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[mediawiki.git] / includes / upload / UploadStash.php

<?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;
        }
}