includes/ContentHandler.php

   1 <?php
   2
   3 /**
   4  * A content handler knows how do deal with a specific type of content on a wiki page.
   5  * Content is stored in the database in a serialized form (using a serialization format aka mime type)
   6  * and is be unserialized into it's native PHP represenation (the content model).
   7  *
   8  * Some content types have a flat model, that is, their native represenation is the
   9  * same as their serialized form. Examples would be JavaScript and CSS code. As of now,
  10  * this also applies to wikitext (mediawiki's default content type), but wikitext
  11  * content may be represented by a DOM or AST structure in the future.
  12  *
  13  */
  14 abstract class ContentHandler {
  15
  16     public static function getContentText( Content $content ) {
  17         if ( !$content ) return '';
  18
  19         if ( $content instanceof TextContent ) {
  20             #XXX: or check by model name?
  21             #XXX: or define $content->allowRawData()?
  22             #XXX: or define $content->getDefaultWikiText()?
  23             return $content->getRawData();
  24         }
  25
  26         #XXX: this must not be used for editing, otherwise we may loose data:
  27         #XXX:      e.g. if this returns the "main" text from a multipart page, all attachments would be lost
  28
  29         return null;
  30     }
  31
  32     public static function makeContent( $text, Title $title, $format = null, $revId = null ) {
  33         $handler = ContentHandler::getForTitle( $title );
  34
  35         #FIXME: pass revid?
  36         return $handler->unserialize( $text, $title, $format );
  37     }
  38
  39     public static function getDefaultModelFor( Title $title ) {
  40         global $wgNamespaceContentModels;
  41
  42         # NOTE: this method must not rely on $title->getContentModelName() directly or indirectly,
  43         #       because it is used to initialized the mContentModelName memebr.
  44
  45         $ns = $title->getNamespace();
  46
  47         $ext = false;
  48         $m = null;
  49         $model = null;
  50
  51         if ( !empty( $wgNamespaceContentModels[ $ns ] ) ) {
  52             $model = $wgNamespaceContentModels[ $ns ];
  53         }
  54
  55         # hook can determin default model
  56         if ( !wfRunHooks( 'DefaultModelFor', array( $title, &$model ) ) ) { #FIXME: document new hook!
  57             if ( $model ) return $model;
  58         }
  59
  60         # Could this page contain custom CSS or JavaScript, based on the title?
  61         $isCssOrJsPage = ( NS_MEDIAWIKI == $ns && preg_match( "!\.(css|js)$!u", $title->getText(), $m ) );
  62         if ( $isCssOrJsPage ) $ext = $m[1];
  63
  64         # hook can force js/css
  65         wfRunHooks( 'TitleIsCssOrJsPage', array( $title, &$isCssOrJsPage, &$ext ) ); #FIXME: add $ext to hook interface spec
  66
  67         # Is this a .css subpage of a user page?
  68         $isJsCssSubpage = ( NS_USER == $ns && !$isCssOrJsPage && preg_match( "/\\/.*\\.(js|css)$/", $title->getText(), $m ) );
  69         if ( $isJsCssSubpage ) $ext = $m[1];
  70
  71         # is this wikitext, according to $wgNamespaceContentModels or the DefaultModelFor hook?
  72         $isWikitext = ( $model == CONTENT_MODEL_WIKITEXT || $model === null );
  73         $isWikitext = ( $isWikitext && !$isCssOrJsPage && !$isJsCssSubpage );
  74
  75         # hook can override $isWikitext
  76         wfRunHooks( 'TitleIsWikitextPage', array( $title, &$isWikitext ) );
  77
  78         if ( !$isWikitext ) {
  79
  80             if ( $ext == 'js' )
  81                 return CONTENT_MODEL_JAVASCRIPT;
  82             else if ( $ext == 'css' )
  83                 return CONTENT_MODEL_CSS;
  84
  85             if ( $model )
  86                 return $model;
  87             else
  88                 return CONTENT_MODEL_TEXT;
  89         }
  90
  91         # we established that is must be wikitext
  92         return CONTENT_MODEL_WIKITEXT;
  93     }
  94
  95     public static function getForTitle( Title $title ) {
  96         $modelName = $title->getContentModelName();
  97         return ContentHandler::getForModelName( $modelName );
  98     }
  99
 100     public static function getForContent( Content $content ) {
 101         $modelName = $content->getModelName();
 102         return ContentHandler::getForModelName( $modelName );
 103     }
 104
 105     public static function getForModelName( $modelName ) {
 106         global $wgContentHandlers;
 107
 108         if ( empty( $wgContentHandlers[$modelName] ) ) {
 109             #FIXME: hook here!
 110             throw new MWException( "No handler for model $modelName registered in \$wgContentHandlers" );
 111         }
 112
 113         if ( is_string( $wgContentHandlers[$modelName] ) ) {
 114             $class = $wgContentHandlers[$modelName];
 115             $wgContentHandlers[$modelName] = new $class( $modelName );
 116         }
 117
 118         return $wgContentHandlers[$modelName];
 119     }
 120
 121     # ----------------------------------------------------------------------------------------------------------
 122     public function __construct( $modelName, $formats ) {
 123         $this->mModelName = $modelName;
 124         $this->mSupportedFormats = $formats;
 125     }
 126
 127     public function getModelName() {
 128         # for wikitext: wikitext; in the future: wikiast, wikidom?
 129         # for wikidata: wikidata
 130         return $this->mModelName;
 131     }
 132
 133
 134     public function getSupportedFormats() {
 135         # for wikitext: "text/x-mediawiki-1", "text/x-mediawiki-2", etc
 136         # for wikidata: "application/json", "application/x-php", etc
 137         return $this->mSupportedFormats;
 138     }
 139
 140     public function getDefaultFormat() {
 141         return $this->mSupportedFormats[0];
 142     }
 143
 144     public abstract function serialize( Content $content, Title $title, $format = null );
 145
 146     public abstract function unserialize( $blob, Title $title, $format = null ); #FIXME: ...and revId?
 147
 148     # public abstract function doPreSaveTransform( $title, $obj ); #TODO...
 149
 150     /**
 151      * Return an Article object suitable for viewing the given object
 152      *
 153      * NOTE: does *not* do special handling for Image and Category pages!
 154      *       Use Article::newFromTitle() for that!
 155      *
 156      * @param type $title
 157      * @return \Article
 158      * @todo Article is being refactored into an action class, keep track of that
 159      */
 160     public function createArticle( Title $title ) {
 161         #XXX: assert that $title->getContentModelName() == $this->getModelname()?
 162         $article = new Article($title);
 163         return $article;
 164     }
 165
 166     /**
 167      * Return an EditPage object suitable for editing the given object
 168      *
 169      * @param type $article
 170      * @return \EditPage
 171      */
 172     public function createEditPage( Article $article ) {
 173         #XXX: assert that $article->getContentObject()->getModelName() == $this->getModelname()?
 174         $editPage = new EditPage( $article );
 175         return $editPage;
 176     }
 177
 178     /**
 179      * Return an ExternalEdit object suitable for editing the given object
 180      *
 181      * @param type $article
 182      * @return \ExternalEdit
 183      */
 184     public function createExternalEdit( IContextSource $context ) {
 185         #XXX: assert that $article->getContentObject()->getModelName() == $this->getModelname()?
 186         $externalEdit = new ExternalEdit( $context );
 187         return $externalEdit;
 188     }
 189
 190     /**
 191     public function updatePage( $title, $obj ) {
 192     }
 193     **/
 194
 195     public function getDiffEngine( Article $article ) {
 196         $de = new DifferenceEngine( $article->getContext() );
 197         return $de;
 198     }
 199
 200     public function getIndexUpdateJobs( Title $title, ParserOutput $parserOutput, $recursive = true ) {
 201             # for wikitext, create a LinksUpdate object
 202             # for wikidata: serialize arrays to json
 203         $update = new LinksUpdate( $title, $parserOutput, $recursive );
 204         return $update;
 205     }
 206
 207     #XXX: is the native model for wikitext a string or the parser output? parse early or parse late?
 208
 209     #TODO: how to handle extra message for JS/CSS previews??
 210     #TODO: Article::showCssOrJsPage ---> specialized classes!
 211 }
 212
 213
 214 abstract class TextContentHandler extends ContentHandler {
 215
 216     public function __construct( $modelName, $formats ) {
 217         parent::__construct( $modelName, $formats );
 218     }
 219
 220     public function serialize( Content $content, Title $title, $format = null ) {
 221         return $content->getRawData();
 222     }
 223
 224 }
 225 class WikitextContentHandler extends TextContentHandler {
 226
 227     public function __construct( $modelName = CONTENT_MODEL_WIKITEXT ) {
 228         parent::__construct( $modelName, array( 'application/x-wikitext' ) ); #FIXME: mime
 229     }
 230
 231     public function unserialize( $text, Title $title, $format = null ) {
 232         return new WikitextContent($text, $title);
 233     }
 234
 235 }
 236
 237 class JavaScriptContentHandler extends TextContentHandler {
 238
 239     public function __construct( $modelName = CONTENT_MODEL_WIKITEXT ) {
 240         parent::__construct( $modelName, array( 'text/javascript' ) );
 241     }
 242
 243     public function unserialize( $text, Title $title, $format = null ) {
 244         return new JavaScriptContent($text, $title);
 245     }
 246
 247 }
 248
 249 class CssContentHandler extends TextContentHandler {
 250
 251     public function __construct( $modelName = CONTENT_MODEL_WIKITEXT ) {
 252         parent::__construct( $modelName, array( 'text/css' ) );
 253     }
 254
 255     public function unserialize( $text, Title $title, $format = null ) {
 256         return new CssContent($text, $title);
 257     }
 258
 259 }