MDL-69549 core: Add context export API

2020-10-15 13:46:25 +08:00
parent 9aeb59af73
commit 17d4bc49f6
20 changed files with 3535 additions and 0 deletions
@@ -0,0 +1,150 @@
+<?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/>.
+
+/**
+ * Content API File Area definition.
+ *
+ * @package     core_files
+ * @copyright   2020 Andrew Nicols <[email protected]>
+ * @license     http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+namespace core;
+
+use coding_exception;
+use context;
+use core\content\export\exporters\course_exporter;
+use core\content\export\exporters\component_exporter;
+use core\content\export\exporters\abstract_mod_exporter;
+use core\content\export\zipwriter;
+use core_component;
+use moodle_url;
+use stdClass;
+use stored_file;
+
+/**
+ * The Content API allows all parts of Moodle to determine details about content within a component, or plugintype.
+ *
+ * This includes the description of files.
+ *
+ * @copyright   2020 Andrew Nicols <[email protected]>
+ * @license     http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class content {
+
+    /**
+     * Check whether the specified user can export content for the specified context.
+     *
+     * @param   context $currentcontext
+     * @param   stdClass $user
+     * @return  bool
+     */
+    public static function can_export_context(context $currentcontext, stdClass $user): bool {
+        return true;
+    }
+
+    /**
+     * Export content for the specified context.
+     *
+     * @param   context $requestedcontext The context to be exported
+     * @param   stdClass $user The user being exported
+     * @param   zipwriter $archive The Zip Archive to export to
+     */
+    public static function export_context(context $requestedcontext, stdClass $user, zipwriter $archive): void {
+        global $USER;
+
+        if ($requestedcontext->contextlevel != CONTEXT_COURSE) {
+            throw new coding_exception('The Content Export API currently only supports the export of courses');
+        }
+
+        if ($USER->id != $user->id) {
+            throw new coding_exception('The Content Export API currently only supports export of the current user');
+        }
+
+        // Ensure that the zipwriter is aware of the requested context.
+        $archive->set_root_context($requestedcontext);
+
+        // Fetch all child contexts, indexed by path.
+        $contextlist = [
+            $requestedcontext->path => $requestedcontext,
+        ];
+        foreach ($requestedcontext->get_child_contexts() as $context) {
+            $contextlist[$context->path] = $context;
+        }
+
+        // Reverse the order by key - this ensures that child contexts are processed before their parent.
+        krsort($contextlist);
+
+        // Get the course modinfo.
+        $modinfo = get_fast_modinfo($requestedcontext->instanceid);
+
+        // Filter out any context which cannot be exported.
+        $contextlist = array_filter($contextlist, function($context) use ($user, $modinfo): bool {
+            if ($context->contextlevel == CONTEXT_COURSE) {
+                return self::can_export_context($context, $user);
+            }
+
+            if ($context->contextlevel == CONTEXT_MODULE) {
+                if (empty($modinfo->cms[$context->instanceid])) {
+                    // Unknown coursemodule in the course.
+                    return false;
+                }
+
+                $cm = $modinfo->cms[$context->instanceid];
+
+                if (!$cm->uservisible) {
+                    // This user cannot view the activity.
+                    return false;
+                }
+
+                // Defer to setting checks.
+                return self::can_export_context($context, $user);
+            }
+
+            // Only course and activities are supported at this time.
+            return false;
+        });
+
+        // Export each context.
+        $exportedcontexts = [];
+        $coursecontroller = new course_exporter($requestedcontext->get_course_context(), $user, $archive);
+        foreach ($contextlist as $context) {
+            if ($context->contextlevel === CONTEXT_MODULE) {
+                $cm = $modinfo->cms[$context->instanceid];
+                $component = "mod_{$cm->modname}";
+
+                // Check for a specific implementation for this module.
+                // This will export any content specific to this activity.
+                // For example, in mod_folder it will export the list of folders.
+                $classname = component_exporter::get_classname_for_component($component);
+                $exportables = [];
+                if (class_exists($classname) && is_a($classname, abstract_mod_exporter::class, true)) {
+                    $controller = new $classname($context, $component, $user, $archive);
+                    $exportables = $controller->get_exportables();
+                }
+
+                // Pass the exportable content to the  course controller for export.
+                $coursecontroller->export_mod_content($context, $exportables);
+
+                $exportedcontexts[$context->id] = $context;
+            } else if ($context->contextlevel === CONTEXT_COURSE) {
+                // Export the course content.
+                $coursecontroller->export_course($exportedcontexts);
+            }
+        }
+
+        $archive->finish();
+    }
+}