->mLastModified = false;
  91                 $this->mContentType = 'application/x-wiki';
  92
  93                 if ( $text ) {
  94                         $this->addText( $text );
  95                 }
  96         }
  97
  98         /**
  99          * Set the number of seconds to get the response cached by a proxy
 100          * @param int $duration
 101          */
 102         function setCacheDuration( $duration ) {
 103                 $this->mCacheDuration = $duration;
 104         }
 105
 106         /**
 107          * Set the HTTP Vary header
 108          * @param string $vary
 109          */
 110         function setVary( $vary ) {
 111                 $this->mVary = $vary;
 112         }
 113
 114         /**
 115          * Set the HTTP response code
 116          * @param string $code
 117          */
 118         function setResponseCode( $code ) {
 119                 $this->mResponseCode = $code;
 120         }
 121
 122         /**
 123          * Set the HTTP header Content-Type
 124          * @param string $type
 125          */
 126         function setContentType( $type ) {
 127                 $this->mContentType = $type;
 128         }
 129
 130         /**
 131          * Disable output.
 132          */
 133         function disable() {
 134                 $this->mDisabled = true;
 135         }
 136
 137         /**
 138          * Add content to the response
 139          * @param string $text
 140          */
 141         function addText( $text ) {
 142                 if ( !$this->mDisabled && $text ) {
 143                         $this->mText .= $text;
 144                 }
 145         }
 146
 147         /**
 148          * Output text
 149          */
 150         function printText() {
 151                 if ( !$this->mDisabled ) {
 152                         print $this->mText;
 153                 }
 154         }
 155
 156         /**
 157          * Construct the header and output it
 158          */
 159         function sendHeaders() {
 160                 if ( $this->mResponseCode ) {
 161                         // For back-compat, it is supported that mResponseCode be a string like " 200 OK"
 162                         // (with leading space and the status message after). Cast response code to an integer
 163                         // to take advantage of PHP's conversion rules which will turn "  200 OK" into 200.
 164                         // http://php.net/string#language.types.string.conversion
 165                         $n = intval( trim( $this->mResponseCode ) );
 166                         HttpStatus::header( $n );
 167                 }
 168
 169                 header( "Content-Type: " . $this->mContentType );
 170
 171                 if ( $this->mLastModified ) {
 172                         header( "Last-Modified: " . $this->mLastModified );
 173                 } else {
 174                         header( "Last-Modified: " . gmdate( "D, d M Y H:i:s" ) . " GMT" );
 175                 }
 176
 177                 if ( $this->mCacheDuration ) {
 178                         # If CDN caches are configured, tell them to cache the response,
 179                         # and tell the client to always check with the CDN. Otherwise,
 180                         # tell the client to use a cached copy, without a way to purge it.
 181
 182                         if ( $this->mConfig->get( 'UseSquid' ) ) {
 183                                 # Expect explicit purge of the proxy cache, but require end user agents
 184                                 # to revalidate against the proxy on each visit.
 185                                 # Surrogate-Control controls our CDN, Cache-Control downstream caches
 186
 187                                 if ( $this->mConfig->get( 'UseESI' ) ) {
 188                                         header( 'Surrogate-Control: max-age=' . $this->mCacheDuration . ', content="ESI/1.0"' );
 189                                         header( 'Cache-Control: s-maxage=0, must-revalidate, max-age=0' );
 190                                 } else {
 191                                         header( 'Cache-Control: s-maxage=' . $this->mCacheDuration . ', must-revalidate, max-age=0' );
 192                                 }
 193
 194                         } else {
 195                                 # Let the client do the caching. Cache is not purged.
 196                                 header( "Expires: " . gmdate( "D, d M Y H:i:s", time() + $this->mCacheDuration ) . " GMT" );
 197                                 header( "Cache-Control: s-maxage={$this->mCacheDuration}," .
 198                                         "public,max-age={$this->mCacheDuration}" );
 199                         }
 200
 201                 } else {
 202                         # always expired, always modified
 203                         header( "Expires: Mon, 26 Jul 1997 05:00:00 GMT" );    // Date in the past
 204                         header( "Cache-Control: no-cache, must-revalidate" );  // HTTP/1.1
 205                         header( "Pragma: no-cache" );                          // HTTP/1.0
 206                 }
 207
 208                 if ( $this->mVary ) {
 209                         header( "Vary: " . $this->mVary );
 210                 }
 211         }
 212
 213         /**
 214          * checkLastModified tells the client to use the client-cached response if
 215          * possible. If successful, the AjaxResponse is disabled so that
 216          * any future call to AjaxResponse::printText() have no effect.
 217          *
 218          * @param string $timestamp
 219          * @return bool Returns true if the response code was set to 304 Not Modified.
 220          */
 221         function checkLastModified( $timestamp ) {
 222                 global $wgCachePages, $wgCacheEpoch, $wgUser;
 223                 $fname = 'AjaxResponse::checkLastModified';
 224
 225                 if ( !$timestamp || $timestamp == '19700101000000' ) {
 226                         wfDebug( "$fname: CACHE DISABLED, NO TIMESTAMP", 'private' );
 227                         return false;
 228                 }
 229
 230                 if ( !$wgCachePages ) {
 231                         wfDebug( "$fname: CACHE DISABLED", 'private' );
 232                         return false;
 233                 }
 234
 235                 $timestamp = wfTimestamp( TS_MW, $timestamp );
 236                 $lastmod = wfTimestamp( TS_RFC2822, max( $timestamp, $wgUser->getTouched(), $wgCacheEpoch ) );
 237
 238                 if ( !empty( $_SERVER['HTTP_IF_MODIFIED_SINCE'] ) ) {
 239                         # IE sends sizes after the date like this:
 240                         # Wed, 20 Aug 2003 06:51:19 GMT; length=5202
 241                         # this breaks strtotime().
 242                         $modsince = preg_replace( '/;.*$/', '', $_SERVER["HTTP_IF_MODIFIED_SINCE"] );
 243                         $modsinceTime = strtotime( $modsince );
 244                         $ismodsince = wfTimestamp( TS_MW, $modsinceTime ? $modsinceTime : 1 );
 245                         wfDebug( "$fname: -- client send If-Modified-Since: $modsince", 'private' );
 246                         wfDebug( "$fname: --  we might send Last-Modified : $lastmod", 'private' );
 247
 248                         if ( ( $ismodsince >= $timestamp )
 249                                 && $wgUser->validateCache( $ismodsince ) &&
 250                                 $ismodsince >= $wgCacheEpoch
 251                         ) {
 252                                 ini_set( 'zlib.output_compression', 0 );
 253                                 $this->setResponseCode( 304 );
 254                                 $this->disable();
 255                                 $this->mLastModified = $lastmod;
 256
 257                                 wfDebug( "$fname: CACHED client: $ismodsince ; user: {$wgUser->getTouched()} ; " .
 258                                         "page: $timestamp ; site $wgCacheEpoch", 'private' );
 259
 260                                 return true;
 261                         } else {
 262                                 wfDebug( "$fname: READY  client: $ismodsince ; user: {$wgUser->getTouched()} ; " .
 263                                         "page: $timestamp ; site $wgCacheEpoch", 'private' );
 264                                 $this->mLastModified = $lastmod;
 265                         }
 266                 } else {
 267                         wfDebug( "$fname: client did not send If-Modified-Since header", 'private' );
 268                         $this->mLastModified = $lastmod;
 269                 }
 270                 return false;
 271         }
 272
 273         /**
 274          * @param string $mckey
 275          * @param int $touched
 276          * @return bool
 277          */
 278         function loadFromMemcached( $mckey, $touched ) {
 279                 if ( !$touched ) {
 280                         return false;
 281                 }
 282
 283                 $mcvalue = ObjectCache::getMainWANInstance()->get( $mckey );
 284                 if ( $mcvalue ) {
 285                         # Check to see if the value has been invalidated
 286                         if ( $touched <= $mcvalue['timestamp'] ) {
 287                                 wfDebug( "Got $mckey from cache" );
 288                                 $this->mText = $mcvalue['value'];
 289
 290                                 return true;
 291                         } else {
 292                                 wfDebug( "$mckey has expired" );
 293                         }
 294                 }
 295
 296                 return false;
 297         }
 298
 299         /**
 300          * @param string $mckey
 301          * @param int $expiry
 302          * @return bool
 303          */
 304         function storeInMemcached( $mckey, $expiry = 86400 ) {
 305                 ObjectCache::getMainWANInstance()->set( $mckey,
 306                         array(
 307                                 'timestamp' => wfTimestampNow(),
 308                                 'value' => $this->mText
 309                         ), $expiry
 310                 );
 311
 312                 return true;
 313         }
 314 }