/
moss.php
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/
moss.php
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<?php
///////////////////////////////////////////////////////////////////////////
// //
// NOTICE OF COPYRIGHT //
// //
// Moss Anti-Plagiarism for Moodle //
// https://github.com/hit-moodle/moodle-plagiarism_moss //
// //
// Copyright (C) 2009 onwards Sun Zhigang http://sunner.cn //
// //
// 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 3 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: //
// //
// http://www.gnu.org/copyleft/gpl.html //
// //
///////////////////////////////////////////////////////////////////////////
/**
* Anti-Plagiarism by Moss
*
* @package plagiarism_moss
* @copyright 2011 Sun Zhigang (http://sunner.cn)
* @author Sun Zhigang
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
defined('MOODLE_INTERNAL') || die('Direct access to this script is forbidden.');
require_once($CFG->dirroot.'/plagiarism/moss/locallib.php');
require_once($CFG->dirroot.'/plagiarism/moss/textlib.php');
/**
* moss script interface
*/
class moss {
protected $moss;
protected $tempdir;
public function __construct($cmid) {
global $CFG, $DB, $UNITTEST;
$this->moss = $DB->get_record('plagiarism_moss', array('cmid' => $cmid));
if (!isset($UNITTEST)) { // testcase can not construct course structure
$this->moss->course = $DB->get_field('course_modules', 'course', array('id' => $this->moss->cmid));
}
$this->tempdir = $CFG->dataroot.'/temp/moss/'.$this->moss->id;
remove_dir($this->tempdir); // Perhaps it is not cleaned in previous run
if (!check_dir_exists($this->tempdir)) {
throw new moodle_exception('errorcreatingdirectory', '', '', $this->tempdir);
}
if ($CFG->ostype == 'WINDOWS') {
// the tempdir will be passed to cygwin which require '/' path spliter
$this->tempdir = str_replace('\\', '/', $this->tempdir);
}
}
public function __destruct() {
if (!debugging('', DEBUG_DEVELOPER)) {
remove_dir($this->tempdir);
}
}
protected function get_config($name) {
$value = get_config('plagiarism_moss', $name);
if ($value === false) {
mtrace("\t!!! WARNING !!! - global settings of moss may not proper.");
}
return $value;
}
/**
* Measure the current course module
*
* @return bool success or not
*/
public function measure() {
global $DB;
if (!moss_enabled($this->moss->cmid)) {
return false;
}
$mosses = $DB->get_records_select('plagiarism_moss', 'tag = ? AND tag != 0', array($this->moss->tag));
foreach ($mosses as $moss) {
if ($moss->cmid == $this->moss->cmid) {
// current moss must be extracted lastly
// to overwrite other files belong to the same person
continue;
}
$this->extract_files($moss);
}
$this->extract_files();
$result = $this->call_moss();
$this->moss->timemeasured = time();
$DB->update_record('plagiarism_moss', $this->moss);
return $result;
}
protected function extract_files($moss = null) {
if ($moss == null) {
$moss = $this->moss;
}
$sizelimit = $this->get_config('maxfilesize');
$fs = get_file_storage();
$files = $fs->get_area_files(get_system_context()->id, 'plagiarism_moss', 'files', $moss->cmid, 'sortorder', false);
foreach ($files as $file) {
if ($file->get_filesize() > $sizelimit) {
continue;
}
$content = $this->get_clear_utf8_content($file);
if (empty($content)) {
continue;
}
$path = $this->tempdir.$file->get_filepath();
$fullpath = $path.$file->get_filename();
if (!check_dir_exists($path)) {
throw new moodle_exception('errorcreatingdirectory', '', '', $path);
}
file_put_contents($fullpath, $content);
}
}
/**
* Convert binary files to text and ensure the charset is UTF8
*
* @param object $file moodle storedfile
* @return content or false
*/
protected function get_clear_utf8_content($file) {
$localewincharset = get_string('localewincharset', 'langconfig');
$filen = $file->get_filename();
$file_type = strtolower(substr($filen, strlen($filen)-4, 4));
if (array_search($file_type, array('.pdf', '.rtf', '.odt', '.doc', 'docx'))) {
$temp_file = $this->tempdir."/$filen.tmp";
$file->copy_content_to($temp_file);
switch ($file_type) {
case '.pdf':
$content = pdf2text($temp_file);
break;
case '.rtf':
$content = textlib_get_instance()->entities_to_utf8(rtf2text($temp_file));
break;
case '.odt':
$content = getTextFromZippedXML($temp_file,'content.xml');
break;
case '.doc':
$antiwordpath = $this->get_config('antiwordpath');
$magic = file_get_contents($temp_file, NULL, NULL, -1, 2);
if ($magic === 'PK') {
// It is really a docx
$content = getTextFromZippedXML($temp_file,'word/document.xml');
} else if (empty($antiwordpath) || !is_executable($antiwordpath)) {
$content = textlib_get_instance()->entities_to_utf8(doc2text($temp_file));
} else {
$content = shell_exec($antiwordpath.' -f -w 0 '.escapeshellarg($temp_file));
if (empty($content)) { // antiword can not recognize this file
$content = textlib_get_instance()->entities_to_utf8(doc2text($temp_file));
}
}
break;
case 'docx':
$content = getTextFromZippedXML($temp_file,'word/document.xml');
break;
}
unlink($temp_file);
return $this->wordwrap($content, 80);
}
// Files no need to covert format go here
$content = $file->get_content();
if (!mb_check_encoding($content, 'UTF-8')) {
if (mb_check_encoding($content, $localewincharset)) {
// Convert content charset to UTF-8
$content = textlib_get_instance()->convert($content, $localewincharset);
} else {
// Unknown charset, possible binary file. Skip it
mtrace("\tSkip unknown charset/binary file ".$file->get_filepath().$file->get_filename());
return false;
}
}
return $content;
}
/**
* Auto wordwarp text
*/
protected function wordwrap($text, $width) {
$i = 0;
$return = '';
$linelen = 0;
$prev_ch = '';
while (($ch = mb_substr($text, $i, 1, 'UTF-8')) !== '') {
if ($linelen >= $width and (!ctype_alnum($prev_ch) or ctype_space($ch))) { // Do not break latin words
$return .= "\n";
$linelen = 0;
}
if ($linelen != 0 or !ctype_space($ch)) { // trim heading whitespaces
$return .= $ch;
$linelen += mb_strwidth($ch, 'UTF-8'); // Multy-byte chars may twice the width
}
if ($ch === "\n") {
$linelen = 0;
}
$i++;
$prev_ch = $ch;
}
return $return;
}
/**
* this function will call moss script and save anti-plagiarism results
*
* @return sucessful true or failed false
*/
protected function call_moss() {
global $CFG, $DB;
$commands = $this->get_commands();
if(empty($commands)) {
mtrace("\tNo valid config to run");
return false;
}
//delete previous results
$this->clean_results();
//connect moss server and save results
foreach($commands as $configid => $cmd) {
$descriptorspec = array(
0 => array('pipe', 'r'), // stdin
1 => array('pipe', 'w'), // stdout
2 => array('pipe', 'w') // stderr
);
$proc = proc_open($cmd, $descriptorspec, $pipes);
if (!is_resource($proc)) {
mtrace("\tCall moss failed.");
return false;
}
//get standard output and standard error output
$out = stream_get_contents($pipes[1]);
$err = stream_get_contents($pipes[2]);
$rval = proc_close($proc);
if ($rval != 0) {
mtrace($out);
mtrace($err);
return false;
}
mtrace(substr_count($out, 'done').' files are uploaded.');
$url_p = '/http:\/\/moss\.stanford\.edu\/results\/\d+/';
if (!preg_match($url_p, $out, $match)) {
mtrace($out);
mtrace($err);
return false;
}
$url = $match[0].'/'; // Some curl do not process 301. Add a tailing / to prevent 301 from moss
if (!$this->save_results($url, $configid)) {
return false;
}
}
return true;
}
/**
* Return commands of moss for all configs
*
* @return array
*/
protected function get_commands() {
global $CFG, $DB;
$settings = $DB->get_records('plagiarism_moss_configs', array('moss' => $this->moss->id));
$fs = get_file_storage();
$context = get_system_context();
$cmds = array();
foreach($settings as $setting) {
if (empty($setting->filepatterns)) { // no filepatterns means invalid
continue;
}
if ($CFG->ostype == 'WINDOWS') {
$cygwin = $this->get_config('cygwinpath');
$perl = $cygwin.'\\bin\\perl.exe';
$mossscrpit = $CFG->dirroot.'\\plagiarism\\moss\\moss';
$cmd = str_replace(' ', '\\ ', $CFG->dirroot.'\\plagiarism\\moss\\moss.bat');
$cmd .= ' "'.$perl.'" "'.$mossscrpit.'"';
} else {
$cmd = '"'.$CFG->dirroot.'/plagiarism/moss/moss'.'"';
}
$cmd .= ' -d';
$cmd .= ' -u '.escapeshellarg($this->get_config('mossuserid'));
$cmd .= ' -l '.escapeshellarg($setting->language);
if (!empty($this->moss->sensitivity)) {
$cmd .= ' -m '.escapeshellarg($this->moss->sensitivity);
}
$basefiles = $fs->get_area_files($context->id, 'plagiarism_moss', 'basefiles', $setting->id, 'filename', false);
foreach ($basefiles as $basefile) {
$realpath = $this->tempdir.'/'.$setting->id.'_'.$basefile->get_filename();
$basefile->copy_content_to($realpath);
$cmd .= ' -b '.escapeshellarg($realpath);
}
$filepatterns = explode(' ', $setting->filepatterns);
foreach ($filepatterns as $filepattern) {
$cmd .= ' '.str_replace(' ', '\\ ', $this->tempdir.'/*/'.$filepattern);
}
if (debugging('', DEBUG_DEVELOPER)) {
mtrace("\t".$cmd);
}
$cmds[$setting->id] = $cmd;
}
return $cmds;
}
/**
* Parse moss result page and store to DB
*
* @param string $url moss result page url
* @param int $configid
* @return true or false
*/
protected function save_results($url, $configid) {
global $DB, $UNITTEST;
mtrace("\tProcessing $url");
if (!$result_page = download_file_content($url)) {
mtrace("\tcan not read $url");
return false;
}
preg_match_all(
'/(?P<link>http:\/\/moss\.stanford\.edu\/results\/\d+\/match\d+\.html)">.+\/(?P<user1>\d+)\/ \((?P<percentage1>\d+)%\).+\/(?P<user2>\d+)\/ \((?P<percentage2>\d+)%\).+right>(?P<linesmatched>\d+)\\n/Us',
$result_page,
$matches,
PREG_SET_ORDER
);
if (!isset($UNITTEST)) { // testcase can not construct course structure
$context = get_context_instance(CONTEXT_COURSE, $this->moss->course);
}
$filepatterns = $DB->get_field('plagiarism_moss_configs', 'filepatterns', array('id' => $configid));
$filepatterns = explode(' ', $filepatterns);
$fs = get_file_storage();
$rank = 0;
foreach ($matches as $result) {
$rank++;
$result['moss'] = $this->moss->id;
$result['config'] = $configid;
$result['rank'] = $rank + 1;
$result1 = (object)$result;
$result1->userid = $result['user1'];
$result1->percentage = $result['percentage1'];
$result2 = (object)$result;
$result2->userid = $result['user2'];
$result2->percentage = $result['percentage2'];
if (!isset($UNITTEST)) { // testcase can not construct course structure
// skip unenrolled users
if (!is_enrolled($context, $result1->userid) and !is_enrolled($context, $result2->userid)) {
continue;
}
}
$result1->id = $DB->insert_record('plagiarism_moss_results', $result1);
$result2->pair = $result1->id;
$result2->id = $DB->insert_record('plagiarism_moss_results', $result2);
$result1->pair = $result2->id;
$DB->update_record('plagiarism_moss_results', $result1);
// update moss_matchedfiles db
for ($i=1; $i<=2; $i++) {
$userid = eval('return $result'.$i.'->userid;');
$resultid = eval('return $result'.$i.'->id;');
$files = $fs->get_directory_files(get_system_context()->id, 'plagiarism_moss', 'files', $this->moss->cmid, "/$userid/");
foreach ($files as $file) {
foreach ($filepatterns as $pattern) {
if (fnmatch($pattern, $file->get_filename())) {
$obj = new stdClass();
$obj->result = $resultid;
$obj->contenthash = $file->get_contenthash();
$DB->insert_record('plagiarism_moss_matchedfiles', $obj);
}
}
}
}
}
mtrace("\tGot $rank pairs");
return true;
}
/**
* Clean current stored results
*/
protected function clean_results() {
global $DB;
$sql = 'DELETE FROM {plagiarism_moss_matchedfiles}
WHERE result in (
SELECT id FROM {plagiarism_moss_results}
WHERE moss = ?
)';
$DB->execute($sql, array($this->moss->id));
$DB->delete_records('plagiarism_moss_results', array('moss' => $this->moss->id));
//TODO: remove cached pages
}
}