mediawiki-extensions-Echo/includes/DiscussionParser.php
Matthew Flaschen 3c37aefdb1 Separate logic for extracting usernames from picking the right one
Pull out the logic that extracts usernames from links.  This allows
it to be reused by the LQT->Flow import code.

Bug: T101979
Change-Id: Ib16a09cf1f388f56944cd1bb564384535728156e
2015-06-12 21:16:59 -04:00

863 lines
25 KiB
PHP

<?php
abstract class EchoDiscussionParser {
const HEADER_REGEX = '^(==+)\s*([^=].*)\s*\1$';
static protected $timestampRegex;
static protected $revisionInterpretationCache = array();
static protected $diffParser;
/**
* Given a Revision object, generates EchoEvent objects for
* the discussion-related actions that occurred in that Revision.
*
* @param $revision Revision object
* @return null
*/
static function generateEventsForRevision( $revision ) {
$interpretation = self::getChangeInterpretationForRevision( $revision );
// use slave database if there is a previous revision
if ( $revision->getPrevious() ) {
$title = Title::newFromID( $revision->getPage() );
// use master database for new page
} else {
$title = Title::newFromID( $revision->getPage(), Title::GAID_FOR_UPDATE );
}
// not a valid title
if ( !$title ) {
return;
}
$userID = $revision->getUser();
$userName = $revision->getUserText();
$user = $userID != 0 ? User::newFromId( $userID ) : User::newFromName( $userName, false );
foreach ( $interpretation as $action ) {
// These two event types are disabled temporarily, there is no need to process them
if ( $action['type'] == 'add-comment' ) {
$fullSection = $action['full-section'];
$header = self::extractHeader( $fullSection );
self::generateMentionEvents( $header, $action['content'], $revision, $user );
} elseif ( $action['type'] == 'new-section-with-comment' ) {
$content = $action['content'];
$header = self::extractHeader( $content );
self::generateMentionEvents( $header, $content, $revision, $user );
}
}
if ( $title->getNamespace() == NS_USER_TALK ) {
$notifyUser = User::newFromName( $title->getText() );
// If the recipient is a valid non-anonymous user and hasn't turned
// off their notifications, generate a talk page post Echo notification.
if ( $notifyUser && $notifyUser->getID() && $notifyUser->getOption( 'echo-notify-show-link' ) ) {
// if this is a minor edit, only notify if the agent doesn't have talk page minor edit notification blocked
if ( !$revision->isMinor() || !$user->isAllowed( 'nominornewtalk' ) ) {
$section = self::detectSectionTitleAndText( $interpretation, $title );
if ( $section['section-text'] === '' ) {
$section['section-text'] = $revision->getComment();
}
EchoEvent::create( array(
'type' => 'edit-user-talk',
'title' => $title,
'extra' => array(
'revid' => $revision->getID(),
'minoredit' => $revision->isMinor(),
'section-title' => $section['section-title'],
'section-text' => $section['section-text']
),
'agent' => $user,
) );
}
}
}
}
/**
* Attempts to determine what section title the edit was performed under (if any)
*
* @param $interpretation array Results of self::getChangeInterpretationForRevision
* @return array Array containing section title and text
* @param Title $title
*/
public static function detectSectionTitleAndText( array $interpretation, Title $title = null ) {
$header = $snippet = '';
$found = false;
foreach ( $interpretation as $action ) {
switch( $action['type'] ) {
case 'add-comment':
$header = self::extractHeader( $action['full-section'] );
$snippet = self::getTextSnippet( self::stripSignature( self::stripHeader( $action['content'] ), $title ), 150 );
break;
case 'new-section-with-comment':
$header = self::extractHeader( $action['content'] );
$snippet = self::getTextSnippet( self::stripSignature( self::stripHeader( $action['content'] ), $title ), 150 );
break;
}
if ( $header ) {
// If we find a second header within the same change interpretation then
// we cannot choose just 1 to link to
if ( $found ) {
$found = false;
break;
}
$found = true;
}
}
if ( $found === false ) {
return array( 'section-title' => '', 'section-text' => '' );
}
return array( 'section-title' => $header, 'section-text' => $snippet );
}
/**
* For an action taken on a talk page, notify users whose user pages
* are linked.
* @param $header string The subject line for the discussion.
* @param $content string The content of the post, as a wikitext string.
* @param $revision Revision object.
* @param $agent User The user who made the comment.
*/
public static function generateMentionEvents( $header, $content, $revision, $agent ) {
$title = $revision->getTitle();
if ( !$title ) {
return;
}
$output = self::parseNonEditWikitext( $content, new Article( $title ) );
$links = $output->getLinks();
if ( !isset( $links[NS_USER] ) || !is_array( $links[NS_USER] ) ) {
return;
}
$mentionedUsers = array();
$count = 0;
foreach ( $links[NS_USER] as $dbk => $page_id ) {
$user = User::newFromName( $dbk );
// we should not add user to 'mention' notification list if
// 1. the user name is not valid
// 2. the user mentions themselves
// 3. the user is the owner of the talk page
// 4. user is anonymous
if (
!$user || $user->isAnon() || $user->getId() == $revision->getUser() ||
( $title->getNamespace() === NS_USER_TALK && $title->getDBkey() === $dbk )
) {
continue;
}
$mentionedUsers[$user->getId()] = $user->getId();
$count++;
// If more than 20 users are being pinged this is likely a spam/attack vector
// Don't send any mention notifications.
if ( $count > 20 ) {
return;
}
}
if ( !$mentionedUsers ) {
return;
}
EchoEvent::create( array(
'type' => 'mention',
'title' => $title,
'extra' => array(
'content' => $content,
'section-title' => $header,
'revid' => $revision->getId(),
'mentioned-users' => $mentionedUsers,
),
'agent' => $agent,
) );
}
/**
* It's like Article::prepareTextForEdit,
* but not for editing (old wikitext usually)
* Stolen from AbuseFilterVariableHolder
*
* @param $wikitext String
* @param $article Article
*
* @return ParserOutput
*/
static function parseNonEditWikitext( $wikitext, $article ) {
static $cache = array();
$cacheKey = md5( $wikitext ) . ':' . $article->getTitle()->getPrefixedText();
if ( isset( $cache[$cacheKey] ) ) {
return $cache[$cacheKey];
}
global $wgParser;
$options = new ParserOptions;
$options->setTidy( true );
$output = $wgParser->parse( $wikitext, $article->getTitle(), $options );
$cache[$cacheKey] = $output;
return $output;
}
/**
* Given a Revision object, returns a talk-page-centric interpretation
* of the changes made in it.
*
* @param $revision Revision object
* @see EchoDiscussionParser::interpretDiff
* @return Array, see interpretDiff for details.
*/
static function getChangeInterpretationForRevision( $revision ) {
if ( $revision->getID() && isset( self::$revisionInterpretationCache[$revision->getID()] ) ) {
return self::$revisionInterpretationCache[$revision->getID()];
}
$userID = $revision->getUser();
$userName = $revision->getUserText();
$user = $userID != 0 ? User::newFromId( $userID ) : User::newFromName( $userName, false );
$prevText = '';
if ( $revision->getParentId() ) {
$prevRevision = Revision::newFromId( $revision->getParentId() );
if ( $prevRevision ) {
$prevText = $prevRevision->getText();
}
}
$changes = self::getMachineReadableDiff( $prevText, $revision->getText() );
$output = self::interpretDiff( $changes, $user->getName(), $revision->getTitle() );
self::$revisionInterpretationCache[$revision->getID()] = $output;
return $output;
}
/**
* Given a machine-readable diff, interprets the changes
* in terms of discussion page actions
*
* @todo Expand recognisable actions.
* @param array $changes Output of EchoEvent::getMachineReadableDiff
* @param string $user Username
* @param Title $title
* @return Array of associative arrays.
* Each entry represents an action, which is classified in the 'action' field.
* All types contain a 'content' field except 'unknown'
* (which instead passes through the machine-readable diff in 'details')
* and 'unknown-change' (which provides 'new_content' and 'old_content')
* action may be:
* - add-comment: A comment signed by the user is added to an
* existing section.
* - new-section-with-comment: A new section is added, containing
* a single comment signed by the user in question.
* - unknown-signed-addition: Some signed content is added, but it
* includes section headers, is signed by another user or
* otherwise confuses the interpretation engine.
* - unknown-multi-signed-addition: Some signed content is added,
* but it contains multiple signatures.
* - unknown-unsigned-addition: Some content is added, but it is
* unsigned.
* - unknown-subtraction: Some content was removed. These actions are
* not currently analysed.
* - unknown-change: Some content was replaced with other content.
* These actions are not currently analysed.
* - unknown: Unrecognised change type.
*/
static function interpretDiff( $changes, $user, Title $title = null ) {
// One extra item in $changes for _info
$actions = array();
foreach ( $changes as $index => $change ) {
if ( !is_numeric( $index ) ) {
continue;
}
if ( !$change['action'] ) {
// Unknown action; skip
continue;
}
if ( $change['action'] == 'add' ) {
$content = trim( $change['content'] );
// The \A means the regex must match at the begining of the string.
// This is slightly different than ^ which matches begining of each
// line in multiline mode.
$startSection = preg_match( "/\A" . self::HEADER_REGEX . '/um', $content );
$sectionCount = self::getSectionCount( $content );
$signedUsers = array_keys( self::extractSignatures( $content, $title ) );
if (
count( $signedUsers ) == 1 &&
in_array( $user, $signedUsers )
) {
if ( $sectionCount === 0 ) {
$fullSection = self::getFullSection( $changes['_info']['rhs'], $change['right-pos'] );
$actions[] = array(
'type' => 'add-comment',
'content' => $content,
'full-section' => $fullSection,
);
} elseif ( $startSection && $sectionCount === 1 ) {
$actions[] = array(
'type' => 'new-section-with-comment',
'content' => $content,
);
} else {
$actions[] = array(
'type' => 'unknown-signed-addition',
'content' => $content,
);
}
} elseif ( count( $signedUsers ) >= 1 ) {
$actions[] = array(
'type' => 'unknown-multi-signed-addition',
'content' => $content,
);
} else {
$actions[] = array(
'type' => 'unknown-unsigned-addition',
'content' => $content,
);
}
} elseif ( $change['action'] == 'subtract' ) {
$actions[] = array(
'type' => 'unknown-subtraction',
'content' => $change['content'],
);
} elseif ( $change['action'] == 'change' ) {
$actions[] = array(
'type' => 'unknown-change',
'old_content' => $change['old_content'],
'new_content' => $change['new_content'],
);
} else {
$actions[] = array(
'type' => 'unknown',
'details' => $change,
);
}
}
// $actions['_diff'] = $changes;
// unset( $actions['_diff']['_info'] );
return $actions;
}
/**
* Finds the section that a given line is in.
*
* @param $lines Array of lines in the page.
* @param $offset int The line to find the full section for.
* @return string Content of the section.
*/
static function getFullSection( $lines, $offset ) {
$content = $lines[$offset - 1];
$headerRegex = '/' . self::HEADER_REGEX . '/um';
// Expand backwards...
$continue = !preg_match( $headerRegex, $lines[$offset - 1] );
$i = $offset - 1;
while ( $continue && $i > 0 ) {
--$i;
$line = $lines[$i];
$content = "$line\n$content";
if ( preg_match( $headerRegex, $line ) ) {
$continue = false;
}
}
// And then forwards...
$continue = true;
$i = $offset - 1;
while ( $continue && $i < count( $lines ) - 1 ) {
++$i;
$line = $lines[$i];
if ( preg_match( $headerRegex, $line ) ) {
$continue = false;
} else {
$content .= "\n$line";
}
}
return trim( $content, "\n" );
}
/**
* Gets the number of section headers in a string.
*
* @param $text string The text.
* @return int Number of section headers found.
*/
static function getSectionCount( $text ) {
$text = trim( $text );
$matches = array();
preg_match_all( '/' . self::HEADER_REGEX . '/um', $text, $matches );
return count( $matches[0] );
}
/**
* Gets the title of a section or sub section
*
* @param $text string The text of the section.
* @return string The title of the section.
*/
static function extractHeader( $text ) {
$text = trim( $text );
$matches = array();
if ( !preg_match_all( '/' . self::HEADER_REGEX . '/um', $text, $matches ) ) {
return false;
}
return trim( end( $matches[2] ) );
}
/**
* Strips out a signature if possible.
*
* @param $text string The wikitext to strip
* @param Title $title
* @return string
*/
static function stripSignature( $text, Title $title = null ) {
$output = self::getUserFromLine( $text, $title );
if ( $output === false ) {
$timestampPos = self::getTimestampPosition( $text );
return substr( $text, 0, $timestampPos );
}
// Use truncate() instead of truncateHTML() because truncateHTML()
// would not strip signature if the text contains < or &
global $wgContLang;
return $wgContLang->truncate( $text, $output[0], '' );
}
/**
* Strips unnecessary indentation and so on from comments
*
* @param $text string The text to strip from
* @return string Stripped wikitext
*/
static function stripIndents( $text ) {
// First strip all indentation from the beginning of lines
$text = preg_replace( '/^\s*\:+/m', '', $text );
// Now if there is only one list item, strip that too
$listRegex = '/^\s*(?:[\:#*]\s*)*[#*]/m';
$matches = array();
if ( preg_match_all( $listRegex, $text, $matches ) ) {
if ( count( $matches ) == 1 ) {
$text = preg_replace( $listRegex, '', $text );
}
}
return $text;
}
/**
* Strips out a section header
* @param $text string The text to strip out the section header from.
* @return string: The same text, with the section header stripped out.
*/
static function stripHeader( $text ) {
$text = preg_replace( '/' . self::HEADER_REGEX . '/um', '', $text );
return $text;
}
/**
* Determines whether the input is a signed comment.
*
* @param $text string The text to check.
* @param $user User|bool If set, will only return true if the comment is
* signed by this user.
* @param Title $title
* @return bool: true or false.
*/
static function isSignedComment( $text, $user = false, Title $title = null ) {
$userData = self::getUserFromLine( $text, $title );
if ( $userData === false ) {
return false;
} elseif ( $user === false ) {
return true;
}
list( , $foundUser ) = $userData;
return User::getCanonicalName( $foundUser, false ) === User::getCanonicalName( $user, false );
}
/**
* Finds the start position, if any, of the timestamp on a line
*
* @param $line string The line to search for a signature on
* @return int|bool Integer position
*/
static function getTimestampPosition( $line ) {
$timestampRegex = self::getTimestampRegex();
$endOfLine = self::getLineEndingRegex();
$tsMatches = array();
if ( !preg_match(
"/$timestampRegex$endOfLine/mu",
$line,
$tsMatches,
PREG_OFFSET_CAPTURE
) ) {
return false;
}
return $tsMatches[0][1];
}
/**
* Finds differences between $oldText and $newText
* and returns the result in a machine-readable format.
*
* @param $oldText string The "left hand side" of the diff.
* @param $newText string The "right hand side" of the diff.
* @throws MWException
* @return Array of changes.
* Each change consists of:
* * An 'action', one of:
* - add
* - subtract
* - change
* * 'content' that was added or removed, or in the case
* of a change, 'old_content' and 'new_content'
* * 'left_pos' and 'right_pos' (in lines) of the change.
*/
static function getMachineReadableDiff( $oldText, $newText ) {
if ( !isset( self::$diffParser ) ) {
self::$diffParser = new EchoDiffParser;
}
return self::$diffParser->getChangeSet( $oldText, $newText );
}
/**
* Finds and extracts signatures in $text
*
* @param $text string The text in which to look for signed comments.
* @param Title $title
* @return array. Associative array, the key is the username, the value
* is the last signature that was found.
*/
static function extractSignatures( $text, Title $title = null ) {
$lines = explode( "\n", $text );
$output = array();
$lineNumber = 0;
foreach ( $lines as $line ) {
++$lineNumber;
// Look for the last user link on the line.
$userData = self::getUserFromLine( $line, $title );
if ( $userData === false ) {
// print "F\t$lineNumber\t$line\n";
continue;
} else {
// print "S\t$lineNumber\n";
}
list( $signaturePos, $user ) = $userData;
$signature = substr( $line, $signaturePos );
$output[$user] = $signature;
}
return $output;
}
/**
* From a line in the signature, extract all the users linked to
*
* @param string $line Line of text potentially including linked user, user talk,
* and contribution pages
* @return array Array of users; empty array for none detected
*/
static public function extractUsersFromLine( $line ) {
/*
* Signatures can look like anything (as defined by i18n messages
* "signature" & "signature-anon").
* A signature can, e.g., be both a link to user & user-talk page.
*
*/
// match all title-like excerpts in this line
if ( !preg_match_all( '/\[\[([^\[]+)\]\]/', $line, $matches ) ) {
return array();
}
$matches = $matches[1];
$usernames = array();
foreach ( $matches as $match ) {
/*
* Create an object out of the link title.
* In theory, links can be [[text]], [[text|text]] or pipe tricks
* [[text|]] or [[|text]].
* In the case of reverse pipe trick, the value we use *could* be
* empty, but Parser::pstPass2 should have normalized that for us
* already.
*/
$match = explode( '|', $match );
$title = Title::newFromText( $match[0] );
// figure out if we the link is related to a user
if ( $title && ( $title->getNamespace() === NS_USER || $title->getNamespace() === NS_USER_TALK ) ) {
$usernames[] = $title->getText();
} elseif ( $title && $title->isSpecial( 'Contributions' ) ) {
$parts = explode( '/', $title->getText(), 2 );
$usernames[] = end( $parts );
} else {
// move on to next matched title-like excerpt
continue;
}
}
return $usernames;
}
/**
* From a line in a wiki page, determine which user, if any,
* has signed it.
*
* @param string $line The line.
* @param Title $title
* @return bool|array false for none, Array for success.
* - First element is the position of the signature.
* - Second element is the normalised user name.
*/
static public function getUserFromLine( $line, Title $title = null ) {
global $wgParser;
/*
* First we call extractUsersFromLine to get all the potential usernames
* from the line. Then, we loop backwards through them, figure out which
* match to a user, regenera the signature based on that user, and
* see if it matches!
*/
$usernames = self::extractUsersFromLine( $line );
$usernames = array_reverse( $usernames );
foreach ( $usernames as $username ) {
// generate (dateless) signature from the user we think we've
// discovered the signature from
// don't validate the username - anon (IP) is fine!
$user = User::newFromName( $username, false );
$sig = $wgParser->preSaveTransform( '~~~', $title ?: Title::newMainPage(), $user, new ParserOptions() );
// see if we can find this user's generated signature in the content
$pos = strrpos( $line, $sig );
if ( $pos !== false ) {
return array( $pos, $username );
}
// couldn't find sig, move on to next link excerpt and try there
}
// couldn't find any matching signature
return false;
}
/**
* Find the last link beginning with a given prefix on a line.
*
* @param $line string The line to search.
* @param $linkPrefix string The prefix to search for.
* @param $failureOffset bool
* @return bool false for failure, array for success.
* - First element is the string offset of the link.
* - Second element is the user the link refers to.
*/
static function getLinkFromLine( $line, $linkPrefix, $failureOffset = false ) {
$offset = 0;
// If extraction failed at another offset, try again.
if ( $failureOffset !== false ) {
$offset = $failureOffset - strlen( $line ) - 1;
}
// Avoid PHP warning: Offset is greater than the length of haystack string
if ( abs( $offset ) > strlen( $line ) ) {
return false;
}
$linkPos = strripos( $line, $linkPrefix, $offset );
if ( $linkPos === false ) {
// print "I\tNo match for $linkPrefix\n";
return false;
}
$linkUser = self::extractUserFromLink( $line, $linkPrefix, $linkPos );
if ( $linkUser === false ) {
// print "E\tExtraction failed\t$linkPrefix\n";
// Look for another place.
return self::getLinkFromLine( $line, $linkPrefix, $linkPos );
} else {
return array( $linkPos, $linkUser );
}
}
/**
* Given text including a link, gives the user that that link refers to
*
* @param $text string The text to extract from.
* @param $prefix string The link prefix that was used to find the link.
* @param $offset int Optionally, the offset of the start of the link.
* @return bool|string Type description
*/
static function extractUserFromLink( $text, $prefix, $offset = 0 ) {
$userPart = substr( $text, strlen( $prefix ) + $offset );
$userMatches = array();
if ( !preg_match(
'/^[^\|\]\#]+/u',
$userPart,
$userMatches
) ) {
// user link is invalid
// print "I\tUser link invalid\t$userPart\n";
// print "E\tCannot find user info to extract\n";
return false;
}
$user = $userMatches[0];
if (
!User::isIP( $user ) &&
User::getCanonicalName( $user ) === false
) {
// Not a real username
// print "E\tInvalid username\n";
return false;
}
return User::getCanonicalName( $userMatches[0], false );
}
/**
* Gets a regular expression fragmentmatching characters that
* can appear in a line after the signature.
*
* @return String regular expression fragment.
*/
static function getLineEndingRegex() {
$ignoredEndings = array(
'\s*',
preg_quote( '}' ),
preg_quote( '{' ),
'\<[^\>]+\>',
preg_quote( '{{' ) . '[^}]+' . preg_quote( '}}' ),
);
$regex = '(?:' . implode( '|', $ignoredEndings ) . ')*';
return $regex;
}
/**
* Gets a regular expression that will match this wiki's
* timestamps as given by ~~~~.
*
* @throws MWException
* @return String regular expression fragment.
*/
static function getTimestampRegex() {
if ( self::$timestampRegex !== null ) {
return self::$timestampRegex;
}
// Step 1: Get an exemplar timestamp
$title = Title::newMainPage();
$user = User::newFromName( 'Test' );
$options = new ParserOptions;
global $wgParser;
$exemplarTimestamp =
$wgParser->preSaveTransform( '~~~~~', $title, $user, $options );
// Step 2: Generalise it
// Trim off the timezone to replace at the end
$output = $exemplarTimestamp;
$tzRegex = '/\s*\(\w+\)\s*$/';
$tzMatches = array();
if ( preg_match( $tzRegex, $output, $tzMatches ) ) {
$output = preg_replace( $tzRegex, '', $output );
}
$output = preg_quote( $output, '/' );
$output = preg_replace( '/[^\d\W]+/u', '[^\d\W]+', $output );
$output = preg_replace( '/\d+/u', '\d+', $output );
if ( $tzMatches ) {
$output .= preg_quote( $tzMatches[0] );
}
if ( !preg_match( "/$output/u", $exemplarTimestamp ) ) {
throw new MWException( "Timestamp regex does not match exemplar" );
}
self::$timestampRegex = $output;
return $output;
}
/**
* This function returns plain text snippet, it also removes html tag,
* template from text content
* @param $text string
* @param $length int default 150
* @return string
*/
static function getTextSnippet( $text, $length = 150 ) {
global $wgLang;
$text = strip_tags( $text );
$attempt = 0;
// 10 attempts at most, the logic here is to find the first }} and
// find the matching {{ for that }}
while ( $attempt < 10 ) {
$closeCurPos = strpos( $text, '}}' );
if ( $closeCurPos === false ) {
break;
}
$tempStr = substr( $text, 0, $closeCurPos + 2 );
$openCurPos = strrpos( $tempStr, '{{' );
if ( $openCurPos === false ) {
$text = substr_replace( $text, '', $closeCurPos, 2 );
} else {
$text = substr_replace( $text, '', $openCurPos, $closeCurPos - $openCurPos + 2 );
}
$attempt++;
}
// See Parser::parse() function, &#160; is replaced specifically, replace it back here
// with a space as this html entity won't be handled by htmlspecialchars_decode()
$text = str_replace( '&#160;', ' ', MessageCache::singleton()->parse( $text )->getText() );
$text = trim( strip_tags( htmlspecialchars_decode( $text ) ) );
// strip out non-useful data for snippet
$text = str_replace( array( '{', '}' ), '', $text );
$text = $wgLang->truncate( $text, $length );
// Return empty string if there is undecoded char left
if ( strpos( $text, '&#' ) !== false ) {
$text = '';
}
return $text;
}
}