diff --git a/question/type/opaque/backup/moodle2/backup_qtype_opaque_plugin.class.php b/question/type/opaque/backup/moodle2/backup_qtype_opaque_plugin.class.php
index 4d435abf183..371fba89d2d 100644
--- a/question/type/opaque/backup/moodle2/backup_qtype_opaque_plugin.class.php
+++ b/question/type/opaque/backup/moodle2/backup_qtype_opaque_plugin.class.php
@@ -60,14 +60,16 @@ class backup_qtype_opaque_plugin extends backup_qtype_plugin {
         $engine->add_child($server);
 
         // set source to populate the data
-        $opaque->set_source_table('question_opaque', array('questionid' => backup::VAR_PARENTID));
+        $opaque->set_source_table('question_opaque',
+                array('questionid' => backup::VAR_PARENTID));
         $engine->set_source_sql('
                 SELECT e.*
                 FROM {question_opaque_engines} e
                 JOIN {question_opaque} qo ON qo.engineid = e.id
                 WHERE qo.id = ?',
                 array(backup::VAR_PARENTID));
-        $server->set_source_table('question_opaque_servers', array('engineid' => backup::VAR_PARENTID));
+        $server->set_source_table('question_opaque_servers',
+                array('engineid' => backup::VAR_PARENTID));
 
         return $plugin;
     }
diff --git a/question/type/opaque/backup/moodle2/restore_qtype_opaque_plugin.class.php b/question/type/opaque/backup/moodle2/restore_qtype_opaque_plugin.class.php
index d8f87d2565f..ea0d6ff5429 100644
--- a/question/type/opaque/backup/moodle2/restore_qtype_opaque_plugin.class.php
+++ b/question/type/opaque/backup/moodle2/restore_qtype_opaque_plugin.class.php
@@ -65,7 +65,8 @@ class restore_qtype_opaque_plugin extends restore_qtype_plugin {
             }
         }
         if (empty($engine->questionengines)) {
-            throw new coding_exception('Missing question engine URLs in an Opaque question backup.');
+            throw new coding_exception(
+                    'Missing question engine URLs in an Opaque question backup.');
         }
 
         // Detect if the question is created or mapped
diff --git a/question/type/opaque/edit_engine_form.php b/question/type/opaque/edit_engine_form.php
index 83ae2a70184..7e450e21219 100644
--- a/question/type/opaque/edit_engine_form.php
+++ b/question/type/opaque/edit_engine_form.php
@@ -28,7 +28,7 @@
 defined('MOODLE_INTERNAL') || die();
 
 require_once($CFG->libdir . '/formslib.php');
-include_once($CFG->libdir . '/validateurlsyntax.php');
+require_once($CFG->libdir . '/validateurlsyntax.php');
 
 
 /**
@@ -42,16 +42,18 @@ class qtype_opaque_engine_edit_form extends moodleform {
         $mform = $this->_form;
 
         $mform->addElement('text', 'enginename', get_string('enginename', 'qtype_opaque'));
-        $mform->addRule('enginename', get_string('missingenginename', 'qtype_opaque'), 'required', null, 'client');
+        $mform->addRule('enginename', get_string('missingenginename', 'qtype_opaque'),
+                'required', null, 'client');
         $mform->setType('enginename', PARAM_MULTILANG);
 
-        $mform->addElement('textarea', 'questionengineurls', get_string('questionengineurls', 'qtype_opaque'),
-                'rows="5" cols="80"');
-        $mform->addRule('questionengineurls', get_string('missingengineurls', 'qtype_opaque'), 'required', null, 'client');
+        $mform->addElement('textarea', 'questionengineurls',
+                get_string('questionengineurls', 'qtype_opaque'), 'rows="5" cols="80"');
+        $mform->addRule('questionengineurls', get_string('missingengineurls', 'qtype_opaque'),
+                'required', null, 'client');
         $mform->setType('questionengineurls', PARAM_RAW);
 
-        $mform->addElement('textarea', 'questionbankurls', get_string('questionbankurls', 'qtype_opaque'),
-                'rows="5" cols="80"');
+        $mform->addElement('textarea', 'questionbankurls',
+                get_string('questionbankurls', 'qtype_opaque'), array('rows' => 5, 'cols' => 80));
         $mform->setType('questionbankurls', PARAM_RAW);
 
         $mform->addElement('text', 'passkey', get_string('passkey', 'qtype_opaque'));
@@ -65,7 +67,8 @@ class qtype_opaque_engine_edit_form extends moodleform {
     }
 
     /**
-     * Validate the contents of a textarea field, which should be a newline-separated list of URLs.
+     * Validate the contents of a textarea field, which should be a
+     * newline-separated list of URLs.
      *
      * @param $data the form data.
      * @param $field the field to validate.
@@ -82,7 +85,8 @@ class qtype_opaque_engine_edit_form extends moodleform {
     }
 
     /**
-     * Extract the contents of a textarea field, which should be a newline-separated list of URLs.
+     * Extract the contents of a textarea field, which should be a
+     * newline-separated list of URLs.
      *
      * @param $data the form data.
      * @param $field the field to extract.
diff --git a/question/type/opaque/edit_opaque_form.php b/question/type/opaque/edit_opaque_form.php
index dbf31d6f1e5..9bdb2e66953 100644
--- a/question/type/opaque/edit_opaque_form.php
+++ b/question/type/opaque/edit_opaque_form.php
@@ -58,12 +58,14 @@ class qtype_opaque_edit_form extends question_edit_form {
         $mform->addRule('engineid', null, 'required', null, 'client');
         $mform->addHelpButton('engineid', 'questionengine', 'qtype_opaque');
 
-        $mform->addElement('text', 'remoteid', get_string('questionid', 'qtype_opaque'), array('size' => 50));
+        $mform->addElement('text', 'remoteid',
+                get_string('questionid', 'qtype_opaque'), array('size' => 50));
         $mform->setType('remoteid', PARAM_RAW);
         $mform->addRule('remoteid', null, 'required', null, 'client');
         $mform->addHelpButton('remoteid', 'questionid', 'qtype_opaque');
 
-        $mform->addElement('text', 'remoteversion', get_string('questionversion', 'qtype_opaque'), array('size' => 3));
+        $mform->addElement('text', 'remoteversion',
+                get_string('questionversion', 'qtype_opaque'), array('size' => 3));
         $mform->setType('remoteversion', PARAM_RAW);
         $mform->addRule('remoteversion', null, 'required', null, 'client');
     }
@@ -91,13 +93,16 @@ class qtype_opaque_edit_form extends question_edit_form {
         // Try connecting to the remote question engine both as extra validation of the id, and
         // also to get the default grade.
         if ($remoteidok) {
-            $metadata = qtype_opaque_get_question_metadata($engine, $data['remoteid'], $data['remoteversion']);
+            $metadata = qtype_opaque_get_question_metadata($engine,
+                    $data['remoteid'], $data['remoteversion']);
             if (is_string($metadata)) {
                 $errors['remoteid'] = $metadata;
-            } else if (!isset($metadata['questionmetadata']['#']['scoring'][0]['#']['marks'][0]['#'])) {
+            } else if (!isset($metadata['questionmetadata']['#']['scoring']
+                    [0]['#']['marks'][0]['#'])) {
                 $errors['remoteid'] = get_string('maxgradenotreturned');
             } else {
-                $this->_defaultmark = $metadata['questionmetadata']['#']['scoring'][0]['#']['marks'][0]['#'];
+                $this->_defaultmark = $metadata['questionmetadata']['#']['scoring']
+                        [0]['#']['marks'][0]['#'];
             }
         }
 
@@ -105,8 +110,8 @@ class qtype_opaque_edit_form extends question_edit_form {
     }
 
     public function get_data($slashed = true) {
-        // We override get_data to to add the defaultmark, which was determined during validation,
-        // to the data that is returned.
+        // We override get_data to to add the defaultmark, which was determined
+        // during validation, to the data that is returned.
         $data = parent::get_data($slashed);
         if (is_object($data) && isset($this->_defaultmark)) {
             $data->defaultmark = $this->_defaultmark;
diff --git a/question/type/opaque/editengine.php b/question/type/opaque/editengine.php
index 67e4e565e26..5b41a9f03af 100644
--- a/question/type/opaque/editengine.php
+++ b/question/type/opaque/editengine.php
@@ -45,10 +45,10 @@ $PAGE->navbar->add(get_string('editquestionengineshort', 'qtype_opaque'));
 // Create form.
 $mform = new qtype_opaque_engine_edit_form('editengine.php');
 
-if ($mform->is_cancelled()){
+if ($mform->is_cancelled()) {
     redirect(new moodle_url('/question/type/opaque/engines.php'));
 
-} else if ($data = $mform->get_data()){
+} else if ($data = $mform->get_data()) {
     $engine = new stdClass();
     if (!empty($data->engineid)) {
         $engine->id = $data->engineid;
diff --git a/question/type/opaque/engines.php b/question/type/opaque/engines.php
index d20b74ba5cb..39baf13bf52 100644
--- a/question/type/opaque/engines.php
+++ b/question/type/opaque/engines.php
@@ -45,8 +45,10 @@ if ($delete) {
         redirect($PAGE->url);
     } else {
         echo $OUTPUT->header();
-        echo $OUTPUT->confirm(get_string('deleteconfigareyousure', 'qtype_opaque', format_string($engine->name)),
-                new moodle_url('/question/type/opaque/engines.php', array('delete' => $delete, 'confirm' => 'yes', 'sesskey' => sesskey())),
+        echo $OUTPUT->confirm(get_string('deleteconfigareyousure', 'qtype_opaque',
+                format_string($engine->name)),
+                new moodle_url('/question/type/opaque/engines.php',
+                        array('delete' => $delete, 'confirm' => 'yes', 'sesskey' => sesskey())),
                 $PAGE->url);
         echo $OUTPUT->footer();
         exit;
@@ -69,11 +71,14 @@ if ($engines) {
 
     foreach ($engines as $engine) {
         echo html_writer::tag('p', format_string($engine->name) .
-                $OUTPUT->action_icon(new moodle_url('/question/type/opaque/testengine.php', array('engineid' => $engine->id)),
+                $OUTPUT->action_icon(new moodle_url('/question/type/opaque/testengine.php',
+                        array('engineid' => $engine->id)),
                         new pix_icon('t/preview', $strtest)) .
-                $OUTPUT->action_icon(new moodle_url('/question/type/opaque/editengine.php', array('engineid' => $engine->id)),
+                $OUTPUT->action_icon(new moodle_url('/question/type/opaque/editengine.php',
+                        array('engineid' => $engine->id)),
                         new pix_icon('t/edit', $stredit)) .
-                $OUTPUT->action_icon(new moodle_url('/question/type/opaque/engines.php', array('delete' => $engine->id)),
+                $OUTPUT->action_icon(new moodle_url('/question/type/opaque/engines.php',
+                        array('delete' => $engine->id)),
                         new pix_icon('t/delete', $strdelete)));
     }
 } else {
@@ -86,5 +91,3 @@ echo html_writer::tag('p', html_writer::link(new moodle_url('/question/type/opaq
 
 // Footer.
 echo $OUTPUT->footer();
-
-?>
diff --git a/question/type/opaque/locallib.php b/question/type/opaque/locallib.php
index 561f5bd866c..6aa65850871 100644
--- a/question/type/opaque/locallib.php
+++ b/question/type/opaque/locallib.php
@@ -33,9 +33,15 @@ require_once($CFG->libdir . '/xmlize.php');
 
 /** User passed on question. Should match the definition in Om.question.Results. */
 define('OPAQUE_ATTEMPTS_PASS', 0);
-/** User got question wrong after all attempts. Should match the definition in om.question.Results. */
+/**
+ * User got question wrong after all attempts. Should match the definition in
+ * om.question.Results.
+ */
 define('OPAQUE_ATTEMPTS_WRONG', -1);
-/** User got question partially correct after all attempts. Should match the definition in om.question.Results. */
+/**
+ * User got question partially correct after all attempts. Should match the
+ * definition in om.question.Results.
+ */
 define('OPAQUE_ATTEMPTS_PARTIALLYCORRECT', -2);
 /** If developer hasn't set the value. Should match the definition in om.question.Results. */
 define('OPAQUE_ATTEMPTS_UNSET', -99);
@@ -71,17 +77,20 @@ class qtype_opaque_engine_manager {
     /**
      * Load the definition of an engine from the database.
      * @param int $engineid the id of the engine to load.
-     * @return mixed On success, and object with fields id, name, questionengines and questionbanks.
-     * The last two fields are arrays of URLs. On an error, returns a string to look up in the
-     * qtype_opaque language file as an error message.
+     * @return mixed On success, and object with fields id, name, questionengines
+     *      and questionbanks. The last two fields are arrays of URLs. On an error,
+     *      returns a string to look up in the qtype_opaque language file as an
+     *      error message.
      */
     public function load_engine_def($engineid) {
         global $DB;
-        $engine = $DB->get_record('question_opaque_engines', array('id' => $engineid), '*', MUST_EXIST);
+        $engine = $DB->get_record('question_opaque_engines',
+                array('id' => $engineid), '*', MUST_EXIST);
 
         $engine->questionengines = array();
         $engine->questionbanks = array();
-        $servers = $DB->get_records('question_opaque_servers', array('engineid' => $engineid), 'id ASC');
+        $servers = $DB->get_records('question_opaque_servers',
+                array('engineid' => $engineid), 'id ASC');
         if (!$servers) {
             throw new moodle_exception('couldnotloadengineservers', 'qtype_opaque', '', $engineid);
         }
@@ -273,10 +282,12 @@ function qtype_opaque_find_or_create_engineid($engine) {
 }
 
 /**
- * @param mixed $engine either an $engine object, or the URL of a particular question engine server.
- * @return a soap connection, either to the specific URL give, or to to one of the question engine servers
- * of this $engine object picked at random. returns a string to look up in the qtype_opaque
- * language file as an error message if a problem arises.
+ * @param mixed $engine either an $engine object, or the URL of a particular
+ *      question engine server.
+ * @return a soap connection, either to the specific URL give, or to to one of
+ *      the question engine servers of this $engine object picked at random.
+ *      returns a string to look up in the qtype_opaque language file as an error
+ *      message if a problem arises.
  */
 function qtype_opaque_connect($engine) {
     if (is_string($engine)) {
@@ -286,7 +297,8 @@ function qtype_opaque_connect($engine) {
     } else {
         $url = $engine->questionengines[array_rand($engine->questionengines)];
     }
-    $connection = new SoapClient($url . '?wsdl', array('soap_version'=>SOAP_1_1, 'exceptions'=>true));
+    $connection = new SoapClient($url . '?wsdl',
+            array('soap_version'=>SOAP_1_1, 'exceptions'=>true));
     if (!is_string($engine)) {
         $engine->urlused = $url;
     }
@@ -294,9 +306,10 @@ function qtype_opaque_connect($engine) {
 }
 
 /**
- * @param mixed $engine either an $engine object, or the URL of a particular question engine server.
- * @return some XML, as parsed by xmlize, on success, or a string to look up in the qtype_opaque
- * language file as an error message.
+ * @param mixed $engine either an $engine object, or the URL of a particular
+ *      question engine server.
+ * @return some XML, as parsed by xmlize, on success, or a string to look up in
+ *      the qtype_opaque language file as an error message.
  */
 function qtype_opaque_get_engine_info($engine) {
     $connection = qtype_opaque_connect($engine);
@@ -305,15 +318,17 @@ function qtype_opaque_get_engine_info($engine) {
 }
 
 /**
- * @param mixed $engine either an $engine object, or the URL of a particular question engine server.
+ * @param mixed $engine either an $engine object, or the URL of a particular
+ *      question engine server.
  * @return The question metadata, as an xmlised array, so, for example,
- * $metadata[questionmetadata][@][#][scoring][0][#][marks][0][#] is the maximum possible score for
- * this question.
+ *      $metadata[questionmetadata][@][#][scoring][0][#][marks][0][#] is the
+ *      maximum possible score for this question.
  */
 function qtype_opaque_get_question_metadata($engine, $remoteid, $remoteversion) {
     $connection = qtype_opaque_connect($engine);
     $questionbaseurl = $engine->questionbanks[array_rand($engine->questionbanks)];
-    $getmetadataresult = $connection->getQuestionMetadata($remoteid, $remoteversion, $questionbaseurl);
+    $getmetadataresult = $connection->getQuestionMetadata(
+            $remoteid, $remoteversion, $questionbaseurl);
     return xmlize($getmetadataresult);
 }
 
@@ -324,7 +339,8 @@ function qtype_opaque_get_question_metadata($engine, $remoteid, $remoteversion)
  * @param int $randomseed
  * @return mixed the result of the soap call on success, or a string error message on failure.
  */
-function qtype_opaque_start_question_session($engine, $remoteid, $remoteversion, $data, $cached_resources) {
+function qtype_opaque_start_question_session($engine, $remoteid, $remoteversion,
+        $data, $cached_resources) {
     $connection = qtype_opaque_connect($engine);
 
     $questionbaseurl = '';
@@ -402,7 +418,8 @@ function qtype_opaque_get_submitted_data(question_attempt_step $step) {
  * @param object $state
  * @return mixed $SESSION->cached_opaque_state on success, a string error message on failure.
  */
-function qtype_opaque_update_state(question_attempt $qa, question_attempt_step $pendingstep = null) {
+function qtype_opaque_update_state(question_attempt $qa,
+        question_attempt_step $pendingstep = null) {
     global $SESSION;
 
     $question = $qa->get_question();
@@ -457,7 +474,8 @@ function qtype_opaque_update_state(question_attempt $qa, question_attempt_step $
 
         $step = qtype_opaque_get_step(0, $qa, $pendingstep);
         $startreturn = qtype_opaque_start_question_session($engine, $question->remoteid,
-                $question->remoteversion, $step->get_all_data(), $resourcecache->list_cached_resources());
+                $question->remoteversion, $step->get_all_data(),
+                $resourcecache->list_cached_resources());
         if (is_string($startreturn)) {
             unset($SESSION->cached_opaque_state);
             return $startreturn;
@@ -478,8 +496,8 @@ function qtype_opaque_update_state(question_attempt $qa, question_attempt_step $
         while ($opaquestate->sequencenumber < $targetseq) {
             $step = qtype_opaque_get_step($opaquestate->sequencenumber + 1, $qa, $pendingstep);
 
-            $processreturn = qtype_opaque_process($opaquestate->engine, $opaquestate->questionsessionid,
-                    qtype_opaque_get_submitted_data($step));
+            $processreturn = qtype_opaque_process($opaquestate->engine,
+                    $opaquestate->questionsessionid, qtype_opaque_get_submitted_data($step));
             if (is_string($processreturn)) {
                 unset($SESSION->cached_opaque_state);
                 return $processreturn;
@@ -553,8 +571,9 @@ function qtype_opaque_extract_stuff_from_response($opaquestate, $response, $reso
             create_function('$matches', 'return str_replace("&amp;", "%26", $matches[0]);'),
             $xhtml);
 
-    // Another hack to take out the next button that most OM questions include, but which does not work in Moodle.
-    // Actually, we remove any non-disabled buttons, and the following script tag.
+    // Another hack to take out the next button that most OM questions include,
+    // but which does not work in Moodle. Actually, we remove any non-disabled
+    // buttons, and the following script tag.
     // TODO think of a better way to do this.
     if ($opaquestate->resultssequencenumber >= 0) {
         $xhtml = qtype_opaque_strip_omact_buttons($xhtml);
@@ -565,7 +584,8 @@ function qtype_opaque_extract_stuff_from_response($opaquestate, $response, $reso
     // Process the CSS (only when we have a StartResponse).
     if (!empty($response->CSS)) {
         $opaquestate->cssfilename = qtype_opaque_stylesheet_filename($response->questionSession);
-        $resourcecache->cache_file($opaquestate->cssfilename, 'text/css;charset=UTF-8', $response->CSS);
+        $resourcecache->cache_file($opaquestate->cssfilename,
+                'text/css;charset=UTF-8', $response->CSS);
     }
 
     // Process the resources.
@@ -575,7 +595,8 @@ function qtype_opaque_extract_stuff_from_response($opaquestate, $response, $reso
     foreach ($response->resources as $key => $resource) {
         if ($resource->filename == 'script.js') {
             $response->resources[$key]->content = preg_replace(
-                    '/(?<=window\.open\(\"\", idprefix|window\.open\(\"\",idprefix)\+(?=\"\w+\"\+id,)/',
+                    '/(?<=' . preg_quote('window.open("", idprefix') . '|' .
+                            preg_quote('window.open("",idprefix') . ')\+(?=\"\w+\"\+id,)/',
                     '.replace(/\W/g,"_")+', $resource->content);
         }
     }
@@ -587,7 +608,7 @@ function qtype_opaque_extract_stuff_from_response($opaquestate, $response, $reso
         $opaquestate->questionsessionid = $response->questionSession;
     }
 
-    if(!empty($response->head)) {
+    if (!empty($response->head)) {
         $opaquestate->headXHTML = $response->head;
     }
 
@@ -595,17 +616,20 @@ function qtype_opaque_extract_stuff_from_response($opaquestate, $response, $reso
 }
 
 /**
- * Strip any buttons, followed by script tags, where the button has an id containing _omact_, and is not disabled.
+ * Strip any buttons, followed by script tags, where the button has an id
+ * containing _omact_, and is not disabled.
  */
 function qtype_opaque_strip_omact_buttons($xhtml) {
-    return preg_replace('|<input(?:(?!disabled=)[^>])*? id="[^"]*_omact_[^"]*"(?:(?!disabled=)[^>])*?><script type="text/javascript">[^<]*</script>|', '', $xhtml);
+    return preg_replace(
+            '|<input(?:(?!disabled=)[^>])*? id="[^"]*_omact_[^"]*"(?:(?!disabled=)[^>])*?>' .
+            '<script type="text/javascript">[^<]*</script>|', '', $xhtml);
 }
 
 /**
  * @param string $secret the secret string for this question engine.
  * @param int $userid the id of the user attempting this question.
- * @return string the passkey that needs to be sent to the quetion engine to show that
- *      we are allowed to start a question session for this user.
+ * @return string the passkey that needs to be sent to the quetion engine to
+ *      show that we are allowed to start a question session for this user.
  */
 function qtype_opaque_generate_passkey($secret, $userid) {
     return md5($secret . $userid);
@@ -615,7 +639,7 @@ function qtype_opaque_generate_passkey($secret, $userid) {
  * OpenMark relies on certain browser-specific class names to be present in the
  * HTML outside the question, in order to apply certian browser-specific layout
  * work-arounds. This function re-implements Om's browser sniffing rules. See
- * https://openmark.dev.java.net/source/browse/openmark/trunk/src/util/misc/UserAgent.java?view=markup
+ * http://java.net/projects/openmark/sources/svn/content/trunk/src/util/misc/UserAgent.java
  * @return string class to add to the HTML.
  */
 function qtype_opaque_browser_type() {
@@ -645,7 +669,8 @@ function qtype_opaque_browser_type() {
 /**
  * This class caches the resources belonging a particular question.
  *
- * There are synchronisation issues if two students are doing the same question at the same time.
+ * There are synchronisation issues if two students are doing the same question
+ * at the same time.
  *
  * @copyright  2010 The Open University
  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
@@ -663,7 +688,8 @@ class qtype_opaque_resource_cache {
      */
     public function __construct($engineid, $remoteid, $remoteversion) {
         global $CFG;
-        $folderstart = $CFG->dataroot . '/opaqueresources/' . $engineid . '/' . $remoteid . '/' . $remoteversion;
+        $folderstart = $CFG->dataroot . '/opaqueresources/' . $engineid . '/' .
+                $remoteid . '/' . $remoteversion;
         $this->folder = $folderstart . '/files';
         if (!is_dir($this->folder)) {
             $this->mkdir_recursive($this->folder);
@@ -672,8 +698,9 @@ class qtype_opaque_resource_cache {
         if (!is_dir($this->metadatafolder)) {
             $this->mkdir_recursive($this->metadatafolder);
         }
-        $this->baseurl = new moodle_url('/question/type/opaque/file.php', array(
-                'engineid' => $engineid, 'remoteid' => $remoteid, 'remoteversion' => $remoteversion));
+        $this->baseurl = new moodle_url('/question/type/opaque/file.php',
+                array('engineid' => $engineid, 'remoteid' => $remoteid,
+                      'remoteversion' => $remoteversion));
     }
 
     /**
@@ -736,17 +763,13 @@ class qtype_opaque_resource_cache {
         // Handle If-Modified-Since
         $file = $this->file_path($filename);
         $filedate = filemtime($file);
-        $ifmodifiedsince = isset($_SERVER['HTTP_IF_MODIFIED_SINCE']) ? $_SERVER['HTTP_IF_MODIFIED_SINCE'] : false;
-        if($ifmodifiedsince && strtotime($ifmodifiedsince)>=$filedate) {
+        $ifmodifiedsince = isset($_SERVER['HTTP_IF_MODIFIED_SINCE']) ?
+                $_SERVER['HTTP_IF_MODIFIED_SINCE'] : false;
+        if ($ifmodifiedsince && strtotime($ifmodifiedsince) >= $filedate) {
             header('HTTP/1.0 304 Not Modified');
             exit;
         }
-        header('Last-Modified: '.gmdate('D, d M Y H:i:s',$filedate).' GMT');
-
-//        // Send expire headers
-//        $lifetime=4*60*60;
-//        header('Cache-Control: max-age='.$lifetime);
-//        header('Expires: '. gmdate('D, d M Y H:i:s', time() + $lifetime) .' GMT');
+        header('Last-Modified: '.gmdate('D, d M Y H:i:s', $filedate).' GMT');
 
         // Type
         header('Content-Type: ' . $mimetype);
@@ -774,7 +797,7 @@ class qtype_opaque_resource_cache {
      * @param array $resources as returned from start or process Opaque methods.
      */
     public function cache_resources($resources) {
-        if(!empty($resources)) {
+        if (!empty($resources)) {
             foreach ($resources as $resource) {
                 $mimetype = $resource->mimeType;
                 if (strpos($resource->mimeType, 'text/') === 0 && !empty($resource->encoding)) {
@@ -821,9 +844,9 @@ class qtype_opaque_resource_cache {
             global $CFG;
             $mode = $CFG->directorypermissions;
         }
-        if (!$this->mkdir_recursive(dirname($folder),$mode)) {
+        if (!$this->mkdir_recursive(dirname($folder), $mode)) {
             return false;
         }
-        return mkdir($folder,$mode);
+        return mkdir($folder, $mode);
     }
 }
diff --git a/question/type/opaque/questiontype.php b/question/type/opaque/questiontype.php
index eae944ef88d..faae8ba7ad3 100644
--- a/question/type/opaque/questiontype.php
+++ b/question/type/opaque/questiontype.php
@@ -88,7 +88,8 @@ class qtype_opaque extends question_type {
         $expout .= "    <engine>\n";
         $engine = $this->enginemanager->load_engine_def($question->options->engineid);
         $expout .= "      <name>\n" . $format->writetext($engine->name, 4) . "      </name>\n";
-        $expout .= "      <passkey>\n" . $format->writetext($engine->passkey, 4) . "      </passkey>\n";
+        $expout .= "      <passkey>\n" . $format->writetext($engine->passkey, 4) .
+                "      </passkey>\n";
         foreach ($engine->questionengines as $qe) {
             $expout .= "      <qe>\n" . $format->writetext($qe, 4) . "      </qe>\n";
         }
diff --git a/question/type/opaque/simpletest/testquestiontype.php b/question/type/opaque/simpletest/testquestiontype.php
index 1e1f4f907d3..22cfdd7e3b3 100644
--- a/question/type/opaque/simpletest/testquestiontype.php
+++ b/question/type/opaque/simpletest/testquestiontype.php
@@ -80,7 +80,7 @@ class qtype_opaque_engine_manager_mock extends qtype_opaque_engine_manager {
  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
 class qtype_opaque_test extends UnitTestCase {
-    var $qtype;
+    protected $qtype;
 
     public function setUp() {
         $this->qtype = new qtype_opaque();
diff --git a/question/type/opaque/styles.css b/question/type/opaque/styles.css
index 98feb88163e..2c229e2466d 100644
--- a/question/type/opaque/styles.css
+++ b/question/type/opaque/styles.css
@@ -11,4 +11,4 @@
     padding: 7em 1em;
     text-align: center;
     background: #eeeeee;
-}
\ No newline at end of file
+}