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