UploadStash.php
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UploadStash.php
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	<?php
	/**
	* Temporary storage for uploaded files.
	*
	* This program 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 2 of the License, or
	* (at your option) any later version.
	*
	* This program 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 this program; if not, write to the Free Software Foundation, Inc.,
	* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
	* http://www.gnu.org/copyleft/gpl.html
	*
	* @file
	*/

	use MediaWiki\Context\RequestContext;
	use MediaWiki\MainConfigNames;
	use MediaWiki\MediaWikiServices;
	use MediaWiki\User\UserIdentity;

	/**
	* UploadStash is intended to accomplish a few things:
	* - Enable applications to temporarily stash files without publishing them to
	* the wiki.
	* - Several parts of MediaWiki do this in similar ways: UploadBase,
	* UploadWizard, and FirefoggChunkedExtension.
	* And there are several that reimplement stashing from scratch, in
	* idiosyncratic ways. The idea is to unify them all here.
	* Mostly all of them are the same except for storing some custom fields,
	* which we subsume into the data array.
	* - Enable applications to find said files later, as long as the db table or
	* temp files haven't been purged.
	* - Enable the uploading user (and ONLY the uploading user) to access said
	* files, and thumbnails of said files, via a URL. We accomplish this using
	* a database table, with ownership checking as you might expect. See
	* SpecialUploadStash, which implements a web interface to some files stored
	* this way.
	*
	* UploadStash right now is mostly intended to show you one user's slice of
	* the entire stash. The user parameter is only optional because there are few
	* cases where we clean out the stash from an automated script. In the future we
	* might refactor this.
	*
	* UploadStash represents the entire stash of temporary files.
	* UploadStashFile is a filestore for the actual physical disk files.
	* UploadFromStash extends UploadBase, and represents a single stashed file as
	* it is moved from the stash to the regular file repository
	*
	* @ingroup Upload
	*/
	class UploadStash {
	// Format of the key for files -- has to be suitable as a filename itself (e.g. ab12cd34ef.jpg)
	public const KEY_FORMAT_REGEX = '/^[\w\-\.]+\.\w*$/';
	private const MAX_US_PROPS_SIZE = 65535;

	/**
	* repository that this uses to store temp files
	* public because we sometimes need to get a LocalFile within the same repo.
	*
	* @var LocalRepo
	*/
	public $repo;

	/** @var array array of initialized repo objects */
	protected $files = [];

	/** @var array cache of the file metadata that's stored in the database */
	protected $fileMetadata = [];

	/** @var array fileprops cache */
	protected $fileProps = [];

	/** @var UserIdentity */
	private $user;

	/**
	* Represents a temporary filestore, with metadata in the database.
	* Designed to be compatible with the session stashing code in UploadBase
	* (should replace it eventually).
	*
	* @param FileRepo $repo
	* @param UserIdentity\|null $user
	*/
	public function __construct( FileRepo $repo, ?UserIdentity $user = null ) {
	// this might change based on wiki's configuration.
	$this->repo = $repo;

	// if a user was passed, use it. otherwise, attempt to use the global request context.
	// this keeps FileRepo from breaking when it creates an UploadStash object
	$this->user = $user ?? RequestContext::getMain()->getUser();
	}

	/**
	* Get a file and its metadata from the stash.
	* The noAuth param is a bit janky but is required for automated scripts
	* which clean out the stash.
	*
	* @param string $key Key under which file information is stored
	* @param bool $noAuth (optional) Don't check authentication. Used by maintenance scripts.
	* @throws UploadStashFileNotFoundException
	* @throws UploadStashNotLoggedInException
	* @throws UploadStashWrongOwnerException
	* @throws UploadStashBadPathException
	* @return UploadStashFile
	*/
	public function getFile( $key, $noAuth = false ) {
	if ( !preg_match( self::KEY_FORMAT_REGEX, $key ) ) {
	throw new UploadStashBadPathException(
	wfMessage( 'uploadstash-bad-path-bad-format', $key )
	);
	}

	if ( !$noAuth && !$this->user->isRegistered() ) {
	throw new UploadStashNotLoggedInException(
	wfMessage( 'uploadstash-not-logged-in' )
	);
	}

	if ( !isset( $this->fileMetadata[$key] ) ) {
	if ( !$this->fetchFileMetadata( $key ) ) {
	// If nothing was received, it's likely due to replication lag.
	// Check the primary DB to see if the record is there.
	$this->fetchFileMetadata( $key, DB_PRIMARY );
	}

	if ( !isset( $this->fileMetadata[$key] ) ) {
	throw new UploadStashFileNotFoundException(
	wfMessage( 'uploadstash-file-not-found', $key )
	);
	}

	// create $this->files[$key]
	$this->initFile( $key );

	// fetch fileprops
	if (
	isset( $this->fileMetadata[$key]['us_props'] ) && strlen( $this->fileMetadata[$key]['us_props'] )
	) {
	$this->fileProps[$key] = unserialize( $this->fileMetadata[$key]['us_props'] );
	} else { // b/c for rows with no us_props
	wfDebug( __METHOD__ . " fetched props for $key from file" );
	$path = $this->fileMetadata[$key]['us_path'];
	$this->fileProps[$key] = $this->repo->getFileProps( $path );
	}
	}

	if ( !$this->files[$key]->exists() ) {
	wfDebug( __METHOD__ . " tried to get file at $key, but it doesn't exist" );
	// @todo Is this not an UploadStashFileNotFoundException case?
	throw new UploadStashBadPathException(
	wfMessage( 'uploadstash-bad-path' )
	);
	}

	if ( !$noAuth && $this->fileMetadata[$key]['us_user'] != $this->user->getId() ) {
	throw new UploadStashWrongOwnerException(
	wfMessage( 'uploadstash-wrong-owner', $key )
	);
	}

	return $this->files[$key];
	}

	/**
	* Getter for file metadata.
	*
	* @param string $key Key under which file information is stored
	* @return array
	*/
	public function getMetadata( $key ) {
	$this->getFile( $key );

	return $this->fileMetadata[$key];
	}

	/**
	* Getter for fileProps
	*
	* @param string $key Key under which file information is stored
	* @return array
	*/
	public function getFileProps( $key ) {
	$this->getFile( $key );

	return $this->fileProps[$key];
	}

	/**
	* Stash a file in a temp directory and record that we did this in the
	* database, along with other metadata.
	*
	* @param string $path Path to file you want stashed
	* @param string\|null $sourceType The type of upload that generated this file
	* (currently, I believe, 'file' or null)
	* @param array\|null $fileProps File props or null to regenerate
	* @throws UploadStashBadPathException
	* @throws UploadStashFileException
	* @throws UploadStashNotLoggedInException
	* @return UploadStashFile\|null File, or null on failure
	*/
	public function stashFile( $path, $sourceType = null, $fileProps = null ) {
	if ( !is_file( $path ) ) {
	wfDebug( __METHOD__ . " tried to stash file at '$path', but it doesn't exist" );
	throw new UploadStashBadPathException(
	wfMessage( 'uploadstash-bad-path' )
	);
	}

	// File props is expensive to generate for large files, so reuse if possible.
	if ( !$fileProps ) {
	$mwProps = new MWFileProps( MediaWikiServices::getInstance()->getMimeAnalyzer() );
	$fileProps = $mwProps->getPropsFromPath( $path, true );
	}
	wfDebug( __METHOD__ . " stashing file at '$path'" );

	// we will be initializing from some tmpnam files that don't have extensions.
	// most of MediaWiki assumes all uploaded files have good extensions. So, we fix this.
	$extension = self::getExtensionForPath( $path );
	if ( !preg_match( "/\\.\\Q$extension\\E$/", $path ) ) {
	$pathWithGoodExtension = "$path.$extension";
	} else {
	$pathWithGoodExtension = $path;
	}

	// If no key was supplied, make one. a mysql insertid would be totally
	// reasonable here, except that for historical reasons, the key is this
	// random thing instead. At least it's not guessable.
	// Some things that when combined will make a suitably unique key.
	// see: http://www.jwz.org/doc/mid.html
	[ $usec, $sec ] = explode( ' ', microtime() );
	$usec = substr( $usec, 2 );
	$key = Wikimedia\base_convert( $sec . $usec, 10, 36 ) . '.' .
	Wikimedia\base_convert( (string)mt_rand(), 10, 36 ) . '.' .
	$this->user->getId() . '.' .
	$extension;

	$this->fileProps[$key] = $fileProps;

	if ( !preg_match( self::KEY_FORMAT_REGEX, $key ) ) {
	throw new UploadStashBadPathException(
	wfMessage( 'uploadstash-bad-path-bad-format', $key )
	);
	}

	wfDebug( __METHOD__ . " key for '$path': $key" );

	// if not already in a temporary area, put it there
	$storeStatus = $this->repo->storeTemp( basename( $pathWithGoodExtension ), $path );

	if ( !$storeStatus->isOK() ) {
	// It is a convention in MediaWiki to only return one error per API
	// exception, even if multiple errors are available.[citation needed]
	// Pick the "first" thing that was wrong, preferring errors to warnings.
	// This is a bit lame, as we may have more info in the
	// $storeStatus and we're throwing it away, but to fix it means
	// redesigning API errors significantly.
	// $storeStatus->value just contains the virtual URL (if anything)
	// which is probably useless to the caller.
	foreach ( $storeStatus->getMessages( 'error' ) as $msg ) {
	throw new UploadStashFileException( $msg );
	}
	foreach ( $storeStatus->getMessages( 'warning' ) as $msg ) {
	throw new UploadStashFileException( $msg );
	}
	// XXX: This isn't a real message, hopefully this case is unreachable
	throw new UploadStashFileException( [ 'unknown', 'no error recorded' ] );
	}
	$stashPath = $storeStatus->value;

	// fetch the current user ID
	if ( !$this->user->isRegistered() ) {
	throw new UploadStashNotLoggedInException(
	wfMessage( 'uploadstash-not-logged-in' )
	);
	}

	// insert the file metadata into the db.
	wfDebug( __METHOD__ . " inserting $stashPath under $key" );
	$dbw = $this->repo->getPrimaryDB();

	$serializedFileProps = serialize( $fileProps );
	if ( strlen( $serializedFileProps ) > self::MAX_US_PROPS_SIZE ) {
	// Database is going to truncate this and make the field invalid.
	// Prioritize important metadata over file handler metadata.
	// File handler should be prepared to regenerate invalid metadata if needed.
	$fileProps['metadata'] = [];
	$serializedFileProps = serialize( $fileProps );
	}

	$insertRow = [
	'us_user' => $this->user->getId(),
	'us_key' => $key,
	'us_orig_path' => $path,
	'us_path' => $stashPath, // virtual URL
	'us_props' => $dbw->encodeBlob( $serializedFileProps ),
	'us_size' => $fileProps['size'],
	'us_sha1' => $fileProps['sha1'],
	'us_mime' => $fileProps['mime'],
	'us_media_type' => $fileProps['media_type'],
	'us_image_width' => $fileProps['width'],
	'us_image_height' => $fileProps['height'],
	'us_image_bits' => $fileProps['bits'],
	'us_source_type' => $sourceType,
	'us_timestamp' => $dbw->timestamp(),
	'us_status' => 'finished'
	];

	$dbw->newInsertQueryBuilder()
	->insertInto( 'uploadstash' )
	->row( $insertRow )
	->caller( __METHOD__ )->execute();

	// store the insertid in the class variable so immediate retrieval
	// (possibly laggy) isn't necessary.
	$insertRow['us_id'] = $dbw->insertId();

	$this->fileMetadata[$key] = $insertRow;

	# create the UploadStashFile object for this file.
	$this->initFile( $key );

	return $this->getFile( $key );
	}

	/**
	* Remove all files from the stash.
	* Does not clean up files in the repo, just the record of them.
	*
	* @throws UploadStashNotLoggedInException
	* @return bool Success
	*/
	public function clear() {
	if ( !$this->user->isRegistered() ) {
	throw new UploadStashNotLoggedInException(
	wfMessage( 'uploadstash-not-logged-in' )
	);
	}

	wfDebug( __METHOD__ . ' clearing all rows for user ' . $this->user->getId() );
	$dbw = $this->repo->getPrimaryDB();
	$dbw->newDeleteQueryBuilder()
	->deleteFrom( 'uploadstash' )
	->where( [ 'us_user' => $this->user->getId() ] )
	->caller( __METHOD__ )->execute();

	# destroy objects.
	$this->files = [];
	$this->fileMetadata = [];

	return true;
	}

	/**
	* Remove a particular file from the stash. Also removes it from the repo.
	*
	* @param string $key
	* @throws UploadStashNoSuchKeyException\|UploadStashNotLoggedInException
	* @throws UploadStashWrongOwnerException
	* @return bool Success
	*/
	public function removeFile( $key ) {
	if ( !$this->user->isRegistered() ) {
	throw new UploadStashNotLoggedInException(
	wfMessage( 'uploadstash-not-logged-in' )
	);
	}

	$dbw = $this->repo->getPrimaryDB();

	// this is a cheap query. it runs on the primary DB so that this function
	// still works when there's lag. It won't be called all that often.
	$row = $dbw->newSelectQueryBuilder()
	->select( 'us_user' )
	->from( 'uploadstash' )
	->where( [ 'us_key' => $key ] )
	->caller( __METHOD__ )->fetchRow();

	if ( !$row ) {
	throw new UploadStashNoSuchKeyException(
	wfMessage( 'uploadstash-no-such-key', $key )
	);
	}

	if ( $row->us_user != $this->user->getId() ) {
	throw new UploadStashWrongOwnerException(
	wfMessage( 'uploadstash-wrong-owner', $key )
	);
	}

	return $this->removeFileNoAuth( $key );
	}

	/**
	* Remove a file (see removeFile), but doesn't check ownership first.
	*
	* @param string $key
	* @return bool Success
	*/
	public function removeFileNoAuth( $key ) {
	wfDebug( __METHOD__ . " clearing row $key" );

	// Ensure we have the UploadStashFile loaded for this key
	$this->getFile( $key, true );

	$dbw = $this->repo->getPrimaryDB();

	$dbw->newDeleteQueryBuilder()
	->deleteFrom( 'uploadstash' )
	->where( [ 'us_key' => $key ] )
	->caller( __METHOD__ )->execute();

	/** @todo Look into UnregisteredLocalFile and find out why the rv here is
	* sometimes wrong (false when file was removed). For now, ignore.
	*/
	$this->files[$key]->remove();

	unset( $this->files[$key] );
	unset( $this->fileMetadata[$key] );

	return true;
	}

	/**
	* List all files in the stash.
	*
	* @throws UploadStashNotLoggedInException
	* @return array\|false
	*/
	public function listFiles() {
	if ( !$this->user->isRegistered() ) {
	throw new UploadStashNotLoggedInException(
	wfMessage( 'uploadstash-not-logged-in' )
	);
	}

	$res = $this->repo->getReplicaDB()->newSelectQueryBuilder()
	->select( 'us_key' )
	->from( 'uploadstash' )
	->where( [ 'us_user' => $this->user->getId() ] )
	->caller( __METHOD__ )->fetchResultSet();

	if ( $res->numRows() == 0 ) {
	// nothing to do.
	return false;
	}

	// finish the read before starting writes.
	$keys = [];
	foreach ( $res as $row ) {
	$keys[] = $row->us_key;
	}

	return $keys;
	}

	/**
	* Find or guess extension -- ensuring that our extension matches our MIME type.
	* Since these files are constructed from php tempnames they may not start off
	* with an extension.
	* XXX this is somewhat redundant with the checks that ApiUpload.php does with incoming
	* uploads versus the desired filename. Maybe we can get that passed to us...
	* @param string $path
	* @return string
	*/
	public static function getExtensionForPath( $path ) {
	$prohibitedFileExtensions = MediaWikiServices::getInstance()
	->getMainConfig()->get( MainConfigNames::ProhibitedFileExtensions );
	// Does this have an extension?
	$n = strrpos( $path, '.' );

	if ( $n !== false ) {
	$extension = $n ? substr( $path, $n + 1 ) : '';
	} else {
	// If not, assume that it should be related to the MIME type of the original file.
	$magic = MediaWikiServices::getInstance()->getMimeAnalyzer();
	$mimeType = $magic->guessMimeType( $path );
	$extension = $magic->getExtensionFromMimeTypeOrNull( $mimeType ) ?? '';
	}

	$extension = File::normalizeExtension( $extension );
	if ( in_array( $extension, $prohibitedFileExtensions ) ) {
	// The file should already be checked for being evil.
	// However, if somehow we got here, we definitely
	// don't want to give it an extension of .php and
	// put it in a web accessible directory.
	return '';
	}

	return $extension;
	}

	/**
	* Helper function: do the actual database query to fetch file metadata.
	*
	* @param string $key
	* @param int $readFromDB Constant (default: DB_REPLICA)
	* @return bool
	*/
	protected function fetchFileMetadata( $key, $readFromDB = DB_REPLICA ) {
	// populate $fileMetadata[$key]
	if ( $readFromDB === DB_PRIMARY ) {
	// sometimes reading from the primary DB is necessary, if there's replication lag.
	$dbr = $this->repo->getPrimaryDB();
	} else {
	$dbr = $this->repo->getReplicaDB();
	}

	$row = $dbr->newSelectQueryBuilder()
	->select( [
	'us_user', 'us_key', 'us_orig_path', 'us_path', 'us_props',
	'us_size', 'us_sha1', 'us_mime', 'us_media_type',
	'us_image_width', 'us_image_height', 'us_image_bits',
	'us_source_type', 'us_timestamp', 'us_status',
	] )
	->from( 'uploadstash' )
	->where( [ 'us_key' => $key ] )
	->caller( __METHOD__ )->fetchRow();

	if ( !is_object( $row ) ) {
	// key wasn't present in the database. this will happen sometimes.
	return false;
	}

	$this->fileMetadata[$key] = (array)$row;
	$this->fileMetadata[$key]['us_props'] = $dbr->decodeBlob( $row->us_props );

	return true;
	}

	/**
	* Helper function: Initialize the UploadStashFile for a given file.
	*
	* @param string $key Key under which to store the object
	* @throws UploadStashZeroLengthFileException
	* @return bool
	*/
	protected function initFile( $key ) {
	$file = new UploadStashFile(
	$this->repo,
	$this->fileMetadata[$key]['us_path'],
	$key,
	$this->fileMetadata[$key]['us_sha1']
	);
	if ( $file->getSize() === 0 ) {
	throw new UploadStashZeroLengthFileException(
	wfMessage( 'uploadstash-zero-length' )
	);
	}
	$this->files[$key] = $file;

	return true;
	}
	}

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