MediaWiki 1.11.0

[autoinstallsdev/mediawiki.git] / includes / LinkFilter.php

diff --git a/includes/LinkFilter.php b/includes/LinkFilter.php
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+<?php
+
+/**
+ * Some functions to help implement an external link filter for spam control.
+ * 
+ * TODO: implement the filter. Currently these are just some functions to help
+ * maintenance/cleanupSpam.php remove links to a single specified domain. The
+ * next thing is to implement functions for checking a given page against a big
+ * list of domains.
+ *
+ * Another cool thing to do would be a web interface for fast spam removal.
+ */
+class LinkFilter {
+       /**
+        * @static
+        */
+       static function matchEntry( $text, $filterEntry ) {
+               $regex = LinkFilter::makeRegex( $filterEntry );
+               return preg_match( $regex, $text );
+       }
+
+       /**
+        * @static
+        */
+       private static function makeRegex( $filterEntry ) {
+               $regex = '!http://';
+               if ( substr( $filterEntry, 0, 2 ) == '*.' ) {
+                       $regex .= '(?:[A-Za-z0-9.-]+\.|)';
+                       $filterEntry = substr( $filterEntry, 2 );
+               }
+               $regex .= preg_quote( $filterEntry, '!' ) . '!Si';
+               return $regex;
+       }
+
+       /**
+        * Make a string to go after an SQL LIKE, which will match the specified
+        * string. There are several kinds of filter entry:
+        *     *.domain.com    -  Produces http://com.domain.%, matches domain.com
+        *                        and www.domain.com
+        *     domain.com      -  Produces http://com.domain./%, matches domain.com
+        *                        or domain.com/ but not www.domain.com
+        *     *.domain.com/x  -  Produces http://com.domain.%/x%, matches
+        *                        www.domain.com/xy
+        *     domain.com/x    -  Produces http://com.domain./x%, matches
+        *                        domain.com/xy but not www.domain.com/xy
+        *
+        * Asterisks in any other location are considered invalid.
+        * 
+        * @static
+        * @param $filterEntry String: domainparts
+        * @param $prot        String: protocol
+        */
+        public static function makeLike( $filterEntry , $prot = 'http://' ) {
+               if ( substr( $filterEntry, 0, 2 ) == '*.' ) {
+                       $subdomains = true;
+                       $filterEntry = substr( $filterEntry, 2 );
+                       if ( $filterEntry == '' ) {
+                               // We don't want to make a clause that will match everything,
+                               // that could be dangerous
+                               return false;
+                       }
+               } else {
+                       $subdomains = false;
+               }
+               // No stray asterisks, that could cause confusion
+               // It's not simple or efficient to handle it properly so we don't
+               // handle it at all.
+               if ( strpos( $filterEntry, '*' ) !== false ) {
+                       return false;
+               }
+               $slash = strpos( $filterEntry, '/' );
+               if ( $slash !== false ) {
+                       $path = substr( $filterEntry, $slash );
+                       $host = substr( $filterEntry, 0, $slash );
+               } else {
+                       $path = '/';
+                       $host = $filterEntry;
+               }
+               // Reverse the labels in the hostname, convert to lower case
+               // For emails reverse domainpart only
+               if ( $prot == 'mailto:' && strpos($host, '@') ) {
+                       // complete email adress 
+                       $mailparts = explode( '@', $host );
+                       $domainpart = strtolower( implode( '.', array_reverse( explode( '.', $mailparts[1] ) ) ) );
+                       $host = $domainpart . '@' . $mailparts[0];
+                       $like = "$prot$host%";
+               } elseif ( $prot == 'mailto:' ) {
+                       // domainpart of email adress only. do not add '.'
+                       $host = strtolower( implode( '.', array_reverse( explode( '.', $host ) ) ) );   
+                       $like = "$prot$host%";                  
+               } else {
+                       $host = strtolower( implode( '.', array_reverse( explode( '.', $host ) ) ) );   
+                       if ( substr( $host, -1, 1 ) !== '.' ) {
+                               $host .= '.';
+                       }
+                       $like = "$prot$host";
+
+                       if ( $subdomains ) {
+                               $like .= '%';
+                       }
+                       if ( !$subdomains || $path !== '/' ) {
+                               $like .= $path . '%';
+                       }
+               }
+               return $like;
+       }
+}
+