mediawiki-extensions-Confir.../FancyCaptcha.php
2007-06-29 01:36:09 +00:00

261 lines
7 KiB
PHP

<?php
/**
* Experimental image-based captcha plugin, using images generated by an
* external tool.
*
* Copyright (C) 2005, 2006 Brion Vibber <brion@pobox.com>
* http://www.mediawiki.org/
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
* http://www.gnu.org/copyleft/gpl.html
*
* @addtogroup Extensions
*/
if ( defined( 'MEDIAWIKI' ) ) {
global $wgCaptchaDirectory;
$wgCaptchaDirectory = "$wgUploadDirectory/captcha"; // bad default :D
global $wgCaptchaDirectoryLevels;
$wgCaptchaDirectoryLevels = 0; // To break into subdirectories
global $wgCaptchaSecret;
$wgCaptchaSecret = "CHANGE_THIS_SECRET!";
$wgExtensionFunctions[] = 'efFancyCaptcha';
function efFancyCaptcha() {
global $wgMessageCache;
require_once( dirname( __FILE__ ) . '/FancyCaptcha.i18n.php' );
foreach( efFancyCaptchaMessages() as $lang => $messages )
$wgMessageCache->addMessages( $messages, $lang );
}
class FancyCaptcha extends SimpleCaptcha {
/**
* Check if the submitted form matches the captcha session data provided
* by the plugin when the form was generated.
*
* @param WebRequest $request
* @param array $info
* @return bool
*/
function keyMatch( $request, $info ) {
global $wgCaptchaSecret;
$answer = $request->getVal( 'wpCaptchaWord' );
$digest = $wgCaptchaSecret . $info['salt'] . $answer . $wgCaptchaSecret . $info['salt'];
$answerHash = substr( md5( $digest ), 0, 16 );
if( $answerHash == $info['hash'] ) {
wfDebug( "FancyCaptcha: answer hash matches expected {$info['hash']}\n" );
return true;
} else {
wfDebug( "FancyCaptcha: answer hashes to $answerHash, expected {$info['hash']}\n" );
return false;
}
}
/**
* Insert the captcha prompt into the edit form.
*/
function getForm() {
$info = $this->pickImage();
if( !$info ) {
die( "out of captcha images; this shouldn't happen" );
}
// Generate a random key for use of this captcha image in this session.
// This is needed so multiple edits in separate tabs or windows can
// go through without extra pain.
$index = $this->storeCaptcha( $info );
wfDebug( "Captcha id $index using hash ${info['hash']}, salt ${info['salt']}.\n" );
$title = Title::makeTitle( NS_SPECIAL, 'Captcha/image' );
return "<p>" .
wfElement( 'img', array(
'src' => $title->getLocalUrl( 'wpCaptchaId=' . urlencode( $index ) ),
'width' => $info['width'],
'height' => $info['height'],
'alt' => '' ) ) .
"</p>\n" .
wfElement( 'input', array(
'type' => 'hidden',
'name' => 'wpCaptchaId',
'id' => 'wpCaptchaId',
'value' => $index ) ) .
"<p>" .
wfElement( 'input', array(
'name' => 'wpCaptchaWord',
'id' => 'wpCaptchaWord',
'tabindex' => 1 ) ) . // tab in before the edit textarea
"</p>\n";
}
/**
* Select a previously generated captcha image from the queue.
* @fixme subject to race conditions if lots of files vanish
* @return mixed tuple of (salt key, text hash) or false if no image to find
*/
function pickImage() {
global $wgCaptchaDirectory, $wgCaptchaDirectoryLevels;
return $this->pickImageDir(
$wgCaptchaDirectory,
$wgCaptchaDirectoryLevels );
}
function pickImageDir( $directory, $levels ) {
if( $levels ) {
$dirs = array();
// Check which subdirs are actually present...
$dir = opendir( $directory );
while( false !== ($entry = readdir( $dir ) ) ) {
if( ctype_xdigit( $entry ) && strlen( $entry ) == 1 ) {
$dirs[] = $entry;
}
}
closedir( $dir );
$place = mt_rand( 0, count( $dirs ) - 1 );
// In case all dirs are not filled,
// cycle through next digits...
for( $j = 0; $j < count( $dirs ); $j++ ) {
$char = $dirs[($place + $j) % count( $dirs )];
$return = $this->pickImageDir( "$directory/$char", $levels - 1 );
if( $return ) {
return $return;
}
}
// Didn't find any images in this directory... empty?
return false;
} else {
return $this->pickImageFromDir( $directory );
}
}
function pickImageFromDir( $directory ) {
if( !is_dir( $directory ) ) {
return false;
}
$n = mt_rand( 0, $this->countFiles( $directory ) - 1 );
$dir = opendir( $directory );
$count = 0;
$entry = readdir( $dir );
$pick = false;
while( false !== $entry ) {
$entry = readdir( $dir );
if( preg_match( '/^image_([0-9a-f]+)_([0-9a-f]+)\\.png$/', $entry, $matches ) ) {
$size = getimagesize( "$directory/$entry" );
$pick = array(
'salt' => $matches[1],
'hash' => $matches[2],
'width' => $size[0],
'height' => $size[1],
'viewed' => false,
);
if( $count++ == $n ) {
break;
}
}
}
closedir( $dir );
return $pick;
}
/**
* Count the number of files in a directory.
* @return int
*/
function countFiles( $dirname ) {
$dir = opendir( $dirname );
$count = 0;
while( false !== ($entry = readdir( $dir ) ) ) {
if( $entry != '.' && $entry != '..' ) {
$count++;
}
}
closedir( $dir );
return $count;
}
function showImage() {
global $wgOut, $wgRequest;
$wgOut->disable();
$info = $this->retrieveCaptcha();
if( $info ) {
if( $info['viewed'] ) {
wfHttpError( 403, 'Access Forbidden', "Can't view captcha image a second time." );
return false;
}
$info['viewed'] = wfTimestamp();
$this->storeCaptcha( $info );
$salt = $info['salt'];
$hash = $info['hash'];
$file = $this->imagePath( $salt, $hash );
if( file_exists( $file ) ) {
global $IP;
require_once "$IP/includes/StreamFile.php";
wfStreamFile( $file );
return true;
}
}
wfHttpError( 500, 'Internal Error', 'Requested bogus captcha image' );
return false;
}
function imagePath( $salt, $hash ) {
global $wgCaptchaDirectory, $wgCaptchaDirectoryLevels;
$file = $wgCaptchaDirectory;
$file .= DIRECTORY_SEPARATOR;
for( $i = 0; $i < $wgCaptchaDirectoryLevels; $i++ ) {
$file .= $hash{$i};
$file .= DIRECTORY_SEPARATOR;
}
$file .= "image_{$salt}_{$hash}.png";
return $file;
}
/**
* Show a message asking the user to enter a captcha on edit
* The result will be treated as wiki text
*
* @param $action Action being performed
* @return string
*/
function getMessage( $action ) {
$name = 'fancycaptcha-' . $action;
$text = wfMsg( $name );
# Obtain a more tailored message, if possible, otherwise, fall back to
# the default for edits
return wfEmptyMsg( $name, $text ) ? wfMsg( 'fancycaptcha-edit' ) : $text;
}
}
} # End invocation guard