includes/AjaxResponse.php

   1 <?php
   2 /**
   3  * Response handler for Ajax requests
   4  *
   5  * @file
   6  * @ingroup Ajax
   7  */
   8
   9 /**
  10  * Handle responses for Ajax requests (send headers, print
  11  * content, that sort of thing)
  12  *
  13  * @ingroup Ajax
  14  */
  15 class AjaxResponse {
  16         /** Number of seconds to get the response cached by a proxy */
  17         private $mCacheDuration;
  18
  19         /** HTTP header Content-Type */
  20         private $mContentType;
  21
  22         /** Disables output. Can be set by calling $AjaxResponse->disable() */
  23         private $mDisabled;
  24
  25         /** Date for the HTTP header Last-modified */
  26         private $mLastModified;
  27
  28         /** HTTP response code */
  29         private $mResponseCode;
  30
  31         /** HTTP Vary header */
  32         private $mVary;
  33
  34         /** Content of our HTTP response */
  35         private $mText;
  36
  37         function __construct( $text = null ) {
  38                 $this->mCacheDuration = null;
  39                 $this->mVary = null;
  40
  41                 $this->mDisabled = false;
  42                 $this->mText = '';
  43                 $this->mResponseCode = '200 OK';
  44                 $this->mLastModified = false;
  45                 $this->mContentType = 'application/x-wiki';
  46
  47                 if ( $text ) {
  48                         $this->addText( $text );
  49                 }
  50         }
  51
  52         function setCacheDuration( $duration ) {
  53                 $this->mCacheDuration = $duration;
  54         }
  55
  56         function setVary( $vary ) {
  57                 $this->mVary = $vary;
  58         }
  59
  60         function setResponseCode( $code ) {
  61                 $this->mResponseCode = $code;
  62         }
  63
  64         function setContentType( $type ) {
  65                 $this->mContentType = $type;
  66         }
  67
  68         function disable() {
  69                 $this->mDisabled = true;
  70         }
  71
  72         /** Add content to the response */
  73         function addText( $text ) {
  74                 if ( ! $this->mDisabled && $text ) {
  75                         $this->mText .= $text;
  76                 }
  77         }
  78
  79         /** Output text */
  80         function printText() {
  81                 if ( ! $this->mDisabled ) {
  82                         print $this->mText;
  83                 }
  84         }
  85
  86         /** Construct the header and output it */
  87         function sendHeaders() {
  88                 global $wgUseSquid, $wgUseESI;
  89
  90                 if ( $this->mResponseCode ) {
  91                         $n = preg_replace( '/^ *(\d+)/', '\1', $this->mResponseCode );
  92                         header( "Status: " . $this->mResponseCode, true, (int)$n );
  93                 }
  94
  95                 header ( "Content-Type: " . $this->mContentType );
  96
  97                 if ( $this->mLastModified ) {
  98                         header ( "Last-Modified: " . $this->mLastModified );
  99                 } else {
 100                         header ( "Last-Modified: " . gmdate( "D, d M Y H:i:s" ) . " GMT" );
 101                 }
 102
 103                 if ( $this->mCacheDuration ) {
 104                         # If squid caches are configured, tell them to cache the response,
 105                         # and tell the client to always check with the squid. Otherwise,
 106                         # tell the client to use a cached copy, without a way to purge it.
 107
 108                         if ( $wgUseSquid ) {
 109                                 # Expect explicite purge of the proxy cache, but require end user agents
 110                                 # to revalidate against the proxy on each visit.
 111                                 # Surrogate-Control controls our Squid, Cache-Control downstream caches
 112
 113                                 if ( $wgUseESI ) {
 114                                         header( 'Surrogate-Control: max-age=' . $this->mCacheDuration . ', content="ESI/1.0"' );
 115                                         header( 'Cache-Control: s-maxage=0, must-revalidate, max-age=0' );
 116                                 } else {
 117                                         header( 'Cache-Control: s-maxage=' . $this->mCacheDuration . ', must-revalidate, max-age=0' );
 118                                 }
 119
 120                         } else {
 121
 122                                 # Let the client do the caching. Cache is not purged.
 123                                 header ( "Expires: " . gmdate( "D, d M Y H:i:s", time() + $this->mCacheDuration ) . " GMT" );
 124                                 header ( "Cache-Control: s-maxage={$this->mCacheDuration},public,max-age={$this->mCacheDuration}" );
 125                         }
 126
 127                 } else {
 128                         # always expired, always modified
 129                         header ( "Expires: Mon, 26 Jul 1997 05:00:00 GMT" );    // Date in the past
 130                         header ( "Cache-Control: no-cache, must-revalidate" );  // HTTP/1.1
 131                         header ( "Pragma: no-cache" );                          // HTTP/1.0
 132                 }
 133
 134                 if ( $this->mVary ) {
 135                         header ( "Vary: " . $this->mVary );
 136                 }
 137         }
 138
 139         /**
 140          * checkLastModified tells the client to use the client-cached response if
 141          * possible. If sucessful, the AjaxResponse is disabled so that
 142          * any future call to AjaxResponse::printText() have no effect. The method
 143          * returns true iff the response code was set to 304 Not Modified.
 144          */
 145         function checkLastModified ( $timestamp ) {
 146                 global $wgCachePages, $wgCacheEpoch, $wgUser;
 147                 $fname = 'AjaxResponse::checkLastModified';
 148
 149                 if ( !$timestamp || $timestamp == '19700101000000' ) {
 150                         wfDebug( "$fname: CACHE DISABLED, NO TIMESTAMP\n" );
 151                         return;
 152                 }
 153
 154                 if ( !$wgCachePages ) {
 155                         wfDebug( "$fname: CACHE DISABLED\n", false );
 156                         return;
 157                 }
 158
 159                 if ( $wgUser->getOption( 'nocache' ) ) {
 160                         wfDebug( "$fname: USER DISABLED CACHE\n", false );
 161                         return;
 162                 }
 163
 164                 $timestamp = wfTimestamp( TS_MW, $timestamp );
 165                 $lastmod = wfTimestamp( TS_RFC2822, max( $timestamp, $wgUser->mTouched, $wgCacheEpoch ) );
 166
 167                 if ( !empty( $_SERVER['HTTP_IF_MODIFIED_SINCE'] ) ) {
 168                         # IE sends sizes after the date like this:
 169                         # Wed, 20 Aug 2003 06:51:19 GMT; length=5202
 170                         # this breaks strtotime().
 171                         $modsince = preg_replace( '/;.*$/', '', $_SERVER["HTTP_IF_MODIFIED_SINCE"] );
 172                         $modsinceTime = strtotime( $modsince );
 173                         $ismodsince = wfTimestamp( TS_MW, $modsinceTime ? $modsinceTime : 1 );
 174                         wfDebug( "$fname: -- client send If-Modified-Since: " . $modsince . "\n", false );
 175                         wfDebug( "$fname: --  we might send Last-Modified : $lastmod\n", false );
 176
 177                         if ( ( $ismodsince >= $timestamp ) && $wgUser->validateCache( $ismodsince ) && $ismodsince >= $wgCacheEpoch ) {
 178                                 ini_set( 'zlib.output_compression', 0 );
 179                                 $this->setResponseCode( "304 Not Modified" );
 180                                 $this->disable();
 181                                 $this->mLastModified = $lastmod;
 182
 183                                 wfDebug( "$fname: CACHED client: $ismodsince ; user: $wgUser->mTouched ; page: $timestamp ; site $wgCacheEpoch\n", false );
 184
 185                                 return true;
 186                         } else {
 187                                 wfDebug( "$fname: READY  client: $ismodsince ; user: $wgUser->mTouched ; page: $timestamp ; site $wgCacheEpoch\n", false );
 188                                 $this->mLastModified = $lastmod;
 189                         }
 190                 } else {
 191                         wfDebug( "$fname: client did not send If-Modified-Since header\n", false );
 192                         $this->mLastModified = $lastmod;
 193                 }
 194         }
 195
 196         /**
 197          * @param $mckey
 198          * @param $touched
 199          * @return bool
 200          */
 201         function loadFromMemcached( $mckey, $touched ) {
 202                 global $wgMemc;
 203
 204                 if ( !$touched ) {
 205                         return false;
 206                 }
 207
 208                 $mcvalue = $wgMemc->get( $mckey );
 209                 if ( $mcvalue ) {
 210                         # Check to see if the value has been invalidated
 211                         if ( $touched <= $mcvalue['timestamp'] ) {
 212                                 wfDebug( "Got $mckey from cache\n" );
 213                                 $this->mText = $mcvalue['value'];
 214
 215                                 return true;
 216                         } else {
 217                                 wfDebug( "$mckey has expired\n" );
 218                         }
 219                 }
 220
 221                 return false;
 222         }
 223
 224         /**
 225          * @param $mckey
 226          * @param $expiry int
 227          * @return bool
 228          */
 229         function storeInMemcached( $mckey, $expiry = 86400 ) {
 230                 global $wgMemc;
 231
 232                 $wgMemc->set( $mckey,
 233                         array(
 234                                 'timestamp' => wfTimestampNow(),
 235                                 'value' => $this->mText
 236                         ), $expiry
 237                 );
 238
 239                 return true;
 240         }
 241 }