Merge "Don't let LinkCache grow indefinitely"

[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
 * @ingroup Upload
 */

/**
 * 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)
        const KEY_FORMAT_REGEX = '/^[\w-\.]+\.\w*$/';

        /**
         * 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;

        // array of initialized repo objects
        protected $files = array();

        // cache of the file metadata that's stored in the database
        protected $fileMetadata = array();

        // fileprops cache
        protected $fileProps = array();

        // current user
        protected $user, $userId, $isLoggedIn;

        /**
         * 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 User $user (default null)
         */
        public function __construct( FileRepo $repo, $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.
                // this keeps FileRepo from breaking when it creates an UploadStash object
                if ( $user ) {
                        $this->user = $user;
                } else {
                        global $wgUser;
                        $this->user = $wgUser;
                }

                if ( is_object( $this->user ) ) {
                        $this->userId = $this->user->getId();
                        $this->isLoggedIn = $this->user->isLoggedIn();
                }
        }

        /**
         * 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, $key ) ) {
                        throw new UploadStashBadPathException( "key '$key' is not in a proper format" );
                }

                if ( !$noAuth && !$this->isLoggedIn ) {
                        throw new UploadStashNotLoggedInException( __METHOD__ .
                                ' No user is logged in, files must belong to users' );
                }

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

                        if ( !isset( $this->fileMetadata[$key] ) ) {
                                throw new UploadStashFileNotFoundException( "key '$key' not found in stash" );
                        }

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

                        // fetch fileprops
                        if ( 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\n" );
                                $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\n" );
                        // @todo Is this not an UploadStashFileNotFoundException case?
                        throw new UploadStashBadPathException( "path doesn't exist" );
                }

                if ( !$noAuth ) {
                        if ( $this->fileMetadata[$key]['us_user'] != $this->userId ) {
                                throw new UploadStashWrongOwnerException( "This file ($key) doesn't "
                                        . "belong to the current user." );
                        }
                }

                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 $sourceType The type of upload that generated this file
         *   (currently, I believe, 'file' or null)
         * @throws UploadStashBadPathException
         * @throws UploadStashFileException
         * @throws UploadStashNotLoggedInException
         * @return UploadStashFile|null File, or null on failure
         */
        public function stashFile( $path, $sourceType = null ) {
                if ( !is_file( $path ) ) {
                        wfDebug( __METHOD__ . " tried to stash file at '$path', but it doesn't exist\n" );
                        throw new UploadStashBadPathException( "path doesn't exist" );
                }
                $fileProps = FSFile::getPropsFromPath( $path );
                wfDebug( __METHOD__ . " stashing file at '$path'\n" );

                // 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
                list( $usec, $sec ) = explode( ' ', microtime() );
                $usec = substr( $usec, 2 );
                $key = wfBaseConvert( $sec . $usec, 10, 36 ) . '.' .
                        wfBaseConvert( mt_rand(), 10, 36 ) . '.' .
                        $this->userId . '.' .
                        $extension;

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

                if ( !preg_match( self::KEY_FORMAT_REGEX, $key ) ) {
                        throw new UploadStashBadPathException( "key '$key' is not in a proper format" );
                }

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

                // 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. We use reset()
                        // to 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.
                        $error = $storeStatus->getErrorsArray();
                        $error = reset( $error );
                        if ( !count( $error ) ) {
                                $error = $storeStatus->getWarningsArray();
                                $error = reset( $error );
                                if ( !count( $error ) ) {
                                        $error = array( 'unknown', 'no error recorded' );
                                }
                        }
                        // At this point, $error should contain the single "most important"
                        // error, plus any parameters.
                        $errorMsg = array_shift( $error );
                        throw new UploadStashFileException( "Error storing file in '$path': "
                                . wfMessage( $errorMsg, $error )->text() );
                }
                $stashPath = $storeStatus->value;

                // fetch the current user ID
                if ( !$this->isLoggedIn ) {
                        throw new UploadStashNotLoggedInException( __METHOD__
                                . ' No user is logged in, files must belong to users' );
                }

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

                $this->fileMetadata[$key] = array(
                        'us_id' => $dbw->nextSequenceValue( 'uploadstash_us_id_seq' ),
                        'us_user' => $this->userId,
                        'us_key' => $key,
                        'us_orig_path' => $path,
                        'us_path' => $stashPath, // virtual URL
                        'us_props' => $dbw->encodeBlob( serialize( $fileProps ) ),
                        '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->insert(
                        'uploadstash',
                        $this->fileMetadata[$key],
                        __METHOD__
                );

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

                # 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->isLoggedIn ) {
                        throw new UploadStashNotLoggedInException( __METHOD__
                                . ' No user is logged in, files must belong to users' );
                }

                wfDebug( __METHOD__ . ' clearing all rows for user ' . $this->userId . "\n" );
                $dbw = $this->repo->getMasterDb();
                $dbw->delete(
                        'uploadstash',
                        array( 'us_user' => $this->userId ),
                        __METHOD__
                );

                # destroy objects.
                $this->files = array();
                $this->fileMetadata = array();

                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->isLoggedIn ) {
                        throw new UploadStashNotLoggedInException( __METHOD__
                                . ' No user is logged in, files must belong to users' );
                }

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

                // this is a cheap query. it runs on the master so that this function
                // still works when there's lag. It won't be called all that often.
                $row = $dbw->selectRow(
                        'uploadstash',
                        'us_user',
                        array( 'us_key' => $key ),
                        __METHOD__
                );

                if ( !$row ) {
                        throw new UploadStashNoSuchKeyException( "No such key ($key), cannot remove" );
                }

                if ( $row->us_user != $this->userId ) {
                        throw new UploadStashWrongOwnerException( "Can't delete: "
                                . "the file ($key) doesn't belong to this user." );
                }

                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\n" );

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

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

                $dbw->delete(
                        'uploadstash',
                        array( 'us_key' => $key ),
                        __METHOD__
                );

                /** @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
         */
        public function listFiles() {
                if ( !$this->isLoggedIn ) {
                        throw new UploadStashNotLoggedInException( __METHOD__
                                . ' No user is logged in, files must belong to users' );
                }

                $dbr = $this->repo->getSlaveDb();
                $res = $dbr->select(
                        'uploadstash',
                        'us_key',
                        array( 'us_user' => $this->userId ),
                        __METHOD__
                );

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

                // finish the read before starting writes.
                $keys = array();
                foreach ( $res as $row ) {
                        array_push( $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
         * @throws UploadStashFileException
         * @return string
         */
        public static function getExtensionForPath( $path ) {
                global $wgFileBlacklist;
                // Does this have an extension?
                $n = strrpos( $path, '.' );
                $extension = null;
                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 = MimeMagic::singleton();
                        $mimeType = $magic->guessMimeType( $path );
                        $extensions = explode( ' ', MimeMagic::singleton()->getExtensionsForType( $mimeType ) );
                        if ( count( $extensions ) ) {
                                $extension = $extensions[0];
                        }
                }

                if ( is_null( $extension ) ) {
                        throw new UploadStashFileException( "extension is null" );
                }

                $extension = File::normalizeExtension( $extension );
                if ( in_array( $extension, $wgFileBlacklist ) ) {
                        // 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 accesible directory.
                        return '';
                }

                return $extension;
        }

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

                $row = $dbr->selectRow(
                        'uploadstash',
                        '*',
                        array( 'us_key' => $key ),
                        __METHOD__
                );

                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 );
                if ( $file->getSize() === 0 ) {
                        throw new UploadStashZeroLengthFileException( "File is zero length" );
                }
                $this->files[$key] = $file;

                return true;
        }
}

class UploadStashFile extends UnregisteredLocalFile {
        private $fileKey;
        private $urlName;
        protected $url;

        /**
         * A LocalFile wrapper around a file that has been temporarily stashed,
         * so we can do things like create thumbnails for it. Arguably
         * UnregisteredLocalFile should be handling its own file repo but that
         * class is a bit retarded currently.
         *
         * @param FileRepo $repo Repository where we should find the path
         * @param string $path Path to file
         * @param string $key Key to store the path and any stashed data under
         * @throws UploadStashBadPathException
         * @throws UploadStashFileNotFoundException
         */
        public function __construct( $repo, $path, $key ) {
                $this->fileKey = $key;

                // resolve mwrepo:// urls
                if ( $repo->isVirtualUrl( $path ) ) {
                        $path = $repo->resolveVirtualUrl( $path );
                } else {
                        // check if path appears to be sane, no parent traversals,
                        // and is in this repo's temp zone.
                        $repoTempPath = $repo->getZonePath( 'temp' );
                        if ( ( !$repo->validateFilename( $path ) ) ||
                                ( strpos( $path, $repoTempPath ) !== 0 )
                        ) {
                                wfDebug( "UploadStash: tried to construct an UploadStashFile "
                                        . "from a file that should already exist at '$path', but path is not valid\n" );
                                throw new UploadStashBadPathException( 'path is not valid' );
                        }

                        // check if path exists! and is a plain file.
                        if ( !$repo->fileExists( $path ) ) {
                                wfDebug( "UploadStash: tried to construct an UploadStashFile from "
                                        . "a file that should already exist at '$path', but path is not found\n" );
                                throw new UploadStashFileNotFoundException( 'cannot find path, or not a plain file' );
                        }
                }

                parent::__construct( false, $repo, $path, false );

                $this->name = basename( $this->path );
        }

        /**
         * A method needed by the file transforming and scaling routines in File.php
         * We do not necessarily care about doing the description at this point
         * However, we also can't return the empty string, as the rest of MediaWiki
         * demands this (and calls to imagemagick convert require it to be there)
         *
         * @return string Dummy value
         */
        public function getDescriptionUrl() {
                return $this->getUrl();
        }

        /**
         * Get the path for the thumbnail (actually any transformation of this file)
         * The actual argument is the result of thumbName although we seem to have
         * buggy code elsewhere that expects a boolean 'suffix'
         *
         * @param string $thumbName Name of thumbnail (e.g. "120px-123456.jpg" ),
         *   or false to just get the path
         * @return string Path thumbnail should take on filesystem, or containing
         *   directory if thumbname is false
         */
        public function getThumbPath( $thumbName = false ) {
                $path = dirname( $this->path );
                if ( $thumbName !== false ) {
                        $path .= "/$thumbName";
                }

                return $path;
        }

        /**
         * Return the file/url base name of a thumbnail with the specified parameters.
         * We override this because we want to use the pretty url name instead of the
         * ugly file name.
         *
         * @param array $params Handler-specific parameters
         * @param int $flags Bitfield that supports THUMB_* constants
         * @return string Base name for URL, like '120px-12345.jpg', or null if there is no handler
         */
        function thumbName( $params, $flags = 0 ) {
                return $this->generateThumbName( $this->getUrlName(), $params );
        }

        /**
         * Helper function -- given a 'subpage', return the local URL,
         * e.g. /wiki/Special:UploadStash/subpage
         * @param string $subPage
         * @return string Local URL for this subpage in the Special:UploadStash space.
         */
        private function getSpecialUrl( $subPage ) {
                return SpecialPage::getTitleFor( 'UploadStash', $subPage )->getLocalURL();
        }

        /**
         * Get a URL to access the thumbnail
         * This is required because the model of how files work requires that
         * the thumbnail urls be predictable. However, in our model the URL is
         * not based on the filename (that's hidden in the db)
         *
         * @param string $thumbName Basename of thumbnail file -- however, we don't
         *   want to use the file exactly
         * @return string URL to access thumbnail, or URL with partial path
         */
        public function getThumbUrl( $thumbName = false ) {
                wfDebug( __METHOD__ . " getting for $thumbName \n" );

                return $this->getSpecialUrl( 'thumb/' . $this->getUrlName() . '/' . $thumbName );
        }

        /**
         * The basename for the URL, which we want to not be related to the filename.
         * Will also be used as the lookup key for a thumbnail file.
         *
         * @return string Base url name, like '120px-123456.jpg'
         */
        public function getUrlName() {
                if ( !$this->urlName ) {
                        $this->urlName = $this->fileKey;
                }

                return $this->urlName;
        }

        /**
         * Return the URL of the file, if for some reason we wanted to download it
         * We tend not to do this for the original file, but we do want thumb icons
         *
         * @return string Url
         */
        public function getUrl() {
                if ( !isset( $this->url ) ) {
                        $this->url = $this->getSpecialUrl( 'file/' . $this->getUrlName() );
                }

                return $this->url;
        }

        /**
         * Parent classes use this method, for no obvious reason, to return the path
         * (relative to wiki root, I assume). But with this class, the URL is
         * unrelated to the path.
         *
         * @return string Url
         */
        public function getFullUrl() {
                return $this->getUrl();
        }

        /**
         * Getter for file key (the unique id by which this file's location &
         * metadata is stored in the db)
         *
         * @return string File key
         */
        public function getFileKey() {
                return $this->fileKey;
        }

        /**
         * Remove the associated temporary file
         * @return status Success
         */
        public function remove() {
                if ( !$this->repo->fileExists( $this->path ) ) {
                        // Maybe the file's already been removed? This could totally happen in UploadBase.
                        return true;
                }

                return $this->repo->freeTemp( $this->path );
        }

        public function exists() {
                return $this->repo->fileExists( $this->path );
        }
}

class UploadStashException extends MWException {
}

class UploadStashFileNotFoundException extends UploadStashException {
}

class UploadStashBadPathException extends UploadStashException {
}

class UploadStashFileException extends UploadStashException {
}

class UploadStashZeroLengthFileException extends UploadStashException {
}

class UploadStashNotLoggedInException extends UploadStashException {
}

class UploadStashWrongOwnerException extends UploadStashException {
}

class UploadStashNoSuchKeyException extends UploadStashException {
}