Count and limit expensive #ask/#show functions, refs 2469

DefaultSettings.php

@@ -471,6 +471,31 @@
 	'smwgQMaxDepth' => 4, // Maximal property depth of queries, e.g. [[rel::<q>[[rel2::Test]]</q>]] has depth 2
 	##
 
+	###
+	# Expensive threshold
+	#
+	# The threshold defined in seconds denotes the ceiling as to when a #ask or
+	# #show call is classified as expensive and will count towards the
+	# $smwgQExpensiveExecutionLimit setting.
+	#
+	# @since 3.0
+	# @default 10
+	##
+	'smwgQExpensiveThreshold' => 10,
+	##
+
+	###
+	# Limit of expensive #ask/#show functions
+	#
+	# The limit will count all classified #ask/#show parser functions and restricts
+	# further use on pages that exceed that limit.
+	#
+	# @since 3.0
+	# @default false (== no limit)
+	##
+	'smwgQExpensiveExecutionLimit' => false,
+	##
+
 	###
 	# The below setting defines which query features should be available by
 	# default.

i18n/en.json

@@ -549,5 +549,6 @@
 	"smw-format-datatable-previous": "Previous",
 	"smw-format-datatable-sortascending": ": activate to sort column ascending",
 	"smw-format-datatable-sortdescending": ": activate to sort column descending",
-	"smw-category-invalid-redirect-target": "Category \"$1\" contains an invalid redirect target to a non-category namespace."
+	"smw-category-invalid-redirect-target": "Category \"$1\" contains an invalid redirect target to a non-category namespace.",
+	"smw-parser-function-expensive-execution-limit": "The parser function has reached the limit for expensive executions (see [https://www.semantic-mediawiki.org/wiki/Help:$smwgQExpensiveExecutionLimit $smwgQExpensiveExecutionLimit])."
 }

includes/Settings.php

@@ -109,6 +109,8 @@ public static function newFromGlobals() {
 			'smwgQConceptMaxDepth' => $GLOBALS['smwgQConceptMaxDepth'],
 			'smwgQConceptFeatures' => $GLOBALS['smwgQConceptFeatures'],
 			'smwgQConceptCacheLifetime' => $GLOBALS['smwgQConceptCacheLifetime'],
+			'smwgQExpensiveThreshold' => $GLOBALS['smwgQExpensiveThreshold'],
+			'smwgQExpensiveExecutionLimit' => $GLOBALS['smwgQExpensiveExecutionLimit'],
 			'smwgQuerySources' => $GLOBALS['smwgQuerySources'],
 			'smwgQTemporaryTablesAutoCommitMode' => $GLOBALS['smwgQTemporaryTablesAutoCommitMode'],
 			'smwgResultFormats' => $GLOBALS['smwgResultFormats'],

src/ParserFunctionFactory.php

@@ -10,6 +10,7 @@
 use SMW\ParserFunctions\SetParserFunction;
 use SMW\ParserFunctions\ConceptParserFunction;
 use SMW\ParserFunctions\DeclareParserFunction;
+use SMW\ParserFunctions\ExpensiveFuncExecutionWatcher;
 use SMW\Utils\CircularReferenceGuard;
 use Parser;
 
@@ -73,10 +74,12 @@ public function getRecurringEventsParser() {
 	 */
 	public function newAskParserFunction( Parser $parser ) {
 
+		$applicationFactory =  ApplicationFactory::getInstance();
+
 		$circularReferenceGuard = new CircularReferenceGuard( 'ask-parser' );
 		$circularReferenceGuard->setMaxRecursionDepth( 2 );
 
-		$parserData = ApplicationFactory::getInstance()->newParserData(
+		$parserData = $applicationFactory->newParserData(
 			$parser->getTitle(),
 			$parser->getOutput()
 		);
@@ -92,10 +95,23 @@ public function newAskParserFunction( Parser $parser ) {
 			$parser->getTargetLanguage()
 		);
 
+		$expensiveFuncExecutionWatcher = new ExpensiveFuncExecutionWatcher(
+			$parserData
+		);
+
+		$expensiveFuncExecutionWatcher->setExpensiveThreshold(
+			$applicationFactory->getSettings()->get( 'smwgQExpensiveThreshold' )
+		);
+
+		$expensiveFuncExecutionWatcher->setExpensiveExecutionLimit(
+			$applicationFactory->getSettings()->get( 'smwgQExpensiveExecutionLimit' )
+		);
+
 		$askParserFunction = new AskParserFunction(
 			$parserData,
 			$messageFormatter,
-			$circularReferenceGuard
+			$circularReferenceGuard,
+			$expensiveFuncExecutionWatcher
 		);
 
 		return $askParserFunction;
@@ -110,29 +126,8 @@ public function newAskParserFunction( Parser $parser ) {
 	 */
 	public function newShowParserFunction( Parser $parser ) {
 
-		$circularReferenceGuard = new CircularReferenceGuard( 'show-parser' );
-		$circularReferenceGuard->setMaxRecursionDepth( 2 );
-
-		$parserData = ApplicationFactory::getInstance()->newParserData(
-			$parser->getTitle(),
-			$parser->getOutput()
-		);
-
-		if ( isset( $parser->getOptions()->smwAskNoDependencyTracking ) ) {
-			$parserData->setOption( $parserData::NO_QUERY_DEPENDENCY_TRACE, $parser->getOptions()->smwAskNoDependencyTracking );
-		}
-
-		// Avoid possible actions during for example stashedit etc.
-		$parserData->setOption( 'request.action', $GLOBALS['wgRequest']->getVal( 'action' ) );
-
-		$messageFormatter = new MessageFormatter(
-			$parser->getTargetLanguage()
-		);
-
 		$showParserFunction = new ShowParserFunction(
-			$parserData,
-			$messageFormatter,
-			$circularReferenceGuard
+			$this->newAskParserFunction( $parser )
 		);
 
 		return $showParserFunction;

src/ParserFunctions/AskParserFunction.php

@@ -52,6 +52,11 @@ class AskParserFunction {
 	 */
 	private $circularReferenceGuard;
 
+	/**
+	 * @var ExpensiveFuncExecutionWatcher
+	 */
+	private $expensiveFuncExecutionWatcher;
+
 	/**
 	 * @var boolean
 	 */
@@ -78,11 +83,13 @@ class AskParserFunction {
 	 * @param ParserData $parserData
 	 * @param MessageFormatter $messageFormatter
 	 * @param CircularReferenceGuard $circularReferenceGuard
+	 * @param ExpensiveFuncExecutionWatcher $expensiveFuncExecutionWatcher
 	 */
-	public function __construct( ParserData $parserData, MessageFormatter $messageFormatter, CircularReferenceGuard $circularReferenceGuard ) {
+	public function __construct( ParserData $parserData, MessageFormatter $messageFormatter, CircularReferenceGuard $circularReferenceGuard, ExpensiveFuncExecutionWatcher $expensiveFuncExecutionWatcher ) {
 		$this->parserData = $parserData;
 		$this->messageFormatter = $messageFormatter;
 		$this->circularReferenceGuard = $circularReferenceGuard;
+		$this->expensiveFuncExecutionWatcher = $expensiveFuncExecutionWatcher;
 	}
 
 	/**
@@ -129,8 +136,8 @@ public function parse( array $functionParams ) {
 
 		// Do we still need this?
 		// Reference found in SRF_Exhibit.php, SRF_Ploticus.php, SRF_Timeline.php, SRF_JitGraph.php
-		global $smwgIQRunningNumber;
-		$smwgIQRunningNumber++;
+		$GLOBALS['smwgIQRunningNumber']++;
+		$result = '';
 
 		$this->applicationFactory = ApplicationFactory::getInstance();
 
@@ -221,6 +228,10 @@ private function doFetchResultsFromFunctionParameters( array $functionParams ) {
 			$contextPage
 		);
 
+		if ( ( $result = $this->hasReachedExpensiveExecutionLimit( $query ) ) !== false ) {
+			return $result;
+		}
+
 		$query->setOption( Query::PROC_CONTEXT, 'AskParserFunction' );
 		$query->setOption( Query::NO_DEPENDENCY_TRACE, $this->noTrace );
 		$query->setOption( 'request.action', $this->parserData->getOption( 'request.action' ) );
@@ -254,6 +265,7 @@ private function doFetchResultsFromFunctionParameters( array $functionParams ) {
 		}
 
 		$this->circularReferenceGuard->unmark( $queryHash );
+		$this->expensiveFuncExecutionWatcher->incrementExpensiveCount( $query );
 
 		// In case of an query error add a marker to the subject for discoverability
 		// of a failed query, don't bail-out as we can have results and errors
@@ -268,6 +280,18 @@ private function doFetchResultsFromFunctionParameters( array $functionParams ) {
 		return $result;
 	}
 
+	private function hasReachedExpensiveExecutionLimit( $query ) {
+
+		if ( $this->expensiveFuncExecutionWatcher->hasReachedExpensiveLimit( $query ) === false ) {
+			return false;
+		}
+
+		// Adding to error in order to be discoverable
+		$this->addProcessingError( array( 'smw-parser-function-expensive-execution-limit' ) );
+
+		return $this->messageFormatter->addFromKey( 'smw-parser-function-expensive-execution-limit' )->getHtml();
+	}
+
 	private function addQueryProfile( $query, $format ) {
 
 		$settings = $this->applicationFactory->getSettings();

src/ParserFunctions/ExpensiveFuncExecutionWatcher.php

@@ -0,0 +1,113 @@
+<?php
+
+namespace SMW\ParserFunctions;
+
+use SMW\ParserData;
+use SMWQuery as Query;
+
+/**
+ * @private
+ *
+ * @license GNU GPL v2+
+ * @since 3.0
+ *
+ * @author mwjames
+ */
+class ExpensiveFuncExecutionWatcher {
+
+	/**
+	 * Idenitifer
+	 */
+	const EXPENSIVE_COUNTER = 'smw-expensiveparsercount';
+
+	/**
+	 * @var ParserData
+	 */
+	private $parserData;
+
+	/**
+	 * @var integer
+	 */
+	private $expensiveThreshold = 10;
+
+	/**
+	 * @var integer|boolean
+	 */
+	private $expensiveExecutionLimit = false;
+
+	/**
+	 * @since 3.0
+	 *
+	 * @param ParserData $parserData
+	 */
+	public function __construct( ParserData $parserData ) {
+		$this->parserData = $parserData;
+	}
+
+	/**
+	 * @since 3.0
+	 *
+	 * @param integer $expensiveThreshold
+	 */
+	public function setExpensiveThreshold( $expensiveThreshold ) {
+		$this->expensiveThreshold = $expensiveThreshold;
+	}
+
+	/**
+	 * @since 3.0
+	 *
+	 * @param integer|boolean $expensiveExecutionLimit
+	 */
+	public function setExpensiveExecutionLimit( $expensiveExecutionLimit ) {
+		$this->expensiveExecutionLimit = $expensiveExecutionLimit;
+	}
+
+	/**
+	 * @since 3.0
+	 *
+	 * @param Query $query
+	 *
+	 * @return boolean
+	 */
+	public function hasReachedExpensiveLimit( Query $query ) {
+
+		if ( $this->expensiveExecutionLimit === false ) {
+			return false;
+		}
+
+		if ( $query->getLimit() == 0 ) {
+			return false;
+		}
+
+		if ( $this->parserData->getOutput()->getExtensionData( self::EXPENSIVE_COUNTER ) < $this->expensiveExecutionLimit ) {
+			return false;
+		}
+
+		return true;
+	}
+
+	/**
+	 * @since 3.0
+	 *
+	 * @param Query $query
+	 *
+	 * @return boolean
+	 */
+	public function incrementExpensiveCount( Query $query ) {
+
+		if ( $this->expensiveExecutionLimit === false || $query->getLimit() == 0 || $query->getOption( Query::PROC_QUERY_TIME ) < $this->expensiveThreshold  ) {
+			return;
+		}
+
+		$output = $this->parserData->getOutput();
+		$expensiveCount = $output->getExtensionData( self::EXPENSIVE_COUNTER );
+
+		if ( !is_int( $expensiveCount ) ) {
+			$expensiveCount = 0;
+		}
+
+		$expensiveCount++;
+		$output->setExtensionData( self::EXPENSIVE_COUNTER, $expensiveCount );
+	}
+
+}

src/ParserFunctions/ShowParserFunction.php

@@ -2,10 +2,6 @@
 
 namespace SMW\ParserFunctions;
 
-use SMW\ParserData;
-use SMW\MessageFormatter;
-use SMW\Utils\CircularReferenceGuard;
-
 /**
  * Class that provides the {{#show}} parser function
  *
@@ -17,31 +13,17 @@
 class ShowParserFunction {
 
 	/**
-	 * @var ParserData
-	 */
-	private $parserData;
-
-	/**
-	 * @var MessageFormatter
-	 */
-	private $messageFormatter;
-
-	/**
-	 * @var CircularReferenceGuard
+	 * @var AskParserFunction
 	 */
-	private $circularReferenceGuard;
+	private $askParserFunction;
 
 	/**
 	 * @since 1.9
 	 *
-	 * @param ParserData $parserData
-	 * @param MessageFormatter $messageFormatter
-	 * @param CircularReferenceGuard $circularReferenceGuard
+	 * @param AskParserFunction $askParserFunction
 	 */
-	public function __construct( ParserData $parserData, MessageFormatter $messageFormatter, CircularReferenceGuard $circularReferenceGuard ) {
-		$this->parserData = $parserData;
-		$this->messageFormatter = $messageFormatter;
-		$this->circularReferenceGuard = $circularReferenceGuard;
+	public function __construct( AskParserFunction $askParserFunction ) {
+		$this->askParserFunction = $askParserFunction;
 	}
 
 	/**
@@ -59,16 +41,8 @@ public function __construct( ParserData $parserData, MessageFormatter $messageFo
 	 * @return string|null
 	 */
 	public function parse( array $rawParams ) {
-
-		$instance = new AskParserFunction(
-			$this->parserData,
-			$this->messageFormatter,
-			$this->circularReferenceGuard
-		);
-
-		$instance->setShowMode( true );
-
-		return $instance->parse( $rawParams );
+		$this->askParserFunction->setShowMode( true );
+		return $this->askParserFunction->parse( $rawParams );
 	}
 
 	/**
@@ -80,7 +54,7 @@ public function parse( array $rawParams ) {
 	 * @return string|null
 	 */
 	public function isQueryDisabled() {
-		return $this->messageFormatter->addFromKey( 'smw_iq_disabled' )->getHtml();
+		return $this->askParserFunction->isQueryDisabled();
 	}
 
 }