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