1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 package com.sun.org.apache.xml.internal.resolver.tools;
19
20 import com.sun.org.apache.xerces.internal.jaxp.SAXParserFactoryImpl;
21 import java.io.IOException;
22 import java.io.InputStream;
23 import java.net.URL;
24 import java.net.MalformedURLException;
25
26 import org.xml.sax.SAXException;
27 import org.xml.sax.XMLReader;
28 import org.xml.sax.InputSource;
29 import org.xml.sax.EntityResolver;
30
31 import javax.xml.transform.sax.SAXSource;
32 import javax.xml.transform.Source;
33 import javax.xml.transform.URIResolver;
34 import javax.xml.transform.TransformerException;
35 import javax.xml.parsers.ParserConfigurationException;
36 import javax.xml.parsers.SAXParserFactory;
37
38 import com.sun.org.apache.xml.internal.resolver.Catalog;
39 import com.sun.org.apache.xml.internal.resolver.CatalogManager;
40 import com.sun.org.apache.xml.internal.resolver.helpers.FileURL;
41
42 /**
43 * A SAX EntityResolver/JAXP URIResolver that uses catalogs.
44 *
45 * <p>This class implements both a SAX EntityResolver and a JAXP URIResolver.
46 * </p>
47 *
48 * <p>This resolver understands OASIS TR9401 catalogs, XCatalogs, and the
49 * current working draft of the OASIS Entity Resolution Technical
50 * Committee specification.</p>
51 *
52 * @see Catalog
53 * @see org.xml.sax.EntityResolver
54 * @see javax.xml.transform.URIResolver
55 *
56 * @author Norman Walsh
57 * <a href="mailto:Norman.Walsh@Sun.COM">Norman.Walsh@Sun.COM</a>
58 *
59 * @version 1.0
60 */
61 public class CatalogResolver implements EntityResolver, URIResolver {
62 /** Make the parser Namespace aware? */
63 public boolean namespaceAware = true;
64
65 /** Make the parser validating? */
66 public boolean validating = false;
67
68 /** The underlying catalog */
69 private Catalog catalog = null;
70
71 /** The catalog manager */
72 private CatalogManager catalogManager = CatalogManager.getStaticManager();
73
74 /** Constructor */
75 public CatalogResolver() {
76 initializeCatalogs(false);
77 }
78
79 /** Constructor */
80 public CatalogResolver(boolean privateCatalog) {
81 initializeCatalogs(privateCatalog);
82 }
83
84 /** Constructor */
85 public CatalogResolver(CatalogManager manager) {
86 catalogManager = manager;
87 initializeCatalogs(!catalogManager.getUseStaticCatalog());
88 }
89
90 /** Initialize catalog */
91 private void initializeCatalogs(boolean privateCatalog) {
92 catalog = catalogManager.getCatalog();
93 }
94
95 /** Return the underlying catalog */
96 public Catalog getCatalog() {
97 return catalog;
98 }
99
100 /**
101 * Implements the guts of the <code>resolveEntity</code> method
102 * for the SAX interface.
103 *
104 * <p>Presented with an optional public identifier and a system
105 * identifier, this function attempts to locate a mapping in the
106 * catalogs.</p>
107 *
108 * <p>If such a mapping is found, it is returned. If no mapping is
109 * found, null is returned.</p>
110 *
111 * @param publicId The public identifier for the entity in question.
112 * This may be null.
113 *
114 * @param systemId The system identifier for the entity in question.
115 * XML requires a system identifier on all external entities, so this
116 * value is always specified.
117 *
118 * @return The resolved identifier (a URI reference).
119 */
120 public String getResolvedEntity (String publicId, String systemId) {
121 String resolved = null;
122
123 if (catalog == null) {
124 catalogManager.debug.message(1, "Catalog resolution attempted with null catalog; ignored");
125 return null;
126 }
127
128 if (systemId != null) {
129 try {
130 resolved = catalog.resolveSystem(systemId);
131 } catch (MalformedURLException me) {
132 catalogManager.debug.message(1, "Malformed URL exception trying to resolve",
133 publicId);
134 resolved = null;
135 } catch (IOException ie) {
136 catalogManager.debug.message(1, "I/O exception trying to resolve", publicId);
137 resolved = null;
138 }
139 }
140
141 if (resolved == null) {
142 if (publicId != null) {
143 try {
144 resolved = catalog.resolvePublic(publicId, systemId);
145 } catch (MalformedURLException me) {
146 catalogManager.debug.message(1, "Malformed URL exception trying to resolve",
147 publicId);
148 } catch (IOException ie) {
149 catalogManager.debug.message(1, "I/O exception trying to resolve", publicId);
150 }
151 }
152
153 if (resolved != null) {
154 catalogManager.debug.message(2, "Resolved public", publicId, resolved);
155 }
156 } else {
157 catalogManager.debug.message(2, "Resolved system", systemId, resolved);
158 }
159
160 return resolved;
161 }
162
163 /**
164 * Implements the <code>resolveEntity</code> method
165 * for the SAX interface.
166 *
167 * <p>Presented with an optional public identifier and a system
168 * identifier, this function attempts to locate a mapping in the
169 * catalogs.</p>
170 *
171 * <p>If such a mapping is found, the resolver attempts to open
172 * the mapped value as an InputSource and return it. Exceptions are
173 * ignored and null is returned if the mapped value cannot be opened
174 * as an input source.</p>
175 *
176 * <p>If no mapping is found (or an error occurs attempting to open
177 * the mapped value as an input source), null is returned and the system
178 * will use the specified system identifier as if no entityResolver
179 * was specified.</p>
180 *
181 * @param publicId The public identifier for the entity in question.
182 * This may be null.
183 *
184 * @param systemId The system identifier for the entity in question.
185 * XML requires a system identifier on all external entities, so this
186 * value is always specified.
187 *
188 * @return An InputSource for the mapped identifier, or null.
189 */
190 public InputSource resolveEntity (String publicId, String systemId) {
191 String resolved = getResolvedEntity(publicId, systemId);
192
193 if (resolved != null) {
194 try {
195 InputSource iSource = new InputSource(resolved);
196 iSource.setPublicId(publicId);
197
198 // Ideally this method would not attempt to open the
199 // InputStream, but there is a bug (in Xerces, at least)
200 // that causes the parser to mistakenly open the wrong
201 // system identifier if the returned InputSource does
202 // not have a byteStream.
203 //
204 // It could be argued that we still shouldn't do this here,
205 // but since the purpose of calling the entityResolver is
206 // almost certainly to open the input stream, it seems to
207 // do little harm.
208 //
209 URL url = new URL(resolved);
210 InputStream iStream = url.openStream();
211 iSource.setByteStream(iStream);
212
213 return iSource;
214 } catch (Exception e) {
215 catalogManager.debug.message(1,
216 "Failed to create InputSource ("
217 + e.toString()
218 + ")", resolved);
219 return null;
220 }
221 }
222
223 return null;
224 }
225
226 /** JAXP URIResolver API */
227 public Source resolve(String href, String base)
228 throws TransformerException {
229
230 String uri = href;
231 String fragment = null;
232 int hashPos = href.indexOf("#");
233 if (hashPos >= 0) {
234 uri = href.substring(0, hashPos);
235 fragment = href.substring(hashPos+1);
236 }
237
238 String result = null;
239
240 try {
241 result = catalog.resolveURI(href);
242 } catch (Exception e) {
243 // nop;
244 }
245
246 if (result == null) {
247 try {
248 URL url = null;
249
250 if (base==null) {
251 url = new URL(uri);
252 result = url.toString();
253 } else {
254 URL baseURL = new URL(base);
255 url = (href.length()==0 ? baseURL : new URL(baseURL, uri));
256 result = url.toString();
257 }
258 } catch (java.net.MalformedURLException mue) {
259 // try to make an absolute URI from the current base
260 String absBase = makeAbsolute(base);
261 if (!absBase.equals(base)) {
262 // don't bother if the absBase isn't different!
263 return resolve(href, absBase);
264 } else {
265 throw new TransformerException("Malformed URL "
266 + href + "(base " + base + ")",
267 mue);
268 }
269 }
270 }
271
272 catalogManager.debug.message(2, "Resolved URI", href, result);
273
274 SAXSource source = new SAXSource();
275 source.setInputSource(new InputSource(result));
276 setEntityResolver(source);
277 return source;
278 }
279
280 /**
281 * <p>Establish an entityResolver for newly resolved URIs.</p>
282 *
283 * <p>This is called from the URIResolver to set an EntityResolver
284 * on the SAX parser to be used for new XML documents that are
285 * encountered as a result of the document() function, xsl:import,
286 * or xsl:include. This is done because the XSLT processor calls
287 * out to the SAXParserFactory itself to create a new SAXParser to
288 * parse the new document. The new parser does not automatically
289 * inherit the EntityResolver of the original (although arguably
290 * it should). See below:</p>
291 *
292 * <tt>"If an application wants to set the ErrorHandler or
293 * EntityResolver for an XMLReader used during a transformation,
294 * it should use a URIResolver to return the SAXSource which
295 * provides (with getXMLReader) a reference to the XMLReader"</tt>
296 *
297 * <p>...quoted from page 118 of the Java API for XML
298 * Processing 1.1 specification</p>
299 *
300 */
301 private void setEntityResolver(SAXSource source) throws TransformerException {
302 XMLReader reader = source.getXMLReader();
303 if (reader == null) {
304 SAXParserFactory spFactory = catalogManager.useServicesMechanism() ?
305 SAXParserFactory.newInstance() : new SAXParserFactoryImpl();
306 spFactory.setNamespaceAware(true);
307 try {
308 reader = spFactory.newSAXParser().getXMLReader();
309 }
310 catch (ParserConfigurationException ex) {
311 throw new TransformerException(ex);
312 }
313 catch (SAXException ex) {
314 throw new TransformerException(ex);
315 }
316 }
317 reader.setEntityResolver(this);
318 source.setXMLReader(reader);
319 }
320
321 /** Attempt to construct an absolute URI */
322 private String makeAbsolute(String uri) {
323 if (uri == null) {
324 uri = "";
325 }
326
327 try {
328 URL url = new URL(uri);
329 return url.toString();
330 } catch (MalformedURLException mue) {
331 try {
332 URL fileURL = FileURL.makeURL(uri);
333 return fileURL.toString();
334 } catch (MalformedURLException mue2) {
335 // bail
336 return uri;
337 }
338 }
339 }
340 }