includes/export/XmlDumpWriter.php

   1 <?php
   2 /**
   3  * XmlDumpWriter
   4  *
   5  * Copyright © 2003, 2005, 2006 Brion Vibber <brion@pobox.com>
   6  * https://www.mediawiki.org/
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along
  19  * with this program; if not, write to the Free Software Foundation, Inc.,
  20  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  21  * http://www.gnu.org/copyleft/gpl.html
  22  *
  23  * @file
  24  */
  25 use MediaWiki\MediaWikiServices;
  26 use MediaWiki\Revision\RevisionRecord;
  27 use MediaWiki\Revision\RevisionStore;
  28 use MediaWiki\Revision\SlotRecord;
  29 use MediaWiki\Revision\SuppressedDataException;
  30 use MediaWiki\Storage\SqlBlobStore;
  31 use Wikimedia\Assert\Assert;
  32
  33 /**
  34  * @ingroup Dump
  35  */
  36 class XmlDumpWriter {
  37
  38         /** Output serialized revision content. */
  39         const WRITE_CONTENT = 0;
  40
  41         /** Only output subs for revision content. */
  42         const WRITE_STUB = 1;
  43
  44         /**
  45          * Only output subs for revision content, indicating that the content has been
  46          * deleted/suppressed. For internal use only.
  47          */
  48         const WRITE_STUB_DELETED = 2;
  49
  50         /**
  51          * @var string[] the schema versions supported for output
  52          * @final
  53          */
  54         public static $supportedSchemas = [
  55                 XML_DUMP_SCHEMA_VERSION_10,
  56                 XML_DUMP_SCHEMA_VERSION_11
  57         ];
  58
  59         /**
  60          * @var string which schema version the generated XML should comply to.
  61          * One of the values from self::$supportedSchemas, using the SCHEMA_VERSION_XX
  62          * constants.
  63          */
  64         private $schemaVersion;
  65
  66         /**
  67          * Title of the currently processed page
  68          *
  69          * @var Title|null
  70          */
  71         private $currentTitle = null;
  72
  73         /**
  74          * @var int Whether to output revision content or just stubs. WRITE_CONTENT or WRITE_STUB.
  75          */
  76         private $contentMode;
  77
  78         /**
  79          * XmlDumpWriter constructor.
  80          *
  81          * @param int $contentMode WRITE_CONTENT or WRITE_STUB.
  82          * @param string $schemaVersion which schema version the generated XML should comply to.
  83          * One of the values from self::$supportedSchemas, using the XML_DUMP_SCHEMA_VERSION_XX
  84          * constants.
  85          */
  86         public function __construct(
  87                 $contentMode = self::WRITE_CONTENT,
  88                 $schemaVersion = XML_DUMP_SCHEMA_VERSION_11
  89         ) {
  90                 Assert::parameter(
  91                         in_array( $contentMode, [ self::WRITE_CONTENT, self::WRITE_STUB ] ),
  92                         '$contentMode',
  93                         'must be one of the following constants: WRITE_CONTENT or WRITE_STUB.'
  94                 );
  95
  96                 Assert::parameter(
  97                         in_array( $schemaVersion, self::$supportedSchemas ),
  98                         '$schemaVersion',
  99                         'must be one of the following schema versions: '
 100                                 . implode( ',', self::$supportedSchemas )
 101                 );
 102
 103                 $this->contentMode = $contentMode;
 104                 $this->schemaVersion = $schemaVersion;
 105         }
 106
 107         /**
 108          * Opens the XML output stream's root "<mediawiki>" element.
 109          * This does not include an xml directive, so is safe to include
 110          * as a subelement in a larger XML stream. Namespace and XML Schema
 111          * references are included.
 112          *
 113          * Output will be encoded in UTF-8.
 114          *
 115          * @return string
 116          */
 117         function openStream() {
 118                 $ver = $this->schemaVersion;
 119                 return Xml::element( 'mediawiki', [
 120                         'xmlns'              => "http://www.mediawiki.org/xml/export-$ver/",
 121                         'xmlns:xsi'          => "http://www.w3.org/2001/XMLSchema-instance",
 122                         /*
 123                          * When a new version of the schema is created, it needs staging on mediawiki.org.
 124                          * This requires a change in the operations/mediawiki-config git repo.
 125                          *
 126                          * Create a changeset like https://gerrit.wikimedia.org/r/#/c/149643/ in which
 127                          * you copy in the new xsd file.
 128                          *
 129                          * After it is reviewed, merged and deployed (sync-docroot), the index.html needs purging.
 130                          * echo "https://www.mediawiki.org/xml/index.html" | mwscript purgeList.php --wiki=aawiki
 131                          */
 132                         'xsi:schemaLocation' => "http://www.mediawiki.org/xml/export-$ver/ " .
 133                                 "http://www.mediawiki.org/xml/export-$ver.xsd",
 134                         'version' => $ver,
 135                         'xml:lang' => MediaWikiServices::getInstance()->getContentLanguage()->getHtmlCode() ],
 136                         null ) .
 137                         "\n" .
 138                         $this->siteInfo();
 139         }
 140
 141         /**
 142          * @return string
 143          */
 144         function siteInfo() {
 145                 $info = [
 146                         $this->sitename(),
 147                         $this->dbname(),
 148                         $this->homelink(),
 149                         $this->generator(),
 150                         $this->caseSetting(),
 151                         $this->namespaces() ];
 152                 return "  <siteinfo>\n    " .
 153                         implode( "\n    ", $info ) .
 154                         "\n  </siteinfo>\n";
 155         }
 156
 157         /**
 158          * @return string
 159          */
 160         function sitename() {
 161                 global $wgSitename;
 162                 return Xml::element( 'sitename', [], $wgSitename );
 163         }
 164
 165         /**
 166          * @return string
 167          */
 168         function dbname() {
 169                 global $wgDBname;
 170                 return Xml::element( 'dbname', [], $wgDBname );
 171         }
 172
 173         /**
 174          * @return string
 175          */
 176         function generator() {
 177                 global $wgVersion;
 178                 return Xml::element( 'generator', [], "MediaWiki $wgVersion" );
 179         }
 180
 181         /**
 182          * @return string
 183          */
 184         function homelink() {
 185                 return Xml::element( 'base', [], Title::newMainPage()->getCanonicalURL() );
 186         }
 187
 188         /**
 189          * @return string
 190          */
 191         function caseSetting() {
 192                 global $wgCapitalLinks;
 193                 // "case-insensitive" option is reserved for future
 194                 $sensitivity = $wgCapitalLinks ? 'first-letter' : 'case-sensitive';
 195                 return Xml::element( 'case', [], $sensitivity );
 196         }
 197
 198         /**
 199          * @return string
 200          */
 201         function namespaces() {
 202                 $spaces = "<namespaces>\n";
 203                 $nsInfo = MediaWikiServices::getInstance()->getNamespaceInfo();
 204                 foreach (
 205                         MediaWikiServices::getInstance()->getContentLanguage()->getFormattedNamespaces()
 206                         as $ns => $title
 207                 ) {
 208                         $spaces .= '      ' .
 209                                 Xml::element( 'namespace',
 210                                         [
 211                                                 'key' => $ns,
 212                                                 'case' => $nsInfo->isCapitalized( $ns )
 213                                                         ? 'first-letter' : 'case-sensitive',
 214                                         ], $title ) . "\n";
 215                 }
 216                 $spaces .= "    </namespaces>";
 217                 return $spaces;
 218         }
 219
 220         /**
 221          * Closes the output stream with the closing root element.
 222          * Call when finished dumping things.
 223          *
 224          * @return string
 225          */
 226         function closeStream() {
 227                 return "</mediawiki>\n";
 228         }
 229
 230         /**
 231          * Opens a "<page>" section on the output stream, with data
 232          * from the given database row.
 233          *
 234          * @param object $row
 235          * @return string
 236          */
 237         public function openPage( $row ) {
 238                 $out = "  <page>\n";
 239                 $this->currentTitle = Title::newFromRow( $row );
 240                 $canonicalTitle = self::canonicalTitle( $this->currentTitle );
 241                 $out .= '    ' . Xml::elementClean( 'title', [], $canonicalTitle ) . "\n";
 242                 $out .= '    ' . Xml::element( 'ns', [], strval( $row->page_namespace ) ) . "\n";
 243                 $out .= '    ' . Xml::element( 'id', [], strval( $row->page_id ) ) . "\n";
 244                 if ( $row->page_is_redirect ) {
 245                         $page = WikiPage::factory( $this->currentTitle );
 246                         $redirect = $page->getRedirectTarget();
 247                         if ( $redirect instanceof Title && $redirect->isValidRedirectTarget() ) {
 248                                 $out .= '    ';
 249                                 $out .= Xml::element( 'redirect', [ 'title' => self::canonicalTitle( $redirect ) ] );
 250                                 $out .= "\n";
 251                         }
 252                 }
 253
 254                 if ( $row->page_restrictions != '' ) {
 255                         $out .= '    ' . Xml::element( 'restrictions', [],
 256                                 strval( $row->page_restrictions ) ) . "\n";
 257                 }
 258
 259                 Hooks::run( 'XmlDumpWriterOpenPage', [ $this, &$out, $row, $this->currentTitle ] );
 260
 261                 return $out;
 262         }
 263
 264         /**
 265          * Closes a "<page>" section on the output stream.
 266          *
 267          * @private
 268          * @return string
 269          */
 270         function closePage() {
 271                 if ( $this->currentTitle !== null ) {
 272                         $linkCache = MediaWikiServices::getInstance()->getLinkCache();
 273                         // In rare cases, link cache has the same key for some pages which
 274                         // might be read as part of the same batch. T220424 and T220316
 275                         $linkCache->clearLink( $this->currentTitle );
 276                 }
 277                 return "  </page>\n";
 278         }
 279
 280         /**
 281          * @return RevisionStore
 282          */
 283         private function getRevisionStore() {
 284                 return MediaWikiServices::getInstance()->getRevisionStore();
 285         }
 286
 287         /**
 288          * @return SqlBlobStore
 289          */
 290         private function getBlobStore() {
 291                 return MediaWikiServices::getInstance()->getBlobStore();
 292         }
 293
 294         /**
 295          * Dumps a "<revision>" section on the output stream, with
 296          * data filled in from the given database row.
 297          *
 298          * @param object $row
 299          * @param null|object[] $slotRows
 300          *
 301          * @return string
 302          * @throws FatalError
 303          * @throws MWException
 304          * @private
 305          */
 306         function writeRevision( $row, $slotRows = null ) {
 307                 $rev = $this->getRevisionStore()->newRevisionFromRowAndSlots(
 308                         $row,
 309                         $slotRows,
 310                         0,
 311                         $this->currentTitle
 312                 );
 313
 314                 $out = "    <revision>\n";
 315                 $out .= "      " . Xml::element( 'id', null, strval( $rev->getId() ) ) . "\n";
 316
 317                 if ( $rev->getParentId() ) {
 318                         $out .= "      " . Xml::element( 'parentid', null, strval( $rev->getParentId() ) ) . "\n";
 319                 }
 320
 321                 $out .= $this->writeTimestamp( $rev->getTimestamp() );
 322
 323                 if ( $rev->isDeleted( RevisionRecord::DELETED_USER ) ) {
 324                         $out .= "      " . Xml::element( 'contributor', [ 'deleted' => 'deleted' ] ) . "\n";
 325                 } else {
 326                         // empty values get written out as uid 0, see T224221
 327                         $user = $rev->getUser();
 328                         $out .= $this->writeContributor(
 329                                 $user ? $user->getId() : 0,
 330                                 $user ? $user->getName() : ''
 331                         );
 332                 }
 333
 334                 if ( $rev->isMinor() ) {
 335                         $out .= "      <minor/>\n";
 336                 }
 337                 if ( $rev->isDeleted( RevisionRecord::DELETED_COMMENT ) ) {
 338                         $out .= "      " . Xml::element( 'comment', [ 'deleted' => 'deleted' ] ) . "\n";
 339                 } else {
 340                         if ( $rev->getComment()->text != '' ) {
 341                                 $out .= "      "
 342                                         . Xml::elementClean( 'comment', [], strval( $rev->getComment()->text ) )
 343                                         . "\n";
 344                         }
 345                 }
 346
 347                 $contentMode = $rev->isDeleted( RevisionRecord::DELETED_TEXT ) ? self::WRITE_STUB_DELETED
 348                         : $this->contentMode;
 349
 350                 foreach ( $rev->getSlots()->getSlots() as $slot ) {
 351                         $out .= $this->writeSlot( $slot, $contentMode );
 352                 }
 353
 354                 if ( $rev->isDeleted( RevisionRecord::DELETED_TEXT ) ) {
 355                         $out .= "      <sha1/>\n";
 356                 } else {
 357                         $out .= "      " . Xml::element( 'sha1', null, strval( $rev->getSha1() ) ) . "\n";
 358                 }
 359
 360                 // Avoid PHP 7.1 warning from passing $this by reference
 361                 $writer = $this;
 362                 $text = '';
 363                 if ( $contentMode === self::WRITE_CONTENT ) {
 364                         $text = $rev->getContent( SlotRecord::MAIN, RevisionRecord::RAW );
 365                 }
 366                 Hooks::run( 'XmlDumpWriterWriteRevision', [ &$writer, &$out, $row, $text, $rev ] );
 367
 368                 $out .= "    </revision>\n";
 369
 370                 return $out;
 371         }
 372
 373         /**
 374          * @param SlotRecord $slot
 375          * @param int $contentMode see the WRITE_XXX constants
 376          *
 377          * @return string
 378          */
 379         private function writeSlot( SlotRecord $slot, $contentMode ) {
 380                 $isMain = $slot->getRole() === SlotRecord::MAIN;
 381                 $isV11 = $this->schemaVersion >= XML_DUMP_SCHEMA_VERSION_11;
 382
 383                 if ( !$isV11 && !$isMain ) {
 384                         // ignore extra slots
 385                         return '';
 386                 }
 387
 388                 $out = '';
 389                 $indent = '      ';
 390
 391                 if ( !$isMain ) {
 392                         // non-main slots are wrapped into an additional element.
 393                         $out .= '      ' . Xml::openElement( 'content' ) . "\n";
 394                         $indent .= '  ';
 395                         $out .= $indent . Xml::element( 'role', null, strval( $slot->getRole() ) ) . "\n";
 396                 }
 397
 398                 if ( $isV11 ) {
 399                         $out .= $indent . Xml::element( 'origin', null, strval( $slot->getOrigin() ) ) . "\n";
 400                 }
 401
 402                 $contentModel = $slot->getModel();
 403                 $contentHandler = ContentHandler::getForModelID( $contentModel );
 404                 $contentFormat = $contentHandler->getDefaultFormat();
 405
 406                 // XXX: The content format is only relevant when actually outputting serialized content.
 407                 // It should probably be an attribute on the text tag.
 408                 $out .= $indent . Xml::element( 'model', null, strval( $contentModel ) ) . "\n";
 409                 $out .= $indent . Xml::element( 'format', null, strval( $contentFormat ) ) . "\n";
 410
 411                 $textAttributes = [
 412                         'xml:space' => 'preserve',
 413                         'bytes' => $slot->getSize(),
 414                 ];
 415
 416                 if ( $isV11 ) {
 417                         $textAttributes['sha1'] = $slot->getSha1();
 418                 }
 419
 420                 if ( $contentMode === self::WRITE_CONTENT ) {
 421                         try {
 422                                 // write <text> tag
 423                                 $out .= $this->writeText( $slot->getContent(), $textAttributes, $indent );
 424                         } catch ( SuppressedDataException $ex ) {
 425                                 // NOTE: this shouldn't happen, since the caller is supposed to have checked
 426                                 // for suppressed content!
 427                                 // write <text> placeholder tag
 428                                 $textAttributes['deleted'] = 'deleted';
 429                                 $out .= $indent . Xml::element( 'text', $textAttributes ) . "\n";
 430                         }
 431                         catch ( Exception $ex ) {
 432                                 if ( $ex instanceof MWException || $ex instanceof RuntimeException ) {
 433                                         // there's no provision in the schema for an attribute that will let
 434                                         // the user know this element was unavailable due to error; an empty
 435                                         // tag is the best we can do
 436                                         $out .= $indent . Xml::element( 'text' ) . "\n";
 437                                         wfLogWarning(
 438                                                 'failed to load content slot ' . $slot->getRole() . ' for revision '
 439                                                 . $slot->getRevision() . "\n"
 440                                         );
 441                                 } else {
 442                                         throw $ex;
 443                                 }
 444                         }
 445                 } elseif ( $contentMode === self::WRITE_STUB_DELETED ) {
 446                         // write <text> placeholder tag
 447                         $textAttributes['deleted'] = 'deleted';
 448                         $out .= $indent . Xml::element( 'text', $textAttributes ) . "\n";
 449                 } else {
 450                         // write <text> stub tag
 451                         if ( $isV11 ) {
 452                                 $textAttributes['location'] = $slot->getAddress();
 453                         }
 454
 455                         // Output the numerical text ID if possible, for backwards compatibility.
 456                         // Note that this is currently the ONLY reason we have a BlobStore here at all.
 457                         // When removing this line, check whether the BlobStore has become unused.
 458                         $textId = $this->getBlobStore()->getTextIdFromAddress( $slot->getAddress() );
 459                         if ( $textId ) {
 460                                 $textAttributes['id'] = $textId;
 461                         } elseif ( !$isV11 ) {
 462                                 throw new InvalidArgumentException(
 463                                         'Cannot produce stubs for non-text-table content blobs with schema version '
 464                                         . $this->schemaVersion
 465                                 );
 466                         }
 467
 468                         $out .= $indent . Xml::element( 'text', $textAttributes ) . "\n";
 469                 }
 470
 471                 if ( !$isMain ) {
 472                         $out .= '      ' . Xml::closeElement( 'content' ) . "\n";
 473                 }
 474
 475                 return $out;
 476         }
 477
 478         /**
 479          * @param Content $content
 480          * @param string[] $textAttributes
 481          * @param string $indent
 482          *
 483          * @return string
 484          */
 485         private function writeText( Content $content, $textAttributes, $indent ) {
 486                 $out = '';
 487
 488                 $contentHandler = $content->getContentHandler();
 489                 $contentFormat = $contentHandler->getDefaultFormat();
 490
 491                 if ( $content instanceof TextContent ) {
 492                         // HACK: For text based models, bypass the serialization step. This allows extensions (like Flow)
 493                         // that use incompatible combinations of serialization format and content model.
 494                         $data = $content->getNativeData();
 495                 } else {
 496                         $data = $content->serialize( $contentFormat );
 497                 }
 498
 499                 $data = $contentHandler->exportTransform( $data, $contentFormat );
 500                 $textAttributes['bytes'] = $size = strlen( $data ); // make sure to use the actual size
 501                 $out .= $indent . Xml::elementClean( 'text', $textAttributes, strval( $data ) ) . "\n";
 502
 503                 return $out;
 504         }
 505
 506         /**
 507          * Dumps a "<logitem>" section on the output stream, with
 508          * data filled in from the given database row.
 509          *
 510          * @param object $row
 511          * @return string
 512          * @private
 513          */
 514         function writeLogItem( $row ) {
 515                 $out = "  <logitem>\n";
 516                 $out .= "    " . Xml::element( 'id', null, strval( $row->log_id ) ) . "\n";
 517
 518                 $out .= $this->writeTimestamp( $row->log_timestamp, "    " );
 519
 520                 if ( $row->log_deleted & LogPage::DELETED_USER ) {
 521                         $out .= "    " . Xml::element( 'contributor', [ 'deleted' => 'deleted' ] ) . "\n";
 522                 } else {
 523                         $out .= $this->writeContributor( $row->log_user, $row->user_name, "    " );
 524                 }
 525
 526                 if ( $row->log_deleted & LogPage::DELETED_COMMENT ) {
 527                         $out .= "    " . Xml::element( 'comment', [ 'deleted' => 'deleted' ] ) . "\n";
 528                 } else {
 529                         $comment = CommentStore::getStore()->getComment( 'log_comment', $row )->text;
 530                         if ( $comment != '' ) {
 531                                 $out .= "    " . Xml::elementClean( 'comment', null, strval( $comment ) ) . "\n";
 532                         }
 533                 }
 534
 535                 $out .= "    " . Xml::element( 'type', null, strval( $row->log_type ) ) . "\n";
 536                 $out .= "    " . Xml::element( 'action', null, strval( $row->log_action ) ) . "\n";
 537
 538                 if ( $row->log_deleted & LogPage::DELETED_ACTION ) {
 539                         $out .= "    " . Xml::element( 'text', [ 'deleted' => 'deleted' ] ) . "\n";
 540                 } else {
 541                         $title = Title::makeTitle( $row->log_namespace, $row->log_title );
 542                         $out .= "    " . Xml::elementClean( 'logtitle', null, self::canonicalTitle( $title ) ) . "\n";
 543                         $out .= "    " . Xml::elementClean( 'params',
 544                                 [ 'xml:space' => 'preserve' ],
 545                                 strval( $row->log_params ) ) . "\n";
 546                 }
 547
 548                 $out .= "  </logitem>\n";
 549
 550                 return $out;
 551         }
 552
 553         /**
 554          * @param string $timestamp
 555          * @param string $indent Default to six spaces
 556          * @return string
 557          */
 558         function writeTimestamp( $timestamp, $indent = "      " ) {
 559                 $ts = wfTimestamp( TS_ISO_8601, $timestamp );
 560                 return $indent . Xml::element( 'timestamp', null, $ts ) . "\n";
 561         }
 562
 563         /**
 564          * @param int $id
 565          * @param string $text
 566          * @param string $indent Default to six spaces
 567          * @return string
 568          */
 569         function writeContributor( $id, $text, $indent = "      " ) {
 570                 $out = $indent . "<contributor>\n";
 571                 if ( $id || !IP::isValid( $text ) ) {
 572                         $out .= $indent . "  " . Xml::elementClean( 'username', null, strval( $text ) ) . "\n";
 573                         $out .= $indent . "  " . Xml::element( 'id', null, strval( $id ) ) . "\n";
 574                 } else {
 575                         $out .= $indent . "  " . Xml::elementClean( 'ip', null, strval( $text ) ) . "\n";
 576                 }
 577                 $out .= $indent . "</contributor>\n";
 578                 return $out;
 579         }
 580
 581         /**
 582          * Warning! This data is potentially inconsistent. :(
 583          * @param object $row
 584          * @param bool $dumpContents
 585          * @return string
 586          */
 587         function writeUploads( $row, $dumpContents = false ) {
 588                 if ( $row->page_namespace == NS_FILE ) {
 589                         $img = MediaWikiServices::getInstance()->getRepoGroup()->getLocalRepo()
 590                                 ->newFile( $row->page_title );
 591                         if ( $img && $img->exists() ) {
 592                                 $out = '';
 593                                 foreach ( array_reverse( $img->getHistory() ) as $ver ) {
 594                                         $out .= $this->writeUpload( $ver, $dumpContents );
 595                                 }
 596                                 $out .= $this->writeUpload( $img, $dumpContents );
 597                                 return $out;
 598                         }
 599                 }
 600                 return '';
 601         }
 602
 603         /**
 604          * @param File $file
 605          * @param bool $dumpContents
 606          * @return string
 607          */
 608         function writeUpload( $file, $dumpContents = false ) {
 609                 if ( $file->isOld() ) {
 610                         $archiveName = "      " .
 611                                 Xml::element( 'archivename', null, $file->getArchiveName() ) . "\n";
 612                 } else {
 613                         $archiveName = '';
 614                 }
 615                 if ( $dumpContents ) {
 616                         $be = $file->getRepo()->getBackend();
 617                         # Dump file as base64
 618                         # Uses only XML-safe characters, so does not need escaping
 619                         # @todo Too bad this loads the contents into memory (script might swap)
 620                         $contents = '      <contents encoding="base64">' .
 621                                 chunk_split( base64_encode(
 622                                         $be->getFileContents( [ 'src' => $file->getPath() ] ) ) ) .
 623                                 "      </contents>\n";
 624                 } else {
 625                         $contents = '';
 626                 }
 627                 if ( $file->isDeleted( File::DELETED_COMMENT ) ) {
 628                         $comment = Xml::element( 'comment', [ 'deleted' => 'deleted' ] );
 629                 } else {
 630                         $comment = Xml::elementClean( 'comment', null, strval( $file->getDescription() ) );
 631                 }
 632                 return "    <upload>\n" .
 633                         $this->writeTimestamp( $file->getTimestamp() ) .
 634                         $this->writeContributor( $file->getUser( 'id' ), $file->getUser( 'text' ) ) .
 635                         "      " . $comment . "\n" .
 636                         "      " . Xml::element( 'filename', null, $file->getName() ) . "\n" .
 637                         $archiveName .
 638                         "      " . Xml::element( 'src', null, $file->getCanonicalUrl() ) . "\n" .
 639                         "      " . Xml::element( 'size', null, $file->getSize() ) . "\n" .
 640                         "      " . Xml::element( 'sha1base36', null, $file->getSha1() ) . "\n" .
 641                         "      " . Xml::element( 'rel', null, $file->getRel() ) . "\n" .
 642                         $contents .
 643                         "    </upload>\n";
 644         }
 645
 646         /**
 647          * Return prefixed text form of title, but using the content language's
 648          * canonical namespace. This skips any special-casing such as gendered
 649          * user namespaces -- which while useful, are not yet listed in the
 650          * XML "<siteinfo>" data so are unsafe in export.
 651          *
 652          * @param Title $title
 653          * @return string
 654          * @since 1.18
 655          */
 656         public static function canonicalTitle( Title $title ) {
 657                 if ( $title->isExternal() ) {
 658                         return $title->getPrefixedText();
 659                 }
 660
 661                 $prefix = MediaWikiServices::getInstance()->getContentLanguage()->
 662                         getFormattedNsText( $title->getNamespace() );
 663
 664                 // @todo Emit some kind of warning to the user if $title->getNamespace() !==
 665                 // NS_MAIN and $prefix === '' (viz. pages in an unregistered namespace)
 666
 667                 if ( $prefix !== '' ) {
 668                         $prefix .= ':';
 669                 }
 670
 671                 return $prefix . $title->getText();
 672         }
 673 }