f21caa41d3
* Consolidate various duplicate docs to the main entry point. Especially the duplication that followed after ExternalStoreFactory and ExternalStoreAccess were introduced with ExternalStore left as deprecated wrapper. * Officially mark ExternalStoreFactory as internal, pointing to ExternalStoreAccess instead. And document why the latter exists, since it seems all its methods could trivially move to the factory class. Follows-up I40c3b553, where it was explained that the factory is meant to be an internal implementation detail, with the access class meant to resemble ExternalStoreMedium. * Use consistent terms for "protocol", "location" and "object" (reduce use of words like medium, backend, type, blob, revision, etc. within this code). * Document that ExternalStore is fundamentally designed as an append-only store (per T247383). Bug: T247383 Change-Id: I1094af7d35a14f9e47b8791f3e4cc888e8cbfc7f
117 lines
3.6 KiB
PHP
117 lines
3.6 KiB
PHP
<?php
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/**
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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* http://www.gnu.org/copyleft/gpl.html
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*
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* @file
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*/
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use Psr\Log\LoggerAwareInterface;
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use Psr\Log\LoggerInterface;
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use Psr\Log\NullLogger;
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/**
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* Base class for external storage.
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*
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* There can be multiple "locations" for a storage medium type (e.g. DB clusters, filesystems).
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* Blobs are stored under URLs of the form `<protocol>://<location>/<path>`. Each type of storage
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* medium has an associated protocol.
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*
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* @see ExternalStoreAccess
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* @ingroup ExternalStorage
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* @since 1.21
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*/
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abstract class ExternalStoreMedium implements LoggerAwareInterface {
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/** @var array Usage context options for this instance */
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protected $params = [];
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/** @var string Default database domain to store content under */
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protected $dbDomain;
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/** @var bool Whether this was factoried with an explicit DB domain */
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protected $isDbDomainExplicit;
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/** @var LoggerInterface */
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protected $logger;
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/**
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* @param array $params Usage context options for this instance:
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* - domain: the DB domain ID of the wiki the content is for [required]
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* - logger: LoggerInterface instance [optional]
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* - isDomainImplicit: whether this was factoried without an explicit DB domain [optional]
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*/
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public function __construct( array $params ) {
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$this->params = $params;
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if ( isset( $params['domain'] ) ) {
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$this->dbDomain = $params['domain'];
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$this->isDbDomainExplicit = empty( $params['isDomainImplicit'] );
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} else {
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throw new InvalidArgumentException( 'Missing DB "domain" parameter.' );
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}
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$this->logger = $params['logger'] ?? new NullLogger();
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}
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public function setLogger( LoggerInterface $logger ) {
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$this->logger = $logger;
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}
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/**
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* Fetch data from given external store URL
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*
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* @param string $url An external store URL
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* @return string|bool The text stored or false on error
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* @throws MWException
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*/
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abstract public function fetchFromURL( $url );
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/**
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* Fetch data from given external store URLs.
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*
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* @param array $urls A list of external store URLs
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* @return string[] Map of (url => text) for the URLs where data was actually found
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*/
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public function batchFetchFromURLs( array $urls ) {
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$retval = [];
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foreach ( $urls as $url ) {
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$data = $this->fetchFromURL( $url );
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// Dont return when false to allow for simpler implementations
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if ( $data !== false ) {
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$retval[$url] = $data;
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}
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}
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return $retval;
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}
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/**
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* Insert a data item into a given location
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*
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* @param string $location The location name
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* @param string $data The data item
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* @return string|bool The URL of the stored data item, or false on error
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* @throws MWException
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*/
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abstract public function store( $location, $data );
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/**
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* Check if a given location is read-only
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*
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* @param string $location The location name
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* @return bool Whether this location is read-only
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* @since 1.31
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*/
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public function isReadOnly( $location ) {
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return false;
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}
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}
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