/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.sun.org.apache.xml.internal.resolver.tools; import java.io.IOException; import java.io.InputStream; import java.net.MalformedURLException; import java.net.URL; import org.xml.sax.InputSource; import org.xml.sax.SAXException; import org.xml.sax.XMLReader; import org.xml.sax.Attributes; import org.xml.sax.helpers.XMLFilterImpl; import com.sun.org.apache.xml.internal.resolver.Catalog; import com.sun.org.apache.xml.internal.resolver.CatalogManager; import com.sun.org.apache.xml.internal.resolver.helpers.FileURL; /** * A SAX XMLFilter that performs catalog-based entity resolution. * * <p>This class implements a SAX XMLFilter that performs entity resolution * using the CatalogResolver. The actual, underlying parser is obtained * from a SAXParserFactory.</p> * </p> * * @see CatalogResolver * @see org.xml.sax.XMLFilter * * @author Norman Walsh * <a href="mailto:Norman.Walsh@Sun.COM">Norman.Walsh@Sun.COM</a> * * @version 1.0 */ public class ResolvingXMLFilter extends XMLFilterImpl { /** * Suppress explanatory message? * * @see #parse(InputSource) */ private static boolean suppressExplanation = false; /** The manager for the underlying resolver. */ CatalogManager catalogManager = CatalogManager.getStaticManager(); /** The underlying catalog resolver. */ private CatalogResolver catalogResolver = null; /** A separate resolver for oasis-xml-pi catalogs. */ private CatalogResolver piCatalogResolver = null; /** Are we in the prolog? Is an oasis-xml-catalog PI valid now? */ private boolean allowXMLCatalogPI = false; /** The base URI of the input document, if known. */ private URL baseURL = null; /** Construct an empty XML Filter with no parent. */ public ResolvingXMLFilter() { super(); catalogResolver = new CatalogResolver(catalogManager); } /** Construct an XML filter with the specified parent. */ public ResolvingXMLFilter(XMLReader parent) { super(parent); catalogResolver = new CatalogResolver(catalogManager); } /** Construct an XML filter with the specified parent. */ public ResolvingXMLFilter(CatalogManager manager) { super(); catalogManager = manager; catalogResolver = new CatalogResolver(catalogManager); } /** Construct an XML filter with the specified parent. */ public ResolvingXMLFilter(XMLReader parent, CatalogManager manager) { super(parent); catalogManager = manager; catalogResolver = new CatalogResolver(catalogManager); } /** * Provide accessto the underlying Catalog. */ public Catalog getCatalog() { return catalogResolver.getCatalog(); } /** * SAX XMLReader API. * * <p>Note that the JAXP 1.1ea2 parser crashes with an InternalError if * it encounters a system identifier that appears to be a relative URI * that begins with a slash. For example, the declaration:</p> * * <pre> * <!DOCTYPE book SYSTEM "/path/to/dtd/on/my/system/docbookx.dtd"> * </pre> * * <p>would cause such an error. As a convenience, this method catches * that error and prints an explanation. (Unfortunately, it's not possible * to identify the particular system identifier that causes the problem.) * </p> * * <p>The underlying error is forwarded after printing the explanatory * message. The message is only every printed once and if * <code>suppressExplanation</code> is set to <code>false</code> before * parsing, it will never be printed.</p> */ public void parse(InputSource input) throws IOException, SAXException { allowXMLCatalogPI = true; setupBaseURI(input.getSystemId()); try { super.parse(input); } catch (InternalError ie) { explain(input.getSystemId()); throw ie; } } /** SAX XMLReader API. * * @see #parse(InputSource) */ public void parse(String systemId) throws IOException, SAXException { allowXMLCatalogPI = true; setupBaseURI(systemId); try { super.parse(systemId); } catch (InternalError ie) { explain(systemId); throw ie; } } /** * Implements the <code>resolveEntity</code> method * for the SAX interface, using an underlying CatalogResolver * to do the real work. */ public InputSource resolveEntity (String publicId, String systemId) { allowXMLCatalogPI = false; String resolved = catalogResolver.getResolvedEntity(publicId, systemId); if (resolved == null && piCatalogResolver != null) { resolved = piCatalogResolver.getResolvedEntity(publicId, systemId); } if (resolved != null) { try { InputSource iSource = new InputSource(resolved); iSource.setPublicId(publicId); // Ideally this method would not attempt to open the // InputStream, but there is a bug (in Xerces, at least) // that causes the parser to mistakenly open the wrong // system identifier if the returned InputSource does // not have a byteStream. // // It could be argued that we still shouldn't do this here, // but since the purpose of calling the entityResolver is // almost certainly to open the input stream, it seems to // do little harm. // URL url = new URL(resolved); InputStream iStream = url.openStream(); iSource.setByteStream(iStream); return iSource; } catch (Exception e) { catalogManager.debug.message(1, "Failed to create InputSource (" + e.toString() + ")", resolved); return null; } } else { return null; } } /** SAX DTDHandler API. * * <p>Captured here only to detect the end of the prolog so that * we can ignore subsequent oasis-xml-catalog PIs. Otherwise * the events are just passed through.</p> */ public void notationDecl (String name, String publicId, String systemId) throws SAXException { allowXMLCatalogPI = false; super.notationDecl(name,publicId,systemId); } /** SAX DTDHandler API. * * <p>Captured here only to detect the end of the prolog so that * we can ignore subsequent oasis-xml-catalog PIs. Otherwise * the events are just passed through.</p> */ public void unparsedEntityDecl (String name, String publicId, String systemId, String notationName) throws SAXException { allowXMLCatalogPI = false; super.unparsedEntityDecl (name, publicId, systemId, notationName); } /** SAX ContentHandler API. * * <p>Captured here only to detect the end of the prolog so that * we can ignore subsequent oasis-xml-catalog PIs. Otherwise * the events are just passed through.</p> */ public void startElement (String uri, String localName, String qName, Attributes atts) throws SAXException { allowXMLCatalogPI = false; super.startElement(uri,localName,qName,atts); } /** SAX ContentHandler API. * * <p>Detect and use the oasis-xml-catalog PI if it occurs.</p> */ public void processingInstruction(String target, String pidata) throws SAXException { if (target.equals("oasis-xml-catalog")) { URL catalog = null; String data = pidata; int pos = data.indexOf("catalog="); if (pos >= 0) { data = data.substring(pos+8); if (data.length() > 1) { String quote = data.substring(0,1); data = data.substring(1); pos = data.indexOf(quote); if (pos >= 0) { data = data.substring(0, pos); try { if (baseURL != null) { catalog = new URL(baseURL, data); } else { catalog = new URL(data); } } catch (MalformedURLException mue) { // nevermind } } } } if (allowXMLCatalogPI) { if (catalogManager.getAllowOasisXMLCatalogPI()) { catalogManager.debug.message(4,"oasis-xml-catalog PI", pidata); if (catalog != null) { try { catalogManager.debug.message(4,"oasis-xml-catalog", catalog.toString()); if (piCatalogResolver == null) { piCatalogResolver = new CatalogResolver(true); } piCatalogResolver.getCatalog().parseCatalog(catalog.toString()); } catch (Exception e) { catalogManager.debug.message(3, "Exception parsing oasis-xml-catalog: " + catalog.toString()); } } else { catalogManager.debug.message(3, "PI oasis-xml-catalog unparseable: " + pidata); } } else { catalogManager.debug.message(4,"PI oasis-xml-catalog ignored: " + pidata); } } else { catalogManager.debug.message(3, "PI oasis-xml-catalog occurred in an invalid place: " + pidata); } } else { super.processingInstruction(target, pidata); } } /** Save the base URI of the document being parsed. */ private void setupBaseURI(String systemId) { URL cwd = null; try { cwd = FileURL.makeURL("basename"); } catch (MalformedURLException mue) { cwd = null; } try { baseURL = new URL(systemId); } catch (MalformedURLException mue) { if (cwd != null) { try { baseURL = new URL(cwd, systemId); } catch (MalformedURLException mue2) { // give up baseURL = null; } } else { // give up baseURL = null; } } } /** Provide one possible explanation for an InternalError. */ private void explain(String systemId) { if (!suppressExplanation) { System.out.println("XMLReader probably encountered bad URI in " + systemId); System.out.println("For example, replace '/some/uri' with 'file:/some/uri'."); } suppressExplanation = true; } }