mediawiki-extensions-RSS/RSSParser.php

458 lines
13 KiB
PHP

<?php
class RSSParser {
protected $maxheads = 32;
protected $reversed = false;
protected $highlight = array();
protected $filter = array();
protected $filterOut = array();
protected $itemTemplate;
protected $url;
protected $etag;
protected $lastModified;
protected $xml;
protected $error;
protected $displayFields = array( 'author', 'title', 'encodedContent', 'description' );
public $client;
/**
* Convenience function that takes a space-separated string and returns an array of words
* @param $str String: list of words
* @return Array words found
*/
private static function explodeOnSpaces( $str ) {
$found = preg_split( '# +#', $str );
return is_array( $found ) ? $found : array();
}
/**
* Take a bit of WikiText that looks like
* <rss max=5>http://example.com/</rss>
* and return an object that can produce rendered output.
*/
function __construct( $url, $args ) {
$this->url = $url;
# Get max number of headlines from argument-array
if ( isset( $args['max'] ) ) {
$this->maxheads = $args['max'];
}
# Get reverse flag from argument array
if ( isset( $args['reverse'] ) ) {
$this->reversed = true;
}
# Get date format from argument array
# FIXME: not used yet
if ( isset( $args['date'] ) ) {
$this->date = $args['date'];
}
# Get highlight terms from argument array
if ( isset( $args['highlight'] ) ) {
# mapping to lowercase here so the regex can be case insensitive below.
$this->highlight = self::explodeOnSpaces( $args['highlight'] );
}
# Get filter terms from argument array
if ( isset( $args['filter'] ) ) {
$this->filter = self::explodeOnSpaces( $args['filter'] );
}
if ( isset( $args['filterout'] ) ) {
$this->filterOut = self::explodeOnSpaces( $args['filterout'] );
}
if ( isset( $args['template'] ) ) {
$titleObject = Title::newFromText( $args['template'], NS_TEMPLATE );
$article = new Article( $titleObject, 0 );
$this->itemTemplate = $article->fetchContent();
} else {
$templateName = isset( $args['templatename'] ) ? $args['templatename'] : 'RSSPost';
$this->itemTemplate = wfMsgNoTrans( 'rss-item', $templateName );
}
}
/**
* Return RSS object for the given URL, maintaining caching.
*
* NOTES ON RETRIEVING REMOTE FILES:
* No attempt will be made to fetch remote files if there is something in cache.
*
* NOTES ON FAILED REQUESTS:
* If there is an HTTP error while fetching an RSS object, the cached version
* will be returned, if it exists.
*
* @return Status object
*/
function fetch() {
if ( !isset( $this->url ) ) {
return Status::newFatal( 'rss-fetch-nourl' );
}
// Flow
// 1. check cache
// 2. if there is a hit, make sure its fresh
// 3. if cached obj fails freshness check, fetch remote
// 4. if remote fails, return stale object, or error
$key = wfMemcKey( 'rss', $this->url );
$cachedFeed = $this->loadFromCache( $key );
if ( $cachedFeed !== false ) {
wfDebugLog( 'RSS', 'Outputting cached feed for ' . $this->url );
return Status::newGood();
}
wfDebugLog( 'RSS', 'Cache Failed, fetching ' . $this->url . ' from remote.' );
$status = $this->fetchRemote( $key );
return $status;
}
/**
* Retrieve the URL from the cache
* @param $key String: lookup key to associate with this item
* @return boolean
*/
protected function loadFromCache( $key ) {
global $wgMemc, $wgRSSCacheCompare;
$data = $wgMemc->get( $key );
if ( !is_array( $data ) ) {
return false;
}
list( $etag, $lastModified, $rss ) =
$data;
if ( !isset( $rss->items ) ) {
return false;
}
wfDebugLog( 'RSS', "Got '$key' from cache" );
# Now that we've verified that we got useful data, keep it around.
$this->rss = $rss;
$this->etag = $etag;
$this->lastModified = $lastModified;
// We only care if $wgRSSCacheCompare is > 0
if ( $wgRSSCacheCompare && time() - $wgRSSCacheCompare > $lastModified ) {
wfDebugLog( 'RSS', 'Content is old enough that we need to check cached content' );
return false;
}
return true;
}
/**
* Store these objects (i.e. etag, lastModified, and RSS) in the cache.
* @param $key String: lookup key to associate with this item
* @return boolean
*/
protected function storeInCache( $key ) {
global $wgMemc, $wgRSSCacheAge;
if ( !isset( $this->rss ) ) {
return false;
}
$r = $wgMemc->set( $key,
array( $this->etag, $this->lastModified, $this->rss ),
$wgRSSCacheAge );
wfDebugLog( 'RSS', "Stored '$key' as in cache? $r");
return true;
}
/**
* Retrieve a feed.
* @param $key String:
* @param $headers Array: headers to send along with the request
* @return Status object
*/
protected function fetchRemote( $key, array $headers = array()) {
global $wgRSSFetchTimeout, $wgRSSUserAgent, $wgRSSProxy;
if ( $this->etag ) {
wfDebugLog( 'RSS', 'Used etag: ' . $this->etag );
$headers['If-None-Match'] = $this->etag;
}
if ( $this->lastModified ) {
$lm = gmdate( 'r', $this->lastModified );
wfDebugLog( 'RSS', "Used last modified: $lm" );
$headers['If-Modified-Since'] = $lm;
}
$client = HttpRequest::factory( $this->url, array(
'timeout' => $wgRSSFetchTimeout,
'proxy' => $wgRSSProxy
) );
$client->setUserAgent( $wgRSSUserAgent );
foreach ( $headers as $header => $value ) {
$client->setHeader( $header, $value );
}
$fetch = $client->execute();
$this->client = $client;
if ( !$fetch->isGood() ) {
wfDebug( 'RSS', 'Request Failed: ' . $fetch->getWikiText() );
return $fetch;
}
$ret = $this->responseToXML( $key );
return $ret;
}
/**
* Render the entire feed so that each item is passed to the
* template which the MediaWiki then displays.
*
* @param $parser the parser param to pass to recursiveTagParse()
* @param $frame the frame param to pass to recursiveTagParse()
*/
function renderFeed( $parser, $frame ) {
$output = '';
if ( isset( $this->itemTemplate ) ) {
$headcnt = 0;
if ( $this->reversed ) {
$this->rss->items = array_reverse( $this->rss->items );
}
foreach ( $this->rss->items as $item ) {
if ( $this->maxheads > 0 && $headcnt >= $this->maxheads ) {
continue;
}
if ( $this->canDisplay( $item ) ) {
$output .= $this->renderItem( $item, $parser, $frame );
$headcnt++;
}
}
}
return $output;
}
/**
* Render each item, filtering it out if necessary, applying any highlighting.
*
* @param $item Array: an array produced by RSSData where keys are the
* names of the RSS elements
* @param $parser Parser the parser param to pass to recursiveTagParse()
* @param $frame the frame param to pass to recursiveTagParse()
*/
protected function renderItem( $item, $parser, $frame ) {
$output = "";
if ( isset( $parser ) && isset( $frame ) ) {
$rendered = $this->itemTemplate;
// $info will only be an XML element name, so we're safe
// using it. $item[$info] is handled by the XML parser --
// and that means bad RSS with stuff like
// <description><script>alert("hi")</script></description> will find its
// rogue <script> tags neutered.
foreach ( array_keys( $item ) as $info ) {
if ( $info != 'link' ) {
$txt = $this->highlightTerms( $this->escapeTemplateParameter( $item[ $info ] ) );
} else {
$txt = $this->sanitizeUrl( $item[ $info ] );
}
$rendered = str_replace( '{{{' . $info . '}}}', $txt, $rendered );
}
$output = $parser->recursiveTagParse( $rendered, $frame );
}
return $output;
}
/**
* Sanitize a URL for inclusion in wikitext. Escapes characters that have
* a special meaning in wikitext, replacing them with URL escape codes, so
* that arbitrary input can be included as a free or bracketed external
* link and both work and be safe.
*/
protected function sanitizeUrl( $url ) {
# Remove control characters
$url = preg_replace( '/[\000-\037\177]/', '', $url );
# Escape other problematic characters
$i = 0;
$out = '';
for ( $i = 0; $i < strlen( $url ); $i++ ) {
$boringLength = strcspn( $url, '<>"[|]\ {', $i );
if ( $boringLength ) {
$out .= substr( $url, $i, $boringLength );
$i += $boringLength;
}
if ( $i < strlen( $url ) ) {
$out .= rawurlencode( $url[$i] );
}
}
return $out;
}
/**
* Sanitize user input for inclusion as a template parameter.
* Unlike in wfEscapeWikiText() as of r77127, this escapes }} in addition
* to the other kinds of markup, to avoid user input ending a template
* invocation.
*/
protected function escapeTemplateParameter( $text ) {
return str_replace(
array( '[', '|', ']', '\'', 'ISBN ',
'RFC ', '://', "\n=", '{{', '}}' ),
array( '&#91;', '&#124;', '&#93;', '&#39;', 'ISBN&#32;',
'RFC&#32;', '&#58;//', "\n&#61;", '&#123;&#123;', '&#125;&#125;' ),
htmlspecialchars( $text )
);
}
/**
* Parse an HTTP response object into an array of relevant RSS data
*
* @param $key String: the key to use to store the parsed response in the cache
* @return parsed RSS object (see RSSParse) or false
*/
protected function responseToXML( $key ) {
wfDebugLog( 'RSS', "Got '" . $this->client->getStatus() . "', updating cache for $key" );
if ( $this->client->getStatus() === 304 ) {
# Not modified, update cache
wfDebugLog( 'RSS', "Got 304, updating cache for $key" );
$this->storeInCache( $key );
} else {
$this->xml = new DOMDocument;
$raw_xml = $this->client->getContent();
if( $raw_xml == '' ) {
return Status::newFatal( 'rss-parse-error', 'No XML content' );
}
wfSuppressWarnings();
$this->xml->loadXML( $raw_xml );
wfRestoreWarnings();
$this->rss = new RSSData( $this->xml );
// if RSS parsed successfully
if ( $this->rss && !$this->rss->error ) {
$this->etag = $this->client->getResponseHeader( 'Etag' );
$this->lastModified =
strtotime( $this->client->getResponseHeader( 'Last-Modified' ) );
wfDebugLog( 'RSS', 'Stored etag (' . $this->etag . ') and Last-Modified (' .
$this->client->getResponseHeader( 'Last-Modified' ) . ') and items (' .
count( $this->rss->items ) . ')!' );
$this->storeInCache( $key );
} else {
return Status::newFatal( 'rss-parse-error', $this->rss->error );
}
}
return Status::newGood();
}
/**
* Determine if a given item should or should not be displayed
*
* @param $item Array: associative array that RSSData produced for an <item>
* @return boolean
*/
protected function canDisplay( array $item ) {
$check = '';
/* We're only going to check the displayable fields */
foreach ( $this->displayFields as $field ) {
if ( isset( $item[$field] ) ) {
$check .= $item[$field];
}
}
if ( $this->filter( $check, 'filterOut' ) ) {
return false;
}
if ( $this->filter( $check, 'filter' ) ) {
return true;
}
return false;
}
/**
* Filters items in or out if the match a string we're looking for.
*
* @param $text String: the text to examine
* @param $filterType String: "filterOut" to check for matches in the
* filterOut member list.
* Otherwise, uses the filter member list.
* @return Boolean: decision to filter or not.
*/
protected function filter( $text, $filterType ) {
if ( $filterType === 'filterOut' ) {
$filter = $this->filterOut;
} else {
$filter = $this->filter;
}
if ( count( $filter ) == 0 ) {
return $filterType !== 'filterOut';
}
/* Using : for delimiter here since it'll be quoted automatically. */
$match = preg_match( ':(' . implode( '|', array_map( 'preg_quote', $filter ) ) . '):i', $text ) ;
if ( $match ) {
return true;
}
return false;
}
/**
* Highlight the words we're supposed to be looking for
*
* @param $text String: the text to look in.
* @return String with matched text highlighted in a <span> element
*/
protected function highlightTerms( $text ) {
if ( count( $this->highlight ) === 0 ) {
return $text;
}
RSSHighlighter::setTerms( $this->highlight );
$highlight = ':'. implode( '|', array_map( 'preg_quote', array_values( $this->highlight ) ) ) . ':i';
return preg_replace_callback( $highlight, 'RSSHighlighter::highlightThis', $text );
}
}
class RSSHighlighter {
static $terms = array();
/**
* Set the list of terms to match for the next highlighting session
* @param $terms Array: list of words to match.
*/
static function setTerms( array $terms ) {
self::$terms = array_flip( array_map( 'strtolower', $terms ) );
}
/**
* Actually replace the supplied list of words with HTML code to highlight the words.
* @param $match Array: list of matched words to highlight.
* The words are assigned colors based upon the order
* they were supplied in setTerms()
* @return String word wrapped in HTML code.
*/
static function highlightThis( $match ) {
$styleStart = "<span style='font-weight: bold; background: none repeat scroll 0%% 0%% rgb(%s); color: %s;'>";
$styleEnd = '</span>';
# bg colors cribbed from Google's highlighting of search terms
$bgcolor = array( '255, 255, 102', '160, 255, 255', '153, 255, 153',
'255, 153, 153', '255, 102, 255', '136, 0, 0', '0, 170, 0', '136, 104, 0',
'0, 70, 153', '153, 0, 153' );
# Spelling out the fg colors instead of using processing time to create this list
$color = array( 'black', 'black', 'black', 'black', 'black',
'white', 'white', 'white', 'white', 'white' );
$index = self::$terms[strtolower( $match[0] )] % count( $bgcolor );
return sprintf( $styleStart, $bgcolor[$index], $color[$index] ) . $match[0] . $styleEnd;
}
}