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[mediawiki.git] / includes / actions / Action.php

<?php
/**
 * Base classes for actions done on pages.
 *
 * 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
 *
 * @file
 */

use MediaWiki\Context\IContextSource;
use MediaWiki\HookContainer\HookContainer;
use MediaWiki\HookContainer\HookRunner;
use MediaWiki\Language\Language;
use MediaWiki\Language\RawMessage;
use MediaWiki\MediaWikiServices;
use MediaWiki\Message\Message;
use MediaWiki\Output\OutputPage;
use MediaWiki\Permissions\Authority;
use MediaWiki\Request\WebRequest;
use MediaWiki\Title\Title;
use MediaWiki\User\User;
use Wikimedia\Message\MessageParam;
use Wikimedia\Message\MessageSpecifier;

/**
 * @defgroup Actions Actions
 */

/**
 * Actions are things which can be done to pages (edit, delete, rollback, etc).  They
 * are distinct from Special Pages because an action must apply to exactly one page.
 *
 * To add an action in an extension, create a subclass of Action, and add the key to
 * $wgActions.
 *
 * Actions generally fall into two groups: the show-a-form-then-do-something-with-the-input
 * format (protect, delete, move, etc), and the just-do-something format (watch, rollback,
 * patrol, etc). The FormAction and FormlessAction classes represent these two groups.
 *
 * @stable to extend
 */
abstract class Action implements MessageLocalizer {

        /**
         * @var Article
         * @since 1.35
         */
        private $article;

        /**
         * IContextSource if specified; otherwise we'll use the Context from the Page
         * @since 1.17
         * @var IContextSource|null
         */
        protected $context;

        /**
         * The fields used to create the HTMLForm
         * @since 1.17
         * @var array
         */
        protected $fields;

        /** @var HookContainer|null */
        private $hookContainer;
        /** @var HookRunner|null */
        private $hookRunner;

        /**
         * Get an appropriate Action subclass for the given action
         * @since 1.17
         *
         * @param string $action
         * @param Article $article
         * @param IContextSource|null $context Falls back to article's context
         * @return Action|false|null False if the action is disabled, null
         *     if it is not recognised
         */
        final public static function factory(
                string $action,
                Article $article,
                ?IContextSource $context = null
        ) {
                return MediaWikiServices::getInstance()
                        ->getActionFactory()
                        ->getAction( $action, $article, $context ?? $article->getContext() );
        }

        /**
         * Get the action that will be executed, not necessarily the one passed
         * passed through the "action" request parameter. Actions disabled in
         * $wgActions will be replaced by "nosuchaction".
         *
         * @since 1.19
         * @param IContextSource $context
         * @return string Action name
         */
        final public static function getActionName( IContextSource $context ) {
                // Optimisation: Reuse/prime the cached value of RequestContext
                return $context->getActionName();
        }

        /**
         * Get the IContextSource in use here
         * @since 1.17
         * @return IContextSource
         */
        final public function getContext() {
                if ( $this->context instanceof IContextSource ) {
                        return $this->context;
                }
                wfDebug( __METHOD__ . ": no context known, falling back to Article's context." );
                return $this->getArticle()->getContext();
        }

        /**
         * Get the WebRequest being used for this instance
         * @since 1.17
         *
         * @return WebRequest
         */
        final public function getRequest() {
                return $this->getContext()->getRequest();
        }

        /**
         * Get the OutputPage being used for this instance
         * @since 1.17
         *
         * @return OutputPage
         */
        final public function getOutput() {
                return $this->getContext()->getOutput();
        }

        /**
         * Shortcut to get the User being used for this instance
         * @since 1.17
         *
         * @return User
         */
        final public function getUser() {
                return $this->getContext()->getUser();
        }

        /**
         * Shortcut to get the Authority executing this instance
         *
         * @return Authority
         * @since 1.39
         */
        final public function getAuthority(): Authority {
                return $this->getContext()->getAuthority();
        }

        /**
         * Shortcut to get the Skin being used for this instance
         * @since 1.17
         *
         * @return Skin
         */
        final public function getSkin() {
                return $this->getContext()->getSkin();
        }

        /**
         * Shortcut to get the user Language being used for this instance
         *
         * @return Language
         */
        final public function getLanguage() {
                return $this->getContext()->getLanguage();
        }

        /**
         * Get a WikiPage object
         * @since 1.35
         *
         * @return WikiPage
         */
        final public function getWikiPage(): WikiPage {
                return $this->getArticle()->getPage();
        }

        /**
         * Get a Article object
         * @since 1.35
         * Overriding this method is deprecated since 1.35
         *
         * @return Article|ImagePage|CategoryPage
         */
        public function getArticle() {
                return $this->article;
        }

        /**
         * Shortcut to get the Title object from the page
         * @since 1.17
         *
         * @return Title
         */
        final public function getTitle() {
                return $this->getWikiPage()->getTitle();
        }

        /**
         * Get a Message object with context set
         * Parameters are the same as wfMessage()
         *
         * @param string|string[]|MessageSpecifier $key
         * @phpcs:ignore Generic.Files.LineLength
         * @param MessageParam|MessageSpecifier|string|int|float|list<MessageParam|MessageSpecifier|string|int|float> ...$params
         *   See Message::params()
         * @return Message
         */
        final public function msg( $key, ...$params ) {
                return $this->getContext()->msg( $key, ...$params );
        }

        /**
         * @since 1.40
         * @internal For use by ActionFactory
         * @param HookContainer $hookContainer
         */
        public function setHookContainer( HookContainer $hookContainer ) {
                $this->hookContainer = $hookContainer;
                $this->hookRunner = new HookRunner( $hookContainer );
        }

        /**
         * @since 1.35
         * @internal since 1.37
         * @return HookContainer
         */
        protected function getHookContainer() {
                if ( !$this->hookContainer ) {
                        $this->hookContainer = MediaWikiServices::getInstance()->getHookContainer();
                }
                return $this->hookContainer;
        }

        /**
         * @since 1.35
         * @internal This is for use by core only. Hook interfaces may be removed
         *   without notice.
         * @return HookRunner
         */
        protected function getHookRunner() {
                if ( !$this->hookRunner ) {
                        $this->hookRunner = new HookRunner( $this->getHookContainer() );
                }
                return $this->hookRunner;
        }

        /**
         * Only public since 1.21
         *
         * @stable to call
         *
         * @param Article $article
         * @param IContextSource $context
         */
        public function __construct( Article $article, IContextSource $context ) {
                $this->article = $article;
                $this->context = $context;
        }

        /**
         * Return the name of the action this object responds to
         * @since 1.17
         *
         * @return string Lowercase name
         */
        abstract public function getName();

        /**
         * Get the permission required to perform this action.  Often, but not always,
         * the same as the action name
         *
         * Implementations of this methods must always return the same value, regardless
         * of parameters passed to the constructor or system state.
         *
         * @since 1.17
         * @stable to override
         *
         * @return string|null
         */
        public function getRestriction() {
                return null;
        }

        /**
         * Indicates whether this action requires read rights
         *
         * Implementations of this methods must always return the same value, regardless
         * of parameters passed to the constructor or system state.
         *
         * @since 1.38
         * @stable to override
         * @return bool
         */
        public function needsReadRights() {
                return true;
        }

        /**
         * Checks if the given user (identified by an object) can perform this action.  Can be
         * overridden by sub-classes with more complicated permissions schemes.  Failures here
         * must throw subclasses of ErrorPageError
         * @since 1.17
         * @stable to override
         *
         * @param User $user
         * @throws UserBlockedError|ReadOnlyError|PermissionsError
         */
        protected function checkCanExecute( User $user ) {
                $right = $this->getRestriction();
                $permissionManager = MediaWikiServices::getInstance()->getPermissionManager();
                if ( $right !== null ) {
                        $permissionManager->throwPermissionErrors( $right, $user, $this->getTitle() );
                }

                // If the action requires an unblock, explicitly check the user's block.
                $checkReplica = !$this->getRequest()->wasPosted();
                if (
                        $this->requiresUnblock() &&
                        $permissionManager->isBlockedFrom( $user, $this->getTitle(), $checkReplica )
                ) {
                        $block = $user->getBlock();
                        if ( $block ) {
                                throw new UserBlockedError(
                                        $block,
                                        $user,
                                        $this->getLanguage(),
                                        $this->getRequest()->getIP()
                                );
                        }

                        throw new PermissionsError( $this->getName(), [ 'badaccess-group0' ] );
                }

                // This should be checked at the end so that the user won't think the
                // error is only temporary when he also don't have the rights to execute
                // this action
                $readOnlyMode = MediaWikiServices::getInstance()->getReadOnlyMode();
                if ( $this->requiresWrite() && $readOnlyMode->isReadOnly() ) {
                        throw new ReadOnlyError();
                }
        }

        /**
         * Indicates whether this action page write access to the wiki.
         *
         * Subclasses must override this method to return true if the operation they will
         * perform is not "safe" per RFC 7231 section 4.2.1. A subclass's operation is "safe"
         * if it is essentially read-only, i.e. the client does not request nor expect any
         * state change that would be observable in the responses to future requests.
         *
         * Implementations of this method must always return the same value, regardless of the
         * parameters passed to the constructor or system state.
         *
         * When handling GET/HEAD requests, subclasses should only perform "safe" operations.
         * Note that subclasses handling POST requests might still implement "safe" operations,
         * particularly in the case where large input parameters are required.
         *
         * @since 1.17
         * @stable to override
         *
         * @return bool
         */
        public function requiresWrite() {
                return true;
        }

        /**
         * Whether this action can still be executed by a blocked user.
         *
         * Implementations of this methods must always return the same value, regardless
         * of parameters passed to the constructor or system state.
         *
         * @since 1.17
         * @stable to override
         *
         * @return bool
         */
        public function requiresUnblock() {
                return true;
        }

        /**
         * Set output headers for noindexing etc.  This function will not be called through
         * the execute() entry point, so only put UI-related stuff in here.
         * @stable to override
         * @since 1.17
         */
        protected function setHeaders() {
                $out = $this->getOutput();
                $out->setRobotPolicy( 'noindex,nofollow' );
                $title = $this->getPageTitle();
                if ( is_string( $title ) ) {
                        // T343849: deprecated
                        wfDeprecated( 'string return from Action::getPageTitle()', '1.41' );
                        $title = ( new RawMessage( '$1' ) )->rawParams( $title );
                }
                $out->setPageTitleMsg( $title );
                $out->setSubtitle( $this->getDescription() );
                $out->setArticleRelated( true );
        }

        /**
         * Returns the name that goes in the `<h1>` page title.
         *
         * Since 1.41, returning a string from this method has been deprecated.
         *
         * @stable to override
         * @return string|Message
         */
        protected function getPageTitle() {
                return ( new RawMessage( '$1' ) )->plaintextParams( $this->getTitle()->getPrefixedText() );
        }

        /**
         * Returns the description that goes below the `<h1>` element.
         *
         * @since 1.17
         * @stable to override
         * @return string HTML
         */
        protected function getDescription() {
                return $this->msg( strtolower( $this->getName() ) )->escaped();
        }

        /**
         * Adds help link with an icon via page indicators.
         * Link target can be overridden by a local message containing a wikilink:
         * the message key is: lowercase action name + '-helppage'.
         * @param string $to Target MediaWiki.org page title or encoded URL.
         * @param bool $overrideBaseUrl Whether $url is a full URL, to avoid MW.o.
         * @since 1.25
         */
        public function addHelpLink( $to, $overrideBaseUrl = false ) {
                $lang = MediaWikiServices::getInstance()->getContentLanguage();
                $target = $lang->lc( $this->getName() . '-helppage' );
                $msg = $this->msg( $target );

                if ( !$msg->isDisabled() ) {
                        $title = Title::newFromText( $msg->plain() );
                        if ( $title instanceof Title ) {
                                $this->getOutput()->addHelpLink( $title->getLocalURL(), true );
                        }
                } else {
                        $this->getOutput()->addHelpLink( $to, $overrideBaseUrl );
                }
        }

        /**
         * The main action entry point.  Do all output for display and send it to the context
         * output.  Do not use globals $wgOut, $wgRequest, etc, in implementations; use
         * $this->getOutput(), etc.
         * @since 1.17
         *
         * @throws ErrorPageError
         */
        abstract public function show();

        /**
         * Call wfTransactionalTimeLimit() if this request was POSTed
         * @since 1.26
         */
        protected function useTransactionalTimeLimit() {
                if ( $this->getRequest()->wasPosted() ) {
                        wfTransactionalTimeLimit();
                }
        }

        /**
         * Indicates whether POST requests handled by this action require write access to the wiki.
         *
         * Subclasses must override this method to return true if any of the operations that
         * they perform on POST requests are not "safe" per RFC 7231 section 4.2.1. A subclass's
         * operation is "safe" if it is essentially read-only, i.e. the client does not request
         * nor expect any state change that would be observable in the responses to future requests.
         *
         * Implementations of this method must always return the same value, regardless of the
         * parameters passed to the constructor or system state.
         *
         * When handling GET/HEAD requests, subclasses should only perform "safe" operations.
         * Note that some subclasses might only perform "safe" operations even for POST requests,
         * particularly in the case where large input parameters are required.
         *
         * @return bool
         * @since 1.27
         * @stable to override
         */
        public function doesWrites() {
                return false;
        }
}