lib/dtl/xml_database_importer.php

   1 <?php
   2
   3 // This file is part of Moodle - http://moodle.org/
   4 //
   5 // Moodle is free software: you can redistribute it and/or modify
   6 // it under the terms of the GNU General Public License as published by
   7 // the Free Software Foundation, either version 3 of the License, or
   8 // (at your option) any later version.
   9 //
  10 // Moodle is distributed in the hope that it will be useful,
  11 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 // GNU General Public License for more details.
  14 //
  15 // You should have received a copy of the GNU General Public License
  16 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  17
  18
  19 /**
  20  * XML format importer class
  21  *
  22  * @package    core
  23  * @subpackage dtl
  24  * @copyright  2008 Andrei Bautu
  25  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  26  */
  27
  28 defined('MOODLE_INTERNAL') || die();
  29
  30 /**
  31  * XML format importer class (uses SAX for speed and low memory footprint).
  32  * Provides logic for parsing XML data and calling appropriate callbacks.
  33  * Subclasses should define XML data sources.
  34  */
  35 abstract class xml_database_importer extends database_importer {
  36     protected $current_table;
  37     protected $current_row;
  38     protected $current_field;
  39     protected $current_data;
  40     protected $current_data_is_null;
  41
  42     /**
  43      * Creates and setups a SAX parser. Subclasses should use this method to
  44      * create the XML parser.
  45      *
  46      * @return resource XML parser resource.
  47      */
  48     protected function get_parser() {
  49         $parser = xml_parser_create();
  50         xml_set_object($parser, $this);
  51         xml_set_element_handler($parser, 'tag_open', 'tag_close');
  52         xml_set_character_data_handler($parser, 'cdata');
  53         xml_parser_set_option($parser, XML_OPTION_CASE_FOLDING, false);
  54         return $parser;
  55     }
  56
  57     /**
  58      * Callback function. Called by the XML parser for opening tags processing.
  59      *
  60      * @param resource $parser XML parser resource.
  61      * @param string $tag name of opening tag
  62      * @param array $attributes set of opening tag XML attributes
  63      * @return void
  64      */
  65     protected function tag_open($parser, $tag, $attributes) {
  66         switch ($tag) {
  67             case 'moodle_database' :
  68                 if (empty($attributes['version']) || empty($attributes['timestamp'])) {
  69                     throw new dbtransfer_exception('malformedxmlexception');
  70                 }
  71                 $this->begin_database_import($attributes['version'], $attributes['timestamp']);
  72                 break;
  73             case 'table' :
  74                 if (isset($this->current_table)) {
  75                     throw new dbtransfer_exception('malformedxmlexception');
  76                 }
  77                 if (empty($attributes['name']) || empty($attributes['schemaHash'])) {
  78                     throw new dbtransfer_exception('malformedxmlexception');
  79                 }
  80                 $this->current_table = $attributes['name'];
  81                 $this->begin_table_import($this->current_table, $attributes['schemaHash']);
  82                 break;
  83             case 'record' :
  84                 if (isset($this->current_row) || !isset($this->current_table)) {
  85                     throw new dbtransfer_exception('malformedxmlexception');
  86                 }
  87                 $this->current_row = new stdClass();
  88                 break;
  89             case 'field' :
  90                 if (isset($this->current_field) || !isset($this->current_row)) {
  91                     throw new dbtransfer_exception('malformedxmlexception');
  92                 }
  93                 $this->current_field = $attributes['name'];
  94                 $this->current_data = '';
  95                 if (isset($attributes['value']) and $attributes['value'] === 'null') {
  96                     $this->current_data_is_null = true;
  97                 } else {
  98                     $this->current_data_is_null = false;
  99                 }
 100                 break;
 101             default :
 102                 throw new dbtransfer_exception('malformedxmlexception');
 103         }
 104     }
 105
 106     /**
 107      * Callback function. Called by the XML parser for closing tags processing.
 108      *
 109      * @param resource $parser XML parser resource.
 110      * @param string $tag name of opening tag
 111      * @return void
 112      */
 113     protected function tag_close($parser, $tag) {
 114         switch ($tag) {
 115             case 'moodle_database' :
 116                 $this->finish_database_import();
 117                 break;
 118
 119             case 'table' :
 120                 $this->finish_table_import($this->current_table);
 121                 $this->current_table = null;
 122                 break;
 123
 124             case 'record' :
 125                 $this->import_table_data($this->current_table, $this->current_row);
 126                 $this->current_row = null;;
 127                 break;
 128
 129             case 'field' :
 130                 $field = $this->current_field;
 131                 if ($this->current_data_is_null) {
 132                     $this->current_row->$field = null;
 133                 } else {
 134                     $this->current_row->$field = $this->current_data;
 135                 }
 136                 $this->current_field        = null;
 137                 $this->current_data         = null;
 138                 $this->current_data_is_null = null;
 139                 break;
 140
 141             default :
 142                 throw new dbtransfer_exception('malformedxmlexception');
 143         }
 144     }
 145
 146     /**
 147      * Callback function. Called by the XML parser for character data processing.
 148      *
 149      * @param resource $parser XML parser resource.
 150      * @param string $data character data to be processed
 151      * @return void
 152      */
 153     protected function cdata($parser, $cdata) {
 154         if (isset($this->current_field)) {
 155             $this->current_data .= $cdata;
 156         }
 157     }
 158 }