includes/Action.php

   1 <?php
   2 /**
   3  * Actions are things which can be done to pages (edit, delete, rollback, etc).  They
   4  * are distinct from Special Pages because an action must apply to exactly one page.
   5  *
   6  * To add an action in an extension, create a subclass of Action, and add the key to
   7  * $wgActions.  There is also the deprecated UnknownAction hook
   8  *
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
  23  *
  24  * @file
  25  */
  26 abstract class Action {
  27
  28         /**
  29          * Page on which we're performing the action
  30          * @var Article
  31          */
  32         protected $page;
  33
  34         /**
  35          * IContextSource if specified; otherwise we'll use the Context from the Page
  36          * @var IContextSource
  37          */
  38         protected $context;
  39
  40         /**
  41          * The fields used to create the HTMLForm
  42          * @var Array
  43          */
  44         protected $fields;
  45
  46         /**
  47          * Get the Action subclass which should be used to handle this action, false if
  48          * the action is disabled, or null if it's not recognised
  49          * @param $action String
  50          * @param $overrides Array
  51          * @return bool|null|string
  52          */
  53         private final static function getClass( $action, array $overrides ) {
  54                 global $wgActions;
  55                 $action = strtolower( $action );
  56
  57                 if ( !isset( $wgActions[$action] ) ) {
  58                         return null;
  59                 }
  60
  61                 if ( $wgActions[$action] === false ) {
  62                         return false;
  63                 } elseif ( $wgActions[$action] === true && isset( $overrides[$action] ) ) {
  64                         return $overrides[$action];
  65                 } elseif ( $wgActions[$action] === true ) {
  66                         return ucfirst( $action ) . 'Action';
  67                 } else {
  68                         return $wgActions[$action];
  69                 }
  70         }
  71
  72         /**
  73          * Get an appropriate Action subclass for the given action
  74          * @param $action String
  75          * @param $page Article
  76          * @return Action|false|null false if the action is disabled, null
  77          *     if it is not recognised
  78          */
  79         public final static function factory( $action, Page $page ) {
  80                 $class = self::getClass( $action, $page->getActionOverrides() );
  81                 if ( $class ) {
  82                         $obj = new $class( $page );
  83                         return $obj;
  84                 }
  85                 return $class;
  86         }
  87
  88         /**
  89          * Check if a given action is recognised, even if it's disabled
  90          *
  91          * @param $name String: name of an action
  92          * @return Bool
  93          */
  94         public final static function exists( $name ) {
  95                 return self::getClass( $name, array() ) !== null;
  96         }
  97
  98         /**
  99          * Get the IContextSource in use here
 100          * @return IContextSource
 101          */
 102         public final function getContext() {
 103                 if ( $this->context instanceof IContextSource ) {
 104                         return $this->context;
 105                 }
 106                 return $this->page->getContext();
 107         }
 108
 109         /**
 110          * Get the WebRequest being used for this instance
 111          *
 112          * @return WebRequest
 113          */
 114         public final function getRequest() {
 115                 return $this->getContext()->getRequest();
 116         }
 117
 118         /**
 119          * Get the OutputPage being used for this instance
 120          *
 121          * @return OutputPage
 122          */
 123         public final function getOutput() {
 124                 return $this->getContext()->getOutput();
 125         }
 126
 127         /**
 128          * Shortcut to get the User being used for this instance
 129          *
 130          * @return User
 131          */
 132         public final function getUser() {
 133                 return $this->getContext()->getUser();
 134         }
 135
 136         /**
 137          * Shortcut to get the Skin being used for this instance
 138          *
 139          * @return Skin
 140          */
 141         public final function getSkin() {
 142                 return $this->getContext()->getSkin();
 143         }
 144
 145         /**
 146          * Shortcut to get the user Language being used for this instance
 147          *
 148          * @return Skin
 149          */
 150         public final function getLang() {
 151                 return $this->getContext()->getLang();
 152         }
 153
 154         /**
 155          * Shortcut to get the Title object from the page
 156          * @return Title
 157          */
 158         public final function getTitle() {
 159                 return $this->page->getTitle();
 160         }
 161
 162         /**
 163          * Get a Message object with context set
 164          * Parameters are the same as wfMessage()
 165          *
 166          * @return Message object
 167          */
 168         public final function msg() {
 169                 $params = func_get_args();
 170                 return call_user_func_array( array( $this->getContext(), 'msg' ), $params );
 171         }
 172
 173         /**
 174          * Protected constructor: use Action::factory( $action, $page ) to actually build
 175          * these things in the real world
 176          * @param Page $page
 177          */
 178         protected function __construct( Page $page ) {
 179                 $this->page = $page;
 180         }
 181
 182         /**
 183          * Return the name of the action this object responds to
 184          * @return String lowercase
 185          */
 186         public abstract function getName();
 187
 188         /**
 189          * Get the permission required to perform this action.  Often, but not always,
 190          * the same as the action name
 191          */
 192         public abstract function getRestriction();
 193
 194         /**
 195          * Checks if the given user (identified by an object) can perform this action.  Can be
 196          * overridden by sub-classes with more complicated permissions schemes.  Failures here
 197          * must throw subclasses of ErrorPageError
 198          *
 199          * @param $user User: the user to check, or null to use the context user
 200          * @throws ErrorPageError
 201          */
 202         protected function checkCanExecute( User $user ) {
 203                 if ( $this->requiresWrite() && wfReadOnly() ) {
 204                         throw new ReadOnlyError();
 205                 }
 206
 207                 if ( $this->getRestriction() !== null && !$user->isAllowed( $this->getRestriction() ) ) {
 208                         throw new PermissionsError( $this->getRestriction() );
 209                 }
 210
 211                 if ( $this->requiresUnblock() && $user->isBlocked() ) {
 212                         $block = $user->mBlock;
 213                         throw new UserBlockedError( $block );
 214                 }
 215         }
 216
 217         /**
 218          * Whether this action requires the wiki not to be locked
 219          * @return Bool
 220          */
 221         public function requiresWrite() {
 222                 return true;
 223         }
 224
 225         /**
 226          * Whether this action can still be executed by a blocked user
 227          * @return Bool
 228          */
 229         public function requiresUnblock() {
 230                 return true;
 231         }
 232
 233         /**
 234          * Set output headers for noindexing etc.  This function will not be called through
 235          * the execute() entry point, so only put UI-related stuff in here.
 236          */
 237         protected function setHeaders() {
 238                 $out = $this->getOutput();
 239                 $out->setRobotPolicy( "noindex,nofollow" );
 240                 $out->setPageTitle( $this->getPageTitle() );
 241                 $this->getOutput()->setSubtitle( $this->getDescription() );
 242                 $out->setArticleRelated( true );
 243         }
 244
 245         /**
 246          * Returns the name that goes in the \<h1\> page title
 247          *
 248          * @return String
 249          */
 250         protected function getPageTitle() {
 251                 return $this->getTitle()->getPrefixedText();
 252         }
 253
 254         /**
 255          * Returns the description that goes below the \<h1\> tag
 256          *
 257          * @return String
 258          */
 259         protected function getDescription() {
 260                 return wfMsg( strtolower( $this->getName() ) );
 261         }
 262
 263         /**
 264          * The main action entry point.  Do all output for display and send it to the context
 265          * output.  Do not use globals $wgOut, $wgRequest, etc, in implementations; use
 266          * $this->getOutput(), etc.
 267          * @throws ErrorPageError
 268          */
 269         public abstract function show();
 270
 271         /**
 272          * Execute the action in a silent fashion: do not display anything or release any errors.
 273          * @param $data Array values that would normally be in the POST request
 274          * @param $captureErrors Bool whether to catch exceptions and just return false
 275          * @return Bool whether execution was successful
 276          */
 277         public abstract function execute();
 278 }
 279
 280 abstract class FormAction extends Action {
 281
 282         /**
 283          * Get an HTMLForm descriptor array
 284          * @return Array
 285          */
 286         protected abstract function getFormFields();
 287
 288         /**
 289          * Add pre- or post-text to the form
 290          * @return String HTML which will be sent to $form->addPreText()
 291          */
 292         protected function preText() { return ''; }
 293
 294         /**
 295          * @return string
 296          */
 297         protected function postText() { return ''; }
 298
 299         /**
 300          * Play with the HTMLForm if you need to more substantially
 301          * @param $form HTMLForm
 302          */
 303         protected function alterForm( HTMLForm $form ) {}
 304
 305         /**
 306          * Get the HTMLForm to control behaviour
 307          * @return HTMLForm|null
 308          */
 309         protected function getForm() {
 310                 $this->fields = $this->getFormFields();
 311
 312                 // Give hooks a chance to alter the form, adding extra fields or text etc
 313                 wfRunHooks( 'ActionModifyFormFields', array( $this->getName(), &$this->fields, $this->page ) );
 314
 315                 $form = new HTMLForm( $this->fields, $this->getContext() );
 316                 $form->setSubmitCallback( array( $this, 'onSubmit' ) );
 317
 318                 // Retain query parameters (uselang etc)
 319                 $form->addHiddenField( 'action', $this->getName() ); // Might not be the same as the query string
 320                 $params = array_diff_key(
 321                         $this->getRequest()->getQueryValues(),
 322                         array( 'action' => null, 'title' => null )
 323                 );
 324                 $form->addHiddenField( 'redirectparams', wfArrayToCGI( $params ) );
 325
 326                 $form->addPreText( $this->preText() );
 327                 $form->addPostText( $this->postText() );
 328                 $this->alterForm( $form );
 329
 330                 // Give hooks a chance to alter the form, adding extra fields or text etc
 331                 wfRunHooks( 'ActionBeforeFormDisplay', array( $this->getName(), &$form, $this->page ) );
 332
 333                 return $form;
 334         }
 335
 336         /**
 337          * Process the form on POST submission.  If you return false from getFormFields(),
 338          * this will obviously never be reached.  If you don't want to do anything with the
 339          * form, just return false here
 340          * @param  $data Array
 341          * @return Bool|Array true for success, false for didn't-try, array of errors on failure
 342          */
 343         public abstract function onSubmit( $data );
 344
 345         /**
 346          * Do something exciting on successful processing of the form.  This might be to show
 347          * a confirmation message (watch, rollback, etc) or to redirect somewhere else (edit,
 348          * protect, etc).
 349          */
 350         public abstract function onSuccess();
 351
 352         /**
 353          * The basic pattern for actions is to display some sort of HTMLForm UI, maybe with
 354          * some stuff underneath (history etc); to do some processing on submission of that
 355          * form (delete, protect, etc) and to do something exciting on 'success', be that
 356          * display something new or redirect to somewhere.  Some actions have more exotic
 357          * behaviour, but that's what subclassing is for :D
 358          */
 359         public function show() {
 360                 $this->setHeaders();
 361
 362                 // This will throw exceptions if there's a problem
 363                 $this->checkCanExecute( $this->getUser() );
 364
 365                 $form = $this->getForm();
 366                 if ( $form->show() ) {
 367                         $this->onSuccess();
 368                 }
 369         }
 370
 371         /**
 372          * @see Action::execute()
 373          * @throws ErrorPageError
 374          * @param array|null $data
 375          * @param bool $captureErrors
 376          * @return bool
 377          */
 378         public function execute( array $data = null, $captureErrors = true ) {
 379                 try {
 380                         // Set a new context so output doesn't leak.
 381                         $this->context = clone $this->page->getContext();
 382
 383                         // This will throw exceptions if there's a problem
 384                         $this->checkCanExecute( $this->getUser() );
 385
 386                         $fields = array();
 387                         foreach ( $this->fields as $key => $params ) {
 388                                 if ( isset( $data[$key] ) ) {
 389                                         $fields[$key] = $data[$key];
 390                                 } elseif ( isset( $params['default'] ) ) {
 391                                         $fields[$key] = $params['default'];
 392                                 } else {
 393                                         $fields[$key] = null;
 394                                 }
 395                         }
 396                         $status = $this->onSubmit( $fields );
 397                         if ( $status === true ) {
 398                                 // This might do permanent stuff
 399                                 $this->onSuccess();
 400                                 return true;
 401                         } else {
 402                                 return false;
 403                         }
 404                 }
 405                 catch ( ErrorPageError $e ) {
 406                         if ( $captureErrors ) {
 407                                 return false;
 408                         } else {
 409                                 throw $e;
 410                         }
 411                 }
 412         }
 413 }
 414
 415 /**
 416  * Actions generally fall into two groups: the show-a-form-then-do-something-with-the-input
 417  * format (protect, delete, move, etc), and the just-do-something format (watch, rollback,
 418  * patrol, etc).
 419  */
 420 abstract class FormlessAction extends Action {
 421
 422         /**
 423          * Show something on GET request.
 424          * @return String|null will be added to the HTMLForm if present, or just added to the
 425          *     output if not.  Return null to not add anything
 426          */
 427         public abstract function onView();
 428
 429         /**
 430          * We don't want an HTMLForm
 431          */
 432         protected function getFormFields() {
 433                 return false;
 434         }
 435
 436         public function onSubmit( $data ) {
 437                 return false;
 438         }
 439
 440         public function onSuccess() {
 441                 return false;
 442         }
 443
 444         public function show() {
 445                 $this->setHeaders();
 446
 447                 // This will throw exceptions if there's a problem
 448                 $this->checkCanExecute( $this->getUser() );
 449
 450                 $this->getOutput()->addHTML( $this->onView() );
 451         }
 452
 453         /**
 454          * Execute the action silently, not giving any output.  Since these actions don't have
 455          * forms, they probably won't have any data, but some (eg rollback) may do
 456          * @param $data Array values that would normally be in the GET request
 457          * @param $captureErrors Bool whether to catch exceptions and just return false
 458          * @return Bool whether execution was successful
 459          */
 460         public function execute( array $data = null, $captureErrors = true ) {
 461                 try {
 462                         // Set a new context so output doesn't leak.
 463                         $this->context = clone $this->page->getContext();
 464                         if ( is_array( $data ) ) {
 465                                 $this->context->setRequest( new FauxRequest( $data, false ) );
 466                         }
 467
 468                         // This will throw exceptions if there's a problem
 469                         $this->checkCanExecute( $this->getUser() );
 470
 471                         $this->onView();
 472                         return true;
 473                 }
 474                 catch ( ErrorPageError $e ) {
 475                         if ( $captureErrors ) {
 476                                 return false;
 477                         } else {
 478                                 throw $e;
 479                         }
 480                 }
 481         }
 482 }