includes/linkeddata/PageDataRequestHandler.php

   1 <?php
   2 /**
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation; either version 2 of the License, or
   6  * (at your option) any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  16  * http://www.gnu.org/copyleft/gpl.html
  17  *
  18  * @file
  19  */
  20
  21 use Wikimedia\Http\HttpAcceptParser;
  22 use Wikimedia\Http\HttpAcceptNegotiator;
  23
  24 /**
  25  * Request handler implementing a data interface for mediawiki pages.
  26  *
  27  * @author Daniel Kinzler
  28  * @author Amir Sarabadanai
  29  */
  30 class PageDataRequestHandler {
  31
  32         /**
  33          * Checks whether the request is complete, i.e. whether it contains all information needed
  34          * to reply with page data.
  35          *
  36          * This does not check whether the request is valid and will actually produce a successful
  37          * response.
  38          *
  39          * @param string|null $subPage
  40          * @param WebRequest $request
  41          *
  42          * @return bool
  43          */
  44         public function canHandleRequest( $subPage, WebRequest $request ) {
  45                 if ( $subPage === '' || $subPage === null ) {
  46                         return $request->getText( 'target' ) !== '';
  47                 }
  48
  49                 $parts = explode( '/', $subPage, 2 );
  50                 if ( $parts !== 2 ) {
  51                         $slot = $parts[0];
  52                         if ( $slot === 'main' || $slot === '' ) {
  53                                 return true;
  54                         }
  55                 }
  56
  57                 return false;
  58         }
  59
  60         /**
  61          * Main method for handling requests.
  62          *
  63          * @param string $subPage
  64          * @param WebRequest $request The request parameters. Known parameters are:
  65          *        - title: the page title
  66          *        - format: the format
  67          *        - oldid|revision: the revision ID
  68          * @param OutputPage $output
  69          *
  70          * @note Instead of an output page, a WebResponse could be sufficient, but
  71          *        redirect logic is currently implemented in OutputPage.
  72          *
  73          * @throws HttpError
  74          */
  75         public function handleRequest( $subPage, WebRequest $request, OutputPage $output ) {
  76                 // No matter what: The response is always public
  77                 $output->getRequest()->response()->header( 'Access-Control-Allow-Origin: *' );
  78
  79                 if ( !$this->canHandleRequest( $subPage, $request ) ) {
  80                         throw new HttpError( 400, wfMessage( 'pagedata-bad-title', $subPage ) );
  81                 }
  82
  83                 $revision = 0;
  84
  85                 $parts = explode( '/', $subPage, 2 );
  86                 if ( $subPage !== '' ) {
  87                         $title = $parts[1];
  88                 } else {
  89                         $title = $request->getText( 'target' );
  90                 }
  91
  92                 $revision = $request->getInt( 'oldid', $revision );
  93                 $revision = $request->getInt( 'revision', $revision );
  94
  95                 if ( $title === null || $title === '' ) {
  96                         //TODO: different error message?
  97                         throw new HttpError( 400, wfMessage( 'pagedata-bad-title', $title ) );
  98                 }
  99
 100                 try {
 101                         $title = Title::newFromTextThrow( $title );
 102                 } catch ( MalformedTitleException $ex ) {
 103                         throw new HttpError( 400, wfMessage( 'pagedata-bad-title', $title ) );
 104                 }
 105
 106                 $this->httpContentNegotiation( $request, $output, $title, $revision );
 107         }
 108
 109         /**
 110          * Applies HTTP content negotiation.
 111          * If the negotiation is successful, this method will set the appropriate redirect
 112          * in the OutputPage object and return. Otherwise, an HttpError is thrown.
 113          *
 114          * @param WebRequest $request
 115          * @param OutputPage $output
 116          * @param Title $title
 117          * @param int $revision The desired revision
 118          *
 119          * @throws HttpError
 120          */
 121         public function httpContentNegotiation(
 122                 WebRequest $request,
 123                 OutputPage $output,
 124                 Title $title,
 125                 $revision = 0
 126         ) {
 127                 $contentHandler = ContentHandler::getForTitle( $title );
 128                 $mimeTypes = $contentHandler->getSupportedFormats();
 129
 130                 $acceptHeader = $request->getHeader( 'Accept' );
 131                 if ( $acceptHeader !== false ) {
 132                         $parser = new HttpAcceptParser();
 133                         $accept = $parser->parseWeights( $acceptHeader );
 134                 } else {
 135                         // anything goes
 136                         $accept = [
 137                                 '*' => 0.1 // just to make extra sure
 138                         ];
 139                         // prefer the default
 140                         $accept[$mimeTypes[0]] = 1;
 141                 }
 142
 143                 $negotiator = new HttpAcceptNegotiator( $mimeTypes );
 144                 $format = $negotiator->getBestSupportedKey( $accept );
 145
 146                 if ( $format === null ) {
 147                         $format = isset( $accept['text/html'] ) ? 'text/html' : null;
 148                 }
 149
 150                 if ( $format === null ) {
 151                         $msg = wfMessage( 'pagedata-not-acceptable', implode( ', ', $mimeTypes ) );
 152                         throw new HttpError( 406, $msg );
 153                 }
 154
 155                 $url = $this->getDocUrl( $title, $format, $revision );
 156                 $output->redirect( $url, 303 );
 157         }
 158
 159         /**
 160          * Returns a url representing the given title.
 161          *
 162          * @param Title $title
 163          * @param string|null $format The (normalized) format name, or ''
 164          * @param int $revision
 165          * @return string
 166          */
 167         private function getDocUrl( Title $title, $format = '', $revision = 0 ) {
 168                 $params = [];
 169
 170                 if ( $revision > 0 ) {
 171                         $params['oldid'] = $revision;
 172                 }
 173
 174                 if ( $format === 'text/html' ) {
 175                         return $title->getFullURL( $params );
 176                 }
 177
 178                 $params[ 'action' ] = 'raw';
 179
 180                 return $title->getFullURL( $params );
 181         }
 182
 183 }