lib/dtl/xml_database_importer.php

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