Issue #22 - WIP - Basic replacement for styles and images.

classes/local/controllers/maintenance_static_page.php

@@ -0,0 +1,214 @@
+<?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/>.
+
+/**
+ * maintenance_static_page class.
+ *
+ * @package    auth_outage
+ * @author     Daniel Thee Roperto <daniel.roperto@catalyst-au.net>
+ * @copyright  2016 Catalyst IT
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace auth_outage\local\controllers;
+
+use auth_outage\local\outage;
+use coding_exception;
+use DOMDocument;
+use DOMElement;
+use invalid_parameter_exception;
+use moodle_url;
+
+defined('MOODLE_INTERNAL') || die();
+
+/**
+ * maintenance_static_page class.
+ *
+ * @package    auth_outage
+ * @author     Daniel Thee Roperto <daniel.roperto@catalyst-au.net>
+ * @copyright  2016 Catalyst IT
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class maintenance_static_page {
+    /** @var int */
+    private static $nextfile = 1;
+
+    /**
+     * Gets the cli maintenance template file location.
+     * @return string
+     */
+    public static function get_template_file() {
+        global $CFG;
+        return $CFG->dataroot.'/climaintenance.template.html';
+    }
+
+    /**
+     * Gets the resources folder in dataroot.
+     *
+     * Warning: this folder will be deleted every time the page is regenerated.
+     *
+     * @return string
+     */
+    public static function get_resources_folder() {
+        global $CFG;
+        return $CFG->dataroot.'/auth_outage/climaintenance';
+    }
+
+    public static function create_from_outage(outage $outage) {
+        global $CFG;
+        $html = file_get_contents($CFG->wwwroot.'/auth/outage/info.php?auth_outage_hide_warning=1&id='.$outage->id);
+        self::create_from_html($html);
+    }
+
+    public static function create_from_html($html) {
+        if (!is_string($html)) {
+            throw new coding_exception('$html is not valid.');
+        }
+
+        $dom = new DOMDocument();
+
+        // Let's assume we have no parsing errors as we cannot rely on a badly-formed page anyway.
+        libxml_use_internal_errors(true);
+        $dom->loadHTML($html);
+        libxml_clear_errors();
+
+        self::generate($dom);
+    }
+
+    private static function generate(DOMDocument $dom) {
+        self::prepare_dataroot();
+        self::remove_script_tags($dom);
+        self::update_link_stylesheet($dom);
+        self::update_link_favicon($dom);
+        self::update_images($dom);
+        file_put_contents(self::get_template_file(), $dom->saveHTML());
+    }
+
+    private static function remove_script_tags(DOMDocument $dom) {
+        $scripts = $dom->getElementsByTagName('script');
+        // List items to remove without changing the DOM.
+        $remove = [];
+        foreach ($scripts as $node) {
+            $remove[] = $node;
+        }
+        // All listed, now remove them.
+        foreach ($remove as $node) {
+            $node->parentNode->removeChild($node);
+        }
+    }
+
+    private static function prepare_dataroot() {
+        $dir = self::get_resources_folder();
+        if (is_dir($dir)) {
+            self::delete_directory_recursively($dir);
+        }
+        mkdir($dir, 0775, true);
+    }
+
+    private static function delete_directory_recursively($dir) {
+        // It should never come from user, but protect against possible attacks anyway.
+        $safedir = self::get_resources_folder();
+        if (substr($dir, 0, strlen($safedir)) !== $safedir) {
+            throw new invalid_parameter_exception('Unsafe to delete: '.$dir);
+        }
+
+        if (!is_dir($dir)) {
+            throw new coding_exception('Not a directory: '.$dir);
+        }
+        $files = scandir($dir);
+        foreach ($files as $file) {
+            if (($file == '.') || ($file == '..')) {
+                continue;
+            }
+            $file = $dir.'/'.$file;
+            if (is_file($file)) {
+                unlink($file);
+                continue;
+            }
+            if (is_dir($file)) {
+                self::delete_directory_recursively($file);
+                continue;
+            }
+            throw new coding_exception('Not a file or directory: '.$file);
+        }
+        rmdir($dir);
+    }
+
+    private static function update_link_stylesheet(DOMDocument $dom) {
+        $links = $dom->getElementsByTagName('link');
+
+        foreach ($links as $link) {
+            $rel = $link->getAttribute("rel");
+            $href = $link->getAttribute("href");
+            if (($rel != 'stylesheet') || ($href == '')) {
+                continue;
+            }
+            $link->setAttribute('href', self::prepare_url($href, 'css'));
+        }
+    }
+
+    private static function update_link_favicon(DOMDocument $dom) {
+        $links = $dom->getElementsByTagName('link');
+
+        foreach ($links as $link) {
+            $rel = $link->getAttribute("rel");
+            $href = $link->getAttribute("href");
+            if (($rel != 'shortcut icon') || ($href == '')) {
+                continue;
+            }
+            $link->setAttribute('href', self::prepare_url($href, 'png')); // Works for most image formats.
+        }
+    }
+
+    private static function update_images(DOMDocument $dom) {
+        $links = $dom->getElementsByTagName('img');
+
+        foreach ($links as $link) {
+            $src = $link->getAttribute("src");
+            if ($src == '') {
+                continue;
+            }
+            $link->setAttribute('src', self::prepare_url($src, 'png')); // Works for most image formats.
+        }
+    }
+
+    private static function prepare_url($url, $type) {
+        global $CFG;
+
+        if (!preg_match('#^http(s)?://#', $url)) {
+            debugging('Found a relative url ('.$url.') -- is it using moodle_url()?');
+            return $url; // Leave hardcoded URLs as it is.
+        }
+
+        if (substr($url, 0, strlen($CFG->wwwroot)) !== $CFG->wwwroot) {
+            return $url; // External URL, leave it.
+        }
+
+        $file = self::$nextfile++;
+        if ($type != '') {
+            $file .= '.'.$type;
+        }
+        $path = self::get_resources_folder().'/'.$file;
+
+        // PHPUnit will use www.example.com as wwwroot and we don't to copy the file.
+        if (!PHPUNIT_TEST) {
+            copy($url, $path);
+        }
+
+        $url = (string)new moodle_url('/auth/outage/maintenance.php/'.$file);
+        return $url;
+    }
+}