MDL-63738 question bank: a link to download a single question

lang/en/question.php

@@ -150,6 +150,7 @@
 $string['exporterror'] = 'Errors occur during exporting!';
 $string['exportfilename'] = 'questions';
 $string['exportnameformat'] = '%Y%m%d-%H%M';
+$string['exportonequestion'] = 'Download this question in Moodle XML format';
 $string['exportquestions'] = 'Export questions to file';
 $string['exportquestions_help'] = 'This function enables the export of a complete category (and any subcategories) of questions to file. Please note that, depending on the file format selected, some question data and certain question types may not be exported.';
 $string['exportquestions_link'] = 'question/export';

lib/questionlib.php

@@ -2251,6 +2251,33 @@ function question_make_export_url($contextid, $categoryid, $format, $withcategor
             "/{$withcontexts}/{$filename}", true);
 }
 
+/**
+ * Get the URL to export a single question (exportone.php).
+ *
+ * @param stdClass|question_definition $question the question definition as obtained from
+ *      question_bank::load_question_data() or question_bank::make_question().
+ *      (Only ->id and ->contextid are used.)
+ * @return moodle_url the requested URL.
+ */
+function question_get_export_single_question_url($question) {
+    $params = ['id' => $question->id, 'sesskey' => sesskey()];
+    $context = context::instance_by_id($question->contextid);
+    switch ($context->contextlevel) {
+        case CONTEXT_MODULE:
+            $params['cmid'] = $context->instanceid;
+            break;
+
+        case CONTEXT_COURSE:
+            $params['courseid'] = $context->instanceid;
+            break;
+
+        default:
+            $params['courseid'] = SITEID;
+    }
+
+    return new moodle_url('/question/exportone.php', $params);
+}
+
 /**
  * Return a list of page types
  * @param string $pagetype current page type

lib/tests/questionlib_test.php

@@ -2000,4 +2000,34 @@ public function test_question_categorylist_parents() {
         $this->assertEquals($cat1->id, $parentcategories[1]);
         $this->assertCount(2, $parentcategories);
     }
+
+    public function test_question_get_export_single_question_url() {
+        $generator = $this->getDataGenerator();
+
+        // Create a course and an activity.
+        $course = $generator->create_course();
+        $quiz = $generator->create_module('quiz', ['course' => $course->id]);
+
+        // Create a question in each place.
+        $questiongenerator = $generator->get_plugin_generator('core_question');
+        $courseqcat = $questiongenerator->create_question_category(['contextid' => context_course::instance($course->id)->id]);
+        $courseq = $questiongenerator->create_question('truefalse', null, ['category' => $courseqcat->id]);
+        $quizqcat = $questiongenerator->create_question_category(['contextid' => context_module::instance($quiz->cmid)->id]);
+        $quizq = $questiongenerator->create_question('truefalse', null, ['category' => $quizqcat->id]);
+        $systemqcat = $questiongenerator->create_question_category();
+        $systemq = $questiongenerator->create_question('truefalse', null, ['category' => $systemqcat->id]);
+
+        // Verify some URLs.
+        $this->assertEquals(new moodle_url('/question/exportone.php',
+                ['id' => $courseq->id, 'courseid' => $course->id, 'sesskey' => sesskey()]),
+                question_get_export_single_question_url(question_bank::load_question_data($courseq->id)));
+
+        $this->assertEquals(new moodle_url('/question/exportone.php',
+                ['id' => $quizq->id, 'cmid' => $quiz->cmid, 'sesskey' => sesskey()]),
+                question_get_export_single_question_url(question_bank::load_question($quizq->id)));
+
+        $this->assertEquals(new moodle_url('/question/exportone.php',
+                ['id' => $systemq->id, 'courseid' => SITEID, 'sesskey' => sesskey()]),
+                question_get_export_single_question_url(question_bank::load_question($systemq->id)));
+    }
 }

question/exportone.php

@@ -0,0 +1,79 @@
+<?php
+// This file is part of Stack - http://stack.maths.ed.ac.uk/
+//
+// Stack 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.
+//
+// Stack 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 Stack.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Script to download the export of a single question.
+ *
+ * @copyright 2015 the Open University
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+require_once(__DIR__.'/../config.php');
+
+require_once($CFG->libdir . '/questionlib.php');
+require_once($CFG->dirroot . '/question/format/xml/format.php');
+
+// Get the parameters from the URL.
+$questionid = required_param('id', PARAM_INT);
+$cmid = optional_param('cmid', 0, PARAM_INT);
+$courseid = optional_param('courseid', 0, PARAM_INT);
+$urlparams = ['id' => $questionid, 'sesskey' => sesskey()];
+
+if ($cmid) {
+    $cm = get_coursemodule_from_id(null, $cmid);
+    require_login($cm->course, false, $cm);
+    $thiscontext = context_module::instance($cmid);
+    $urlparams['cmid'] = $cmid;
+} else if ($courseid) {
+    require_login($courseid, false);
+    $thiscontext = context_course::instance($courseid);
+    $urlparams['courseid'] = $courseid;
+} else {
+    print_error('missingcourseorcmid', 'question');
+}
+require_sesskey();
+
+// Load the necessary data.
+$contexts = new question_edit_contexts($thiscontext);
+$questiondata = question_bank::load_question_data($questionid);
+
+// Check permissions.
+question_require_capability_on($questiondata, 'view');
+
+// Initialise $PAGE. Nothing is output, so this does not really matter. Just avoids notices.
+$nexturl = new moodle_url('/question/type/stack/questiontestrun.php', $urlparams);
+$PAGE->set_url('/question/exportone.php', $urlparams);
+$PAGE->set_heading($COURSE->fullname);
+$PAGE->set_pagelayout('admin');
+
+// Set up the export format.
+$qformat = new qformat_xml();
+$filename = question_default_export_filename($COURSE, $questiondata) .
+        $qformat->export_file_extension();
+$qformat->setContexts($contexts->having_one_edit_tab_cap('export'));
+$qformat->setCourse($COURSE);
+$qformat->setQuestions([$questiondata]);
+$qformat->setCattofile(false);
+$qformat->setContexttofile(false);
+
+// Do the export.
+if (!$qformat->exportpreprocess()) {
+    send_file_not_found();
+}
+if (!$content = $qformat->exportprocess(true)) {
+    send_file_not_found();
+}
+send_file($content, $filename, 0, 0, true, true, $qformat->mime_type());

question/preview.php

@@ -274,6 +274,12 @@
 }
 print_collapsible_region_end();
 
+// Output a link to export this single question.
+if (question_has_capability_on($question, 'view')) {
+    echo html_writer::link(question_get_export_single_question_url($question),
+            get_string('exportonequestion', 'question'));
+}
+
 // Display the settings form.
 $optionsform->display();
 

question/tests/behat/preview_question.feature

@@ -78,3 +78,7 @@ Feature: A teacher can preview questions in the question bank
   Scenario: Preview lets the teacher "Fill in correct response" while previewing
     When I press "Fill in correct responses"
     Then the field "Answer:" matches value "3.14"
+
+  @javascript @_switch_window
+  Scenario: Preview has an option to export the individual quesiton.
+    Then following "Download this question in Moodle XML format" should download between "1000" and "2500" bytes