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 extends ContextSource {
  27
  28         // Page on which we're performing the action
  29         // @var Article
  30         protected $page;
  31
  32         // The fields used to create the HTMLForm
  33         // @var Array
  34         protected $fields;
  35
  36         /**
  37          * Get the Action subclass which should be used to handle this action, false if
  38          * the action is disabled, or null if it's not recognised
  39          * @param $action String
  40          * @return bool|null|string
  41          */
  42         private final static function getClass( $action ) {
  43                 global $wgActions;
  44                 $action = strtolower( $action );
  45
  46                 if ( !isset( $wgActions[$action] ) ) {
  47                         return null;
  48                 }
  49
  50                 if ( $wgActions[$action] === false ) {
  51                         return false;
  52                 }
  53
  54                 elseif ( $wgActions[$action] === true ) {
  55                         return ucfirst( $action ) . 'Action';
  56                 }
  57
  58                 else {
  59                         return $wgActions[$action];
  60                 }
  61         }
  62
  63         /**
  64          * Get an appropriate Action subclass for the given action
  65          * @param $action String
  66          * @param $page Article
  67          * @return Action|false|null false if the action is disabled, null
  68          *     if it is not recognised
  69          */
  70         public final static function factory( $action, Article $page ) {
  71                 $class = self::getClass( $action );
  72                 if ( $class ) {
  73                         $obj = new $class( $page );
  74                         return $obj;
  75                 }
  76                 return $class;
  77         }
  78
  79         /**
  80          * Check if a given action is recognised, even if it's disabled
  81          *
  82          * @param $name String: name of an action
  83          * @return Bool
  84          */
  85         public final static function exists( $name ) {
  86                 return self::getClass( $name ) !== null;
  87         }
  88
  89         /**
  90          * Protected constructor: use Action::factory( $action, $page ) to actually build
  91          * these things in the real world
  92          * @param Article $page
  93          */
  94         protected function __construct( Article $page ) {
  95                 $this->page = $page;
  96                 $this->setContext( $page->getContext() );
  97         }
  98
  99         /**
 100          * Return the name of the action this object responds to
 101          * @return String lowercase
 102          */
 103         public abstract function getName();
 104
 105         /**
 106          * Get the permission required to perform this action.  Often, but not always,
 107          * the same as the action name
 108          */
 109         public abstract function getRestriction();
 110
 111         /**
 112          * Checks if the given user (identified by an object) can perform this action.  Can be
 113          * overridden by sub-classes with more complicated permissions schemes.  Failures here
 114          * must throw subclasses of ErrorPageError
 115          *
 116          * @param $user User: the user to check, or null to use the context user
 117          * @throws ErrorPageError
 118          */
 119         protected function checkCanExecute( User $user ) {
 120                 if ( $this->requiresWrite() && wfReadOnly() ) {
 121                         throw new ReadOnlyError();
 122                 }
 123
 124                 if ( $this->getRestriction() !== null && !$user->isAllowed( $this->getRestriction() ) ) {
 125                         throw new PermissionsError( $this->getRestriction() );
 126                 }
 127
 128                 if ( $this->requiresUnblock() && $user->isBlocked() ) {
 129                         $block = $user->mBlock;
 130                         throw new UserBlockedError( $block );
 131                 }
 132         }
 133
 134         /**
 135          * Whether this action requires the wiki not to be locked
 136          * @return Bool
 137          */
 138         public function requiresWrite() {
 139                 return true;
 140         }
 141
 142         /**
 143          * Whether this action can still be executed by a blocked user
 144          * @return Bool
 145          */
 146         public function requiresUnblock() {
 147                 return true;
 148         }
 149
 150         /**
 151          * Set output headers for noindexing etc.  This function will not be called through
 152          * the execute() entry point, so only put UI-related stuff in here.
 153          */
 154         protected function setHeaders() {
 155                 $out = $this->getOutput();
 156                 $out->setRobotPolicy( "noindex,nofollow" );
 157                 $out->setPageTitle( $this->getTitle()->getPrefixedText() );
 158                 $this->getOutput()->setSubtitle( $this->getDescription() );
 159                 $out->setArticleRelated( true );
 160         }
 161
 162         /**
 163          * Returns the name that goes in the \<h1\> page title
 164          *
 165          * @return String
 166          */
 167         protected function getDescription() {
 168                 return wfMsg( strtolower( $this->getName() ) );
 169         }
 170
 171         /**
 172          * The main action entry point.  Do all output for display and send it to the context
 173          * output.  Do not use globals $wgOut, $wgRequest, etc, in implementations; use
 174          * $this->getOutput(), etc.
 175          * @throws ErrorPageError
 176          */
 177         public abstract function show();
 178
 179         /**
 180          * Execute the action in a silent fashion: do not display anything or release any errors.
 181          * @param $data Array values that would normally be in the POST request
 182          * @param $captureErrors Bool whether to catch exceptions and just return false
 183          * @return Bool whether execution was successful
 184          */
 185         public abstract function execute();
 186 }
 187
 188 abstract class FormAction extends Action {
 189
 190         /**
 191          * Get an HTMLForm descriptor array
 192          * @return Array
 193          */
 194         protected abstract function getFormFields();
 195
 196         /**
 197          * Add pre- or post-text to the form
 198          * @return String HTML which will be sent to $form->addPreText()
 199          */
 200         protected function preText() { return ''; }
 201         protected function postText() { return ''; }
 202
 203         /**
 204          * Play with the HTMLForm if you need to more substantially
 205          * @param $form HTMLForm
 206          */
 207         protected function alterForm( HTMLForm $form ) {}
 208
 209         /**
 210          * Get the HTMLForm to control behaviour
 211          * @return HTMLForm|null
 212          */
 213         protected function getForm() {
 214                 $this->fields = $this->getFormFields();
 215
 216                 // Give hooks a chance to alter the form, adding extra fields or text etc
 217                 wfRunHooks( 'ActionModifyFormFields', array( $this->getName(), &$this->fields, $this->page ) );
 218
 219                 $form = new HTMLForm( $this->fields, $this->getContext() );
 220                 $form->setSubmitCallback( array( $this, 'onSubmit' ) );
 221
 222                 // Retain query parameters (uselang etc)
 223                 $form->addHiddenField( 'action', $this->getName() ); // Might not be the same as the query string
 224                 $params = array_diff_key(
 225                         $this->getRequest()->getQueryValues(),
 226                         array( 'action' => null, 'title' => null )
 227                 );
 228                 $form->addHiddenField( 'redirectparams', wfArrayToCGI( $params ) );
 229
 230                 $form->addPreText( $this->preText() );
 231                 $form->addPostText( $this->postText() );
 232                 $this->alterForm( $form );
 233
 234                 // Give hooks a chance to alter the form, adding extra fields or text etc
 235                 wfRunHooks( 'ActionBeforeFormDisplay', array( $this->getName(), &$form, $this->page ) );
 236
 237                 return $form;
 238         }
 239
 240         /**
 241          * Process the form on POST submission.  If you return false from getFormFields(),
 242          * this will obviously never be reached.  If you don't want to do anything with the
 243          * form, just return false here
 244          * @param  $data Array
 245          * @return Bool|Array true for success, false for didn't-try, array of errors on failure
 246          */
 247         public abstract function onSubmit( $data );
 248
 249         /**
 250          * Do something exciting on successful processing of the form.  This might be to show
 251          * a confirmation message (watch, rollback, etc) or to redirect somewhere else (edit,
 252          * protect, etc).
 253          */
 254         public abstract function onSuccess();
 255
 256         /**
 257          * The basic pattern for actions is to display some sort of HTMLForm UI, maybe with
 258          * some stuff underneath (history etc); to do some processing on submission of that
 259          * form (delete, protect, etc) and to do something exciting on 'success', be that
 260          * display something new or redirect to somewhere.  Some actions have more exotic
 261          * behaviour, but that's what subclassing is for :D
 262          */
 263         public function show() {
 264                 $this->setHeaders();
 265
 266                 // This will throw exceptions if there's a problem
 267                 $this->checkCanExecute( $this->getUser() );
 268
 269                 $form = $this->getForm();
 270                 if ( $form->show() ) {
 271                         $this->onSuccess();
 272                 }
 273         }
 274
 275         /**
 276          * @see Action::execute()
 277          * @throws ErrorPageError
 278          * @param array|null $data
 279          * @param bool $captureErrors
 280          * @return bool
 281          */
 282         public function execute( array $data = null, $captureErrors = true ) {
 283                 try {
 284                         // Set a new context so output doesn't leak.
 285                         $this->setContext( clone $this->page->getContext() );
 286
 287                         // This will throw exceptions if there's a problem
 288                         $this->checkCanExecute( $this->getUser() );
 289
 290                         $fields = array();
 291                         foreach ( $this->fields as $key => $params ) {
 292                                 if ( isset( $data[$key] ) ) {
 293                                         $fields[$key] = $data[$key];
 294                                 } elseif ( isset( $params['default'] ) ) {
 295                                         $fields[$key] = $params['default'];
 296                                 } else {
 297                                         $fields[$key] = null;
 298                                 }
 299                         }
 300                         $status = $this->onSubmit( $fields );
 301                         if ( $status === true ) {
 302                                 // This might do permanent stuff
 303                                 $this->onSuccess();
 304                                 return true;
 305                         } else {
 306                                 return false;
 307                         }
 308                 }
 309                 catch ( ErrorPageError $e ) {
 310                         if ( $captureErrors ) {
 311                                 return false;
 312                         } else {
 313                                 throw $e;
 314                         }
 315                 }
 316         }
 317 }
 318
 319 /**
 320  * Actions generally fall into two groups: the show-a-form-then-do-something-with-the-input
 321  * format (protect, delete, move, etc), and the just-do-something format (watch, rollback,
 322  * patrol, etc).
 323  */
 324 abstract class FormlessAction extends Action {
 325
 326         /**
 327          * Show something on GET request.
 328          * @return String|null will be added to the HTMLForm if present, or just added to the
 329          *     output if not.  Return null to not add anything
 330          */
 331         public abstract function onView();
 332
 333         /**
 334          * We don't want an HTMLForm
 335          */
 336         protected function getFormFields() {
 337                 return false;
 338         }
 339
 340         public function onSubmit( $data ) {
 341                 return false;
 342         }
 343
 344         public function onSuccess() {
 345                 return false;
 346         }
 347
 348         public function show() {
 349                 $this->setHeaders();
 350
 351                 // This will throw exceptions if there's a problem
 352                 $this->checkCanExecute( $this->getUser() );
 353
 354                 $this->getOutput()->addHTML( $this->onView() );
 355         }
 356
 357         /**
 358          * Execute the action silently, not giving any output.  Since these actions don't have
 359          * forms, they probably won't have any data, but some (eg rollback) may do
 360          * @param $data Array values that would normally be in the GET request
 361          * @param $captureErrors Bool whether to catch exceptions and just return false
 362          * @return Bool whether execution was successful
 363          */
 364         public function execute( array $data = null, $captureErrors = true ) {
 365                 try {
 366                         // Set a new context so output doesn't leak.
 367                         $context = clone $this->page->getContext();
 368                         if ( is_array( $data ) ) {
 369                                 $context->setRequest( new FauxRequest( $data, false ) );
 370                         }
 371                         $this->setContext( $context );
 372
 373                         // This will throw exceptions if there's a problem
 374                         $this->checkCanExecute( $this->getUser() );
 375
 376                         $this->onView();
 377                         return true;
 378                 }
 379                 catch ( ErrorPageError $e ) {
 380                         if ( $captureErrors ) {
 381                                 return false;
 382                         } else {
 383                                 throw $e;
 384                         }
 385                 }
 386         }
 387 }