includes/AjaxResponse.php

   1 <?php
   2 /**
   3  * Response handler for Ajax requests
   4  *
   5  * @file
   6  * @ingroup Ajax
   7  */
   8
   9 if ( !defined( 'MEDIAWIKI' ) ) {
  10         die( 1 );
  11 }
  12
  13 /**
  14  * Handle responses for Ajax requests (send headers, print
  15  * content, that sort of thing)
  16  *
  17  * @ingroup Ajax
  18  */
  19 class AjaxResponse {
  20         /** Number of seconds to get the response cached by a proxy */
  21         private $mCacheDuration;
  22
  23         /** HTTP header Content-Type */
  24         private $mContentType;
  25
  26         /** Disables output. Can be set by calling $AjaxResponse->disable() */
  27         private $mDisabled;
  28
  29         /** Date for the HTTP header Last-modified */
  30         private $mLastModified;
  31
  32         /** HTTP response code */
  33         private $mResponseCode;
  34
  35         /** HTTP Vary header */
  36         private $mVary;
  37
  38         /** Content of our HTTP response */
  39         private $mText;
  40
  41         function __construct( $text = null ) {
  42                 $this->mCacheDuration = null;
  43                 $this->mVary = null;
  44
  45                 $this->mDisabled = false;
  46                 $this->mText = '';
  47                 $this->mResponseCode = '200 OK';
  48                 $this->mLastModified = false;
  49                 $this->mContentType = 'application/x-wiki';
  50
  51                 if ( $text ) {
  52                         $this->addText( $text );
  53                 }
  54         }
  55
  56         function setCacheDuration( $duration ) {
  57                 $this->mCacheDuration = $duration;
  58         }
  59
  60         function setVary( $vary ) {
  61                 $this->mVary = $vary;
  62         }
  63
  64         function setResponseCode( $code ) {
  65                 $this->mResponseCode = $code;
  66         }
  67
  68         function setContentType( $type ) {
  69                 $this->mContentType = $type;
  70         }
  71
  72         function disable() {
  73                 $this->mDisabled = true;
  74         }
  75
  76         /** Add content to the response */
  77         function addText( $text ) {
  78                 if ( ! $this->mDisabled && $text ) {
  79                         $this->mText .= $text;
  80                 }
  81         }
  82
  83         /** Output text */
  84         function printText() {
  85                 if ( ! $this->mDisabled ) {
  86                         print $this->mText;
  87                 }
  88         }
  89
  90         /** Construct the header and output it */
  91         function sendHeaders() {
  92                 global $wgUseSquid, $wgUseESI;
  93
  94                 if ( $this->mResponseCode ) {
  95                         $n = preg_replace( '/^ *(\d+)/', '\1', $this->mResponseCode );
  96                         header( "Status: " . $this->mResponseCode, true, (int)$n );
  97                 }
  98
  99                 header ( "Content-Type: " . $this->mContentType );
 100
 101                 if ( $this->mLastModified ) {
 102                         header ( "Last-Modified: " . $this->mLastModified );
 103                 } else {
 104                         header ( "Last-Modified: " . gmdate( "D, d M Y H:i:s" ) . " GMT" );
 105                 }
 106
 107                 if ( $this->mCacheDuration ) {
 108                         # If squid caches are configured, tell them to cache the response,
 109                         # and tell the client to always check with the squid. Otherwise,
 110                         # tell the client to use a cached copy, without a way to purge it.
 111
 112                         if ( $wgUseSquid ) {
 113                                 # Expect explicite purge of the proxy cache, but require end user agents
 114                                 # to revalidate against the proxy on each visit.
 115                                 # Surrogate-Control controls our Squid, Cache-Control downstream caches
 116
 117                                 if ( $wgUseESI ) {
 118                                         header( 'Surrogate-Control: max-age=' . $this->mCacheDuration . ', content="ESI/1.0"' );
 119                                         header( 'Cache-Control: s-maxage=0, must-revalidate, max-age=0' );
 120                                 } else {
 121                                         header( 'Cache-Control: s-maxage=' . $this->mCacheDuration . ', must-revalidate, max-age=0' );
 122                                 }
 123
 124                         } else {
 125
 126                                 # Let the client do the caching. Cache is not purged.
 127                                 header ( "Expires: " . gmdate( "D, d M Y H:i:s", time() + $this->mCacheDuration ) . " GMT" );
 128                                 header ( "Cache-Control: s-maxage={$this->mCacheDuration},public,max-age={$this->mCacheDuration}" );
 129                         }
 130
 131                 } else {
 132                         # always expired, always modified
 133                         header ( "Expires: Mon, 26 Jul 1997 05:00:00 GMT" );    // Date in the past
 134                         header ( "Cache-Control: no-cache, must-revalidate" );  // HTTP/1.1
 135                         header ( "Pragma: no-cache" );                          // HTTP/1.0
 136                 }
 137
 138                 if ( $this->mVary ) {
 139                         header ( "Vary: " . $this->mVary );
 140                 }
 141         }
 142
 143         /**
 144          * checkLastModified tells the client to use the client-cached response if
 145          * possible. If sucessful, the AjaxResponse is disabled so that
 146          * any future call to AjaxResponse::printText() have no effect. The method
 147          * returns true iff the response code was set to 304 Not Modified.
 148          */
 149         function checkLastModified ( $timestamp ) {
 150                 global $wgCachePages, $wgCacheEpoch, $wgUser;
 151                 $fname = 'AjaxResponse::checkLastModified';
 152
 153                 if ( !$timestamp || $timestamp == '19700101000000' ) {
 154                         wfDebug( "$fname: CACHE DISABLED, NO TIMESTAMP\n" );
 155                         return;
 156                 }
 157
 158                 if ( !$wgCachePages ) {
 159                         wfDebug( "$fname: CACHE DISABLED\n", false );
 160                         return;
 161                 }
 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
 181                         if ( ( $ismodsince >= $timestamp ) && $wgUser->validateCache( $ismodsince ) && $ismodsince >= $wgCacheEpoch ) {
 182                                 ini_set( 'zlib.output_compression', 0 );
 183                                 $this->setResponseCode( "304 Not Modified" );
 184                                 $this->disable();
 185                                 $this->mLastModified = $lastmod;
 186
 187                                 wfDebug( "$fname: CACHED client: $ismodsince ; user: $wgUser->mTouched ; page: $timestamp ; site $wgCacheEpoch\n", false );
 188
 189                                 return true;
 190                         } else {
 191                                 wfDebug( "$fname: READY  client: $ismodsince ; user: $wgUser->mTouched ; page: $timestamp ; site $wgCacheEpoch\n", false );
 192                                 $this->mLastModified = $lastmod;
 193                         }
 194                 } else {
 195                         wfDebug( "$fname: client did not send If-Modified-Since header\n", false );
 196                         $this->mLastModified = $lastmod;
 197                 }
 198         }
 199
 200         function loadFromMemcached( $mckey, $touched ) {
 201                 global $wgMemc;
 202
 203                 if ( !$touched ) {
 204                         return false;
 205                 }
 206
 207                 $mcvalue = $wgMemc->get( $mckey );
 208                 if ( $mcvalue ) {
 209                         # Check to see if the value has been invalidated
 210                         if ( $touched <= $mcvalue['timestamp'] ) {
 211                                 wfDebug( "Got $mckey from cache\n" );
 212                                 $this->mText = $mcvalue['value'];
 213
 214                                 return true;
 215                         } else {
 216                                 wfDebug( "$mckey has expired\n" );
 217                         }
 218                 }
 219
 220                 return false;
 221         }
 222
 223         function storeInMemcached( $mckey, $expiry = 86400 ) {
 224                 global $wgMemc;
 225
 226                 $wgMemc->set( $mckey,
 227                         array(
 228                                 'timestamp' => wfTimestampNow(),
 229                                 'value' => $this->mText
 230                         ), $expiry
 231                 );
 232
 233                 return true;
 234         }
 235 }