Load limiting work for Recentchanges RSS/Atom feeds:

* Cache feeds for up to a day
* Maximum number of rows to show
* Minimum timeout between changes to re-cache
* Maximum article size to show diffs for (will show diff link instead for larger)
* Also, return 500 error if asked for an invalid feed format instead of silently showing the html

diff --git a/includes/DefaultSettings.php b/includes/DefaultSettings.php
index 690671b..79e6a6f 100644 (file)
--- a/includes/DefaultSettings.php
+++ b/includes/DefaultSettings.php
@@ -787,6 +787,20 @@ $wgUseExternalDiffEngine = false;
 # Use RC Patrolling to check for vandalism
 $wgUseRCPatrol = true;
 
+# Set maximum number of results to return in syndication feeds
+# (RSS, Atom) for eg Recentchanges, Newpages.
+$wgFeedLimit = 50;
+
+# _Minimum_ timeout for cached Recentchanges feed, in seconds.
+# A cached version will continue to be served out even if changes
+# are made, until this many seconds runs out since the last render.
+$wgFeedCacheTimeout = 60;
+
+# When generating Recentchanges RSS/Atom feed, diffs will not be
+# generated for pages larger than this size.
+$wgFeedDiffCutoff = 32768;
+
+
 # Additional namespaces. If the namespaces defined in Language.php and Namespace.php are insufficient,
 # you can create new ones here, for example, to import Help files in other languages.
 # PLEASE NOTE: Once you delete a namespace, the pages in that namespace will no longer be accessible.

diff --git a/includes/Feed.php b/includes/Feed.php
index 8d4188f..c3cd371 100644 (file)
--- a/includes/Feed.php
+++ b/includes/Feed.php
@@ -134,20 +134,48 @@ class ChannelFeed extends FeedItem {
        /**#@-*/
        
        /**
-        * @todo document
-        * @param string $mimetype (optional) type of output
+        * Setup and send HTTP headers. Don't send any content;
+        * content might end up being cached and re-sent with
+        * these same headers later.
+        *
+        * This should be called from the outHeader() method,
+        * but can also be called separately.
+        *
+        * @access public
         */
-       function outXmlHeader( $mimetype='application/xml' ) {
-               global $wgServer, $wgStylePath, $wgOut;
+       function httpHeaders() {
+               global $wgOut;
                
                # We take over from $wgOut, excepting its cache header info
                $wgOut->disable();
+               $mimetype = $this->contentType();
                header( "Content-type: $mimetype; charset=UTF-8" );
                $wgOut->sendCacheControl();
                
+       }
+       
+       /**
+        * Return an internet media type to be sent in the headers.
+        *
+        * @return string
+        * @access private
+        */
+       function contentType() {
+               return 'application/xml';
+       }
+       
+       /**
+        * Output the initial XML headers with a stylesheet for legibility
+        * if someone finds it in a browser.
+        * @access private
+        */
+       function outXmlHeader() {
+               global $wgServer, $wgStylePath;
+               
+               $this->httpHeaders();
                print '<' . '?xml version="1.0" encoding="utf-8"?' . ">\n";
                print '<' . '?xml-stylesheet type="text/css" href="' .
-                       htmlspecialchars( "$wgServer$wgStylePath/feed.css" ) . '"?' . ">\n";
+                       htmlspecialchars( "$wgServer$wgStylePath/common/feed.css" ) . '"?' . ">\n";
        }
 }
 

diff --git a/includes/SpecialRecentchanges.php b/includes/SpecialRecentchanges.php
index 4d7ad65..2a833a3 100644 (file)
--- a/includes/SpecialRecentchanges.php
+++ b/includes/SpecialRecentchanges.php
@@ -28,22 +28,34 @@ function wfSpecialRecentchanges( $par ) {
 
        $days = $wgRequest->getInt( 'days', $defaultDays );
        $hideminor = $wgRequest->getBool( 'hideminor', $wgUser->getOption( 'hideminor' ) ) ? 1 : 0;
-       $from = $wgRequest->getText( 'from' );
-       $hidebots = $wgRequest->getBool( 'hidebots', true ) ? 1 : 0;
-       $hideliu = $wgRequest->getBool( 'hideliu', false ) ? 1 : 0;
-       $hidepatrolled = $wgRequest->getBool( 'hidepatrolled', false ) ? 1 : 0;
-
        list( $limit, $offset ) = wfCheckLimits( 100, 'rclimit' );
-
-       # Get query parameters from path
-       if( $par ) {
-               $bits = preg_split( '/\s*,\s*/', trim( $par ) );
-               if( in_array( 'hidebots', $bits ) ) $hidebots = 1;
-               if( in_array( 'bots', $bits ) ) $hidebots = 0;
-               if( in_array( 'hideminor', $bits ) ) $hideminor = 1;
-               if( in_array( 'minor', $bits ) ) $hideminor = 0;
-               if( in_array( 'hideliu', $bits) ) $hideliu = 1;
-               if( in_array( 'hidepatrolled', $bits) ) $hidepatrolled = 1;
+       
+       # As a feed, use limited settings only
+       if( $feedFormat ) {
+               $from = null;
+               $hidebots = 1;
+               $hideliu = 0;
+               $hidepatrolled = 0;
+               global $wgFeedLimit;
+               if( $limit > $wgFeedLimit ) {
+                       $limit = $wgFeedLimit;
+               }
+       } else {
+               $from = $wgRequest->getText( 'from' );
+               $hidebots = $wgRequest->getBool( 'hidebots', true ) ? 1 : 0;
+               $hideliu = $wgRequest->getBool( 'hideliu', false ) ? 1 : 0;
+               $hidepatrolled = $wgRequest->getBool( 'hidepatrolled', false ) ? 1 : 0;
+       
+               # Get query parameters from path
+               if( $par ) {
+                       $bits = preg_split( '/\s*,\s*/', trim( $par ) );
+                       if( in_array( 'hidebots', $bits ) ) $hidebots = 1;
+                       if( in_array( 'bots', $bits ) ) $hidebots = 0;
+                       if( in_array( 'hideminor', $bits ) ) $hideminor = 1;
+                       if( in_array( 'minor', $bits ) ) $hideminor = 0;
+                       if( in_array( 'hideliu', $bits) ) $hideliu = 1;
+                       if( in_array( 'hidepatrolled', $bits) ) $hidepatrolled = 1;
+               }
        }
 
 
@@ -57,8 +69,8 @@ function wfSpecialRecentchanges( $par ) {
 
        # Get last modified date, for client caching
        # Don't use this if we are using the patrol feature, patrol changes don't update the timestamp
-       if ( !$wgUseRCPatrol ) {
-               $lastmod = $dbr->selectField( 'recentchanges', 'MAX(rc_timestamp)', false, $fname );
+       $lastmod = $dbr->selectField( 'recentchanges', 'MAX(rc_timestamp)', false, $fname );
+       if ( $feedFormat || !$wgUseRCPatrol ) {
                if( $lastmod && $wgOut->checkLastModified( $lastmod ) ){
                        # Client cache fresh and headers sent, nothing more to do.
                        return;
@@ -132,44 +144,10 @@ function wfSpecialRecentchanges( $par ) {
 
        $wgOut->addHTML( $note."\n" );
 
-       if( isset($wgFeedClasses[$feedFormat]) ) {
-               $feed = new $wgFeedClasses[$feedFormat](
-                       $wgSitename . ' - ' . wfMsg( 'recentchanges' ) . ' [' . $wgContLanguageCode . ']',
-                       htmlspecialchars( wfMsg( 'recentchangestext' ) ),
-                       $wgTitle->getFullUrl() );
-               $feed->outHeader();
-               
-               # Merge adjacent edits by one user
-               $sorted = array();
-               $n = 0;
-               foreach( $rows as $obj ) {
-                       if( $n > 0 &&
-                               $obj->rc_namespace >= 0 &&
-                           $obj->rc_cur_id == $sorted[$n-1]->rc_cur_id &&
-                           $obj->rc_user_text == $sorted[$n-1]->rc_user_text ) {
-                               $sorted[$n-1]->rc_last_oldid = $obj->rc_last_oldid;
-                       } else {
-                               $sorted[$n] = $obj;
-                               $n++;
-                       }
-                       $first = false;
-               }
-               
-               foreach( $sorted as $obj ) {
-                       $title = Title::makeTitle( $obj->rc_namespace, $obj->rc_title );
-                       $talkpage = $title->getTalkPage();
-                       $item = new FeedItem(
-                               $title->getPrefixedText(),
-                               rcFormatDiff( $obj ),
-                               $title->getFullURL(),
-                               $obj->rc_timestamp,
-                               $obj->rc_user_text,
-                               $talkpage->getFullURL()
-                               );
-                       $feed->outItem( $item );
-               }
-               $feed->outFooter();
+       if( $feedFormat ) {
+               rcOutputFeed( $rows, $feedFormat, $limit, $hideminor, $lastmod );
        } else {
+               # Web output...
                $wgOut->setSyndicated( true );
                $list =& new ChangesList( $sk );
                $s = $list->beginRecentChangesList();
@@ -192,6 +170,103 @@ function wfSpecialRecentchanges( $par ) {
        }
 }
 
+function rcOutputFeed( $rows, $feedFormat, $limit, $hideminor, $lastmod ) {
+       global $messageMemc, $wgDBname, $wgFeedCacheTimeout;
+       global $wgFeedClasses, $wgTitle, $wgSitename, $wgContLanguageCode;
+       
+       if( !isset( $wgFeedClasses[$feedFormat] ) ) {
+               wfHttpError( 500, "Internal Server Error", "Unsupported feed type." );
+               return false;
+       }
+       
+       $timekey = "$wgDBname:rcfeed:timestamp";
+       $key = "$wgDBname:rcfeed:$feedFormat:limit:$limit:minor:$hideminor";
+       
+       $feedTitle = $wgSitename . ' - ' . wfMsgForContent( 'recentchanges' ) .
+               ' [' . $wgContLanguageCode . ']';
+       $feed = new $wgFeedClasses[$feedFormat](
+               $feedTitle,
+               htmlspecialchars( wfMsgForContent( 'recentchangestext' ) ),
+               $wgTitle->getFullUrl() );
+
+       /**
+        * Bumping around loading up diffs can be pretty slow, so where
+        * possible we want to cache the feed output so the next visitor
+        * gets it quick too.
+        */
+       $cachedFeed = false;
+       if( $feedLastmod = $messageMemc->get( $timekey ) ) {
+               /**
+                * If the cached feed was rendered very recently, we may
+                * go ahead and use it even if there have been edits made
+                * since it was rendered. This keeps a swarm of requests
+                * from being too bad on a super-frequently edited wiki.
+                */
+               if( time() - wfTimestamp( TS_UNIX, $feedLastmod )
+                               < $wgFeedCacheTimeout
+                       || wfTimestamp( TS_UNIX, $feedLastmod )
+                               > wfTimestamp( TS_UNIX, $lastmod ) ) {
+                       wfDebug( "RC: loading feed from cache ($key; $feedLastmod; $lastmod)...\n" );
+                       $cachedFeed = $messageMemc->get( $key );
+               } else {
+                       wfDebug( "RC: cached feed timestamp check failed ($feedLastmod; $lastmod)\n" );
+               }
+       }
+       if( is_string( $cachedFeed ) ) {
+               wfDebug( "RC: Outputting cached feed\n" );
+               $feed->httpHeaders();
+               echo $cachedFeed;
+       } else {
+               wfDebug( "RC: rendering new feed and caching it\n" );
+               ob_start();
+               rcDoOutputFeed( $rows, $feed );
+               $cachedFeed = ob_get_contents();
+               ob_end_flush();
+               
+               $expire = 3600 * 24; # One day
+               $messageMemc->set( $key, $cachedFeed );
+               $messageMemc->set( $timekey, wfTimestamp( TS_MW ), $expire );
+       }
+       return true;
+}
+
+function rcDoOutputFeed( $rows, &$feed ) {
+       global $wgSitename, $wgFeedClasses, $wgContLanguageCode;
+       
+       $feed->outHeader();
+       
+       # Merge adjacent edits by one user
+       $sorted = array();
+       $n = 0;
+       foreach( $rows as $obj ) {
+               if( $n > 0 &&
+                       $obj->rc_namespace >= 0 &&
+                       $obj->rc_cur_id == $sorted[$n-1]->rc_cur_id &&
+                       $obj->rc_user_text == $sorted[$n-1]->rc_user_text ) {
+                       $sorted[$n-1]->rc_last_oldid = $obj->rc_last_oldid;
+               } else {
+                       $sorted[$n] = $obj;
+                       $n++;
+               }
+               $first = false;
+       }
+       
+       foreach( $sorted as $obj ) {
+               $title = Title::makeTitle( $obj->rc_namespace, $obj->rc_title );
+               $talkpage = $title->getTalkPage();
+               $item = new FeedItem(
+                       $title->getPrefixedText(),
+                       rcFormatDiff( $obj ),
+                       $title->getFullURL(),
+                       $obj->rc_timestamp,
+                       $obj->rc_user_text,
+                       $talkpage->getFullURL()
+                       );
+               $feed->outItem( $item );
+       }
+       $feed->outFooter();
+}
+
 /**
  *
  */
@@ -217,7 +292,7 @@ function rcDaysLink( $lim, $d, $page='Recentchanges', $more='' ) {
 }
 
 /**
- *
+ * Used also by Recentchangeslinked
  */
 function rcDayLimitLinks( $days, $limit, $page='Recentchanges', $more='', $doall = false, $minorLink = '',
        $botLink = '', $liuLink = '', $patrLink = '' ) {
@@ -239,19 +314,8 @@ function rcDayLimitLinks( $days, $limit, $page='Recentchanges', $more='', $doall
 }
 
 /**
- * Obsolete? Isn't called from anywhere and $mlink isn't defined
+ * Format a diff for the newsfeed
  */
-function rcLimitLinks( $page='Recentchanges', $more='', $doall = false ) {
-       if ($more != '') $more .= '&';
-       $cl = rcCountLink( 50, 0, $page, $more ) . ' | ' .
-         rcCountLink( 100, 0, $page, $more  ) . ' | ' .
-         rcCountLink( 250, 0, $page, $more  ) . ' | ' .
-         rcCountLink( 500, 0, $page, $more  ) .
-         ( $doall ? ( ' | ' . rcCountLink( 0, $days, $page, $more ) ) : '' );
-       $note = wfMsg( 'rclinks', $cl, '', $mlink );
-       return $note;
-}
-
 function rcFormatDiff( $row ) {
        $fname = 'rcFormatDiff';
        wfProfileIn( $fname );
@@ -283,9 +347,24 @@ function rcFormatDiff( $row ) {
                                array( 'old_flags', 'old_text' ),
                                array( 'old_id' => $row->rc_last_oldid ) );
                        $oldtext = Article::getRevisionText( $oldrow );
-                       $diffText = DifferenceEngine::getDiff( $oldtext, $newtext,
-                         wfMsg( 'revisionasof', $wgContLang->timeanddate( $row->rc_timestamp ) ),
-                         wfMsg( 'currentrev' ) );
+                       
+                       global $wgFeedDiffCutoff;
+                       if( strlen( $newtext ) > $wgFeedDiffCutoff ||
+                           strlen( $oldtext ) > $wgFeedDiffCutoff ) {
+                           $titleObj = Title::makeTitle( $row->rc_namespace, $row->rc_title );
+                               $diffLink = $titleObj->escapeFullUrl(
+                                       'diff=' . $row->rc_this_oldid .
+                                       '&oldid=' . $row->rc_last_oldid );
+                           $diffText = '<a href="' .
+                               $diffLink .
+                               '">' .
+                               htmlspecialchars( wfMsgForContent( 'difference' ) ) .
+                               '</a>';
+                       } else {
+                               $diffText = DifferenceEngine::getDiff( $oldtext, $newtext,
+                                 wfMsg( 'revisionasof', $wgContLang->timeanddate( $row->rc_timestamp ) ),
+                                 wfMsg( 'currentrev' ) );
+                       }
                        wfProfileOut( "$fname-dodiff" );
                } else {
                        $diffText = '<p><b>' . wfMsg( 'newpage' ) . '</b></p>' .