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                         if ( $request->getText( 'target', '' ) === '' ) {
  47                                 return false;
  48                         } else {
  49                                 return true;
  50                         }
  51                 }
  52
  53                 $parts = explode( '/', $subPage, 2 );
  54                 if ( $parts !== 2 ) {
  55                         $slot = $parts[0];
  56                         if ( $slot === 'main' || $slot === '' ) {
  57                                 return true;
  58                         }
  59                 }
  60
  61                 return false;
  62         }
  63
  64         /**
  65          * Main method for handling requests.
  66          *
  67          * @param string $subPage
  68          * @param WebRequest $request The request parameters. Known parameters are:
  69          *        - title: the page title
  70          *        - format: the format
  71          *        - oldid|revision: the revision ID
  72          * @param OutputPage $output
  73          *
  74          * @note Instead of an output page, a WebResponse could be sufficient, but
  75          *        redirect logic is currently implemented in OutputPage.
  76          *
  77          * @throws HttpError
  78          */
  79         public function handleRequest( $subPage, WebRequest $request, OutputPage $output ) {
  80                 // No matter what: The response is always public
  81                 $output->getRequest()->response()->header( 'Access-Control-Allow-Origin: *' );
  82
  83                 if ( !$this->canHandleRequest( $subPage, $request ) ) {
  84                         throw new HttpError( 400, wfMessage( 'pagedata-bad-title', $subPage ) );
  85                 }
  86
  87                 $revision = 0;
  88
  89                 $parts = explode( '/', $subPage, 2 );
  90                 if ( $subPage !== '' ) {
  91                         $title = $parts[1];
  92                 } else {
  93                         $title = $request->getText( 'target', '' );
  94                 }
  95
  96                 $revision = $request->getInt( 'oldid', $revision );
  97                 $revision = $request->getInt( 'revision', $revision );
  98
  99                 if ( $title === null || $title === '' ) {
 100                         //TODO: different error message?
 101                         throw new HttpError( 400, wfMessage( 'pagedata-bad-title', $title ) );
 102                 }
 103
 104                 try {
 105                         $title = Title::newFromTextThrow( $title );
 106                 } catch ( MalformedTitleException $ex ) {
 107                         throw new HttpError( 400, wfMessage( 'pagedata-bad-title', $title ) );
 108                 }
 109
 110                 $this->httpContentNegotiation( $request, $output, $title, $revision );
 111         }
 112
 113         /**
 114          * Applies HTTP content negotiation.
 115          * If the negotiation is successful, this method will set the appropriate redirect
 116          * in the OutputPage object and return. Otherwise, an HttpError is thrown.
 117          *
 118          * @param WebRequest $request
 119          * @param OutputPage $output
 120          * @param Title $title
 121          * @param int $revision The desired revision
 122          *
 123          * @throws HttpError
 124          */
 125         public function httpContentNegotiation(
 126                 WebRequest $request,
 127                 OutputPage $output,
 128                 Title $title,
 129                 $revision = 0
 130         ) {
 131                 $contentHandler = ContentHandler::getForTitle( $title );
 132                 $mimeTypes = $contentHandler->getSupportedFormats();
 133
 134                 $acceptHeader = $request->getHeader( 'Accept' );
 135                 if ( $acceptHeader !== false ) {
 136                         $parser = new HttpAcceptParser();
 137                         $accept = $parser->parseWeights( $acceptHeader );
 138                 } else {
 139                         // anything goes
 140                         $accept = [
 141                                 '*' => 0.1 // just to make extra sure
 142                         ];
 143                         // prefer the default
 144                         $accept[$mimeTypes[0]] = 1;
 145                 }
 146
 147                 $negotiator = new HttpAcceptNegotiator( $mimeTypes );
 148                 $format = $negotiator->getBestSupportedKey( $accept, null );
 149
 150                 if ( $format === null ) {
 151                         $format = isset( $accept['text/html'] ) ? 'text/html' : null;
 152                 }
 153
 154                 if ( $format === null ) {
 155                         $msg = wfMessage( 'pagedata-not-acceptable', implode( ', ', $mimeTypes ) );
 156                         throw new HttpError( 406, $msg );
 157                 }
 158
 159                 $url = $this->getDocUrl( $title, $format, $revision );
 160                 $output->redirect( $url, 303 );
 161         }
 162
 163         /**
 164          * Returns a url representing the given title.
 165          *
 166          * @param Title $title
 167          * @param string|null $format The (normalized) format name, or ''
 168          * @param int $revision
 169          * @return string
 170          */
 171         private function getDocUrl( Title $title, $format = '', $revision = 0 ) {
 172                 $params = [];
 173
 174                 if ( $revision > 0 ) {
 175                         $params['oldid'] = $revision;
 176                 }
 177
 178                 if ( $format === 'text/html' ) {
 179                         return $title->getFullURL( $params );
 180                 }
 181
 182                 $params[ 'action' ] = 'raw';
 183
 184                 return $title->getFullURL( $params );
 185         }
 186
 187 }