3 * @defgroup FileBackend File backend
6 * File backend is used to interact with file storage systems,
7 * such as the local file system, NFS, or cloud storage systems.
11 * Base class for all file backends.
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License as published by
15 * the Free Software Foundation; either version 2 of the License, or
16 * (at your option) any later version.
18 * This program is distributed in the hope that it will be useful,
19 * but WITHOUT ANY WARRANTY; without even the implied warranty of
20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 * GNU General Public License for more details.
23 * You should have received a copy of the GNU General Public License along
24 * with this program; if not, write to the Free Software Foundation, Inc.,
25 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
26 * http://www.gnu.org/copyleft/gpl.html
29 * @ingroup FileBackend
30 * @author Aaron Schulz
34 * @brief Base class for all file backend classes (including multi-write backends).
36 * This class defines the methods as abstract that subclasses must implement.
37 * Outside callers can assume that all backends will have these functions.
39 * All "storage paths" are of the format "mwstore://<backend>/<container>/<path>".
40 * The "<path>" portion is a relative path that uses UNIX file system (FS)
41 * notation, though any particular backend may not actually be using a local
42 * filesystem. Therefore, the relative paths are only virtual.
44 * Backend contents are stored under wiki-specific container names by default.
45 * For legacy reasons, this has no effect for the FS backend class, and per-wiki
46 * segregation must be done by setting the container paths appropriately.
48 * FS-based backends are somewhat more restrictive due to the existence of real
49 * directory files; a regular file cannot have the same name as a directory. Other
50 * backends with virtual directories may not have this limitation. Callers should
51 * store files in such a way that no files and directories are under the same path.
53 * Methods of subclasses should avoid throwing exceptions at all costs.
54 * As a corollary, external dependencies should be kept to a minimum.
56 * @ingroup FileBackend
59 abstract class FileBackend
{
60 protected $name; // string; unique backend name
61 protected $wikiId; // string; unique wiki name
62 protected $readOnly; // string; read-only explanation message
63 protected $parallelize; // string; when to do operations in parallel
64 protected $concurrency; // integer; how many operations can be done in parallel
66 /** @var LockManager */
67 protected $lockManager;
68 /** @var FileJournal */
69 protected $fileJournal;
72 * Create a new backend instance from configuration.
73 * This should only be called from within FileBackendGroup.
76 * - name : The unique name of this backend.
77 * This should consist of alphanumberic, '-', and '_' characters.
78 * This name should not be changed after use.
79 * - wikiId : Prefix to container names that is unique to this wiki.
80 * It should only consist of alphanumberic, '-', and '_' characters.
81 * - lockManager : Registered name of a file lock manager to use.
82 * - fileJournal : File journal configuration; see FileJournal::factory().
83 * Journals simply log changes to files stored in the backend.
84 * - readOnly : Write operations are disallowed if this is a non-empty string.
85 * It should be an explanation for the backend being read-only.
86 * - parallelize : When to do file operations in parallel (when possible).
87 * Allowed values are "implicit", "explicit" and "off".
88 * - concurrency : How many file operations can be done in parallel.
90 * @param $config Array
93 public function __construct( array $config ) {
94 $this->name
= $config['name'];
95 if ( !preg_match( '!^[a-zA-Z0-9-_]{1,255}$!', $this->name
) ) {
96 throw new MWException( "Backend name `{$this->name}` is invalid." );
98 $this->wikiId
= isset( $config['wikiId'] )
100 : wfWikiID(); // e.g. "my_wiki-en_"
101 $this->lockManager
= ( $config['lockManager'] instanceof LockManager
)
102 ?
$config['lockManager']
103 : LockManagerGroup
::singleton()->get( $config['lockManager'] );
104 $this->fileJournal
= isset( $config['fileJournal'] )
105 ?
( ( $config['fileJournal'] instanceof FileJournal
)
106 ?
$config['fileJournal']
107 : FileJournal
::factory( $config['fileJournal'], $this->name
) )
108 : FileJournal
::factory( array( 'class' => 'NullFileJournal' ), $this->name
);
109 $this->readOnly
= isset( $config['readOnly'] )
110 ?
(string)$config['readOnly']
112 $this->parallelize
= isset( $config['parallelize'] )
113 ?
(string)$config['parallelize']
115 $this->concurrency
= isset( $config['concurrency'] )
116 ?
(int)$config['concurrency']
121 * Get the unique backend name.
122 * We may have multiple different backends of the same type.
123 * For example, we can have two Swift backends using different proxies.
127 final public function getName() {
132 * Get the wiki identifier used for this backend (possibly empty).
133 * Note that this might *not* be in the same format as wfWikiID().
138 final public function getWikiId() {
139 return $this->wikiId
;
143 * Check if this backend is read-only
147 final public function isReadOnly() {
148 return ( $this->readOnly
!= '' );
152 * Get an explanatory message if this backend is read-only
154 * @return string|bool Returns false if the backend is not read-only
156 final public function getReadOnlyReason() {
157 return ( $this->readOnly
!= '' ) ?
$this->readOnly
: false;
161 * This is the main entry point into the backend for write operations.
162 * Callers supply an ordered list of operations to perform as a transaction.
163 * Files will be locked, the stat cache cleared, and then the operations attempted.
164 * If any serious errors occur, all attempted operations will be rolled back.
166 * $ops is an array of arrays. The outer array holds a list of operations.
167 * Each inner array is a set of key value pairs that specify an operation.
169 * Supported operations and their parameters. The supported actions are:
177 * a) Create a new file in storage with the contents of a string
181 * 'dst' => <storage path>,
182 * 'content' => <string of new file contents>,
183 * 'overwrite' => <boolean>,
184 * 'overwriteSame' => <boolean>,
185 * 'disposition' => <Content-Disposition header value>
189 * b) Copy a file system file into storage
193 * 'src' => <file system path>,
194 * 'dst' => <storage path>,
195 * 'overwrite' => <boolean>,
196 * 'overwriteSame' => <boolean>,
197 * 'disposition' => <Content-Disposition header value>
201 * c) Copy a file within storage
205 * 'src' => <storage path>,
206 * 'dst' => <storage path>,
207 * 'overwrite' => <boolean>,
208 * 'overwriteSame' => <boolean>,
209 * 'disposition' => <Content-Disposition header value>
213 * d) Move a file within storage
217 * 'src' => <storage path>,
218 * 'dst' => <storage path>,
219 * 'overwrite' => <boolean>,
220 * 'overwriteSame' => <boolean>,
221 * 'disposition' => <Content-Disposition header value>
225 * e) Delete a file within storage
229 * 'src' => <storage path>,
230 * 'ignoreMissingSource' => <boolean>
234 * f) Do nothing (no-op)
241 * Boolean flags for operations (operation-specific):
242 * - ignoreMissingSource : The operation will simply succeed and do
243 * nothing if the source file does not exist.
244 * - overwrite : Any destination file will be overwritten.
245 * - overwriteSame : An error will not be given if a file already
246 * exists at the destination that has the same
247 * contents as the new contents to be written there.
248 * - disposition : When supplied, the backend will add a Content-Disposition
249 * header when GETs/HEADs of the destination file are made.
250 * Backends that don't support file metadata will ignore this.
251 * See http://tools.ietf.org/html/rfc6266 (since 1.20).
253 * $opts is an associative of boolean flags, including:
254 * - force : Operation precondition errors no longer trigger an abort.
255 * Any remaining operations are still attempted. Unexpected
256 * failures may still cause remaning operations to be aborted.
257 * - nonLocking : No locks are acquired for the operations.
258 * This can increase performance for non-critical writes.
259 * This has no effect unless the 'force' flag is set.
260 * - allowStale : Don't require the latest available data.
261 * This can increase performance for non-critical writes.
262 * This has no effect unless the 'force' flag is set.
263 * - nonJournaled : Don't log this operation batch in the file journal.
264 * This limits the ability of recovery scripts.
265 * - parallelize : Try to do operations in parallel when possible.
266 * - bypassReadOnly : Allow writes in read-only mode (since 1.20).
267 * - preserveCache : Don't clear the process cache before checking files.
268 * This should only be used if all entries in the process
269 * cache were added after the files were already locked (since 1.20).
271 * @remarks Remarks on locking:
272 * File system paths given to operations should refer to files that are
273 * already locked or otherwise safe from modification from other processes.
274 * Normally these files will be new temp files, which should be adequate.
278 * This returns a Status, which contains all warnings and fatals that occurred
279 * during the operation. The 'failCount', 'successCount', and 'success' members
280 * will reflect each operation attempted.
282 * The status will be "OK" unless:
283 * - a) unexpected operation errors occurred (network partitions, disk full...)
284 * - b) significant operation errors occurred and 'force' was not set
286 * @param $ops Array List of operations to execute in order
287 * @param $opts Array Batch operation options
290 final public function doOperations( array $ops, array $opts = array() ) {
291 if ( empty( $opts['bypassReadOnly'] ) && $this->isReadOnly() ) {
292 return Status
::newFatal( 'backend-fail-readonly', $this->name
, $this->readOnly
);
294 if ( empty( $opts['force'] ) ) { // sanity
295 unset( $opts['nonLocking'] );
296 unset( $opts['allowStale'] );
298 return $this->doOperationsInternal( $ops, $opts );
302 * @see FileBackend::doOperations()
304 abstract protected function doOperationsInternal( array $ops, array $opts );
307 * Same as doOperations() except it takes a single operation.
308 * If you are doing a batch of operations that should either
309 * all succeed or all fail, then use that function instead.
311 * @see FileBackend::doOperations()
313 * @param $op Array Operation
314 * @param $opts Array Operation options
317 final public function doOperation( array $op, array $opts = array() ) {
318 return $this->doOperations( array( $op ), $opts );
322 * Performs a single create operation.
323 * This sets $params['op'] to 'create' and passes it to doOperation().
325 * @see FileBackend::doOperation()
327 * @param $params Array Operation parameters
328 * @param $opts Array Operation options
331 final public function create( array $params, array $opts = array() ) {
332 return $this->doOperation( array( 'op' => 'create' ) +
$params, $opts );
336 * Performs a single store operation.
337 * This sets $params['op'] to 'store' and passes it to doOperation().
339 * @see FileBackend::doOperation()
341 * @param $params Array Operation parameters
342 * @param $opts Array Operation options
345 final public function store( array $params, array $opts = array() ) {
346 return $this->doOperation( array( 'op' => 'store' ) +
$params, $opts );
350 * Performs a single copy operation.
351 * This sets $params['op'] to 'copy' and passes it to doOperation().
353 * @see FileBackend::doOperation()
355 * @param $params Array Operation parameters
356 * @param $opts Array Operation options
359 final public function copy( array $params, array $opts = array() ) {
360 return $this->doOperation( array( 'op' => 'copy' ) +
$params, $opts );
364 * Performs a single move operation.
365 * This sets $params['op'] to 'move' and passes it to doOperation().
367 * @see FileBackend::doOperation()
369 * @param $params Array Operation parameters
370 * @param $opts Array Operation options
373 final public function move( array $params, array $opts = array() ) {
374 return $this->doOperation( array( 'op' => 'move' ) +
$params, $opts );
378 * Performs a single delete operation.
379 * This sets $params['op'] to 'delete' and passes it to doOperation().
381 * @see FileBackend::doOperation()
383 * @param $params Array Operation parameters
384 * @param $opts Array Operation options
387 final public function delete( array $params, array $opts = array() ) {
388 return $this->doOperation( array( 'op' => 'delete' ) +
$params, $opts );
392 * Perform a set of independent file operations on some files.
394 * This does no locking, nor journaling, and possibly no stat calls.
395 * Any destination files that already exist will be overwritten.
396 * This should *only* be used on non-original files, like cache files.
398 * Supported operations and their parameters:
406 * a) Create a new file in storage with the contents of a string
410 * 'dst' => <storage path>,
411 * 'content' => <string of new file contents>,
412 * 'disposition' => <Content-Disposition header value>
415 * b) Copy a file system file into storage
419 * 'src' => <file system path>,
420 * 'dst' => <storage path>,
421 * 'disposition' => <Content-Disposition header value>
424 * c) Copy a file within storage
428 * 'src' => <storage path>,
429 * 'dst' => <storage path>,
430 * 'disposition' => <Content-Disposition header value>
433 * d) Move a file within storage
437 * 'src' => <storage path>,
438 * 'dst' => <storage path>,
439 * 'disposition' => <Content-Disposition header value>
442 * e) Delete a file within storage
446 * 'src' => <storage path>,
447 * 'ignoreMissingSource' => <boolean>
450 * f) Do nothing (no-op)
457 * @par Boolean flags for operations (operation-specific):
458 * - ignoreMissingSource : The operation will simply succeed and do
459 * nothing if the source file does not exist.
460 * - disposition : When supplied, the backend will add a Content-Disposition
461 * header when GETs/HEADs of the destination file are made.
462 * Backends that don't support file metadata will ignore this.
463 * See http://tools.ietf.org/html/rfc6266 (since 1.20).
465 * $opts is an associative of boolean flags, including:
466 * - bypassReadOnly : Allow writes in read-only mode (since 1.20)
469 * This returns a Status, which contains all warnings and fatals that occurred
470 * during the operation. The 'failCount', 'successCount', and 'success' members
471 * will reflect each operation attempted for the given files. The status will be
472 * considered "OK" as long as no fatal errors occurred.
474 * @param $ops Array Set of operations to execute
475 * @param $opts Array Batch operation options
479 final public function doQuickOperations( array $ops, array $opts = array() ) {
480 if ( empty( $opts['bypassReadOnly'] ) && $this->isReadOnly() ) {
481 return Status
::newFatal( 'backend-fail-readonly', $this->name
, $this->readOnly
);
483 foreach ( $ops as &$op ) {
484 $op['overwrite'] = true; // avoids RTTs in key/value stores
486 return $this->doQuickOperationsInternal( $ops );
490 * @see FileBackend::doQuickOperations()
493 abstract protected function doQuickOperationsInternal( array $ops );
496 * Same as doQuickOperations() except it takes a single operation.
497 * If you are doing a batch of operations, then use that function instead.
499 * @see FileBackend::doQuickOperations()
501 * @param $op Array Operation
505 final public function doQuickOperation( array $op ) {
506 return $this->doQuickOperations( array( $op ) );
510 * Performs a single quick create operation.
511 * This sets $params['op'] to 'create' and passes it to doQuickOperation().
513 * @see FileBackend::doQuickOperation()
515 * @param $params Array Operation parameters
519 final public function quickCreate( array $params ) {
520 return $this->doQuickOperation( array( 'op' => 'create' ) +
$params );
524 * Performs a single quick store operation.
525 * This sets $params['op'] to 'store' and passes it to doQuickOperation().
527 * @see FileBackend::doQuickOperation()
529 * @param $params Array Operation parameters
533 final public function quickStore( array $params ) {
534 return $this->doQuickOperation( array( 'op' => 'store' ) +
$params );
538 * Performs a single quick copy operation.
539 * This sets $params['op'] to 'copy' and passes it to doQuickOperation().
541 * @see FileBackend::doQuickOperation()
543 * @param $params Array Operation parameters
547 final public function quickCopy( array $params ) {
548 return $this->doQuickOperation( array( 'op' => 'copy' ) +
$params );
552 * Performs a single quick move operation.
553 * This sets $params['op'] to 'move' and passes it to doQuickOperation().
555 * @see FileBackend::doQuickOperation()
557 * @param $params Array Operation parameters
561 final public function quickMove( array $params ) {
562 return $this->doQuickOperation( array( 'op' => 'move' ) +
$params );
566 * Performs a single quick delete operation.
567 * This sets $params['op'] to 'delete' and passes it to doQuickOperation().
569 * @see FileBackend::doQuickOperation()
571 * @param $params Array Operation parameters
575 final public function quickDelete( array $params ) {
576 return $this->doQuickOperation( array( 'op' => 'delete' ) +
$params );
580 * Concatenate a list of storage files into a single file system file.
581 * The target path should refer to a file that is already locked or
582 * otherwise safe from modification from other processes. Normally,
583 * the file will be a new temp file, which should be adequate.
585 * @param $params Array Operation parameters
587 * - srcs : ordered source storage paths (e.g. chunk1, chunk2, ...)
588 * - dst : file system path to 0-byte temp file
591 abstract public function concatenate( array $params );
594 * Prepare a storage directory for usage.
595 * This will create any required containers and parent directories.
596 * Backends using key/value stores only need to create the container.
598 * The 'noAccess' and 'noListing' parameters works the same as in secure(),
599 * except they are only applied *if* the directory/container had to be created.
600 * These flags should always be set for directories that have private files.
602 * @param $params Array
604 * - dir : storage directory
605 * - noAccess : try to deny file access (since 1.20)
606 * - noListing : try to deny file listing (since 1.20)
607 * - bypassReadOnly : allow writes in read-only mode (since 1.20)
610 final public function prepare( array $params ) {
611 if ( empty( $params['bypassReadOnly'] ) && $this->isReadOnly() ) {
612 return Status
::newFatal( 'backend-fail-readonly', $this->name
, $this->readOnly
);
614 return $this->doPrepare( $params );
618 * @see FileBackend::prepare()
620 abstract protected function doPrepare( array $params );
623 * Take measures to block web access to a storage directory and
624 * the container it belongs to. FS backends might add .htaccess
625 * files whereas key/value store backends might revoke container
626 * access to the storage user representing end-users in web requests.
627 * This is not guaranteed to actually do anything.
629 * @param $params Array
631 * - dir : storage directory
632 * - noAccess : try to deny file access
633 * - noListing : try to deny file listing
634 * - bypassReadOnly : allow writes in read-only mode (since 1.20)
637 final public function secure( array $params ) {
638 if ( empty( $params['bypassReadOnly'] ) && $this->isReadOnly() ) {
639 return Status
::newFatal( 'backend-fail-readonly', $this->name
, $this->readOnly
);
641 return $this->doSecure( $params );
645 * @see FileBackend::secure()
647 abstract protected function doSecure( array $params );
650 * Remove measures to block web access to a storage directory and
651 * the container it belongs to. FS backends might remove .htaccess
652 * files whereas key/value store backends might grant container
653 * access to the storage user representing end-users in web requests.
654 * This essentially can undo the result of secure() calls.
656 * @param $params Array
658 * - dir : storage directory
659 * - access : try to allow file access
660 * - listing : try to allow file listing
661 * - bypassReadOnly : allow writes in read-only mode (since 1.20)
665 final public function publish( array $params ) {
666 if ( empty( $params['bypassReadOnly'] ) && $this->isReadOnly() ) {
667 return Status
::newFatal( 'backend-fail-readonly', $this->name
, $this->readOnly
);
669 return $this->doPublish( $params );
673 * @see FileBackend::publish()
675 abstract protected function doPublish( array $params );
678 * Delete a storage directory if it is empty.
679 * Backends using key/value stores may do nothing unless the directory
680 * is that of an empty container, in which case it will be deleted.
682 * @param $params Array
684 * - dir : storage directory
685 * - recursive : recursively delete empty subdirectories first (since 1.20)
686 * - bypassReadOnly : allow writes in read-only mode (since 1.20)
689 final public function clean( array $params ) {
690 if ( empty( $params['bypassReadOnly'] ) && $this->isReadOnly() ) {
691 return Status
::newFatal( 'backend-fail-readonly', $this->name
, $this->readOnly
);
693 return $this->doClean( $params );
697 * @see FileBackend::clean()
699 abstract protected function doClean( array $params );
702 * Check if a file exists at a storage path in the backend.
703 * This returns false if only a directory exists at the path.
705 * @param $params Array
707 * - src : source storage path
708 * - latest : use the latest available data
709 * @return bool|null Returns null on failure
711 abstract public function fileExists( array $params );
714 * Get the last-modified timestamp of the file at a storage path.
716 * @param $params Array
718 * - src : source storage path
719 * - latest : use the latest available data
720 * @return string|bool TS_MW timestamp or false on failure
722 abstract public function getFileTimestamp( array $params );
725 * Get the contents of a file at a storage path in the backend.
726 * This should be avoided for potentially large files.
728 * @param $params Array
730 * - src : source storage path
731 * - latest : use the latest available data
732 * @return string|bool Returns false on failure
734 abstract public function getFileContents( array $params );
737 * Get the size (bytes) of a file at a storage path in the backend.
739 * @param $params Array
741 * - src : source storage path
742 * - latest : use the latest available data
743 * @return integer|bool Returns false on failure
745 abstract public function getFileSize( array $params );
748 * Get quick information about a file at a storage path in the backend.
749 * If the file does not exist, then this returns false.
750 * Otherwise, the result is an associative array that includes:
751 * - mtime : the last-modified timestamp (TS_MW)
752 * - size : the file size (bytes)
753 * Additional values may be included for internal use only.
755 * @param $params Array
757 * - src : source storage path
758 * - latest : use the latest available data
759 * @return Array|bool|null Returns null on failure
761 abstract public function getFileStat( array $params );
764 * Get a SHA-1 hash of the file at a storage path in the backend.
766 * @param $params Array
768 * - src : source storage path
769 * - latest : use the latest available data
770 * @return string|bool Hash string or false on failure
772 abstract public function getFileSha1Base36( array $params );
775 * Get the properties of the file at a storage path in the backend.
776 * Returns FSFile::placeholderProps() on failure.
778 * @param $params Array
780 * - src : source storage path
781 * - latest : use the latest available data
784 abstract public function getFileProps( array $params );
787 * Stream the file at a storage path in the backend.
788 * If the file does not exists, an HTTP 404 error will be given.
789 * Appropriate HTTP headers (Status, Content-Type, Content-Length)
790 * will be sent if streaming began, while none will be sent otherwise.
791 * Implementations should flush the output buffer before sending data.
793 * @param $params Array
795 * - src : source storage path
796 * - headers : list of additional HTTP headers to send on success
797 * - latest : use the latest available data
800 abstract public function streamFile( array $params );
803 * Returns a file system file, identical to the file at a storage path.
804 * The file returned is either:
805 * - a) A local copy of the file at a storage path in the backend.
806 * The temporary copy will have the same extension as the source.
807 * - b) An original of the file at a storage path in the backend.
808 * Temporary files may be purged when the file object falls out of scope.
810 * Write operations should *never* be done on this file as some backends
811 * may do internal tracking or may be instances of FileBackendMultiWrite.
812 * In that later case, there are copies of the file that must stay in sync.
813 * Additionally, further calls to this function may return the same file.
815 * @param $params Array
817 * - src : source storage path
818 * - latest : use the latest available data
819 * @return FSFile|null Returns null on failure
821 abstract public function getLocalReference( array $params );
824 * Get a local copy on disk of the file at a storage path in the backend.
825 * The temporary copy will have the same file extension as the source.
826 * Temporary files may be purged when the file object falls out of scope.
828 * @param $params Array
830 * - src : source storage path
831 * - latest : use the latest available data
832 * @return TempFSFile|null Returns null on failure
834 abstract public function getLocalCopy( array $params );
837 * Check if a directory exists at a given storage path.
838 * Backends using key/value stores will check if the path is a
839 * virtual directory, meaning there are files under the given directory.
841 * Storage backends with eventual consistency might return stale data.
843 * @param $params array
845 * - dir : storage directory
846 * @return bool|null Returns null on failure
849 abstract public function directoryExists( array $params );
852 * Get an iterator to list *all* directories under a storage directory.
853 * If the directory is of the form "mwstore://backend/container",
854 * then all directories in the container will be listed.
855 * If the directory is of form "mwstore://backend/container/dir",
856 * then all directories directly under that directory will be listed.
857 * Results will be storage directories relative to the given directory.
859 * Storage backends with eventual consistency might return stale data.
861 * @param $params array
863 * - dir : storage directory
864 * - topOnly : only return direct child dirs of the directory
865 * @return Traversable|Array|null Returns null on failure
868 abstract public function getDirectoryList( array $params );
871 * Same as FileBackend::getDirectoryList() except only lists
872 * directories that are immediately under the given directory.
874 * Storage backends with eventual consistency might return stale data.
876 * @param $params array
878 * - dir : storage directory
879 * @return Traversable|Array|null Returns null on failure
882 final public function getTopDirectoryList( array $params ) {
883 return $this->getDirectoryList( array( 'topOnly' => true ) +
$params );
887 * Get an iterator to list *all* stored files under a storage directory.
888 * If the directory is of the form "mwstore://backend/container",
889 * then all files in the container will be listed.
890 * If the directory is of form "mwstore://backend/container/dir",
891 * then all files under that directory will be listed.
892 * Results will be storage paths relative to the given directory.
894 * Storage backends with eventual consistency might return stale data.
896 * @param $params array
898 * - dir : storage directory
899 * - topOnly : only return direct child files of the directory (since 1.20)
900 * @return Traversable|Array|null Returns null on failure
902 abstract public function getFileList( array $params );
905 * Same as FileBackend::getFileList() except only lists
906 * files that are immediately under the given directory.
908 * Storage backends with eventual consistency might return stale data.
910 * @param $params array
912 * - dir : storage directory
913 * @return Traversable|Array|null Returns null on failure
916 final public function getTopFileList( array $params ) {
917 return $this->getFileList( array( 'topOnly' => true ) +
$params );
921 * Preload persistent file stat and property cache into in-process cache.
922 * This should be used when stat calls will be made on a known list of a many files.
924 * @param $paths Array Storage paths
927 public function preloadCache( array $paths ) {}
930 * Invalidate any in-process file stat and property cache.
931 * If $paths is given, then only the cache for those files will be cleared.
933 * @param $paths Array Storage paths (optional)
936 public function clearCache( array $paths = null ) {}
939 * Lock the files at the given storage paths in the backend.
940 * This will either lock all the files or none (on failure).
942 * Callers should consider using getScopedFileLocks() instead.
944 * @param $paths Array Storage paths
945 * @param $type integer LockManager::LOCK_* constant
948 final public function lockFiles( array $paths, $type ) {
949 return $this->lockManager
->lock( $paths, $type );
953 * Unlock the files at the given storage paths in the backend.
955 * @param $paths Array Storage paths
956 * @param $type integer LockManager::LOCK_* constant
959 final public function unlockFiles( array $paths, $type ) {
960 return $this->lockManager
->unlock( $paths, $type );
964 * Lock the files at the given storage paths in the backend.
965 * This will either lock all the files or none (on failure).
966 * On failure, the status object will be updated with errors.
968 * Once the return value goes out scope, the locks will be released and
969 * the status updated. Unlock fatals will not change the status "OK" value.
971 * @param $paths Array Storage paths
972 * @param $type integer LockManager::LOCK_* constant
973 * @param $status Status Status to update on lock/unlock
974 * @return ScopedLock|null Returns null on failure
976 final public function getScopedFileLocks( array $paths, $type, Status
$status ) {
977 return ScopedLock
::factory( $this->lockManager
, $paths, $type, $status );
981 * Get an array of scoped locks needed for a batch of file operations.
983 * Normally, FileBackend::doOperations() handles locking, unless
984 * the 'nonLocking' param is passed in. This function is useful if you
985 * want the files to be locked for a broader scope than just when the
986 * files are changing. For example, if you need to update DB metadata,
987 * you may want to keep the files locked until finished.
989 * @see FileBackend::doOperations()
991 * @param $ops Array List of file operations to FileBackend::doOperations()
992 * @param $status Status Status to update on lock/unlock
993 * @return Array List of ScopedFileLocks or null values
996 abstract public function getScopedLocksForOps( array $ops, Status
$status );
999 * Get the root storage path of this backend.
1000 * All container paths are "subdirectories" of this path.
1002 * @return string Storage path
1005 final public function getRootStoragePath() {
1006 return "mwstore://{$this->name}";
1010 * Get the file journal object for this backend
1012 * @return FileJournal
1014 final public function getJournal() {
1015 return $this->fileJournal
;
1019 * Check if a given path is a "mwstore://" path.
1020 * This does not do any further validation or any existence checks.
1022 * @param $path string
1025 final public static function isStoragePath( $path ) {
1026 return ( strpos( $path, 'mwstore://' ) === 0 );
1030 * Split a storage path into a backend name, a container name,
1031 * and a relative file path. The relative path may be the empty string.
1032 * This does not do any path normalization or traversal checks.
1034 * @param $storagePath string
1035 * @return Array (backend, container, rel object) or (null, null, null)
1037 final public static function splitStoragePath( $storagePath ) {
1038 if ( self
::isStoragePath( $storagePath ) ) {
1039 // Remove the "mwstore://" prefix and split the path
1040 $parts = explode( '/', substr( $storagePath, 10 ), 3 );
1041 if ( count( $parts ) >= 2 && $parts[0] != '' && $parts[1] != '' ) {
1042 if ( count( $parts ) == 3 ) {
1043 return $parts; // e.g. "backend/container/path"
1045 return array( $parts[0], $parts[1], '' ); // e.g. "backend/container"
1049 return array( null, null, null );
1053 * Normalize a storage path by cleaning up directory separators.
1054 * Returns null if the path is not of the format of a valid storage path.
1056 * @param $storagePath string
1057 * @return string|null
1059 final public static function normalizeStoragePath( $storagePath ) {
1060 list( $backend, $container, $relPath ) = self
::splitStoragePath( $storagePath );
1061 if ( $relPath !== null ) { // must be for this backend
1062 $relPath = self
::normalizeContainerPath( $relPath );
1063 if ( $relPath !== null ) {
1064 return ( $relPath != '' )
1065 ?
"mwstore://{$backend}/{$container}/{$relPath}"
1066 : "mwstore://{$backend}/{$container}";
1073 * Get the parent storage directory of a storage path.
1074 * This returns a path like "mwstore://backend/container",
1075 * "mwstore://backend/container/...", or null if there is no parent.
1077 * @param $storagePath string
1078 * @return string|null
1080 final public static function parentStoragePath( $storagePath ) {
1081 $storagePath = dirname( $storagePath );
1082 list( $b, $cont, $rel ) = self
::splitStoragePath( $storagePath );
1083 return ( $rel === null ) ?
null : $storagePath;
1087 * Get the final extension from a storage or FS path
1089 * @param $path string
1092 final public static function extensionFromPath( $path ) {
1093 $i = strrpos( $path, '.' );
1094 return strtolower( $i ?
substr( $path, $i +
1 ) : '' );
1098 * Check if a relative path has no directory traversals
1100 * @param $path string
1104 final public static function isPathTraversalFree( $path ) {
1105 return ( self
::normalizeContainerPath( $path ) !== null );
1109 * Build a Content-Disposition header value per RFC 6266.
1111 * @param $type string One of (attachment, inline)
1112 * @param $filename string Suggested file name (should not contain slashes)
1116 final public static function makeContentDisposition( $type, $filename = '' ) {
1119 $type = strtolower( $type );
1120 if ( !in_array( $type, array( 'inline', 'attachment' ) ) ) {
1121 throw new MWException( "Invalid Content-Disposition type '$type'." );
1125 if ( strlen( $filename ) ) {
1126 $parts[] = "filename*=UTF-8''" . rawurlencode( basename( $filename ) );
1129 return implode( ';', $parts );
1133 * Validate and normalize a relative storage path.
1134 * Null is returned if the path involves directory traversal.
1135 * Traversal is insecure for FS backends and broken for others.
1137 * This uses the same traversal protection as Title::secureAndSplit().
1139 * @param $path string Storage path relative to a container
1140 * @return string|null
1142 final protected static function normalizeContainerPath( $path ) {
1143 // Normalize directory separators
1144 $path = strtr( $path, '\\', '/' );
1145 // Collapse any consecutive directory separators
1146 $path = preg_replace( '![/]{2,}!', '/', $path );
1147 // Remove any leading directory separator
1148 $path = ltrim( $path, '/' );
1149 // Use the same traversal protection as Title::secureAndSplit()
1150 if ( strpos( $path, '.' ) !== false ) {
1154 strpos( $path, './' ) === 0 ||
1155 strpos( $path, '../' ) === 0 ||
1156 strpos( $path, '/./' ) !== false ||
1157 strpos( $path, '/../' ) !== false