diff options
Diffstat (limited to 'www/wiki/extensions/SemanticMediaWiki/includes/export/SMW_Serializer_RDFXML.php')
| -rw-r--r-- | www/wiki/extensions/SemanticMediaWiki/includes/export/SMW_Serializer_RDFXML.php | 277 |
1 files changed, 277 insertions, 0 deletions
diff --git a/www/wiki/extensions/SemanticMediaWiki/includes/export/SMW_Serializer_RDFXML.php b/www/wiki/extensions/SemanticMediaWiki/includes/export/SMW_Serializer_RDFXML.php new file mode 100644 index 00000000..4848dcf0 --- /dev/null +++ b/www/wiki/extensions/SemanticMediaWiki/includes/export/SMW_Serializer_RDFXML.php @@ -0,0 +1,277 @@ +<?php + +/** + * File holding the SMWRDFXMLSerializer class that provides basic functions for + * serialising OWL data in RDF/XML syntax. + * + * @ingroup SMW + * + * @author Markus Krötzsch + */ + +/** + * Class for serializing exported data (encoded as SMWExpData object) in + * RDF/XML. + * + * @ingroup SMW + */ +class SMWRDFXMLSerializer extends SMWSerializer { + /** + * True if the $pre_ns_buffer contains the beginning of a namespace + * declaration block to which further declarations for the current + * context can be appended. + */ + protected $namespace_block_started; + /** + * True if the namespaces that are added at the current serialization stage + * become global, i.e. remain available for all later contexts. This is the + * case in RDF/XML only as long as the header has not been streamed to the + * client (reflected herein by calling flushContent()). Later, namespaces + * can only be added locally to individual elements, thus requiring them to + * be re-added multiple times if used in many elements. + */ + protected $namespaces_are_global; + + public function clear() { + parent::clear(); + $this->namespaces_are_global = false; + $this->namespace_block_started = false; + } + + protected function serializeHeader() { + $this->namespaces_are_global = true; + $this->namespace_block_started = true; + $this->pre_ns_buffer = + "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n" . + "<!DOCTYPE rdf:RDF[\n" . + "\t<!ENTITY rdf " . $this->makeValueEntityString( SMWExporter::getInstance()->expandURI( '&rdf;' ) ) . ">\n" . + "\t<!ENTITY rdfs " . $this->makeValueEntityString( SMWExporter::getInstance()->expandURI( '&rdfs;' ) ) . ">\n" . + "\t<!ENTITY owl " . $this->makeValueEntityString( SMWExporter::getInstance()->expandURI( '&owl;' ) ) . ">\n" . + "\t<!ENTITY swivt " . $this->makeValueEntityString( SMWExporter::getInstance()->expandURI( '&swivt;' ) ) . ">\n" . + // A note on "wiki": this namespace is crucial as a fallback when it would be illegal to start e.g. with a number. + // In this case, one can always use wiki:... followed by "_" and possibly some namespace, since _ is legal as a first character. + "\t<!ENTITY wiki " . $this->makeValueEntityString( SMWExporter::getInstance()->expandURI( '&wiki;' ) ) . ">\n" . + "\t<!ENTITY category " . $this->makeValueEntityString( SMWExporter::getInstance()->expandURI( '&category;' ) ) . ">\n" . + "\t<!ENTITY property " . $this->makeValueEntityString( SMWExporter::getInstance()->expandURI( '&property;' ) ) . ">\n" . + "\t<!ENTITY wikiurl " . $this->makeValueEntityString( SMWExporter::getInstance()->expandURI( '&wikiurl;' ) ) . ">\n" . + "]>\n\n" . + "<rdf:RDF\n" . + "\txmlns:rdf=\"&rdf;\"\n" . + "\txmlns:rdfs=\"&rdfs;\"\n" . + "\txmlns:owl =\"&owl;\"\n" . + "\txmlns:swivt=\"&swivt;\"\n" . + "\txmlns:wiki=\"&wiki;\"\n" . + "\txmlns:category=\"&category;\"\n" . + "\txmlns:property=\"&property;\""; + $this->global_namespaces = [ 'rdf' => true, 'rdfs' => true, 'owl' => true, 'swivt' => true, 'wiki' => true, 'property' => true, 'category' => true ]; + $this->post_ns_buffer .= ">\n\n"; + } + + protected function serializeFooter() { + $this->post_ns_buffer .= "\t<!-- Created by Semantic MediaWiki, https://www.semantic-mediawiki.org/ -->\n"; + $this->post_ns_buffer .= '</rdf:RDF>'; + } + + public function serializeDeclaration( $uri, $typename ) { + $this->post_ns_buffer .= "\t<$typename rdf:about=\"$uri\" />\n"; + } + + public function serializeExpData( SMWExpData $expData ) { + $this->serializeNestedExpData( $expData, '' ); + $this->serializeNamespaces(); + if ( !$this->namespaces_are_global ) { + $this->pre_ns_buffer .= $this->post_ns_buffer; + $this->post_ns_buffer = ''; + $this->namespace_block_started = false; + } + } + + public function flushContent() { + $result = parent::flushContent(); + $this->namespaces_are_global = false; // must not be done before calling the parent method (which may declare namespaces) + $this->namespace_block_started = false; + return $result; + } + + protected function serializeNamespace( $shortname, $uri ) { + if ( $this->namespaces_are_global ) { + $this->global_namespaces[$shortname] = true; + $this->pre_ns_buffer .= "\n\t"; + } else { + $this->pre_ns_buffer .= ' '; + } + $this->pre_ns_buffer .= "xmlns:$shortname=\"$uri\""; + } + + /** + * Serialize the given SMWExpData object, possibly recursively with + * increased indentation. + * + * @param $expData SMWExpData containing the data to be serialised. + * @param $indent string specifying a prefix for indentation (usually a sequence of tabs) + */ + protected function serializeNestedExpData( SMWExpData $expData, $indent ) { + $this->recordDeclarationTypes( $expData ); + + $type = $expData->extractMainType()->getQName(); + if ( !$this->namespace_block_started ) { // start new ns block + $this->pre_ns_buffer .= "\t$indent<$type"; + $this->namespace_block_started = true; + } else { // continue running block + $this->post_ns_buffer .= "\t$indent<$type"; + } + + if ( ( $expData->getSubject() instanceof SMWExpResource ) && + !$expData->getSubject()->isBlankNode() ) { + $this->post_ns_buffer .= ' rdf:about="' . $expData->getSubject()->getUri() . '"'; + } // else: blank node, no "rdf:about" + + if ( count( $expData->getProperties() ) == 0 ) { // nothing else to export + $this->post_ns_buffer .= " />\n"; + } else { // process data + $this->post_ns_buffer .= ">\n"; + + foreach ( $expData->getProperties() as $property ) { + $prop_decl_queued = false; + $isClassTypeProp = $this->isOWLClassTypeProperty( $property ); + + foreach ( $expData->getValues( $property ) as $valueElement ) { + $this->requireNamespace( $property->getNamespaceID(), $property->getNamespace() ); + + if ( $valueElement instanceof SMWExpLiteral ) { + $prop_decl_type = SMW_SERIALIZER_DECL_APROP; + $this->serializeExpLiteral( $property, $valueElement, "\t\t$indent" ); + } elseif ( $valueElement instanceof SMWExpResource ) { + $prop_decl_type = SMW_SERIALIZER_DECL_OPROP; + $this->serializeExpResource( $property, $valueElement, "\t\t$indent", $isClassTypeProp ); + } elseif ( $valueElement instanceof SMWExpData ) { + $prop_decl_type = SMW_SERIALIZER_DECL_OPROP; + + $collection = $valueElement->getCollection(); + if ( $collection !== false ) { // RDF-style collection (list) + $this->serializeExpCollection( $property, $collection, "\t\t$indent", $isClassTypeProp ); + } elseif ( count( $valueElement->getProperties() ) > 0 ) { // resource with data + $this->post_ns_buffer .= "\t\t$indent<" . $property->getQName() . ">\n"; + $this->serializeNestedExpData( $valueElement, "\t\t$indent" ); + $this->post_ns_buffer .= "\t\t$indent</" . $property->getQName() . ">\n"; + } else { // resource without data + $this->serializeExpResource( $property, $valueElement->getSubject(), "\t\t$indent", $isClassTypeProp ); + } + } // else: no other types of export elements + + if ( !$prop_decl_queued ) { + $this->requireDeclaration( $property, $prop_decl_type ); + $prop_decl_queued = true; + } + } + } + $this->post_ns_buffer .= "\t$indent</" . $type . ">\n"; + } + } + + /** + * Add to the output a serialization of a property assignment where an + * SMWExpLiteral is the object. It is assumed that a suitable subject + * block has already been openend. + * + * @param $expResourceProperty SMWExpNsResource the property to use + * @param $expLiteral SMWExpLiteral the data value to use + * @param $indent string specifying a prefix for indentation (usually a sequence of tabs) + */ + protected function serializeExpLiteral( SMWExpNsResource $expResourceProperty, SMWExpLiteral $expLiteral, $indent ) { + $this->post_ns_buffer .= $indent . '<' . $expResourceProperty->getQName(); + + // https://www.w3.org/TR/rdf-syntax-grammar/#section-Syntax-languages + // "... to indicate that the included content is in the given language. + // Typed literals which includes XML literals are not affected by this + // attribute. The most specific in-scope language present (if any) is + // applied to property element string literal ..." + if ( $expLiteral->getDatatype() !== '' && $expLiteral->getLang() !== '' ) { + $this->post_ns_buffer .= ' xml:lang="' . $expLiteral->getLang() . '"'; + } elseif ( $expLiteral->getDatatype() !== '' ) { + $this->post_ns_buffer .= ' rdf:datatype="' . $expLiteral->getDatatype() . '"'; + } + + $this->post_ns_buffer .= '>' . $this->makeAttributeValueString( $expLiteral->getLexicalForm() ); + $this->post_ns_buffer .= '</' . $expResourceProperty->getQName() . ">\n"; + } + + /** + * Add to the output a serialization of a property assignment where an + * SMWExpResource is the object. It is assumed that a suitable subject + * block has already been openend. + * + * @param $expResourceProperty SMWExpNsResource the property to use + * @param $expResource SMWExpResource the data value to use + * @param $indent string specifying a prefix for indentation (usually a sequence of tabs) + * @param $isClassTypeProp boolean whether the resource must be declared as a class + */ + protected function serializeExpResource( SMWExpNsResource $expResourceProperty, SMWExpResource $expResource, $indent, $isClassTypeProp ) { + $this->post_ns_buffer .= $indent . '<' . $expResourceProperty->getQName(); + if ( !$expResource->isBlankNode() ) { + if ( ( $expResource instanceof SMWExpNsResource ) && ( $expResource->getNamespaceID() == 'wiki' ) ) { + // very common case, reduce bandwidth + $this->post_ns_buffer .= ' rdf:resource="&wiki;' . $expResource->getLocalName() . '"'; + } else { + $uriValue = $this->makeAttributeValueString( $expResource->getUri() ); + $this->post_ns_buffer .= ' rdf:resource="' . $uriValue . '"'; + } + } + $this->post_ns_buffer .= "/>\n"; + if ( $isClassTypeProp ) { + $this->requireDeclaration( $expResource, SMW_SERIALIZER_DECL_CLASS ); + } + } + + /** + * Add a serialization of the given SMWExpResource to the output, + * assuming that an opening property tag is alerady there. + * + * @param $expResourceProperty SMWExpNsResource the property to use + * @param $expResource array of (SMWExpResource or SMWExpData) + * @param $indent string specifying a prefix for indentation (usually a sequence of tabs) + * @param $isClassTypeProp boolean whether the resource must be declared as a class + * + * @bug The $isClassTypeProp parameter is not properly taken into account. + * @bug Individual resources are not serialised properly. + */ + protected function serializeExpCollection( SMWExpNsResource $expResourceProperty, array $collection, $indent, $isClassTypeProp ) { + $this->post_ns_buffer .= $indent . '<' . $expResourceProperty->getQName() . " rdf:parseType=\"Collection\">\n"; + foreach ( $collection as $expElement ) { + if ( $expElement instanceof SMWExpData ) { + $this->serializeNestedExpData( $expElement, $indent ); + } else { + // FIXME: the below is not the right thing to do here + //$this->serializeExpResource( $expResourceProperty, $expElement, $indent ); + } + if ( $isClassTypeProp ) { + // FIXME: $expResource is undefined + //$this->requireDeclaration( $expResource, SMW_SERIALIZER_DECL_CLASS ); + } + } + $this->post_ns_buffer .= "$indent</" . $expResourceProperty->getQName() . ">\n"; + } + + /** + * Escape a string in the special form that is required for values in + * DTD entity declarations in XML. Namely, this require the percent sign + * to be replaced. + * + * @param $string string to be escaped + * @return string + */ + protected function makeValueEntityString( $string ) { + return "'" . str_replace( '%', '%', $string ) . "'"; + } + + /** + * Escape a string as required for using it in XML attribute values. + * + * @param $string string to be escaped + * @return string + */ + protected function makeAttributeValueString( $string ) { + return str_replace( [ '&', '>', '<' ], [ '&', '>', '<' ], $string ); + } + +} |