format.php in Quiz 6.5

File

includes/moodle/question/format/xml/format.php

<?php

// $Id$
//

///////////////////////////////////////////////////////////////

// XML import/export
//

//////////////////////////////////////////////////////////////////////////

// Based on default.php, included by ../import.php

/**
 * @package questionbank
 * @subpackage importexport
 */
require_once "{$CFG->libdir}/xmlize.php";
class qformat_xml extends qformat_default {
  function provide_import() {
    return true;
  }
  function provide_export() {
    return true;
  }

  // IMPORT FUNCTIONS START HERE

  /**
   * Translate human readable format name
   * into internal Moodle code number
   * @param string name format name from xml file
   * @return int Moodle format code
   */
  function trans_format($name) {
    $name = trim($name);
    if ($name == 'moodle_auto_format') {
      $id = 0;
    }
    elseif ($name == 'html') {
      $id = 1;
    }
    elseif ($name == 'plain_text') {
      $id = 2;
    }
    elseif ($name == 'wiki_like') {
      $id = 3;
    }
    elseif ($name == 'markdown') {
      $id = 4;
    }
    else {
      $id = 0;

      // or maybe warning required
    }
    return $id;
  }

  /**
   * Translate human readable single answer option
   * to internal code number
   * @param string name true/false
   * @return int internal code number
   */
  function trans_single($name) {
    $name = trim($name);
    if ($name == "false" || !$name) {
      return 0;
    }
    else {
      return 1;
    }
  }

  /**
   * process text string from xml file
   * @param array $text bit of xml tree after ['text']
   * @return string processed text
   */
  function import_text($text) {

    // quick sanity check
    if (empty($text)) {
      return '';
    }
    $data = $text[0]['#'];
    return addslashes(trim($data));
  }

  /**
   * return the value of a node, given a path to the node
   * if it doesn't exist return the default value
   * @param array xml data to read
   * @param array path path to node expressed as array
   * @param mixed default
   * @param bool istext process as text
   * @param string error if set value must exist, return false and issue message if not
   * @return mixed value
   */
  function getpath($xml, $path, $default, $istext = false, $error = '') {
    foreach ($path as $index) {
      if (!isset($xml[$index])) {
        if (!empty($error)) {
          $this
            ->error($error);
          return false;
        }
        else {
          return $default;
        }
      }
      else {
        $xml = $xml[$index];
      }
    }
    if ($istext) {
      if (!is_string($xml)) {
        $this
          ->error(get_string('invalidxml', 'qformat_xml'));
      }
      $xml = addslashes(trim($xml));
    }
    return $xml;
  }

  /**
   * import parts of question common to all types
   * @param $question array question question array from xml tree
   * @return object question object
   */
  function import_headers($question) {

    // get some error strings
    $error_noname = get_string('xmlimportnoname', 'quiz');
    $error_noquestion = get_string('xmlimportnoquestion', 'quiz');

    // this routine initialises the question object
    $qo = $this
      ->defaultquestion();

    // question name
    $qo->name = $this
      ->getpath($question, array(
      '#',
      'name',
      0,
      '#',
      'text',
      0,
      '#',
    ), '', true, $error_noname);
    $qo->questiontext = $this
      ->getpath($question, array(
      '#',
      'questiontext',
      0,
      '#',
      'text',
      0,
      '#',
    ), '', true);
    $qo->questiontextformat = $this
      ->getpath($question, array(
      '#',
      'questiontext',
      0,
      '@',
      'format',
    ), '');
    $qo->image = $this
      ->getpath($question, array(
      '#',
      'image',
      0,
      '#',
    ), $qo->image);
    $image_base64 = $this
      ->getpath($question, array(
      '#',
      'image_base64',
      '0',
      '#',
    ), '');
    if (!empty($image_base64)) {
      $qo->image = $this
        ->importimagefile($qo->image, stripslashes($image_base64));
    }
    $qo->generalfeedback = $this
      ->getpath($question, array(
      '#',
      'generalfeedback',
      0,
      '#',
      'text',
      0,
      '#',
    ), $qo->generalfeedback, true);
    $qo->defaultgrade = $this
      ->getpath($question, array(
      '#',
      'defaultgrade',
      0,
      '#',
    ), $qo->defaultgrade);
    $qo->penalty = $this
      ->getpath($question, array(
      '#',
      'penalty',
      0,
      '#',
    ), $qo->penalty);
    return $qo;
  }

  /**
   * import the common parts of a single answer
   * @param array answer xml tree for single answer
   * @return object answer object
   */
  function import_answer($answer) {
    $fraction = $this
      ->getpath($answer, array(
      '@',
      'fraction',
    ), 0);
    $text = $this
      ->getpath($answer, array(
      '#',
      'text',
      0,
      '#',
    ), '', true);
    $feedback = $this
      ->getpath($answer, array(
      '#',
      'feedback',
      0,
      '#',
      'text',
      0,
      '#',
    ), '', true);
    $ans = null;
    $ans->answer = $text;
    $ans->fraction = $fraction / 100;
    $ans->feedback = $feedback;
    return $ans;
  }

  /**
   * import multiple choice question
   * @param array question question array from xml tree
   * @return object question object
   */
  function import_multichoice($question) {

    // get common parts
    $qo = $this
      ->import_headers($question);

    // 'header' parts particular to multichoice
    $qo->qtype = MULTICHOICE;
    $single = $this
      ->getpath($question, array(
      '#',
      'single',
      0,
      '#',
    ), 'true');
    $qo->single = $this
      ->trans_single($single);
    $shuffleanswers = $this
      ->getpath($question, array(
      '#',
      'shuffleanswers',
      0,
      '#',
    ), 'false');
    $qo->answernumbering = $this
      ->getpath($question, array(
      '#',
      'answernumbering',
      0,
      '#',
    ), 'abc');
    $qo->shuffleanswers = $this
      ->trans_single($shuffleanswers);
    $qo->correctfeedback = $this
      ->getpath($question, array(
      '#',
      'correctfeedback',
      0,
      '#',
      'text',
      0,
      '#',
    ), '', true);
    $qo->partiallycorrectfeedback = $this
      ->getpath($question, array(
      '#',
      'partiallycorrectfeedback',
      0,
      '#',
      'text',
      0,
      '#',
    ), '', true);
    $qo->incorrectfeedback = $this
      ->getpath($question, array(
      '#',
      'incorrectfeedback',
      0,
      '#',
      'text',
      0,
      '#',
    ), '', true);

    // There was a time on the 1.8 branch when it could output an empty answernumbering tag, so fix up any found.
    if (empty($qo->answernumbering)) {
      $qo->answernumbering = 'abc';
    }

    // run through the answers
    $answers = $question['#']['answer'];
    $a_count = 0;
    foreach ($answers as $answer) {
      $ans = $this
        ->import_answer($answer);
      $qo->answer[$a_count] = $ans->answer;
      $qo->fraction[$a_count] = $ans->fraction;
      $qo->feedback[$a_count] = $ans->feedback;
      ++$a_count;
    }
    return $qo;
  }

  /**
   * import cloze type question
   * @param array question question array from xml tree
   * @return object question object
   */
  function import_multianswer($questions) {
    $questiontext = $questions['#']['questiontext'][0]['#']['text'];
    $qo = qtype_multianswer_extract_question($this
      ->import_text($questiontext));

    // 'header' parts particular to multianswer
    $qo->qtype = MULTIANSWER;
    $qo->course = $this->course;
    $qo->generalfeedback = $this
      ->getpath($questions, array(
      '#',
      'generalfeedback',
      0,
      '#',
      'text',
      0,
      '#',
    ), '', true);
    if (!empty($questions)) {
      $qo->name = $this
        ->import_text($questions['#']['name'][0]['#']['text']);
    }
    return $qo;
  }

  /**
   * import true/false type question
   * @param array question question array from xml tree
   * @return object question object
   */
  function import_truefalse($question) {

    // get common parts
    $qo = $this
      ->import_headers($question);

    // 'header' parts particular to true/false
    $qo->qtype = TRUEFALSE;

    // get answer info
    //
    // In the past, it used to be assumed that the two answers were in the file
    // true first, then false. Howevever that was not always true. Now, we
    // try to match on the answer text, but in old exports, this will be a localised
    // string, so if we don't find true or false, we fall back to the old system.
    $first = true;
    $warning = false;
    foreach ($question['#']['answer'] as $answer) {
      $answertext = $this
        ->getpath($answer, array(
        '#',
        'text',
        0,
        '#',
      ), '', true);
      $feedback = $this
        ->getpath($answer, array(
        '#',
        'feedback',
        0,
        '#',
        'text',
        0,
        '#',
      ), '', true);
      if ($answertext != 'true' && $answertext != 'false') {
        $warning = true;
        $answertext = $first ? 'true' : 'false';

        // Old style file, assume order is true/false.
      }
      if ($answertext == 'true') {
        $qo->answer = $answer['@']['fraction'] == 100;
        $qo->correctanswer = $qo->answer;
        $qo->feedbacktrue = $feedback;
      }
      else {
        $qo->answer = $answer['@']['fraction'] != 100;
        $qo->correctanswer = $qo->answer;
        $qo->feedbackfalse = $feedback;
      }
      $first = false;
    }
    if ($warning) {
      $a = new stdClass();
      $a->questiontext = $qo->questiontext;
      $a->answer = get_string($qo->answer ? 'true' : 'false', 'quiz');
      notify(get_string('truefalseimporterror', 'quiz', $a));
    }
    return $qo;
  }

  /**
   * import short answer type question
   * @param array question question array from xml tree
   * @return object question object
   */
  function import_shortanswer($question) {

    // get common parts
    $qo = $this
      ->import_headers($question);

    // header parts particular to shortanswer
    $qo->qtype = SHORTANSWER;

    // get usecase
    $qo->usecase = $this
      ->getpath($question, array(
      '#',
      'usecase',
      0,
      '#',
    ), $qo->usecase);

    // run through the answers
    $answers = $question['#']['answer'];
    $a_count = 0;
    foreach ($answers as $answer) {
      $ans = $this
        ->import_answer($answer);
      $qo->answer[$a_count] = $ans->answer;
      $qo->fraction[$a_count] = $ans->fraction;
      $qo->feedback[$a_count] = $ans->feedback;
      ++$a_count;
    }
    return $qo;
  }

  /**
   * import description type question
   * @param array question question array from xml tree
   * @return object question object
   */
  function import_description($question) {

    // get common parts
    $qo = $this
      ->import_headers($question);

    // header parts particular to shortanswer
    $qo->qtype = DESCRIPTION;
    $qo->defaultgrade = 0;
    $qo->length = 0;
    return $qo;
  }

  /**
   * import numerical type question
   * @param array question question array from xml tree
   * @return object question object
   */
  function import_numerical($question) {

    // get common parts
    $qo = $this
      ->import_headers($question);

    // header parts particular to numerical
    $qo->qtype = NUMERICAL;

    // get answers array
    $answers = $question['#']['answer'];
    $qo->answer = array();
    $qo->feedback = array();
    $qo->fraction = array();
    $qo->tolerance = array();
    foreach ($answers as $answer) {

      // answer outside of <text> is deprecated
      $answertext = trim($this
        ->getpath($answer, array(
        '#',
        0,
      ), ''));
      $qo->answer[] = $this
        ->getpath($answer, array(
        '#',
        'text',
        0,
        '#',
      ), $answertext, true);
      if (empty($qo->answer)) {
        $qo->answer = '*';
      }
      $qo->feedback[] = $this
        ->getpath($answer, array(
        '#',
        'feedback',
        0,
        '#',
        'text',
        0,
        '#',
      ), '', true);
      $qo->tolerance[] = $this
        ->getpath($answer, array(
        '#',
        'tolerance',
        0,
        '#',
      ), 0);

      // fraction as a tag is deprecated
      $fraction = $this
        ->getpath($answer, array(
        '@',
        'fraction',
      ), 0) / 100;
      $qo->fraction[] = $this
        ->getpath($answer, array(
        '#',
        'fraction',
        0,
        '#',
      ), $fraction);

      // deprecated
    }

    // get units array
    $qo->unit = array();
    $units = $this
      ->getpath($question, array(
      '#',
      'units',
      0,
      '#',
      'unit',
    ), array());
    if (!empty($units)) {
      $qo->multiplier = array();
      foreach ($units as $unit) {
        $qo->multiplier[] = $this
          ->getpath($unit, array(
          '#',
          'multiplier',
          0,
          '#',
        ), 1);
        $qo->unit[] = $this
          ->getpath($unit, array(
          '#',
          'unit_name',
          0,
          '#',
        ), '', true);
      }
    }
    return $qo;
  }

  /**
   * import matching type question
   * @param array question question array from xml tree
   * @return object question object
   */
  function import_matching($question) {

    // get common parts
    $qo = $this
      ->import_headers($question);

    // header parts particular to matching
    $qo->qtype = MATCH;
    $qo->shuffleanswers = $this
      ->getpath($question, array(
      '#',
      'shuffleanswers',
      0,
      '#',
    ), 1);

    // get subquestions
    $subquestions = $question['#']['subquestion'];
    $qo->subquestions = array();
    $qo->subanswers = array();

    // run through subquestions
    foreach ($subquestions as $subquestion) {
      $qo->subquestions[] = $this
        ->getpath($subquestion, array(
        '#',
        'text',
        0,
        '#',
      ), '', true);
      $qo->subanswers[] = $this
        ->getpath($subquestion, array(
        '#',
        'answer',
        0,
        '#',
        'text',
        0,
        '#',
      ), '', true);
    }
    return $qo;
  }

  /**
   * import  essay type question
   * @param array question question array from xml tree
   * @return object question object
   */
  function import_essay($question) {

    // get common parts
    $qo = $this
      ->import_headers($question);

    // header parts particular to essay
    $qo->qtype = ESSAY;

    // get feedback
    $qo->feedback = $this
      ->getpath($question, array(
      '#',
      'answer',
      0,
      '#',
      'feedback',
      0,
      '#',
      'text',
      0,
      '#',
    ), '', true);

    // get fraction - <fraction> tag is deprecated
    $qo->fraction = $this
      ->getpath($question, array(
      '@',
      'fraction',
    ), 0) / 100;
    $q0->fraction = $this
      ->getpath($question, array(
      '#',
      'fraction',
      0,
      '#',
    ), $qo->fraction);
    return $qo;
  }
  function import_calculated($question) {

    // import numerical question
    // get common parts
    $qo = $this
      ->import_headers($question);

    // header parts particular to numerical
    $qo->qtype = CALCULATED;

    //CALCULATED;

    // get answers array
    // echo "<pre> question";print_r($question);echo "</pre>";
    $answers = $question['#']['answer'];
    $qo->answers = array();
    $qo->feedback = array();
    $qo->fraction = array();
    $qo->tolerance = array();
    $qo->tolerancetype = array();
    $qo->correctanswerformat = array();
    $qo->correctanswerlength = array();
    $qo->feedback = array();
    foreach ($answers as $answer) {

      // answer outside of <text> is deprecated
      if (!empty($answer['#']['text'])) {
        $answertext = $this
          ->import_text($answer['#']['text']);
      }
      else {
        $answertext = trim($answer['#'][0]);
      }
      if ($answertext == '') {
        $qo->answers[] = '*';
      }
      else {
        $qo->answers[] = $answertext;
      }
      $qo->feedback[] = $this
        ->import_text($answer['#']['feedback'][0]['#']['text']);
      $qo->tolerance[] = $answer['#']['tolerance'][0]['#'];

      // fraction as a tag is deprecated
      if (!empty($answer['#']['fraction'][0]['#'])) {
        $qo->fraction[] = $answer['#']['fraction'][0]['#'];
      }
      else {
        $qo->fraction[] = $answer['@']['fraction'] / 100;
      }
      $qo->tolerancetype[] = $answer['#']['tolerancetype'][0]['#'];
      $qo->correctanswerformat[] = $answer['#']['correctanswerformat'][0]['#'];
      $qo->correctanswerlength[] = $answer['#']['correctanswerlength'][0]['#'];
    }

    // get units array
    $qo->unit = array();
    if (isset($question['#']['units'][0]['#']['unit'])) {
      $units = $question['#']['units'][0]['#']['unit'];
      $qo->multiplier = array();
      foreach ($units as $unit) {
        $qo->multiplier[] = $unit['#']['multiplier'][0]['#'];
        $qo->unit[] = $unit['#']['unit_name'][0]['#'];
      }
    }
    $datasets = $question['#']['dataset_definitions'][0]['#']['dataset_definition'];
    $qo->dataset = array();
    $qo->datasetindex = 0;
    foreach ($datasets as $dataset) {
      $qo->datasetindex++;
      $qo->dataset[$qo->datasetindex] = new stdClass();
      $qo->dataset[$qo->datasetindex]->status = $this
        ->import_text($dataset['#']['status'][0]['#']['text']);
      $qo->dataset[$qo->datasetindex]->name = $this
        ->import_text($dataset['#']['name'][0]['#']['text']);
      $qo->dataset[$qo->datasetindex]->type = $dataset['#']['type'][0]['#'];
      $qo->dataset[$qo->datasetindex]->distribution = $this
        ->import_text($dataset['#']['distribution'][0]['#']['text']);
      $qo->dataset[$qo->datasetindex]->max = $this
        ->import_text($dataset['#']['maximum'][0]['#']['text']);
      $qo->dataset[$qo->datasetindex]->min = $this
        ->import_text($dataset['#']['minimum'][0]['#']['text']);
      $qo->dataset[$qo->datasetindex]->length = $this
        ->import_text($dataset['#']['decimals'][0]['#']['text']);
      $qo->dataset[$qo->datasetindex]->distribution = $this
        ->import_text($dataset['#']['distribution'][0]['#']['text']);
      $qo->dataset[$qo->datasetindex]->itemcount = $dataset['#']['itemcount'][0]['#'];
      $qo->dataset[$qo->datasetindex]->datasetitem = array();
      $qo->dataset[$qo->datasetindex]->itemindex = 0;
      $qo->dataset[$qo->datasetindex]->number_of_items = $dataset['#']['number_of_items'][0]['#'];
      $datasetitems = $dataset['#']['dataset_items'][0]['#']['dataset_item'];
      foreach ($datasetitems as $datasetitem) {
        $qo->dataset[$qo->datasetindex]->itemindex++;
        $qo->dataset[$qo->datasetindex]->datasetitem[$qo->dataset[$qo->datasetindex]->itemindex] = new stdClass();
        $qo->dataset[$qo->datasetindex]->datasetitem[$qo->dataset[$qo->datasetindex]->itemindex]->itemnumber = $datasetitem['#']['number'][0]['#'];

        //[0]['#']['number'][0]['#'] ; // [0]['numberitems'] ;//['#']['number'][0]['#'];// $datasetitems['#']['number'][0]['#'];
        $qo->dataset[$qo->datasetindex]->datasetitem[$qo->dataset[$qo->datasetindex]->itemindex]->value = $datasetitem['#']['value'][0]['#'];

        //$datasetitem['#']['value'][0]['#'];
      }
    }

    // echo "<pre>loaded qo";print_r($qo);echo "</pre>";
    return $qo;
  }

  /**
   * this is not a real question type. It's a dummy type used
   * to specify the import category
   * format is:
   * <question type="category">
   *     <category>tom/dick/harry</category>
   * </question>
   */
  function import_category($question) {
    $qo = new stdClass();
    $qo->qtype = 'category';
    $qo->category = $this
      ->import_text($question['#']['category'][0]['#']['text']);
    return $qo;
  }

  /**
   * parse the array of lines into an array of questions
   * this *could* burn memory - but it won't happen that much
   * so fingers crossed!
   * @param array lines array of lines from the input file
   * @return array (of objects) question objects
   */
  function readquestions($lines) {

    // we just need it as one big string
    $text = implode($lines, " ");
    unset($lines);

    // this converts xml to big nasty data structure
    // the 0 means keep white space as it is (important for markdown format)
    // print_r it if you want to see what it looks like!
    $xml = xmlize($text, 0);

    // set up array to hold all our questions
    $questions = array();

    // iterate through questions
    foreach ($xml['quiz']['#']['question'] as $question) {
      $question_type = $question['@']['type'];
      $questiontype = get_string('questiontype', 'quiz', $question_type);
      if ($question_type == 'multichoice') {
        $qo = $this
          ->import_multichoice($question);
      }
      elseif ($question_type == 'truefalse') {
        $qo = $this
          ->import_truefalse($question);
      }
      elseif ($question_type == 'shortanswer') {
        $qo = $this
          ->import_shortanswer($question);
      }
      elseif ($question_type == 'numerical') {
        $qo = $this
          ->import_numerical($question);
      }
      elseif ($question_type == 'description') {
        $qo = $this
          ->import_description($question);
      }
      elseif ($question_type == 'matching') {
        $qo = $this
          ->import_matching($question);
      }
      elseif ($question_type == 'cloze') {
        $qo = $this
          ->import_multianswer($question);
      }
      elseif ($question_type == 'essay') {
        $qo = $this
          ->import_essay($question);
      }
      elseif ($question_type == 'calculated') {
        $qo = $this
          ->import_calculated($question);
      }
      elseif ($question_type == 'category') {
        $qo = $this
          ->import_category($question);
      }
      else {

        // try for plugin support
        // no default question, as the plugin can call
        // import_headers() itself if it wants to
        if (!($qo = $this
          ->try_importing_using_qtypes($question))) {
          $notsupported = get_string('xmltypeunsupported', 'quiz', $question_type);
          $this
            ->error($notsupported);
          $qo = null;
        }
      }

      // stick the result in the $questions array
      if ($qo) {
        $questions[] = $qo;
      }
    }
    return $questions;
  }

  // EXPORT FUNCTIONS START HERE
  function export_file_extension() {

    // override default type so extension is .xml
    return ".xml";
  }

  /**
   * Turn the internal question code into a human readable form
   * (The code used to be numeric, but this remains as some of
   * the names don't match the new internal format)
   * @param mixed type_id Internal code
   * @return string question type string
   */
  function get_qtype($type_id) {
    switch ($type_id) {
      case TRUEFALSE:
        $name = 'truefalse';
        break;
      case MULTICHOICE:
        $name = 'multichoice';
        break;
      case SHORTANSWER:
        $name = 'shortanswer';
        break;
      case NUMERICAL:
        $name = 'numerical';
        break;
      case MATCH:
        $name = 'matching';
        break;
      case DESCRIPTION:
        $name = 'description';
        break;
      case MULTIANSWER:
        $name = 'cloze';
        break;
      case ESSAY:
        $name = 'essay';
        break;
      case CALCULATED:
        $name = 'calculated';
        break;
      default:
        $name = false;
    }
    return $name;
  }

  /**
   * Convert internal Moodle text format code into
   * human readable form
   * @param int id internal code
   * @return string format text
   */
  function get_format($id) {
    switch ($id) {
      case 0:
        $name = "moodle_auto_format";
        break;
      case 1:
        $name = "html";
        break;
      case 2:
        $name = "plain_text";
        break;
      case 3:
        $name = "wiki_like";
        break;
      case 4:
        $name = "markdown";
        break;
      default:
        $name = "unknown";
    }
    return $name;
  }

  /**
   * Convert internal single question code into
   * human readable form
   * @param int id single question code
   * @return string single question string
   */
  function get_single($id) {
    switch ($id) {
      case 0:
        $name = "false";
        break;
      case 1:
        $name = "true";
        break;
      default:
        $name = "unknown";
    }
    return $name;
  }

  /**
   * generates <text></text> tags, processing raw text therein
   * @param int ilev the current indent level
   * @param boolean short stick it on one line
   * @return string formatted text
   */
  function writetext($raw, $ilev = 0, $short = true) {
    $indent = str_repeat("  ", $ilev);

    // if required add CDATA tags
    if (!empty($raw) and htmlspecialchars($raw) != $raw) {
      $raw = "<![CDATA[{$raw}]]>";
    }
    if ($short) {
      $xml = "{$indent}<text>{$raw}</text>\n";
    }
    else {
      $xml = "{$indent}<text>\n{$raw}\n{$indent}</text>\n";
    }
    return $xml;
  }
  function xmltidy($content) {

    // can only do this if tidy is installed
    if (extension_loaded('tidy')) {
      $config = array(
        'input-xml' => true,
        'output-xml' => true,
        'indent' => true,
        'wrap' => 0,
      );
      $tidy = new tidy();
      $tidy
        ->parseString($content, $config, 'utf8');
      $tidy
        ->cleanRepair();
      return $tidy->value;
    }
    else {
      return $content;
    }
  }
  function presave_process($content) {

    // override method to allow us to add xml headers and footers
    // add the xml headers and footers
    $content = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n" . "<quiz>\n" . $content . "\n" . "</quiz>";

    // make the xml look nice
    $content = $this
      ->xmltidy($content);
    return $content;
  }

  /**
   * Include an image encoded in base 64
   * @param string imagepath The location of the image file
   * @return string xml code segment
   */
  function writeimage($imagepath) {
    global $CFG;
    if (empty($imagepath)) {
      return '';
    }
    $courseid = $this->course->id;
    if (!($binary = file_get_contents("{$CFG->dataroot}/{$courseid}/{$imagepath}"))) {
      return '';
    }
    $content = "    <image_base64>\n" . addslashes(base64_encode($binary)) . "\n" . "\n    </image_base64>\n";
    return $content;
  }

  /**
   * Turns question into an xml segment
   * @param array question question array
   * @return string xml segment
   */
  function writequestion($question) {
    global $CFG, $QTYPES;

    // initial string;
    $expout = "";

    // add comment
    $expout .= "\n\n<!-- question: {$question->id}  -->\n";

    // check question type
    if (!($question_type = $this
      ->get_qtype($question->qtype))) {

      // must be a plugin then, so just accept the name supplied
      $question_type = $question->qtype;
    }

    // add opening tag
    // generates specific header for Cloze and category type question
    if ($question->qtype == 'category') {
      $categorypath = $this
        ->writetext($question->category);
      $expout .= "  <question type=\"category\">\n";
      $expout .= "    <category>\n";
      $expout .= "        {$categorypath}\n";
      $expout .= "    </category>\n";
      $expout .= "  </question>\n";
      return $expout;
    }
    elseif ($question->qtype != MULTIANSWER) {

      // for all question types except Close
      $name_text = $this
        ->writetext($question->name);
      $qtformat = $this
        ->get_format($question->questiontextformat);
      $question_text = $this
        ->writetext($question->questiontext);
      $generalfeedback = $this
        ->writetext($question->generalfeedback);
      $expout .= "  <question type=\"{$question_type}\">\n";
      $expout .= "    <name>{$name_text}</name>\n";
      $expout .= "    <questiontext format=\"{$qtformat}\">\n";
      $expout .= $question_text;
      $expout .= "    </questiontext>\n";
      $expout .= "    <image>{$question->image}</image>\n";
      $expout .= $this
        ->writeimage($question->image);
      $expout .= "    <generalfeedback>\n";
      $expout .= $generalfeedback;
      $expout .= "    </generalfeedback>\n";
      $expout .= "    <defaultgrade>{$question->defaultgrade}</defaultgrade>\n";
      $expout .= "    <penalty>{$question->penalty}</penalty>\n";
      $expout .= "    <hidden>{$question->hidden}</hidden>\n";
    }
    else {

      // for Cloze type only
      $name_text = $this
        ->writetext($question->name);
      $question_text = $this
        ->writetext($question->questiontext);
      $generalfeedback = $this
        ->writetext($question->generalfeedback);
      $expout .= "  <question type=\"{$question_type}\">\n";
      $expout .= "    <name>{$name_text}</name>\n";
      $expout .= "    <questiontext>\n";
      $expout .= $question_text;
      $expout .= "    </questiontext>\n";
      $expout .= "    <generalfeedback>\n";
      $expout .= $generalfeedback;
      $expout .= "    </generalfeedback>\n";
    }
    if (!empty($question->options->shuffleanswers)) {
      $expout .= "    <shuffleanswers>{$question->options->shuffleanswers}</shuffleanswers>\n";
    }
    else {
      $expout .= "    <shuffleanswers>0</shuffleanswers>\n";
    }

    // output depends on question type
    switch ($question->qtype) {
      case 'category':

        // not a qtype really - dummy used for category switching
        break;
      case TRUEFALSE:
        foreach ($question->options->answers as $answer) {
          $fraction_pc = round($answer->fraction * 100);
          if ($answer->id == $question->options->trueanswer) {
            $answertext = 'true';
          }
          else {
            $answertext = 'false';
          }
          $expout .= "    <answer fraction=\"{$fraction_pc}\">\n";
          $expout .= $this
            ->writetext($answertext, 3) . "\n";
          $expout .= "      <feedback>\n";
          $expout .= $this
            ->writetext($answer->feedback, 4, false);
          $expout .= "      </feedback>\n";
          $expout .= "    </answer>\n";
        }
        break;
      case MULTICHOICE:
        $expout .= "    <single>" . $this
          ->get_single($question->options->single) . "</single>\n";
        $expout .= "    <shuffleanswers>" . $this
          ->get_single($question->options->shuffleanswers) . "</shuffleanswers>\n";
        $expout .= "    <correctfeedback>" . $this
          ->writetext($question->options->correctfeedback, 3) . "</correctfeedback>\n";
        $expout .= "    <partiallycorrectfeedback>" . $this
          ->writetext($question->options->partiallycorrectfeedback, 3) . "</partiallycorrectfeedback>\n";
        $expout .= "    <incorrectfeedback>" . $this
          ->writetext($question->options->incorrectfeedback, 3) . "</incorrectfeedback>\n";
        $expout .= "    <answernumbering>{$question->options->answernumbering}</answernumbering>\n";
        foreach ($question->options->answers as $answer) {
          $percent = $answer->fraction * 100;
          $expout .= "      <answer fraction=\"{$percent}\">\n";
          $expout .= $this
            ->writetext($answer->answer, 4, false);
          $expout .= "      <feedback>\n";
          $expout .= $this
            ->writetext($answer->feedback, 5, false);
          $expout .= "      </feedback>\n";
          $expout .= "    </answer>\n";
        }
        break;
      case SHORTANSWER:
        $expout .= "    <usecase>{$question->options->usecase}</usecase>\n ";
        foreach ($question->options->answers as $answer) {
          $percent = 100 * $answer->fraction;
          $expout .= "    <answer fraction=\"{$percent}\">\n";
          $expout .= $this
            ->writetext($answer->answer, 3, false);
          $expout .= "      <feedback>\n";
          $expout .= $this
            ->writetext($answer->feedback, 4, false);
          $expout .= "      </feedback>\n";
          $expout .= "    </answer>\n";
        }
        break;
      case NUMERICAL:
        foreach ($question->options->answers as $answer) {
          $tolerance = $answer->tolerance;
          $percent = 100 * $answer->fraction;
          $expout .= "<answer fraction=\"{$percent}\">\n";

          // <text> tags are an added feature, old filed won't have them
          $expout .= "    <text>{$answer->answer}</text>\n";
          $expout .= "    <tolerance>{$tolerance}</tolerance>\n";
          $expout .= "    <feedback>" . $this
            ->writetext($answer->feedback) . "</feedback>\n";

          // fraction tag is deprecated
          // $expout .= "    <fraction>{$answer->fraction}</fraction>\n";
          $expout .= "</answer>\n";
        }
        $units = $question->options->units;
        if (count($units)) {
          $expout .= "<units>\n";
          foreach ($units as $unit) {
            $expout .= "  <unit>\n";
            $expout .= "    <multiplier>{$unit->multiplier}</multiplier>\n";
            $expout .= "    <unit_name>{$unit->unit}</unit_name>\n";
            $expout .= "  </unit>\n";
          }
          $expout .= "</units>\n";
        }
        break;
      case MATCH:
        foreach ($question->options->subquestions as $subquestion) {
          $expout .= "<subquestion>\n";
          $expout .= $this
            ->writetext($subquestion->questiontext);
          $expout .= "<answer>" . $this
            ->writetext($subquestion->answertext) . "</answer>\n";
          $expout .= "</subquestion>\n";
        }
        break;
      case DESCRIPTION:

        // nothing more to do for this type
        break;
      case MULTIANSWER:
        $a_count = 1;
        foreach ($question->options->questions as $question) {
          $thispattern = addslashes("{#" . $a_count . "}");
          $thisreplace = $question->questiontext;
          $expout = ereg_replace($thispattern, $thisreplace, $expout);
          $a_count++;
        }
        break;
      case ESSAY:
        if (!empty($question->options->answers)) {
          foreach ($question->options->answers as $answer) {
            $percent = 100 * $answer->fraction;
            $expout .= "<answer fraction=\"{$percent}\">\n";
            $expout .= "    <feedback>" . $this
              ->writetext($answer->feedback) . "</feedback>\n";

            // fraction tag is deprecated
            // $expout .= "    <fraction>{$answer->fraction}</fraction>\n";
            $expout .= "</answer>\n";
          }
        }
        break;
      case CALCULATED:
        foreach ($question->options->answers as $answer) {
          $tolerance = $answer->tolerance;
          $tolerancetype = $answer->tolerancetype;
          $correctanswerlength = $answer->correctanswerlength;
          $correctanswerformat = $answer->correctanswerformat;
          $percent = 100 * $answer->fraction;
          $expout .= "<answer fraction=\"{$percent}\">\n";

          // "<text/>" tags are an added feature, old files won't have them
          $expout .= "    <text>{$answer->answer}</text>\n";
          $expout .= "    <tolerance>{$tolerance}</tolerance>\n";
          $expout .= "    <tolerancetype>{$tolerancetype}</tolerancetype>\n";
          $expout .= "    <correctanswerformat>{$correctanswerformat}</correctanswerformat>\n";
          $expout .= "    <correctanswerlength>{$correctanswerformat}</correctanswerlength>\n";
          $expout .= "    <feedback>" . $this
            ->writetext($answer->feedback) . "</feedback>\n";
          $expout .= "</answer>\n";
        }
        $units = $question->options->units;
        if (count($units)) {
          $expout .= "<units>\n";
          foreach ($units as $unit) {
            $expout .= "  <unit>\n";
            $expout .= "    <multiplier>{$unit->multiplier}</multiplier>\n";
            $expout .= "    <unit_name>{$unit->unit}</unit_name>\n";
            $expout .= "  </unit>\n";
          }
          $expout .= "</units>\n";
        }

        //echo "<pre> question calc";print_r($question);echo "</pre>";

        //First, we a new function to get all the   data itmes in the database

        //   $question_datasetdefs =$QTYPES['calculated']->get_datasets_for_export ($question);
        //    echo "<pre> question defs";print_r($question_datasetdefs);echo "</pre>";

        //If there are question_datasets
        if (isset($question->options->datasets) && count($question->options->datasets)) {

          // there should be
          $expout .= "<dataset_definitions>\n";
          foreach ($question->options->datasets as $def) {
            $expout .= "<dataset_definition>\n";
            $expout .= "    <status>" . $this
              ->writetext($def->status) . "</status>\n";
            $expout .= "    <name>" . $this
              ->writetext($def->name) . "</name>\n";
            $expout .= "    <type>calculated</type>\n";
            $expout .= "    <distribution>" . $this
              ->writetext($def->distribution) . "</distribution>\n";
            $expout .= "    <minimum>" . $this
              ->writetext($def->minimum) . "</minimum>\n";
            $expout .= "    <maximum>" . $this
              ->writetext($def->maximum) . "</maximum>\n";
            $expout .= "    <decimals>" . $this
              ->writetext($def->decimals) . "</decimals>\n";
            $expout .= "    <itemcount>{$def->itemcount}</itemcount>\n";
            if ($def->itemcount > 0) {
              $expout .= "    <dataset_items>\n";
              foreach ($def->items as $item) {
                $expout .= "        <dataset_item>\n";
                $expout .= "           <number>" . $item->itemnumber . "</number>\n";
                $expout .= "           <value>" . $item->value . "</value>\n";
                $expout .= "        </dataset_item>\n";
              }
              $expout .= "    </dataset_items>\n";
              $expout .= "    <number_of_items>" . $def->number_of_items . "</number_of_items>\n";
            }
            $expout .= "</dataset_definition>\n";
          }
          $expout .= "</dataset_definitions>\n";
        }
        break;
      default:

        // try support by optional plugin
        if (!($data = $this
          ->try_exporting_using_qtypes($question->qtype, $question))) {
          notify(get_string('unsupportedexport', 'qformat_xml', $QTYPES[$question->qtype]
            ->menu_name()));
        }
        $expout .= $data;
    }

    // close the question tag
    $expout .= "</question>\n";
    return $expout;
  }

}

Classes

Name	Description
qformat_xml