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          * @throws HttpError
  44          */
  45         public function canHandleRequest( $subPage, WebRequest $request ) {
  46                 if ( $subPage === '' || $subPage === null ) {
  47                         if ( $request->getText( 'target', '' ) === '' ) {
  48                                 return false;
  49                         } else {
  50                                 return true;
  51                         }
  52                 }
  53
  54                 $parts = explode( '/', $subPage, 2 );
  55                 if ( $parts !== 2 ) {
  56                         $slot = $parts[0];
  57                         if ( $slot === 'main' || $slot === '' ) {
  58                                 return true;
  59                         }
  60                 }
  61
  62                 return false;
  63         }
  64
  65         /**
  66          * Main method for handling requests.
  67          *
  68          * @param string $subPage
  69          * @param WebRequest $request The request parameters. Known parameters are:
  70          *        - title: the page title
  71          *        - format: the format
  72          *        - oldid|revision: the revision ID
  73          * @param OutputPage $output
  74          *
  75          * @note: Instead of an output page, a WebResponse could be sufficient, but
  76          *        redirect logic is currently implemented in OutputPage.
  77          *
  78          * @throws HttpError
  79          */
  80         public function handleRequest( $subPage, WebRequest $request, OutputPage $output ) {
  81                 // No matter what: The response is always public
  82                 $output->getRequest()->response()->header( 'Access-Control-Allow-Origin: *' );
  83
  84                 if ( !$this->canHandleRequest( $subPage, $request ) ) {
  85                         throw new HttpError( 400, wfMessage( 'pagedata-bad-title', $subPage ) );
  86                 }
  87
  88                 $revision = 0;
  89
  90                 $parts = explode( '/', $subPage, 2 );
  91                 if ( $subPage !== '' ) {
  92                         $title = $parts[1];
  93                 } else {
  94                         $title = $request->getText( 'target', '' );
  95                 }
  96
  97                 $revision = $request->getInt( 'oldid', $revision );
  98                 $revision = $request->getInt( 'revision', $revision );
  99
 100                 if ( $title === null || $title === '' ) {
 101                         //TODO: different error message?
 102                         throw new HttpError( 400, wfMessage( 'pagedata-bad-title', $title ) );
 103                 }
 104
 105                 try {
 106                         $title = Title::newFromTextThrow( $title );
 107                 } catch ( MalformedTitleException $ex ) {
 108                         throw new HttpError( 400, wfMessage( 'pagedata-bad-title', $title ) );
 109                 }
 110
 111                 $this->httpContentNegotiation( $request, $output, $title, $revision );
 112         }
 113
 114         /**
 115          * Applies HTTP content negotiation.
 116          * If the negotiation is successful, this method will set the appropriate redirect
 117          * in the OutputPage object and return. Otherwise, an HttpError is thrown.
 118          *
 119          * @param WebRequest $request
 120          * @param OutputPage $output
 121          * @param Title $title
 122          * @param int $revision The desired revision
 123          *
 124          * @throws HttpError
 125          */
 126         public function httpContentNegotiation(
 127                 WebRequest $request,
 128                 OutputPage $output,
 129                 Title $title,
 130                 $revision = 0
 131         ) {
 132                 $contentHandler = ContentHandler::getForTitle( $title );
 133                 $mimeTypes = $contentHandler->getSupportedFormats();
 134
 135                 $headers = $request->getAllHeaders();
 136                 if ( isset( $headers['ACCEPT'] ) ) {
 137                         $parser = new HttpAcceptParser();
 138                         $accept = $parser->parseWeights( $headers['ACCEPT'] );
 139                 } else {
 140                         // anything goes
 141                         $accept = [
 142                                 '*' => 0.1 // just to make extra sure
 143                         ];
 144                         // prefer the default
 145                         $accept[$mimeTypes[0]] = 1;
 146                 }
 147
 148                 $negotiator = new HttpAcceptNegotiator( $mimeTypes );
 149                 $format = $negotiator->getBestSupportedKey( $accept, null );
 150
 151                 if ( $format === null ) {
 152                         $format = isset( $accept['text/html'] ) ? 'text/html' : null;
 153                 }
 154
 155                 if ( $format === null ) {
 156                         $msg = wfMessage( 'pagedata-not-acceptable', implode( ', ', $mimeTypes ) );
 157                         throw new HttpError( 406, $msg );
 158                 }
 159
 160                 $url = $this->getDocUrl( $title, $format, $revision );
 161                 $output->redirect( $url, 303 );
 162         }
 163
 164         /**
 165          * Returns a url representing the given title.
 166          *
 167          * @param Title $title
 168          * @param string|null $format The (normalized) format name, or ''
 169          * @param int $revision
 170          * @return string
 171          */
 172         private function getDocUrl( Title $title, $format = '', $revision = 0 ) {
 173                 $params = [];
 174
 175                 if ( $revision > 0 ) {
 176                         $params['oldid'] = $revision;
 177                 }
 178
 179                 if ( $format === 'text/html' ) {
 180                         return $title->getFullURL( $params );
 181                 }
 182
 183                 $params[ 'action' ] = 'raw';
 184
 185                 return $title->getFullURL( $params );
 186         }
 187
 188 }