includes/content/WikiTextStructure.php
<?php
use HtmlFormatter\HtmlFormatter;
use MediaWiki\Parser\ParserOutput;
use MediaWiki\Parser\Sanitizer;
/**
* Class allowing to explore the structure of parsed wikitext.
*/
class WikiTextStructure {
private ?string $openingText = null;
private ?string $allText = null;
/** @var string[] */
private array $auxText = [];
private ParserOutput $parserOutput;
/**
* Selectors to elements that are excluded entirely from search
*/
private const EXCLUDED_ELEMENT_SELECTORS = [
// "it looks like you don't have javascript enabled..." – do not need to index
'audio', 'video',
// CSS stylesheets aren't content
'style',
// The [1] for references from Cite
'sup.reference',
// The ↑ next to references in the references section from Cite
'.mw-cite-backlink',
// Headings are already indexed in their own field.
'h1', 'h2', 'h3', 'h4', 'h5', 'h6',
// Collapsed fields are hidden by default, so we don't want them showing up.
'.autocollapse',
// Content explicitly decided to be not searchable by editors such
// as custom navigation templates.
'.navigation-not-searchable',
// User-facing interface code prompting the user to act from WikibaseMediaInfo
'.wbmi-entityview-emptyCaption',
];
/**
* Selectors to elements that are considered auxiliary to the article text for search
*/
private const AUXILIARY_ELEMENT_SELECTORS = [
// Thumbnail captions aren't really part of the text proper
'.thumbcaption',
'figcaption',
// Neither are tables
'table',
// Common style for "See also:".
'.rellink',
// Common style for calling out helpful links at the top of the article.
'.dablink',
// New class users can use to mark stuff as auxiliary to searches.
'.searchaux',
];
/**
* @param ParserOutput $parserOutput
*/
public function __construct( ParserOutput $parserOutput ) {
$this->parserOutput = $parserOutput;
}
/**
* Gets headings from the page.
* @return string[]
* First strip out things that look like references. We can't use HTML filtering because
* the references come back as <sup> tags without a class. To keep from breaking stuff like
* ==Applicability of the strict mass–energy equivalence formula, ''E'' = ''mc''<sup>2</sup>==
* we don't remove the whole <sup> tag.
*
* We also don't want to strip the <sup> tag and remove everything that looks like [2] because,
* I don't know, maybe there is a band named Word [2] Foo r something. Whatever.
*
* So we only strip things that look like <sup> tags wrapping a reference. And since the data
* looks like:
* Reference in heading <sup>[1]</sup><sup>[2]</sup>
* we can not really use HtmlFormatter as we have no suitable selector.
*/
public function headings() {
$headings = [];
$tocData = $this->parserOutput->getTOCData();
if ( $tocData === null ) {
return $headings;
}
$ignoredHeadings = $this->getIgnoredHeadings();
foreach ( $tocData->getSections() as $heading ) {
$heading = $heading->line;
// Some wikis wrap the brackets in a span:
// https://en.wikipedia.org/wiki/MediaWiki:Cite_reference_link
$heading = preg_replace( '/<\/?span>/', '', $heading );
// Normalize [] so the following regexp would work.
$heading = preg_replace( [ '/[/', '/]/' ], [ '[', ']' ], $heading );
$heading = preg_replace( '/<sup>\s*\[\s*\d+\s*\]\s*<\/sup>/i', '', $heading );
// Strip tags from the heading or else we'll display them (escaped) in search results
$heading = trim( Sanitizer::stripAllTags( $heading ) );
// Note that we don't take the level of the heading into account - all headings are equal.
// Except the ones we ignore.
if ( !in_array( $heading, $ignoredHeadings ) ) {
$headings[] = $heading;
}
}
return $headings;
}
/**
* Parse a message content into an array. This function is generally used to
* parse settings stored as i18n messages (see search-ignored-headings).
*
* @param string $message
* @return string[]
*/
public static function parseSettingsInMessage( $message ) {
$lines = explode( "\n", $message );
// Remove comments
$lines = preg_replace( '/#.*$/', '', $lines );
// Remove extra spaces
$lines = array_map( 'trim', $lines );
// Remove empty lines
return array_filter( $lines );
}
/**
* Gets a list of heading to ignore.
* @return string[]
*/
private function getIgnoredHeadings() {
static $ignoredHeadings = null;
if ( $ignoredHeadings === null ) {
$ignoredHeadings = [];
$source = wfMessage( 'search-ignored-headings' )->inContentLanguage();
if ( $source->isBlank() ) {
// Try the old version too, just in case
$source = wfMessage( 'cirrussearch-ignored-headings' )->inContentLanguage();
}
if ( !$source->isDisabled() ) {
$lines = self::parseSettingsInMessage( $source->plain() );
// Now we just have headings!
$ignoredHeadings = $lines;
}
}
return $ignoredHeadings;
}
/**
* Extract parts of the text - opening, main and auxiliary.
*/
private function extractWikitextParts() {
if ( $this->allText !== null ) {
return;
}
$text = $this->parserOutput->getRawText();
if ( $text === '' ) {
$this->allText = "";
// empty text - nothing to seek here
return;
}
$this->openingText = $this->extractTextBeforeFirstHeading( $text );
$formatter = new HtmlFormatter( $text );
// Strip elements from the page that we never want in the search text.
$formatter->remove( self::EXCLUDED_ELEMENT_SELECTORS );
$formatter->filterContent();
// Strip elements from the page that are auxiliary text. These will still be
// searched, but matches will be ranked lower and non-auxiliary matches will be
// preferred in highlighting.
$formatter->remove( self::AUXILIARY_ELEMENT_SELECTORS );
$auxiliaryElements = $formatter->filterContent();
$this->allText = trim( Sanitizer::stripAllTags( $formatter->getText() ) );
foreach ( $auxiliaryElements as $auxiliaryElement ) {
$this->auxText[] =
trim( Sanitizer::stripAllTags( $formatter->getText( $auxiliaryElement ) ) );
}
}
/**
* Get text before first heading.
* @param string $text
* @return string|null
*/
private function extractTextBeforeFirstHeading( $text ) {
$matches = [];
if ( !preg_match( '/<h[123456]\b/', $text, $matches, PREG_OFFSET_CAPTURE ) ) {
// There isn't a first heading, so we interpret this as the article
// being entirely without heading.
return null;
}
$text = substr( $text, 0, $matches[ 0 ][ 1 ] );
if ( !$text ) {
// There isn't any text before the first heading, so we declare there isn't
// a first heading.
return null;
}
$formatter = new HtmlFormatter( $text );
$formatter->remove( self::EXCLUDED_ELEMENT_SELECTORS );
$formatter->remove( self::AUXILIARY_ELEMENT_SELECTORS );
$formatter->filterContent();
$text = trim( Sanitizer::stripAllTags( $formatter->getText() ) );
if ( !$text ) {
// There isn't any text after filtering before the first heading, so we declare
// that there isn't a first heading.
return null;
}
return $text;
}
/**
* @return string|null
*/
public function getOpeningText() {
$this->extractWikitextParts();
return $this->openingText;
}
/**
* @return string
*/
public function getMainText() {
$this->extractWikitextParts();
return $this->allText;
}
/**
* @return string[]
*/
public function getAuxiliaryText() {
$this->extractWikitextParts();
return $this->auxText;
}
/**
* Get the "defaultsort" property
* @return string|null
*/
public function getDefaultSort() {
$sort = $this->parserOutput->getPageProperty( 'defaultsort' );
if ( $sort === false ) {
return null;
}
return $sort;
}
}