Question formats

Importing or exporting questions

Questions coming from other Moodle courses or from other e-learning systems (i.e. Blackboard, Webct etc.) can be imported in Moodle. Similarlay Moodle offers a process to export questions to other systems in different format ( XML, QTI etc.). The import and export code is mostly written in format.php files located in a directory specific to the type of format files from which the import or export is done.

examples:
- question/format/aiken/format.php
- question/format/blackboard/format.php
- question/format/qti2/format.php
- question/format/xml/format.php

there is a default class qformat_default defined in question/format.php and the process is controlled by

question/import.php
question/export.php

The simplest and most comprehensive import/export type is probably the Moodle XML format. It is worth studying this file (question/format/xml/format.php) along with the parent class (question/format.php) to get an understanding of what is going on. Some other custom formats circumvent the normal rules and structure and should be studied with caution.

Some things to note:

Study the question/format.php file to establish which methods must be overridden.
Each format.php file can support import, export or both indicated by the provide_import() and provide_export() methods
Do not read or write directly to the database, this is handled for you by the parent class
when importing, question objects need to be in a format suitable for use by the questiontype->save_options() method (see question/type/questiontype.php class). The easiest way to get this information is to do a print_r($question); at the start of the save_options() method for the appropriate question type when a question is saved. The imported object must be the same format.
when importing, obtain 'empty' question objects from the defaultquestion() method, which sets all required properties to their default values.
for exporting the $question object is supplied to the format class. Again, print_r($question) can be used to learn the format.

The question/format.php code flow for import

When importing questions

the import.php selects the file and import format
- pass the control to format.php and format/$format/format.php

$format being the selected file format ( Blackboard, XML etc.)

       require("format.php");  // Parent class
       require("format/$format/format.php");
       $classname = "qformat_$format";
       $qformat = new $classname();
       if (! $qformat->importpreprocess($category,$course)) {  // Do anything before that we need to
           error( $txt->importerror ,
                     "$CFG->wwwroot/question/import.php?courseid={$course->id}&category=$category->id");
       }
       if (! $qformat->importprocess($importfile, $params->matchgrades) ) {  // Process the uploaded file
           error( $txt->importerror ,
                 "$CFG->wwwroot/question/import.php?courseid={$course->id}&category=$category->id");
       }
       if (! $qformat->importpostprocess()) {                  // In case anything needs to be done after

format.php call format/$format/format.php (i.e. the the specific format.php)

to read the imput file and return the questions (if any) that are in the imported files

        if (! $questions = $this->readquestions($lines)) {   // Extract all the questions
           notify( get_string('noquestionsinfile','quiz') );
           return false;
       }
       notify( get_string('importingquestions','quiz',count($questions)) );

get list of valid answer grades

        $grades = get_grade_options();
       $gradeoptionsfull = $grades->gradeoptionsfull;

Process some data and store each question

check for answer grades validity (must match fixed list of grades)
store question general parameters DIRECTLY in the dadabase

           $question->category = $this->category->id;
           $question->stamp = make_unique_id_code();  // Set the unique code (not to be changed)
           if (!$question->id = insert_record("question", $question)) {
               error( get_string('cannotinsert','quiz') );
           }
           $this->questionids[] = $question->id;

save the options using the qtype->save_question_options() function

$QTYPES being the different questiontypes (shortanwer,truefalse etc.)

           global $QTYPES;
           $result = $QTYPES[$question->qtype]
                   ->save_question_options($question);

diplay errors or notices

           if (!empty($result->error)) {
               notify($result->error);
               return false;
           }
           if (!empty($result->notice)) {
               notify($result->notice);
               return true;
           }

if noerrors and no notices

Give the question a unique version stamp determined by question_hash()

           set_field('question', 'version', question_hash($question), 'id', $question->id);

Process the next question until the last question in the file

Return to the question or quiz editing.

Documentation

Question formats

Importing or exporting questions

The question/format.php code flow for import

See also