first commit

admin/tool/dbtransfer/classes/privacy/provider.php

@@ -0,0 +1,46 @@
+<?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/>.
+
+/**
+ * Privacy Subsystem implementation for tool_dbtransfer.
+ *
+ * @package    tool_dbtransfer
+ * @copyright  2018 Zig Tan <zig@moodle.com>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace tool_dbtransfer\privacy;
+
+defined('MOODLE_INTERNAL') || die();
+
+/**
+ * Privacy Subsystem for tool_dbtransfer implementing null_provider.
+ *
+ * @copyright  2018 Zig Tan <zig@moodle.com>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class provider implements \core_privacy\local\metadata\null_provider {
+
+    /**
+     * Get the language string identifier with the component's language
+     * file to explain why this plugin stores no data.
+     *
+     * @return  string
+     */
+    public static function get_reason(): string {
+        return 'privacy:metadata';
+    }
+}

admin/tool/dbtransfer/cli/migrate.php

@@ -0,0 +1,191 @@
+<?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/>.
+
+/**
+ * This script migrates data from current database to another
+ *
+ * This script is not intended for beginners!
+ * Potential problems:
+ * - su to apache account or sudo before execution
+ * - already broken DB scheme or invalid data
+ *
+ * @package    tool_dbtransfer
+ * @copyright  2012 Petr Skoda {@link http://skodak.org/}
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+define('CLI_SCRIPT', true);
+
+require(__DIR__.'/../../../../config.php');
+require_once($CFG->libdir.'/clilib.php');
+require_once(__DIR__.'/../locallib.php');
+
+$help =
+    "Database migration script.
+
+It is strongly recommended to turn off the web server
+or enable CLI maintenance mode before starting the migration.
+
+Options:
+--dbtype=TYPE         Database type.
+--dblibrary=TYPE      Database library. Defaults to 'native'.
+--dbhost=HOST         Database host.
+--dbname=NAME         Database name.
+--dbuser=USERNAME     Database user.
+--dbpass=PASSWORD     Database password.
+--dbport=NUMBER       Database port.
+--prefix=STRING       Table prefix for above database tables.
+--dbsocket=PATH       Use database sockets. Available for some databases only.
+-h, --help            Print out this help.
+
+Example:
+\$ sudo -u www-data /usr/bin/php admin/tool/dbtransfer/cli/migrate.php
+";
+
+// Now get cli options.
+list($options, $unrecognized) = cli_get_params(
+    array(
+        'dbtype'            => null,
+        'dblibrary'         => 'native',
+        'dbhost'            => null,
+        'dbname'            => null,
+        'dbuser'            => null,
+        'dbpass'            => null,
+        'dbport'            => null,
+        'prefix'            => null,
+        'dbsocket'          => null,
+        'maintenance'       => null,
+        'list'              => false,
+        'help'              => false,
+    ),
+    array(
+        'm' => 'maintenance',
+        'l' => 'list',
+        'h' => 'help',
+    )
+);
+
+if ($options['help']) {
+    echo $help;
+    exit(0);
+}
+
+if (empty($CFG->version)) {
+    cli_error(get_string('missingconfigversion', 'debug'));
+}
+
+echo "\n".get_string('cliheading', 'tool_dbtransfer')."\n\n";
+
+$drivers = tool_dbtransfer_get_drivers();
+
+if (!isset($options['dbtype'])) {
+    $choose = array();
+    foreach ($drivers as $driver => $name) {
+        list($dbtype, $dblibrary) = explode('/', $driver);
+        $choose[$dbtype] = $dbtype;
+    }
+    $optionsstr = implode(', ', $choose);
+    cli_heading(get_string('databasetypehead', 'install')." ($optionsstr)");
+    $options['dbtype'] = cli_input(get_string('clitypevalue', 'admin'), '', $choose, true);
+}
+
+$choose = array();
+foreach ($drivers as $driver => $name) {
+    list($dbtype, $dblibrary) = explode('/', $driver);
+    if ($dbtype === $options['dbtype']) {
+        $choose[$dblibrary] = $dblibrary;
+    }
+}
+if (!isset($options['dblibrary']) or !isset($choose[$options['dblibrary']])) {
+    $optionsstr = implode(', ', $choose);
+    cli_heading('Database library'." ($optionsstr)"); // Note: no need to localise unless we add real PDO drivers.
+    $options['dblibrary'] = cli_input(get_string('clitypevalue', 'admin'), '', $choose, true);
+}
+
+if (!isset($options['dbhost'])) {
+    cli_heading(get_string('databasehost', 'install'));
+    $options['dbhost'] = cli_input(get_string('clitypevalue', 'admin'));
+}
+
+if (!isset($options['dbname'])) {
+    cli_heading(get_string('databasename', 'install'));
+    $options['dbname'] = cli_input(get_string('clitypevalue', 'admin'));
+}
+
+if (!isset($options['dbuser'])) {
+    cli_heading(get_string('databaseuser', 'install'));
+    $options['dbuser'] = cli_input(get_string('clitypevalue', 'admin'));
+}
+
+if (!isset($options['dbpass'])) {
+    cli_heading(get_string('databasepass', 'install'));
+    $options['dbpass'] = cli_input(get_string('clitypevalue', 'admin'));
+}
+
+if (!isset($options['prefix'])) {
+    cli_heading(get_string('dbprefix', 'install'));
+    $options['prefix'] = cli_input(get_string('clitypevalue', 'admin'));
+}
+
+if (!isset($options['dbport'])) {
+    cli_heading(get_string('dbport', 'install'));
+    $options['dbport'] = cli_input(get_string('clitypevalue', 'admin'));
+}
+
+if ($CFG->ostype !== 'WINDOWS') {
+    if (!isset($options['dbsocket'])) {
+        cli_heading(get_string('databasesocket', 'install'));
+        $options['dbsocket'] = cli_input(get_string('clitypevalue', 'admin'));
+    }
+}
+
+$a = (object)array('dbtypefrom' => $CFG->dbtype, 'dbtype' => $options['dbtype'],
+    'dbname' => $options['dbname'], 'dbhost' => $options['dbhost']);
+cli_heading(get_string('transferringdbto', 'tool_dbtransfer', $a));
+
+// Try target DB connection.
+$problem = '';
+
+$targetdb = moodle_database::get_driver_instance($options['dbtype'], $options['dblibrary']);
+$dboptions = array();
+if ($options['dbport']) {
+    $dboptions['dbport'] = $options['dbport'];
+}
+if ($options['dbsocket']) {
+    $dboptions['dbsocket'] = $options['dbsocket'];
+}
+try {
+    $targetdb->connect($options['dbhost'], $options['dbuser'], $options['dbpass'], $options['dbname'],
+        $options['prefix'], $dboptions);
+    if ($targetdb->get_tables()) {
+        $problem .= get_string('targetdatabasenotempty', 'tool_dbtransfer');
+    }
+} catch (moodle_exception $e) {
+    $problem .= $e->debuginfo."\n\n";
+    $problem .= get_string('notargetconectexception', 'tool_dbtransfer');
+}
+
+if ($problem !== '') {
+    echo $problem."\n\n";
+    exit(1);
+}
+
+$feedback = new text_progress_trace();
+tool_dbtransfer_transfer_database($DB, $targetdb, $feedback);
+$feedback->finished();
+
+cli_heading(get_string('success'));
+exit(0);

admin/tool/dbtransfer/database_export_form.php

@@ -0,0 +1,50 @@
+<?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/>.
+
+/**
+ * Transfer form
+ *
+ * @package    tool_dbtransfer
+ * @copyright  2008 Petr Skoda {@link http://skodak.org/}
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+defined('MOODLE_INTERNAL') || die;
+
+require_once($CFG->libdir.'/formslib.php');
+
+
+/**
+ * Definition of db export settings form.
+ *
+ * @package    tool_dbtransfer
+ * @copyright  2008 Petr Skoda {@link http://skodak.org/}
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class database_export_form extends moodleform {
+    /**
+     * Define the export form.
+     */
+    public function definition() {
+        $mform = $this->_form;
+
+        $mform->addElement('header', 'database', get_string('dbexport', 'tool_dbtransfer'));
+        $mform->addElement('textarea', 'description', get_string('description'), array('rows'=>5, 'cols'=>60));
+        $mform->setType('description', PARAM_TEXT);
+
+        $this->add_action_buttons(false, get_string('exportdata', 'tool_dbtransfer'));
+    }
+}

admin/tool/dbtransfer/database_transfer_form.php

@@ -0,0 +1,116 @@
+<?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/>.
+
+/**
+ * Transfer form
+ *
+ * @package    tool_dbtransfer
+ * @copyright  2008 Petr Skoda {@link http://skodak.org/}
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+defined('MOODLE_INTERNAL') || die;
+
+require_once($CFG->libdir.'/formslib.php');
+require_once(__DIR__.'/locallib.php');
+
+
+/**
+ * Definition of db transfer settings form.
+ *
+ * @copyright  2008 Petr Skoda {@link http://skodak.org/}
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class database_transfer_form extends moodleform {
+
+    /**
+     * Define transfer form.
+     */
+    protected function definition() {
+        global $CFG;
+
+        $mform = $this->_form;
+
+        $mform->addElement('header', 'database', get_string('targetdatabase', 'tool_dbtransfer'));
+
+        $drivers = tool_dbtransfer_get_drivers();
+        $drivers = array_reverse($drivers, true);
+        $drivers[''] = get_string('choosedots');
+        $drivers = array_reverse($drivers, true);
+
+        $mform->addElement('select', 'driver', get_string('dbtype', 'install'), $drivers);
+        $mform->setType('driver', PARAM_RAW);
+
+        $mform->addElement('text', 'dbhost', get_string('databasehost', 'install'));
+        $mform->setType('dbhost', PARAM_HOST);
+
+        $mform->addElement('text', 'dbname', get_string('databasename', 'install'));
+        $mform->setType('dbname', PARAM_ALPHANUMEXT);
+
+        $mform->addElement('text', 'dbuser', get_string('databaseuser', 'install'));
+        $mform->setType('dbuser', PARAM_ALPHANUMEXT);
+
+        $mform->addElement('passwordunmask', 'dbpass', get_string('databasepass', 'install'));
+        $mform->setType('dbpass', PARAM_RAW);
+
+        $mform->addElement('text', 'prefix', get_string('dbprefix', 'install'));
+        $mform->setType('prefix', PARAM_ALPHANUMEXT);
+
+        $mform->addElement('text', 'dbport', get_string('dbport', 'install'));
+        $mform->setType('dbport', PARAM_INT);
+
+        if ($CFG->ostype !== 'WINDOWS') {
+            $mform->addElement('text', 'dbsocket', get_string('databasesocket', 'install'));
+        } else {
+            $mform->addElement('hidden', 'dbsocket');
+        }
+        $mform->setType('dbsocket', PARAM_RAW);
+
+        $mform->addRule('driver', get_string('required'), 'required', null);
+        $mform->addRule('dbhost', get_string('required'), 'required', null);
+        $mform->addRule('dbname', get_string('required'), 'required', null);
+        $mform->addRule('dbuser', get_string('required'), 'required', null);
+        $mform->addRule('dbpass', get_string('required'), 'required', null);
+        if (!isset($drivers['mysqli/native'])) {
+            $mform->addRule('prefix', get_string('required'), 'required', null);
+        }
+
+        $mform->addElement('header', 'database', get_string('options', 'tool_dbtransfer'));
+
+        $mform->addElement('advcheckbox', 'enablemaintenance', get_string('enablemaintenance', 'tool_dbtransfer'));
+        $mform->setType('enablemaintenance', PARAM_BOOL);
+        $mform->addHelpButton('enablemaintenance', 'enablemaintenance', 'tool_dbtransfer');
+
+        $this->add_action_buttons(false, get_string('transferdata', 'tool_dbtransfer'));
+    }
+
+    /**
+     * Validate prefix is present for non-mysql drivers.
+     * @param array $data
+     * @param array $files
+     * @return array
+     */
+    public function validation($data, $files) {
+        $errors = parent::validation($data, $files);
+        if ($data['driver'] !== 'mysqli/native') {
+            // This is a bloody hack, let's pretend we do not need to look at db family...
+            if ($data['prefix'] === '') {
+                $errors['prefix'] = get_string('required');
+            }
+        }
+        return $errors;
+    }
+}

admin/tool/dbtransfer/dbexport.php

@@ -0,0 +1,44 @@
+<?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/>.
+
+/**
+ * Export
+ *
+ * @package    tool_dbtransfer
+ * @copyright  2008 Petr Skoda {@link http://skodak.org/}
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+define('NO_OUTPUT_BUFFERING', true);
+
+require('../../../config.php');
+require_once('locallib.php');
+require_once('database_export_form.php');
+
+admin_externalpage_setup('tooldbexport');
+
+// Create form.
+$form = new database_export_form();
+
+if ($data = $form->get_data()) {
+    tool_dbtransfer_export_xml_database($data->description, $DB);
+    die;
+}
+
+echo $OUTPUT->header();
+// TODO: add some more info here.
+$form->display();
+echo $OUTPUT->footer();

admin/tool/dbtransfer/index.php

@@ -0,0 +1,108 @@
+<?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/>.
+
+/**
+ * Transfer tool
+ *
+ * @package    tool_dbtransfer
+ * @copyright  2008 Petr Skoda {@link http://skodak.org/}
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+define('NO_OUTPUT_BUFFERING', true);
+
+require('../../../config.php');
+require_once('locallib.php');
+require_once('database_transfer_form.php');
+
+admin_externalpage_setup('tooldbtransfer');
+
+// Create the form.
+$form = new database_transfer_form();
+$problem = '';
+
+// If we have valid input.
+if ($data = $form->get_data()) {
+    // Connect to the other database.
+    list($dbtype, $dblibrary) = explode('/', $data->driver);
+    $targetdb = moodle_database::get_driver_instance($dbtype, $dblibrary);
+    $dboptions = array();
+    if ($data->dbport) {
+        $dboptions['dbport'] = $data->dbport;
+    }
+    if ($data->dbsocket) {
+        $dboptions['dbsocket'] = $data->dbsocket;
+    }
+    try {
+        $targetdb->connect($data->dbhost, $data->dbuser, $data->dbpass, $data->dbname, $data->prefix, $dboptions);
+        if ($targetdb->get_tables()) {
+            $problem .= get_string('targetdatabasenotempty', 'tool_dbtransfer');
+        }
+    } catch (moodle_exception $e) {
+        $problem .= get_string('notargetconectexception', 'tool_dbtransfer').'<br />'.$e->debuginfo;
+    }
+
+    if ($problem === '') {
+        // Scroll down to the bottom when finished.
+        $PAGE->requires->js_init_code("window.scrollTo(0, 5000000);");
+
+        // Enable CLI maintenance mode if requested.
+        if ($data->enablemaintenance) {
+            $PAGE->set_pagelayout('maintenance');
+            tool_dbtransfer_create_maintenance_file();
+        }
+
+        // Start output.
+        echo $OUTPUT->header();
+        $data->dbtype = $dbtype;
+        $data->dbtypefrom = $CFG->dbtype;
+        echo $OUTPUT->heading(get_string('transferringdbto', 'tool_dbtransfer', $data));
+
+        // Do the transfer.
+        $CFG->tool_dbransfer_migration_running = true;
+        try {
+            $feedback = new html_list_progress_trace();
+            tool_dbtransfer_transfer_database($DB, $targetdb, $feedback);
+            $feedback->finished();
+        } catch (Exception $e) {
+            if ($data->enablemaintenance) {
+                tool_dbtransfer_maintenance_callback();
+            }
+            unset($CFG->tool_dbransfer_migration_running);
+            throw $e;
+        }
+        unset($CFG->tool_dbransfer_migration_running);
+
+        // Finish up.
+        echo $OUTPUT->notification(get_string('success'), 'notifysuccess');
+        echo $OUTPUT->continue_button("$CFG->wwwroot/$CFG->admin/");
+        echo $OUTPUT->footer();
+        die;
+    }
+}
+
+// Otherwise display the settings form.
+echo $OUTPUT->header();
+echo $OUTPUT->heading(get_string('transferdbtoserver', 'tool_dbtransfer'));
+
+$info = format_text(get_string('transferdbintro', 'tool_dbtransfer'), FORMAT_MARKDOWN);
+echo $OUTPUT->box($info);
+
+$form->display();
+if ($problem !== '') {
+    echo $OUTPUT->box($problem, 'generalbox error');
+}
+echo $OUTPUT->footer();

admin/tool/dbtransfer/lang/en/tool_dbtransfer.php

@@ -0,0 +1,43 @@
+<?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/>.
+
+/**
+ * Strings for component 'tool_generator', language 'en'.
+ *
+ * @package    tool_dbtransfer
+ * @copyright  2011 Petr Skoda {@link http://skodak.org/}
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+$string['clidriverlist'] = 'Available database drivers for migration';
+$string['cliheading'] = 'Database migration - make sure nobody is accessing the server during migration!';
+$string['climigrationnotice'] = 'Database migration in progress, please wait until the migration completes and server administrator updates configuration and deletes the $CFG->dataroot/climaintenance.html file.';
+$string['convertinglogdisplay'] = 'Converting log display actions';
+$string['dbexport'] = 'Database export';
+$string['dbtransfer'] = 'Database migration';
+$string['enablemaintenance'] = 'Enable maintenance mode';
+$string['enablemaintenance_help'] = 'This option enables maintanance mode during and after the database migration, it prevents access of all users until the migration is completed. Please note that administrator has to manually delete $CFG->dataroot/climaintenance.html file after updating config.php settings to resume normal operation.';
+$string['exportdata'] = 'Export data';
+$string['notargetconectexception'] = 'Can not connect target database, sorry.';
+$string['options'] = 'Options';
+$string['pluginname'] = 'Database transfer';
+$string['targetdatabase'] = 'Target database';
+$string['targetdatabasenotempty'] = 'Target database must not contain any tables with given prefix!';
+$string['transferdata'] = 'Transfer data';
+$string['transferdbintro'] = 'This script will transfer the entire contents of this database to another database server. It is often used for migration of data to different database type.';
+$string['transferdbtoserver'] = 'Transfer this Moodle database to another server';
+$string['transferringdbto'] = 'Transferring this {$a->dbtypefrom} database to {$a->dbtype} database "{$a->dbname}" on "{$a->dbhost}"';
+$string['privacy:metadata'] = 'The Database transfer plugin does not store any personal data.';

admin/tool/dbtransfer/locallib.php

@@ -0,0 +1,208 @@
+<?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/>.
+
+/**
+ * Export db content to file.
+ *
+ * @package    tool_dbtransfer
+ * @copyright  2008 Petr Skoda {@link http://skodak.org/}
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+defined('MOODLE_INTERNAL') || die;
+/*
+
+TODO:
+  - exporting to server file >2GB fails in 32bit operating systems - needs warning
+  - we may run out of disk space exporting to server file - we must verify the file is not truncated; read from the end of file?
+  - when sending file >4GB - FAT32 limit, Apache limit, browser limit - needs warning
+  - there must be some form of progress bar during export, transfer - new tracking class could be passed around
+  - command line operation - could work around some 2G/4G limits in PHP; useful for cron full backups
+  - by default allow exporting into empty database only (no tables with the same prefix yet)
+  - all dangerous operation (like deleting of all data) should be confirmed by key found in special file in dataroot
+    (user would need file access to dataroot which might prevent various "accidents")
+  - implement "Export/import running" notification in lib/setup.php (similar to new upgrade flag in config table)
+  - gzip compression when storing xml file - the xml is very verbose and full of repeated tags (zip is not suitable here at all)
+    this could help us keep the files below 2G (expected ratio is > 10:1)
+
+*/
+
+require_once($CFG->libdir.'/adminlib.php');
+require_once($CFG->libdir.'/dtllib.php');
+
+/**
+ * Initiate database export.
+ * @param string $description
+ * @param moodle_database $mdb
+ * @return does not return, calls die()
+ */
+function tool_dbtransfer_export_xml_database($description, $mdb) {
+    core_php_time_limit::raise();
+
+    \core\session\manager::write_close(); // Release session.
+
+    header('Content-Type: application/xhtml+xml; charset=utf-8');
+    header('Content-Disposition: attachment; filename=database.xml');
+    header('Expires: 0');
+    header('Cache-Control: must-revalidate,post-check=0,pre-check=0');
+    header('Pragma: public');
+
+    while(@ob_flush());
+
+    $var = new file_xml_database_exporter('php://output', $mdb);
+    $var->export_database($description);
+
+    // No more output.
+    die;
+}
+
+/**
+ * Initiate database transfer.
+ * @param moodle_database $sourcedb
+ * @param moodle_database $targetdb
+ * @param progress_trace $feedback
+ * @return void
+ */
+function tool_dbtransfer_transfer_database(moodle_database $sourcedb, moodle_database $targetdb, progress_trace $feedback = null) {
+    core_php_time_limit::raise();
+
+    \core\session\manager::write_close(); // Release session.
+
+    $var = new database_mover($sourcedb, $targetdb, true, $feedback);
+    $var->export_database(null);
+
+    tool_dbtransfer_rebuild_target_log_actions($targetdb, $feedback);
+}
+
+/**
+ * Very hacky function for rebuilding of log actions in target database.
+ * @param moodle_database $target
+ * @param progress_trace $feedback
+ * @return void
+ * @throws Exception on conversion error
+ */
+function tool_dbtransfer_rebuild_target_log_actions(moodle_database $target, progress_trace $feedback = null) {
+    global $DB, $CFG;
+    require_once("$CFG->libdir/upgradelib.php");
+
+    $feedback->output(get_string('convertinglogdisplay', 'tool_dbtransfer'));
+
+    $olddb = $DB;
+    $DB = $target;
+    try {
+        $DB->delete_records('log_display', array('component'=>'moodle'));
+        log_update_descriptions('moodle');
+        $plugintypes = core_component::get_plugin_types();
+        foreach ($plugintypes as $type => $location) {
+            $plugs = core_component::get_plugin_list($type);
+            foreach ($plugs as $plug => $fullplug) {
+                $component = $type.'_'.$plug;
+                $DB->delete_records('log_display', array('component'=>$component));
+                log_update_descriptions($component);
+            }
+        }
+    } catch (Exception $e) {
+        $DB = $olddb;
+        throw $e;
+    }
+    $DB = $olddb;
+    $feedback->output(get_string('done', 'core_dbtransfer', null), 1);
+}
+
+/**
+ * Returns list of fully working database drivers present in system.
+ * @return array
+ */
+function tool_dbtransfer_get_drivers() {
+    global $CFG;
+
+    $files = new RegexIterator(new DirectoryIterator("$CFG->libdir/dml"), '|^.*_moodle_database\.php$|');
+    $drivers = array();
+
+    foreach ($files as $file) {
+        $matches = null;
+        preg_match('|^([a-z0-9]+)_([a-z]+)_moodle_database\.php$|', $file->getFilename(), $matches);
+        if (!$matches) {
+            continue;
+        }
+        $dbtype = $matches[1];
+        $dblibrary = $matches[2];
+
+        if ($dbtype === 'sqlite3') {
+            // The sqlite3 driver is not fully working yet and should not be returned.
+            continue;
+        }
+
+        $targetdb = moodle_database::get_driver_instance($dbtype, $dblibrary, false);
+        if ($targetdb->driver_installed() !== true) {
+            continue;
+        }
+
+        $driver = $dbtype.'/'.$dblibrary;
+
+        $drivers[$driver] = $targetdb->get_name();
+    };
+
+    return $drivers;
+}
+
+/**
+ * Create CLI maintenance file to prevent all access.
+ */
+function tool_dbtransfer_create_maintenance_file() {
+    global $CFG;
+
+    core_shutdown_manager::register_function('tool_dbtransfer_maintenance_callback');
+
+    $options = new stdClass();
+    $options->trusted = false;
+    $options->noclean = false;
+    $options->filter = false;
+    $options->para = true;
+    $options->newlines = false;
+
+    $message = format_text(get_string('climigrationnotice', 'tool_dbtransfer'), FORMAT_MARKDOWN, $options);
+    $message = bootstrap_renderer::early_error_content($message, '', '', array());
+    $html = <<<OET
+<!DOCTYPE html>
+<html>
+<header><meta http-equiv="Content-Type" content="text/html; charset=utf-8" /><header/>
+<body>$message</body>
+</html>
+OET;
+
+    file_put_contents("$CFG->dataroot/climaintenance.html", $html);
+    @chmod("$CFG->dataroot/climaintenance.html", $CFG->filepermissions);
+}
+
+/**
+ * This callback is responsible for unsetting maintenance mode
+ * if the migration is interrupted.
+ */
+function tool_dbtransfer_maintenance_callback() {
+    global $CFG;
+
+    if (empty($CFG->tool_dbransfer_migration_running)) {
+        // Migration was finished properly - keep the maintenance file in place.
+        return;
+    }
+
+    if (file_exists("$CFG->dataroot/climaintenance.html")) {
+        // Failed migration, revert to normal site operation.
+        unlink("$CFG->dataroot/climaintenance.html");
+        error_log('tool_dbtransfer: Interrupted database migration detected, switching off CLI maintenance mode.');
+    }
+}

admin/tool/dbtransfer/settings.php

@@ -0,0 +1,33 @@
+<?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/>.
+
+/**
+ * Add hidden links db transfer tool
+ *
+ * @package    tool_dbtransfer
+ * @copyright  2011 Petr Skoda {@link http://skodak.org/}
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+defined('MOODLE_INTERNAL') || die;
+
+if ($hassiteconfig) {
+    $ADMIN->add('experimental', new admin_externalpage('tooldbtransfer', get_string('dbtransfer', 'tool_dbtransfer'),
+        $CFG->wwwroot.'/'.$CFG->admin.'/tool/dbtransfer/index.php', 'moodle/site:config', false));
+    // DB export/import is not ready yet - keep it hidden for now.
+    $ADMIN->add('experimental', new admin_externalpage('tooldbexport', get_string('dbexport', 'tool_dbtransfer'),
+        $CFG->wwwroot.'/'.$CFG->admin.'/tool/dbtransfer/dbexport.php', 'moodle/site:config', true));
+}

admin/tool/dbtransfer/version.php

@@ -0,0 +1,29 @@
+<?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/>.
+
+/**
+ * Version details.
+ *
+ * @package    tool_dbtransfer
+ * @copyright  2008 Petr Skoda {@link http://skodak.org/}
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+defined('MOODLE_INTERNAL') || die();
+
+$plugin->version   = 2024042200; // The current plugin version (Date: YYYYMMDDXX).
+$plugin->requires  = 2024041600; // Requires this Moodle version.
+$plugin->component = 'tool_dbtransfer'; // Full name of the plugin (used for diagnostics).