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