maintenance/fetchText.php

   1 <?php
   2 /**
   3  * Communications protocol.
   4  * This is used by dumpTextPass.php when the --spawn option is present.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along
  17  * with this program; if not, write to the Free Software Foundation, Inc.,
  18  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  19  * http://www.gnu.org/copyleft/gpl.html
  20  *
  21  * @file
  22  * @ingroup Maintenance
  23  */
  24
  25 require_once __DIR__ . '/Maintenance.php';
  26
  27 use Wikimedia\Rdbms\IDatabase;
  28
  29 /**
  30  * Maintenance script used to fetch page text in a subprocess.
  31  *
  32  * @ingroup Maintenance
  33  */
  34 class FetchText extends Maintenance {
  35         public function __construct() {
  36                 parent::__construct();
  37                 $this->addDescription( "Fetch the raw revision blob from an old_id.\n" .
  38                         "NOTE: Export transformations are NOT applied. " .
  39                         "This is left to backupTextPass.php"
  40                 );
  41         }
  42
  43         /**
  44          * returns a string containing the following in order:
  45          *   textid
  46          *   \n
  47          *   length of text (-1 on error = failure to retrieve/unserialize/gunzip/etc)
  48          *   \n
  49          *   text  (may be empty)
  50          *
  51          * note that the text string itself is *not* followed by newline
  52          */
  53         public function execute() {
  54                 $db = $this->getDB( DB_REPLICA );
  55                 $stdin = $this->getStdin();
  56                 while ( !feof( $stdin ) ) {
  57                         $line = fgets( $stdin );
  58                         if ( $line === false ) {
  59                                 // We appear to have lost contact...
  60                                 break;
  61                         }
  62                         $textId = intval( $line );
  63                         $text = $this->doGetText( $db, $textId );
  64                         if ( $text === false ) {
  65                                 # actual error, not zero-length text
  66                                 $textLen = "-1";
  67                         } else {
  68                                 $textLen = strlen( $text );
  69                         }
  70                         $this->output( $textId . "\n" . $textLen . "\n" . $text );
  71                 }
  72         }
  73
  74         /**
  75          * May throw a database error if, say, the server dies during query.
  76          * @param IDatabase $db
  77          * @param int $id The old_id
  78          * @return string
  79          */
  80         private function doGetText( $db, $id ) {
  81                 $id = intval( $id );
  82                 $row = $db->selectRow( 'text',
  83                         [ 'old_text', 'old_flags' ],
  84                         [ 'old_id' => $id ],
  85                         __METHOD__ );
  86                 $text = Revision::getRevisionText( $row );
  87                 if ( $text === false ) {
  88                         return false;
  89                 }
  90
  91                 return $text;
  92         }
  93 }
  94
  95 $maintClass = FetchText::class;
  96 require_once RUN_MAINTENANCE_IF_MAIN;