MDL-16263 A way for students to flag/bookmark, particular questions during a quiz attempt for later review.

This is an initial implementation that is now at a working state, but with a few things left to do. It seemed like a good idea to commit it before leaving work on Friday night.

question/preview.php

@@ -68,10 +68,13 @@
         $quiz->review = $CFG->quiz_review;
         require_login($courseid, false);
         $quiz->course = $courseid;
+        $context = get_context_instance(CONTEXT_COURSE, $courseid);
     } else if (!$quiz = $DB->get_record('quiz', array('id' => $quizid))) {
         print_error('invalidquizid', 'quiz', '', $quizid);
     } else {
-        require_login($quiz->course, false, get_coursemodule_from_instance('quiz', $quizid, $quiz->course));
+        $cm = get_coursemodule_from_instance('quiz', $quizid, $quiz->course);
+        require_login($quiz->course, false, $cm);
+        $context = get_context_instance(CONTEXT_MODULE, $cm->id);
     }
 
 
@@ -187,7 +190,7 @@
     }
 
     // TODO: should not use quiz-specific function here
-    $options = quiz_get_renderoptions($quiz->review, $curstate);
+    $options = quiz_get_renderoptions($quiz, $attempt, $context, $curstate);
 
     // Fill in the correct responses (unless the question is in readonly mode)
     if ($fillcorrect && !$options->readonly) {

question/qengine.js

@@ -0,0 +1,38 @@
+// This script, and the YUI libraries that it needs, are inluded by
+// the require_js calls in get_html_head_contributions in lib/questionlib.php.
+
+question_flag_changer = {
+    init_flag: function(checkboxid, postdata) {
+        var checkbox = document.getElementById(checkboxid);
+        checkbox.ajaxpostdata = postdata;
+        checkbox.className += ' jsworking';
+        question_flag_changer.update_image(checkbox);
+        YAHOO.util.Event.addListener(checkbox, 'change', this.checkbox_state_change);
+        YAHOO.util.Event.addListener(checkbox, 'focus', 'blur()');
+    },
+
+    checkbox_state_change: function(e) {
+        var checkbox = e.target ? e.target : e.srcElement;
+        question_flag_changer.update_image(checkbox);
+        var postdata = checkbox.ajaxpostdata
+        if (checkbox.checked) {
+            postdata += '&newstate=1'
+        } else {
+            postdata += '&newstate=0'
+        }
+        YAHOO.util.Connect.asyncRequest('POST', qengine_config.wwwroot + '/question/toggleflag.php', null, postdata);
+    },
+
+    update_image: function(checkbox) {
+        var img = document.getElementById(checkbox.id + 'img');
+        if (checkbox.checked) {
+            img.src = qengine_config.pixpath + '/i/flagged.png';
+            img.alt = qengine_config.flaggedalt;
+            img.title = qengine_config.unflagtooltip;
+        } else {
+            img.src = qengine_config.pixpath + '/i/unflagged.png';
+            img.alt = qengine_config.unflaggedalt;
+            img.title = qengine_config.flagtooltip;
+        }
+    }
+};

question/toggleflag.php

@@ -0,0 +1,48 @@
+<?php  // $Id$
+/**
+ * Used by ajax calls to toggle the flagged state of a question in an attempt.
+ * @license http://www.gnu.org/copyleft/gpl.html GNU Public License
+ * @package questionbank
+ */
+
+require_once('../config.php');
+require_once($CFG->libdir.'/questionlib.php');
+
+// Parameters
+$sessionid = required_param('qsid', PARAM_INT);
+$attemptid = required_param('aid', PARAM_INT);
+$questionid = required_param('qid', PARAM_INT);
+$newstate = required_param('newstate', PARAM_BOOL);
+$checksum = required_param('checksum', PARAM_ALPHANUM);
+
+// Check user is logged in.
+require_login();
+
+// Check the sesskey.
+if (!confirm_sesskey()) {
+    echo 'sesskey failure';
+}
+
+// Check the checksum - it is very hard to know who a question session belongs
+// to, so we require that checksum parameter is matches an md5 hash of the 
+// three ids and the users username. Since we are only updating a flag, that
+// probably makes it sufficiently difficult for malicious users to toggle
+// other users flags.
+if ($checksum != md5($attemptid . "_" . $USER->secret . "_" . $questionid . "_" . $sessionid)) {
+    echo 'checksum failure';
+}
+
+// Check that the requested session really exists
+$questionsession = $DB->get_record('question_sessions', array('id' => $sessionid,
+        'attemptid' => $attemptid, 'questionid' => $questionid));
+if (!$questionsession) {
+    echo 'invalid ids';
+}
+
+// Now change state
+if (!question_update_flag($sessionid, $newstate)) {
+    echo 'update failed';
+}
+
+echo 'OK';
+?>

question/type/question.html

@@ -13,7 +13,8 @@
       <div class="grade">
         <?php echo get_string('marks', 'quiz').': '.$grade; ?>
       </div>
-    <?php } ?>
+    <?php }
+    $this->print_question_flag($question, $state, $options->flags); ?>
   </div>
   <div class="content">
     <?php $this->print_question_formulation_and_controls($question, $state, $cmoptions, $options);

question/type/questiontype.php

@@ -879,7 +879,69 @@ class default_questiontype {
         include "$CFG->dirroot/question/type/question.html";
     }
 
-    /*
+    /**
+     * Render the question flag, assuming $flagsoption allows it. You will probably
+     * never need to override this method.
+     *
+     * @param object $question the question
+     * @param object $state its current state
+     * @param integer $flagsoption the option that says whether flags should be displayed.
+     */
+    protected function print_question_flag($question, $state, $flagsoption) {
+        global $CFG;
+        switch ($flagsoption) {
+            case QUESTION_FLAGSSHOWN:
+                $flagcontent = $this->get_question_flag_tag($state->flagged);
+                break;
+            case QUESTION_FLAGSEDITABLE:
+                $id = $question->name_prefix . '_flagged';
+                if ($state->flagged) {
+                    $checked = 'checked="checked" ';
+                } else {
+                    $checked = '';
+                }
+                $qsid = $state->questionsessionid;
+                $aid = $state->attempt;
+                $qid = $state->question;
+                $checksum = question_get_toggleflag_checksum($aid, $qid, $qsid);
+                $postdata = "qsid=$qsid&aid=$aid&qid=$qid&checksum=$checksum&sesskey=" . sesskey();
+                $flagcontent = '<input type="checkbox" id="' . $id . '" name="' . $id .
+                        '" value="1" ' . $checked . ' />' . 
+                        '<label for="' . $id . '">' . $this->get_question_flag_tag(
+                        $state->flagged, $id . 'img') . '</label>' .
+                        "\n" . '<script type="text/javascript">question_flag_changer.init_flag(' .
+                        "'$id', '$postdata');</script>";
+                break;
+            default:
+                $flagcontent = '';
+        }
+        if ($flagcontent) {
+            echo '<div class="questionflag">' . $flagcontent . "</div>\n";
+        }
+    }
+
+    /**
+     * Work out the actual img tag needed for the flag
+     *
+     * @param boolean $flagged whether the question is currently flagged.
+     * @param string $id an id to be added as an attribute to the img (optional). 
+     * @return string the img tag.
+     */
+    protected function get_question_flag_tag($flagged, $id = '') {
+        global $CFG;
+        if ($id) {
+            $id = 'id="' . $id . '" ';
+        }
+        if ($flagged) {
+            $img = 'flagged.png';
+        } else {
+            $img = 'unflagged.png';
+        }
+        return '<img ' . $id . 'src="' . $CFG->pixpath . '/i/' . $img .
+                '" alt="' . get_string('flagthisquestion', 'question') . '" />';
+    }
+
+    /**
      * Print history of responses
      *
      * Used by print_question()