MDL-39507 questions: fix pluginfile URLs before format_text.

This commit build's on Jean-Michel's work, tidying up a few lose ends.

lib/questionlib.php

@@ -1219,11 +1219,6 @@ function question_categorylist($categoryid) {
     return $categorylist;
 }
 
-function to_plain_text($text, $format, $options) {
-    $text = str_replace('@@PLUGINFILE@@/', 'http://example.com/', $text);
-    return html_to_text(format_text($text, $format, $options), 0, false);
-}
-
 //===========================
 // Import/Export Functions
 //===========================

mod/quiz/editlib.php

@@ -1013,12 +1013,8 @@ function quiz_question_tostring($question, $showicon = false,
     }
     $result .= shorten_text(format_string($question->name), 200) . '</span>';
     if ($showquestiontext) {
-        $formatoptions = new stdClass();
-        $formatoptions->noclean = true;
-        $formatoptions->para = false;
-        $questiontext = strip_tags(format_text($question->questiontext,
-                $question->questiontextformat,
-                $formatoptions, $COURSE->id));
+        $questiontext = question_utils::to_plain_text($question->questiontext,
+                $question->questiontextformat, array('noclean' => true, 'para' => false));
         $questiontext = shorten_text($questiontext, 200);
         $result .= '<span class="questiontext">';
         if (!empty($questiontext)) {

question/engine/lib.php

@@ -818,6 +818,22 @@ public static function optional_param_mark($parname) {
         return self::clean_param_mark(
                 optional_param($parname, null, PARAM_RAW_TRIMMED));
     }
+
+    /**
+     * Convert part of some question content to plain text.
+     * @param string $text the text.
+     * @param int $format the text format.
+     * @param array $options formatting options. Passed to {@link format_text}.
+     * @return float|string|null cleaned mark as a float if possible. Otherwise '' or null.
+     */
+    public static function to_plain_text($text, $format, $options = array('noclean' => 'true')) {
+        // The following call to html_to_text uses the option that strips out
+        // all URLs, but format_text complains if it finds @@PLUGINFILE@@ tokens.
+        // So, we need to replace @@PLUGINFILE@@ with a real URL, but it doesn't
+        // matter what. We use http://example.com/.
+        $text = str_replace('@@PLUGINFILE@@/', 'http://example.com/', $text);
+        return html_to_text(format_text($text, $format, $options), 0, false);
+    }
 }
 
 

question/format.php

@@ -933,11 +933,8 @@ protected function writequestion($question) {
      * during import to let the user see roughly what is going on.
      */
     protected function format_question_text($question) {
-        global $DB;
-        $formatoptions = new stdClass();
-        $formatoptions->noclean = true;
-        return to_plain_text($question->questiontext,
-                $question->questiontextformat, $formatoptions);
+        return question_utils::to_plain_text($question->questiontext,
+                $question->questiontextformat);
     }
 }
 

question/format/xhtml/format.php

@@ -66,11 +66,11 @@ protected function writequestion($question) {
         $expout .= "<h3>$question->name</h3>\n";
 
         // Format and add the question text.
-        $text = question_rewrite_question_urls($question->questiontext, 'pluginfile.php',
-                $question->contextid, 'question', $filearea,
-                '', $question->id);
+        $text = question_rewrite_question_preview_urls($question->questiontext, $question->id,
+                $question->contextid, 'question', 'questiontext', $question->id,
+                $question->contextid, 'qformat_xhtml');
         $expout .= '<p class="questiontext">' . format_text($text,
-                $question->questiontextformat) . "</p>\n";
+                $question->questiontextformat, array('noclean' => true)) . "</p>\n";
 
         // Selection depends on question type.
         switch($question->qtype) {

question/format/xhtml/lib.php

@@ -0,0 +1,58 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle 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.
+//
+// Moodle 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 Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Standard plugin entry points of the HTML question export format.
+ *
+ * @package   qformat_xhtml
+ * @copyright 2013 The Open University
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+
+defined('MOODLE_INTERNAL') || die();
+
+
+/**
+ * Serve question files when they are displayed in this export format.
+ *
+ * @param context $previewcontext the quiz context
+ * @param int $questionid the question id.
+ * @param context $filecontext the file (question) context
+ * @param string $filecomponent the component the file belongs to.
+ * @param string $filearea the file area.
+ * @param array $args remaining file args.
+ * @param bool $forcedownload.
+ * @param array $options additional options affecting the file serving.
+ */
+function qformat_xhtml_question_preview_pluginfile($previewcontext, $questionid,
+        $filecontext, $filecomponent, $filearea, $args, $forcedownload, $options = array()) {
+    global $CFG;
+
+    list($context, $course, $cm) = get_context_info_array($previewcontext->id);
+    require_login($course, false, $cm);
+
+    question_require_capability_on($questionid, 'view');
+
+    $fs = get_file_storage();
+    $relativepath = implode('/', $args);
+    $fullpath = "/{$filecontext->id}/{$filecomponent}/{$filearea}/{$relativepath}";
+    if (!$file = $fs->get_file_by_hash(sha1($fullpath)) or $file->is_directory()) {
+        send_file_not_found();
+    }
+
+    send_stored_file($file, 0, 0, $forcedownload, $options);
+}

question/type/essay/question.php

@@ -70,9 +70,8 @@ public function get_expected_data() {
 
     public function summarise_response(array $response) {
         if (isset($response['answer'])) {
-            $formatoptions = new stdClass();
-            $formatoptions->para = false;
-            return html_to_text($response['answer'], FORMAT_HTML, $formatoptions);
+            return question_utils::to_plain_text($response['answer'],
+                    $response['answerformat'], array('para' => false));
         } else {
             return null;
         }

question/type/multichoice/questiontype.php

@@ -203,8 +203,8 @@ public function get_possible_responses($questiondata) {
             $responses = array();
 
             foreach ($questiondata->options->answers as $aid => $answer) {
-                $responses[$aid] = new question_possible_response(to_plain_text(
-                        $answer->answer, $answer->answerformat, array('noclean' => true)),
+                $responses[$aid] = new question_possible_response(
+                        question_utils::to_plain_text($answer->answer, $answer->answerformat),
                         $answer->fraction);
             }
 
@@ -214,9 +214,8 @@ public function get_possible_responses($questiondata) {
             $parts = array();
 
             foreach ($questiondata->options->answers as $aid => $answer) {
-                $parts[$aid] = array($aid =>
-                        new question_possible_response(to_plain_text(
-                        $answer->answer, $answer->answerformat, array('noclean' => true)),
+                $parts[$aid] = array($aid => new question_possible_response(
+                        question_utils::to_plain_text($answer->answer, $answer->answerformat),
                         $answer->fraction));
             }
 

question/type/questionbase.php

@@ -333,7 +333,7 @@ public function format_text($text, $format, $qa, $component, $filearea, $itemid,
      * @return string the equivalent plain text.
      */
     public function html_to_text($text, $format) {
-        return to_plain_text($text, $format, array('noclean' => true));
+        return question_utils::to_plain_text($text, $format);
     }
 
     /** @return the result of applying {@link format_text()} to the question text. */