includes/actions/Action.php

   1 <?php
   2 /**
   3  * Base classes for actions done on pages.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
  18  *
  19  * @file
  20  */
  21
  22 /**
  23  * @defgroup Actions Action done on pages
  24  */
  25
  26 /**
  27  * Actions are things which can be done to pages (edit, delete, rollback, etc).  They
  28  * are distinct from Special Pages because an action must apply to exactly one page.
  29  *
  30  * To add an action in an extension, create a subclass of Action, and add the key to
  31  * $wgActions.  There is also the deprecated UnknownAction hook
  32  *
  33  * Actions generally fall into two groups: the show-a-form-then-do-something-with-the-input
  34  * format (protect, delete, move, etc), and the just-do-something format (watch, rollback,
  35  * patrol, etc). The FormAction and FormlessAction classes represent these two groups.
  36  */
  37 abstract class Action {
  38
  39         /**
  40          * Page on which we're performing the action
  41          * @since 1.17
  42          * @var WikiPage|Article|ImagePage|CategoryPage|Page $page
  43          */
  44         protected $page;
  45
  46         /**
  47          * IContextSource if specified; otherwise we'll use the Context from the Page
  48          * @since 1.17
  49          * @var IContextSource $context
  50          */
  51         protected $context;
  52
  53         /**
  54          * The fields used to create the HTMLForm
  55          * @since 1.17
  56          * @var array $fields
  57          */
  58         protected $fields;
  59
  60         /**
  61          * Get the Action subclass which should be used to handle this action, false if
  62          * the action is disabled, or null if it's not recognised
  63          * @param string $action
  64          * @param array $overrides
  65          * @return bool|null|string|callable|Action
  66          */
  67         final private static function getClass( $action, array $overrides ) {
  68                 global $wgActions;
  69                 $action = strtolower( $action );
  70
  71                 if ( !isset( $wgActions[$action] ) ) {
  72                         return null;
  73                 }
  74
  75                 if ( $wgActions[$action] === false ) {
  76                         return false;
  77                 } elseif ( $wgActions[$action] === true && isset( $overrides[$action] ) ) {
  78                         return $overrides[$action];
  79                 } elseif ( $wgActions[$action] === true ) {
  80                         return ucfirst( $action ) . 'Action';
  81                 } else {
  82                         return $wgActions[$action];
  83                 }
  84         }
  85
  86         /**
  87          * Get an appropriate Action subclass for the given action
  88          * @since 1.17
  89          * @param string $action
  90          * @param Page $page
  91          * @param IContextSource|null $context
  92          * @return Action|bool|null False if the action is disabled, null
  93          *     if it is not recognised
  94          */
  95         final public static function factory( $action, Page $page, IContextSource $context = null ) {
  96                 $classOrCallable = self::getClass( $action, $page->getActionOverrides() );
  97
  98                 if ( is_string( $classOrCallable ) ) {
  99                         if ( !class_exists( $classOrCallable ) ) {
 100                                 return false;
 101                         }
 102                         $obj = new $classOrCallable( $page, $context );
 103                         return $obj;
 104                 }
 105
 106                 if ( is_callable( $classOrCallable ) ) {
 107                         return call_user_func_array( $classOrCallable, [ $page, $context ] );
 108                 }
 109
 110                 return $classOrCallable;
 111         }
 112
 113         /**
 114          * Get the action that will be executed, not necessarily the one passed
 115          * passed through the "action" request parameter. Actions disabled in
 116          * $wgActions will be replaced by "nosuchaction".
 117          *
 118          * @since 1.19
 119          * @param IContextSource $context
 120          * @return string Action name
 121          */
 122         final public static function getActionName( IContextSource $context ) {
 123                 global $wgActions;
 124
 125                 $request = $context->getRequest();
 126                 $actionName = $request->getVal( 'action', 'view' );
 127
 128                 // Check for disabled actions
 129                 if ( isset( $wgActions[$actionName] ) && $wgActions[$actionName] === false ) {
 130                         $actionName = 'nosuchaction';
 131                 }
 132
 133                 // Workaround for bug #20966: inability of IE to provide an action dependent
 134                 // on which submit button is clicked.
 135                 if ( $actionName === 'historysubmit' ) {
 136                         if ( $request->getBool( 'revisiondelete' ) ) {
 137                                 $actionName = 'revisiondelete';
 138                         } elseif ( $request->getBool( 'editchangetags' ) ) {
 139                                 $actionName = 'editchangetags';
 140                         } else {
 141                                 $actionName = 'view';
 142                         }
 143                 } elseif ( $actionName == 'editredlink' ) {
 144                         $actionName = 'edit';
 145                 }
 146
 147                 // Trying to get a WikiPage for NS_SPECIAL etc. will result
 148                 // in WikiPage::factory throwing "Invalid or virtual namespace -1 given."
 149                 // For SpecialPages et al, default to action=view.
 150                 if ( !$context->canUseWikiPage() ) {
 151                         return 'view';
 152                 }
 153
 154                 $action = Action::factory( $actionName, $context->getWikiPage(), $context );
 155                 if ( $action instanceof Action ) {
 156                         return $action->getName();
 157                 }
 158
 159                 return 'nosuchaction';
 160         }
 161
 162         /**
 163          * Check if a given action is recognised, even if it's disabled
 164          * @since 1.17
 165          *
 166          * @param string $name Name of an action
 167          * @return bool
 168          */
 169         final public static function exists( $name ) {
 170                 return self::getClass( $name, [] ) !== null;
 171         }
 172
 173         /**
 174          * Get the IContextSource in use here
 175          * @since 1.17
 176          * @return IContextSource
 177          */
 178         final public function getContext() {
 179                 if ( $this->context instanceof IContextSource ) {
 180                         return $this->context;
 181                 } elseif ( $this->page instanceof Article ) {
 182                         // NOTE: $this->page can be a WikiPage, which does not have a context.
 183                         wfDebug( __METHOD__ . ": no context known, falling back to Article's context.\n" );
 184                         return $this->page->getContext();
 185                 }
 186
 187                 wfWarn( __METHOD__ . ': no context known, falling back to RequestContext::getMain().' );
 188                 return RequestContext::getMain();
 189         }
 190
 191         /**
 192          * Get the WebRequest being used for this instance
 193          * @since 1.17
 194          *
 195          * @return WebRequest
 196          */
 197         final public function getRequest() {
 198                 return $this->getContext()->getRequest();
 199         }
 200
 201         /**
 202          * Get the OutputPage being used for this instance
 203          * @since 1.17
 204          *
 205          * @return OutputPage
 206          */
 207         final public function getOutput() {
 208                 return $this->getContext()->getOutput();
 209         }
 210
 211         /**
 212          * Shortcut to get the User being used for this instance
 213          * @since 1.17
 214          *
 215          * @return User
 216          */
 217         final public function getUser() {
 218                 return $this->getContext()->getUser();
 219         }
 220
 221         /**
 222          * Shortcut to get the Skin being used for this instance
 223          * @since 1.17
 224          *
 225          * @return Skin
 226          */
 227         final public function getSkin() {
 228                 return $this->getContext()->getSkin();
 229         }
 230
 231         /**
 232          * Shortcut to get the user Language being used for this instance
 233          *
 234          * @return Language
 235          */
 236         final public function getLanguage() {
 237                 return $this->getContext()->getLanguage();
 238         }
 239
 240         /**
 241          * Shortcut to get the Title object from the page
 242          * @since 1.17
 243          *
 244          * @return Title
 245          */
 246         final public function getTitle() {
 247                 return $this->page->getTitle();
 248         }
 249
 250         /**
 251          * Get a Message object with context set
 252          * Parameters are the same as wfMessage()
 253          *
 254          * @return Message
 255          */
 256         final public function msg() {
 257                 $params = func_get_args();
 258                 return call_user_func_array( [ $this->getContext(), 'msg' ], $params );
 259         }
 260
 261         /**
 262          * Constructor.
 263          *
 264          * Only public since 1.21
 265          *
 266          * @param Page $page
 267          * @param IContextSource|null $context
 268          */
 269         public function __construct( Page $page, IContextSource $context = null ) {
 270                 if ( $context === null ) {
 271                         wfWarn( __METHOD__ . ' called without providing a Context object.' );
 272                         // NOTE: We could try to initialize $context using $page->getContext(),
 273                         //      if $page is an Article. That however seems to not work seamlessly.
 274                 }
 275
 276                 $this->page = $page;
 277                 $this->context = $context;
 278         }
 279
 280         /**
 281          * Return the name of the action this object responds to
 282          * @since 1.17
 283          *
 284          * @return string Lowercase name
 285          */
 286         abstract public function getName();
 287
 288         /**
 289          * Get the permission required to perform this action.  Often, but not always,
 290          * the same as the action name
 291          * @since 1.17
 292          *
 293          * @return string|null
 294          */
 295         public function getRestriction() {
 296                 return null;
 297         }
 298
 299         /**
 300          * Checks if the given user (identified by an object) can perform this action.  Can be
 301          * overridden by sub-classes with more complicated permissions schemes.  Failures here
 302          * must throw subclasses of ErrorPageError
 303          * @since 1.17
 304          *
 305          * @param User $user The user to check, or null to use the context user
 306          * @throws UserBlockedError|ReadOnlyError|PermissionsError
 307          */
 308         protected function checkCanExecute( User $user ) {
 309                 $right = $this->getRestriction();
 310                 if ( $right !== null ) {
 311                         $errors = $this->getTitle()->getUserPermissionsErrors( $right, $user );
 312                         if ( count( $errors ) ) {
 313                                 throw new PermissionsError( $right, $errors );
 314                         }
 315                 }
 316
 317                 if ( $this->requiresUnblock() && $user->isBlocked() ) {
 318                         $block = $user->getBlock();
 319                         throw new UserBlockedError( $block );
 320                 }
 321
 322                 // This should be checked at the end so that the user won't think the
 323                 // error is only temporary when he also don't have the rights to execute
 324                 // this action
 325                 if ( $this->requiresWrite() && wfReadOnly() ) {
 326                         throw new ReadOnlyError();
 327                 }
 328         }
 329
 330         /**
 331          * Whether this action requires the wiki not to be locked
 332          * @since 1.17
 333          *
 334          * @return bool
 335          */
 336         public function requiresWrite() {
 337                 return true;
 338         }
 339
 340         /**
 341          * Whether this action can still be executed by a blocked user
 342          * @since 1.17
 343          *
 344          * @return bool
 345          */
 346         public function requiresUnblock() {
 347                 return true;
 348         }
 349
 350         /**
 351          * Set output headers for noindexing etc.  This function will not be called through
 352          * the execute() entry point, so only put UI-related stuff in here.
 353          * @since 1.17
 354          */
 355         protected function setHeaders() {
 356                 $out = $this->getOutput();
 357                 $out->setRobotPolicy( "noindex,nofollow" );
 358                 $out->setPageTitle( $this->getPageTitle() );
 359                 $out->setSubtitle( $this->getDescription() );
 360                 $out->setArticleRelated( true );
 361         }
 362
 363         /**
 364          * Returns the name that goes in the \<h1\> page title
 365          *
 366          * @return string
 367          */
 368         protected function getPageTitle() {
 369                 return $this->getTitle()->getPrefixedText();
 370         }
 371
 372         /**
 373          * Returns the description that goes below the \<h1\> tag
 374          * @since 1.17
 375          *
 376          * @return string HTML
 377          */
 378         protected function getDescription() {
 379                 return $this->msg( strtolower( $this->getName() ) )->escaped();
 380         }
 381
 382         /**
 383          * Adds help link with an icon via page indicators.
 384          * Link target can be overridden by a local message containing a wikilink:
 385          * the message key is: lowercase action name + '-helppage'.
 386          * @param string $to Target MediaWiki.org page title or encoded URL.
 387          * @param bool $overrideBaseUrl Whether $url is a full URL, to avoid MW.o.
 388          * @since 1.25
 389          */
 390         public function addHelpLink( $to, $overrideBaseUrl = false ) {
 391                 global $wgContLang;
 392                 $msg = wfMessage( $wgContLang->lc(
 393                         Action::getActionName( $this->getContext() )
 394                         ) . '-helppage' );
 395
 396                 if ( !$msg->isDisabled() ) {
 397                         $helpUrl = Skin::makeUrl( $msg->plain() );
 398                         $this->getOutput()->addHelpLink( $helpUrl, true );
 399                 } else {
 400                         $this->getOutput()->addHelpLink( $to, $overrideBaseUrl );
 401                 }
 402         }
 403
 404         /**
 405          * The main action entry point.  Do all output for display and send it to the context
 406          * output.  Do not use globals $wgOut, $wgRequest, etc, in implementations; use
 407          * $this->getOutput(), etc.
 408          * @since 1.17
 409          *
 410          * @throws ErrorPageError
 411          */
 412         abstract public function show();
 413
 414         /**
 415          * Call wfTransactionalTimeLimit() if this request was POSTed
 416          * @since 1.26
 417          */
 418         protected function useTransactionalTimeLimit() {
 419                 if ( $this->getRequest()->wasPosted() ) {
 420                         wfTransactionalTimeLimit();
 421                 }
 422         }
 423
 424         /**
 425          * Indicates whether this action may perform database writes
 426          * @return bool
 427          * @since 1.27
 428          */
 429         public function doesWrites() {
 430                 return false;
 431         }
 432 }