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 use MediaWiki\MediaWikiServices;
  24
  25 /**
  26  * Handle responses for Ajax requests (send headers, print
  27  * content, that sort of thing)
  28  *
  29  * @ingroup Ajax
  30  */
  31 class AjaxResponse {
  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|bool $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          * @var Config
  76          */
  77         private $mConfig;
  78
  79         /**
  80          * @param string|null $text
  81          * @param Config|null $config
  82          */
  83         function __construct( $text = null, Config $config = null ) {
  84                 $this->mCacheDuration = null;
  85                 $this->mVary = null;
  86                 $this->mConfig = $config ?: MediaWikiServices::getInstance()->getMainConfig();
  87
  88                 $this->mDisabled = false;
  89                 $this->mText = '';
  90                 $this->mResponseCode = 200;
  91                 $this->mLastModified = false;
  92                 $this->mContentType = 'application/x-wiki';
  93
  94                 if ( $text ) {
  95                         $this->addText( $text );
  96                 }
  97         }
  98
  99         /**
 100          * Set the number of seconds to get the response cached by a proxy
 101          * @param int $duration
 102          */
 103         function setCacheDuration( $duration ) {
 104                 $this->mCacheDuration = $duration;
 105         }
 106
 107         /**
 108          * Set the HTTP Vary header
 109          * @param string $vary
 110          */
 111         function setVary( $vary ) {
 112                 $this->mVary = $vary;
 113         }
 114
 115         /**
 116          * Set the HTTP response code
 117          * @param string $code
 118          */
 119         function setResponseCode( $code ) {
 120                 $this->mResponseCode = $code;
 121         }
 122
 123         /**
 124          * Set the HTTP header Content-Type
 125          * @param string $type
 126          */
 127         function setContentType( $type ) {
 128                 $this->mContentType = $type;
 129         }
 130
 131         /**
 132          * Disable output.
 133          */
 134         function disable() {
 135                 $this->mDisabled = true;
 136         }
 137
 138         /**
 139          * Add content to the response
 140          * @param string $text
 141          */
 142         function addText( $text ) {
 143                 if ( !$this->mDisabled && $text ) {
 144                         $this->mText .= $text;
 145                 }
 146         }
 147
 148         /**
 149          * Output text
 150          */
 151         function printText() {
 152                 if ( !$this->mDisabled ) {
 153                         print $this->mText;
 154                 }
 155         }
 156
 157         /**
 158          * Construct the header and output it
 159          */
 160         function sendHeaders() {
 161                 if ( $this->mResponseCode ) {
 162                         // For back-compat, it is supported that mResponseCode be a string like " 200 OK"
 163                         // (with leading space and the status message after). Cast response code to an integer
 164                         // to take advantage of PHP's conversion rules which will turn "  200 OK" into 200.
 165                         // https://secure.php.net/manual/en/language.types.string.php#language.types.string.conversion
 166                         $n = intval( trim( $this->mResponseCode ) );
 167                         HttpStatus::header( $n );
 168                 }
 169
 170                 header( "Content-Type: " . $this->mContentType );
 171
 172                 if ( $this->mLastModified ) {
 173                         header( "Last-Modified: " . $this->mLastModified );
 174                 } else {
 175                         header( "Last-Modified: " . gmdate( "D, d M Y H:i:s" ) . " GMT" );
 176                 }
 177
 178                 if ( $this->mCacheDuration ) {
 179                         # If CDN caches are configured, tell them to cache the response,
 180                         # and tell the client to always check with the CDN. Otherwise,
 181                         # tell the client to use a cached copy, without a way to purge it.
 182
 183                         if ( $this->mConfig->get( 'UseSquid' ) ) {
 184                                 # Expect explicit purge of the proxy cache, but require end user agents
 185                                 # to revalidate against the proxy on each visit.
 186                                 # Surrogate-Control controls our CDN, Cache-Control downstream caches
 187
 188                                 if ( $this->mConfig->get( 'UseESI' ) ) {
 189                                         header( 'Surrogate-Control: max-age=' . $this->mCacheDuration . ', content="ESI/1.0"' );
 190                                         header( 'Cache-Control: s-maxage=0, must-revalidate, max-age=0' );
 191                                 } else {
 192                                         header( 'Cache-Control: s-maxage=' . $this->mCacheDuration . ', must-revalidate, max-age=0' );
 193                                 }
 194
 195                         } else {
 196                                 # Let the client do the caching. Cache is not purged.
 197                                 header( "Expires: " . gmdate( "D, d M Y H:i:s", time() + $this->mCacheDuration ) . " GMT" );
 198                                 header( "Cache-Control: s-maxage={$this->mCacheDuration}," .
 199                                         "public,max-age={$this->mCacheDuration}" );
 200                         }
 201
 202                 } else {
 203                         # always expired, always modified
 204                         header( "Expires: Mon, 26 Jul 1997 05:00:00 GMT" );    // Date in the past
 205                         header( "Cache-Control: no-cache, must-revalidate" );  // HTTP/1.1
 206                         header( "Pragma: no-cache" );                          // HTTP/1.0
 207                 }
 208
 209                 if ( $this->mVary ) {
 210                         header( "Vary: " . $this->mVary );
 211                 }
 212         }
 213
 214         /**
 215          * checkLastModified tells the client to use the client-cached response if
 216          * possible. If successful, the AjaxResponse is disabled so that
 217          * any future call to AjaxResponse::printText() have no effect.
 218          *
 219          * @param string $timestamp
 220          * @return bool Returns true if the response code was set to 304 Not Modified.
 221          */
 222         function checkLastModified( $timestamp ) {
 223                 global $wgCachePages, $wgCacheEpoch, $wgUser;
 224                 $fname = 'AjaxResponse::checkLastModified';
 225
 226                 if ( !$timestamp || $timestamp == '19700101000000' ) {
 227                         wfDebug( "$fname: CACHE DISABLED, NO TIMESTAMP", 'private' );
 228                         return false;
 229                 }
 230
 231                 if ( !$wgCachePages ) {
 232                         wfDebug( "$fname: CACHE DISABLED", 'private' );
 233                         return false;
 234                 }
 235
 236                 $timestamp = wfTimestamp( TS_MW, $timestamp );
 237                 $lastmod = wfTimestamp( TS_RFC2822, max( $timestamp, $wgUser->getTouched(), $wgCacheEpoch ) );
 238
 239                 if ( !empty( $_SERVER['HTTP_IF_MODIFIED_SINCE'] ) ) {
 240                         # IE sends sizes after the date like this:
 241                         # Wed, 20 Aug 2003 06:51:19 GMT; length=5202
 242                         # this breaks strtotime().
 243                         $modsince = preg_replace( '/;.*$/', '', $_SERVER["HTTP_IF_MODIFIED_SINCE"] );
 244                         $modsinceTime = strtotime( $modsince );
 245                         $ismodsince = wfTimestamp( TS_MW, $modsinceTime ? $modsinceTime : 1 );
 246                         wfDebug( "$fname: -- client send If-Modified-Since: $modsince", 'private' );
 247                         wfDebug( "$fname: --  we might send Last-Modified : $lastmod", 'private' );
 248
 249                         if ( ( $ismodsince >= $timestamp )
 250                                 && $wgUser->validateCache( $ismodsince ) &&
 251                                 $ismodsince >= $wgCacheEpoch
 252                         ) {
 253                                 ini_set( 'zlib.output_compression', 0 );
 254                                 $this->setResponseCode( 304 );
 255                                 $this->disable();
 256                                 $this->mLastModified = $lastmod;
 257
 258                                 wfDebug( "$fname: CACHED client: $ismodsince ; user: {$wgUser->getTouched()} ; " .
 259                                         "page: $timestamp ; site $wgCacheEpoch", 'private' );
 260
 261                                 return true;
 262                         } else {
 263                                 wfDebug( "$fname: READY  client: $ismodsince ; user: {$wgUser->getTouched()} ; " .
 264                                         "page: $timestamp ; site $wgCacheEpoch", 'private' );
 265                                 $this->mLastModified = $lastmod;
 266                         }
 267                 } else {
 268                         wfDebug( "$fname: client did not send If-Modified-Since header", 'private' );
 269                         $this->mLastModified = $lastmod;
 270                 }
 271                 return false;
 272         }
 273
 274         /**
 275          * @param string $mckey
 276          * @param int $touched
 277          * @return bool
 278          */
 279         function loadFromMemcached( $mckey, $touched ) {
 280                 if ( !$touched ) {
 281                         return false;
 282                 }
 283
 284                 $mcvalue = ObjectCache::getMainWANInstance()->get( $mckey );
 285                 if ( $mcvalue ) {
 286                         # Check to see if the value has been invalidated
 287                         if ( $touched <= $mcvalue['timestamp'] ) {
 288                                 wfDebug( "Got $mckey from cache" );
 289                                 $this->mText = $mcvalue['value'];
 290
 291                                 return true;
 292                         } else {
 293                                 wfDebug( "$mckey has expired" );
 294                         }
 295                 }
 296
 297                 return false;
 298         }
 299
 300         /**
 301          * @param string $mckey
 302          * @param int $expiry
 303          * @return bool
 304          */
 305         function storeInMemcached( $mckey, $expiry = 86400 ) {
 306                 ObjectCache::getMainWANInstance()->set( $mckey,
 307                         [
 308                                 'timestamp' => wfTimestampNow(),
 309                                 'value' => $this->mText
 310                         ], $expiry
 311                 );
 312
 313                 return true;
 314         }
 315 }