Proyectos de Subversion Moodle

<?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/>.

/**

 * General database export class

 *

 * @package    core_dtl

 * @copyright  2008 Andrei Bautu

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

defined('MOODLE_INTERNAL') || die();

/**

 * Base class for database export operations. This class defines basic callbacks

 * for export operations and implements the @see export_database and

 * @export_table methods generic export processing. In general, subclasses will

 * override callback methods to provide specific output and (optionally)

 * @see export_database to add functionality.

 * Between a single pair of calls to @see begin_database_export and

 * @see finish_database_export, multiple non-overlapping pairs of calls may

 * be made to @see begin_table_export and @see finish_database_export for

 * different tables. Between one pair of calls to @see begin_table_export and

 * @see finish_database_export multiple calls may be made to

 * @see export_table_data for the same table.

 */

abstract class database_exporter {

    /** @var moodle_database Connection to the source database (a @see moodle_database object). */

    protected $mdb;

    /** @var database_manager Database manager of the source database (a @see database_manager object). */

    protected $manager;

    /** @var xmldb_structure Source database schema in XMLDB format (a @see xmldb_structure object). */

    protected $schema;

    /**

     * Boolean flag - whether or not to check that XML database schema matches

     * the RDBMS database schema before exporting (used by

     * @see export_database).

     * @var bool

     */

    protected $check_schema;

    /**

     * Object constructor.

     *

     * @param moodle_database $mdb Connection to the source database (a

     * @see moodle_database object).

     * @param boolean $check_schema - whether or not to check that XML database

     * schema matches the RDBMS database schema before exporting (used by

     * @see export_database).

     */

    public function __construct(moodle_database $mdb, $check_schema=true) {

        $this->mdb          = $mdb;

        $this->manager      = $mdb->get_manager();

        $this->schema       = $this->manager->get_install_xml_schema();

        $this->check_schema = $check_schema;

    }

    /**

     * Callback function. Should be called only once database per export

     * operation, before any other export operations. Subclasses should export

     * basic database information (version and timestamp).

     *

     * @param float $version the version of the system which generating the data

     * @param string $release moodle release info

     * @param string $timestamp the timestamp of the data (in ISO 8601) format.

     * @param string $description a user description of the data.

     * @return void

     */

    abstract public function begin_database_export($version, $release, $timestamp, $description);

    /**

     * Callback function. Should be called only once per table export operation,

     * before any other table export operations. Subclasses should export

     * basic database information (name and schema's hash).

     *

     * @param xmldb_table $table - XMLDB object for the exported table

     * @return void

     */

    abstract public function begin_table_export(xmldb_table $table);

    /**

     * Callback function. Should be called only once per table export operation,

     * after all other table export operations.

     *

     * @param xmldb_table $table - XMLDB object for the exported table

     */

    abstract public function finish_table_export(xmldb_table $table);

    /**

     * Callback function. Should be called only once database per export

     * operation, after all database export operations.

     */

    abstract public function finish_database_export();

    /**

     * Callback function. Should be called only once per record export operation,

     * only between @see begin_table_export and @see finish_table_export calls.

     * It will insert table data. Subclasses should export basic record

     * information (data values).

     *

     * @param xmldb_table $table - XMLDB object of the table from which data was retrieved

     * @param object $data - data object (fields and values from record)

     * @return void

     */

    abstract public function export_table_data(xmldb_table $table, $data);

    /**

     * Generic method to export the database. It checks the schema (if

     * @see $check_schema is true), queries the database and calls

     * appropriate callbacks.

     *

     * @throws dbtransfer_exception if any checking (e.g. database schema) fails

     *

     * @param string $description a user description of the data.

     */

    public function export_database($description=null) {

        global $CFG;

        $options = [

            'changedcolumns' => false, // Column types may be fixed by transfer.

            'missingindexes' => false, // No need to worry about indexes for transfering data.

            'extraindexes' => false

        ];

        if ($this->check_schema and $errors = $this->manager->check_database_schema($this->schema, $options)) {

            $details = '';

            foreach ($errors as $table=>$items) {

                $details .= '<div>'.get_string('tablex', 'dbtransfer', $table);

                $details .= '<ul>';

                foreach ($items as $item) {

                    $details .= '<li>'.$item.'</li>';

                }

                $details .= '</ul></div>';

            }

            throw new dbtransfer_exception('exportschemaexception', $details);

        }

        $tables = $this->schema->getTables();

        $this->begin_database_export($CFG->version, $CFG->release, date('c'), $description);

        foreach ($tables as $table) {

            $rs = $this->mdb->export_table_recordset($table->getName());

            if (!$rs) {

                throw new ddl_table_missing_exception($table->getName());

            }

            $this->begin_table_export($table);

            foreach ($rs as $row) {

                $this->export_table_data($table, $row);

            }

            $this->finish_table_export($table);

            $rs->close();

        }

        $this->finish_database_export();

    }

}