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          * @var WikiPage|Article|ImagePage|CategoryPage|Page $page
  42          */
  43         protected $page;
  44
  45         /**
  46          * IContextSource if specified; otherwise we'll use the Context from the Page
  47          * @var IContextSource $context
  48          */
  49         protected $context;
  50
  51         /**
  52          * The fields used to create the HTMLForm
  53          * @var array $fields
  54          */
  55         protected $fields;
  56
  57         /**
  58          * Get the Action subclass which should be used to handle this action, false if
  59          * the action is disabled, or null if it's not recognised
  60          * @param string $action
  61          * @param array $overrides
  62          * @return bool|null|string|callable
  63          */
  64         final private static function getClass( $action, array $overrides ) {
  65                 global $wgActions;
  66                 $action = strtolower( $action );
  67
  68                 if ( !isset( $wgActions[$action] ) ) {
  69                         return null;
  70                 }
  71
  72                 if ( $wgActions[$action] === false ) {
  73                         return false;
  74                 } elseif ( $wgActions[$action] === true && isset( $overrides[$action] ) ) {
  75                         return $overrides[$action];
  76                 } elseif ( $wgActions[$action] === true ) {
  77                         return ucfirst( $action ) . 'Action';
  78                 } else {
  79                         return $wgActions[$action];
  80                 }
  81         }
  82
  83         /**
  84          * Get an appropriate Action subclass for the given action
  85          * @param string $action
  86          * @param Page $page
  87          * @param IContextSource $context
  88          * @return Action|bool|null False if the action is disabled, null
  89          *     if it is not recognised
  90          */
  91         final public static function factory( $action, Page $page, IContextSource $context = null ) {
  92                 $classOrCallable = self::getClass( $action, $page->getActionOverrides() );
  93
  94                 if ( is_string( $classOrCallable ) ) {
  95                         $obj = new $classOrCallable( $page, $context );
  96                         return $obj;
  97                 }
  98
  99                 if ( is_callable( $classOrCallable ) ) {
 100                         return call_user_func_array( $classOrCallable, array( $page, $context ) );
 101                 }
 102
 103                 return $classOrCallable;
 104         }
 105
 106         /**
 107          * Get the action that will be executed, not necessarily the one passed
 108          * passed through the "action" request parameter. Actions disabled in
 109          * $wgActions will be replaced by "nosuchaction".
 110          *
 111          * @since 1.19
 112          * @param IContextSource $context
 113          * @return string Action name
 114          */
 115         final public static function getActionName( IContextSource $context ) {
 116                 global $wgActions;
 117
 118                 $request = $context->getRequest();
 119                 $actionName = $request->getVal( 'action', 'view' );
 120
 121                 // Check for disabled actions
 122                 if ( isset( $wgActions[$actionName] ) && $wgActions[$actionName] === false ) {
 123                         $actionName = 'nosuchaction';
 124                 }
 125
 126                 // Workaround for bug #20966: inability of IE to provide an action dependent
 127                 // on which submit button is clicked.
 128                 if ( $actionName === 'historysubmit' ) {
 129                         if ( $request->getBool( 'revisiondelete' ) ) {
 130                                 $actionName = 'revisiondelete';
 131                         } else {
 132                                 $actionName = 'view';
 133                         }
 134                 } elseif ( $actionName == 'editredlink' ) {
 135                         $actionName = 'edit';
 136                 }
 137
 138                 // Trying to get a WikiPage for NS_SPECIAL etc. will result
 139                 // in WikiPage::factory throwing "Invalid or virtual namespace -1 given."
 140                 // For SpecialPages et al, default to action=view.
 141                 if ( !$context->canUseWikiPage() ) {
 142                         return 'view';
 143                 }
 144
 145                 $action = Action::factory( $actionName, $context->getWikiPage(), $context );
 146                 if ( $action instanceof Action ) {
 147                         return $action->getName();
 148                 }
 149
 150                 return 'nosuchaction';
 151         }
 152
 153         /**
 154          * Check if a given action is recognised, even if it's disabled
 155          *
 156          * @param string $name Name of an action
 157          * @return bool
 158          */
 159         final public static function exists( $name ) {
 160                 return self::getClass( $name, array() ) !== null;
 161         }
 162
 163         /**
 164          * Get the IContextSource in use here
 165          * @return IContextSource
 166          */
 167         final public function getContext() {
 168                 if ( $this->context instanceof IContextSource ) {
 169                         return $this->context;
 170                 } elseif ( $this->page instanceof Article ) {
 171                         // NOTE: $this->page can be a WikiPage, which does not have a context.
 172                         wfDebug( __METHOD__ . ": no context known, falling back to Article's context.\n" );
 173                         return $this->page->getContext();
 174                 }
 175
 176                 wfWarn( __METHOD__ . ': no context known, falling back to RequestContext::getMain().' );
 177                 return RequestContext::getMain();
 178         }
 179
 180         /**
 181          * Get the WebRequest being used for this instance
 182          *
 183          * @return WebRequest
 184          */
 185         final public function getRequest() {
 186                 return $this->getContext()->getRequest();
 187         }
 188
 189         /**
 190          * Get the OutputPage being used for this instance
 191          *
 192          * @return OutputPage
 193          */
 194         final public function getOutput() {
 195                 return $this->getContext()->getOutput();
 196         }
 197
 198         /**
 199          * Shortcut to get the User being used for this instance
 200          *
 201          * @return User
 202          */
 203         final public function getUser() {
 204                 return $this->getContext()->getUser();
 205         }
 206
 207         /**
 208          * Shortcut to get the Skin being used for this instance
 209          *
 210          * @return Skin
 211          */
 212         final public function getSkin() {
 213                 return $this->getContext()->getSkin();
 214         }
 215
 216         /**
 217          * Shortcut to get the user Language being used for this instance
 218          *
 219          * @return Language
 220          */
 221         final public function getLanguage() {
 222                 return $this->getContext()->getLanguage();
 223         }
 224
 225         /**
 226          * Shortcut to get the Title object from the page
 227          * @return Title
 228          */
 229         final public function getTitle() {
 230                 return $this->page->getTitle();
 231         }
 232
 233         /**
 234          * Get a Message object with context set
 235          * Parameters are the same as wfMessage()
 236          *
 237          * @return Message
 238          */
 239         final public function msg() {
 240                 $params = func_get_args();
 241                 return call_user_func_array( array( $this->getContext(), 'msg' ), $params );
 242         }
 243
 244         /**
 245          * Constructor.
 246          *
 247          * Only public since 1.21
 248          *
 249          * @param Page $page
 250          * @param IContextSource $context
 251          */
 252         public function __construct( Page $page, IContextSource $context = null ) {
 253                 if ( $context === null ) {
 254                         wfWarn( __METHOD__ . ' called without providing a Context object.' );
 255                         // NOTE: We could try to initialize $context using $page->getContext(),
 256                         //      if $page is an Article. That however seems to not work seamlessly.
 257                 }
 258
 259                 $this->page = $page;
 260                 $this->context = $context;
 261         }
 262
 263         /**
 264          * Return the name of the action this object responds to
 265          * @return string Lowercase name
 266          */
 267         abstract public function getName();
 268
 269         /**
 270          * Get the permission required to perform this action.  Often, but not always,
 271          * the same as the action name
 272          * @return string|null
 273          */
 274         public function getRestriction() {
 275                 return null;
 276         }
 277
 278         /**
 279          * Checks if the given user (identified by an object) can perform this action.  Can be
 280          * overridden by sub-classes with more complicated permissions schemes.  Failures here
 281          * must throw subclasses of ErrorPageError
 282          *
 283          * @param User $user The user to check, or null to use the context user
 284          * @throws UserBlockedError|ReadOnlyError|PermissionsError
 285          */
 286         protected function checkCanExecute( User $user ) {
 287                 $right = $this->getRestriction();
 288                 if ( $right !== null ) {
 289                         $errors = $this->getTitle()->getUserPermissionsErrors( $right, $user );
 290                         if ( count( $errors ) ) {
 291                                 throw new PermissionsError( $right, $errors );
 292                         }
 293                 }
 294
 295                 if ( $this->requiresUnblock() && $user->isBlocked() ) {
 296                         $block = $user->getBlock();
 297                         throw new UserBlockedError( $block );
 298                 }
 299
 300                 // This should be checked at the end so that the user won't think the
 301                 // error is only temporary when he also don't have the rights to execute
 302                 // this action
 303                 if ( $this->requiresWrite() && wfReadOnly() ) {
 304                         throw new ReadOnlyError();
 305                 }
 306         }
 307
 308         /**
 309          * Whether this action requires the wiki not to be locked
 310          * @return bool
 311          */
 312         public function requiresWrite() {
 313                 return true;
 314         }
 315
 316         /**
 317          * Whether this action can still be executed by a blocked user
 318          * @return bool
 319          */
 320         public function requiresUnblock() {
 321                 return true;
 322         }
 323
 324         /**
 325          * Set output headers for noindexing etc.  This function will not be called through
 326          * the execute() entry point, so only put UI-related stuff in here.
 327          */
 328         protected function setHeaders() {
 329                 $out = $this->getOutput();
 330                 $out->setRobotPolicy( "noindex,nofollow" );
 331                 $out->setPageTitle( $this->getPageTitle() );
 332                 $this->getOutput()->setSubtitle( $this->getDescription() );
 333                 $out->setArticleRelated( true );
 334         }
 335
 336         /**
 337          * Returns the name that goes in the \<h1\> page title
 338          *
 339          * @return string
 340          */
 341         protected function getPageTitle() {
 342                 return $this->getTitle()->getPrefixedText();
 343         }
 344
 345         /**
 346          * Returns the description that goes below the \<h1\> tag
 347          *
 348          * @return string
 349          */
 350         protected function getDescription() {
 351                 return $this->msg( strtolower( $this->getName() ) )->escaped();
 352         }
 353
 354         /**
 355          * The main action entry point.  Do all output for display and send it to the context
 356          * output.  Do not use globals $wgOut, $wgRequest, etc, in implementations; use
 357          * $this->getOutput(), etc.
 358          * @throws ErrorPageError
 359          */
 360         abstract public function show();
 361 }