1 /* 2 * Copyright (c) 2009, 2013, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package com.sun.xml.internal.dtdparser; 27 28 import org.xml.sax.EntityResolver; 29 import org.xml.sax.InputSource; 30 31 import java.io.File; 32 import java.io.FileInputStream; 33 import java.io.IOException; 34 import java.io.InputStream; 35 import java.net.URL; 36 import java.net.URLConnection; 37 import java.util.Hashtable; 38 39 /** 40 * This entity resolver class provides a number of utilities which can help 41 * managment of external parsed entities in XML. These are commonly used 42 * to hold markup declarations that are to be used as part of a Document 43 * Type Declaration (DTD), or to hold text marked up with XML. 44 * <p/> 45 * <P> Features include: <UL> 46 * <p/> 47 * <LI> Static factory methods are provided for constructing SAX InputSource 48 * objects from Files, URLs, or MIME objects. This eliminates a class of 49 * error-prone coding in applications. 50 * <p/> 51 * <LI> Character encodings for XML documents are correctly supported: <UL> 52 * <p/> 53 * <LI> The encodings defined in the RFCs for MIME content types 54 * (2046 for general MIME, and 2376 for XML in particular), are 55 * supported, handling <em>charset=...</em> attributes and accepting 56 * content types which are known to be safe for use with XML; 57 * <p/> 58 * <LI> The character encoding autodetection algorithm identified 59 * in the XML specification is used, and leverages all of 60 * the JDK 1.1 (and later) character encoding support. 61 * <p/> 62 * <LI> The use of MIME typing may optionally be disabled, forcing the 63 * use of autodetection, to support web servers which don't correctly 64 * report MIME types for XML. For example, they may report text that 65 * is encoded in EUC-JP as being US-ASCII text, leading to fatal 66 * errors during parsing. 67 * <p/> 68 * <LI> The InputSource objects returned by this class always 69 * have a <code>java.io.Reader</code> available as the "character 70 * stream" property. 71 * <p/> 72 * </UL> 73 * <p/> 74 * <LI> Catalog entries can map public identifiers to Java resources or 75 * to local URLs. These are used to reduce network dependencies and loads, 76 * and will often be used for external DTD components. For example, packages 77 * shipping DTD files as resources in JAR files can eliminate network traffic 78 * when accessing them, and sites may provide local caches of common DTDs. 79 * Note that no particular catalog syntax is supported by this class, only 80 * the notion of a set of entries. 81 * <p/> 82 * </UL> 83 * <p/> 84 * <P> Subclasses can perform tasks such as supporting new URI schemes for 85 * URIs which are not URLs, such as URNs (see RFC 2396) or for accessing 86 * MIME entities which are part of a <em>multipart/related</em> group 87 * (see RFC 2387). They may also be used to support particular catalog 88 * syntaxes, such as the <a href="http://www.oasis-open.org/html/a401.htm"> 89 * SGML/Open Catalog (SOCAT)</a> which supports the SGML notion of "Formal 90 * Public Identifiers (FPIs). 91 * 92 * @author David Brownell 93 * @author Janet Koenig 94 * @version 1.3 00/02/24 95 */ 96 public class Resolver implements EntityResolver { 97 private boolean ignoringMIME; 98 99 // table mapping public IDs to (local) URIs 100 private Hashtable id2uri; 101 102 // tables mapping public IDs to resources and classloaders 103 private Hashtable id2resource; 104 private Hashtable id2loader; 105 106 // 107 // table of MIME content types (less attributes!) known 108 // to be mostly "OK" to use with XML MIME entities. the 109 // idea is to rule out obvious braindamage ("image/jpg") 110 // not the subtle stuff ("text/html") that might actually 111 // be (or become) safe. 112 // 113 private static final String types [] = { 114 "application/xml", 115 "text/xml", 116 "text/plain", 117 "text/html", // commonly mis-inferred 118 "application/x-netcdf", // this is often illegal XML 119 "content/unknown" 120 }; 121 122 /** 123 * Constructs a resolver. 124 */ 125 public Resolver() { 126 } 127 128 /** 129 * Returns an input source, using the MIME type information and URL 130 * scheme to statically determine the correct character encoding if 131 * possible and otherwise autodetecting it. MIME carefully specifies 132 * the character encoding defaults, and how attributes of the content 133 * type can change it. XML further specifies two mandatory encodings 134 * (UTF-8 and UTF-16), and includes an XML declaration which can be 135 * used to internally label most documents encoded using US-ASCII 136 * supersets (such as Shift_JIS, EUC-JP, ISO-2022-*, ISO-8859-*, and 137 * more). 138 * <p/> 139 * <P> This method can be used to access XML documents which do not 140 * have URIs (such as servlet input streams, or most JavaMail message 141 * entities) and to support access methods such as HTTP POST or PUT. 142 * (URLs normally return content using the GET method.) 143 * <p/> 144 * <P> <em> The caller should set the system ID in order for relative URIs 145 * found in this document to be interpreted correctly.</em> In some cases, 146 * a custom resolver will need to be used; for example, documents 147 * may be grouped in a single MIME "multipart/related" bundle, and 148 * relative URLs would refer to other documents in that bundle. 149 * 150 * @param contentType The MIME content type for the source for which 151 * an InputSource is desired, such as <em>text/xml;charset=utf-8</em>. 152 * @param stream The input byte stream for the input source. 153 * @param checkType If true, this verifies that the content type is known 154 * to support XML documents, such as <em>application/xml</em>. 155 * @param scheme Unless this is "file", unspecified MIME types 156 * default to US-ASCII. Files are always autodetected since most 157 * file systems discard character encoding information. 158 */ 159 public static InputSource createInputSource(String contentType, 160 InputStream stream, 161 boolean checkType, 162 String scheme) throws IOException { 163 InputSource retval; 164 String charset = null; 165 166 if (contentType != null) { 167 int index; 168 169 contentType = contentType.toLowerCase(); 170 index = contentType.indexOf(';'); 171 if (index != -1) { 172 String attributes; 173 174 attributes = contentType.substring(index + 1); 175 contentType = contentType.substring(0, index); 176 177 // use "charset=..." if it's available 178 index = attributes.indexOf("charset"); 179 if (index != -1) { 180 attributes = attributes.substring(index + 7); 181 // strip out subsequent attributes 182 if ((index = attributes.indexOf(';')) != -1) 183 attributes = attributes.substring(0, index); 184 // find start of value 185 if ((index = attributes.indexOf('=')) != -1) { 186 attributes = attributes.substring(index + 1); 187 // strip out rfc822 comments 188 if ((index = attributes.indexOf('(')) != -1) 189 attributes = attributes.substring(0, index); 190 // double quotes are optional 191 if ((index = attributes.indexOf('"')) != -1) { 192 attributes = attributes.substring(index + 1); 193 attributes = attributes.substring(0, 194 attributes.indexOf('"')); 195 } 196 charset = attributes.trim(); 197 // XXX "\;", "\)" etc were mishandled above 198 } 199 } 200 } 201 202 // 203 // Check MIME type. 204 // 205 if (checkType) { 206 boolean isOK = false; 207 for (int i = 0; i < types.length; i++) 208 if (types[i].equals(contentType)) { 209 isOK = true; 210 break; 211 } 212 if (!isOK) 213 throw new IOException("Not XML: " + contentType); 214 } 215 216 // 217 // "text/*" MIME types have hard-wired character set 218 // defaults, as specified in the RFCs. For XML, we 219 // ignore the system "file.encoding" property since 220 // autodetection is more correct. 221 // 222 if (charset == null) { 223 contentType = contentType.trim(); 224 if (contentType.startsWith("text/")) { 225 if (!"file".equalsIgnoreCase(scheme)) 226 charset = "US-ASCII"; 227 } 228 // "application/*" has no default 229 } 230 } 231 232 retval = new InputSource(XmlReader.createReader(stream, charset)); 233 retval.setByteStream(stream); 234 retval.setEncoding(charset); 235 return retval; 236 } 237 238 239 /** 240 * Creates an input source from a given URI. 241 * 242 * @param uri the URI (system ID) for the entity 243 * @param checkType if true, the MIME content type for the entity 244 * is checked for document type and character set encoding. 245 */ 246 static public InputSource createInputSource(URL uri, boolean checkType) 247 throws IOException { 248 249 URLConnection conn = uri.openConnection(); 250 InputSource retval; 251 252 if (checkType) { 253 String contentType = conn.getContentType(); 254 retval = createInputSource(contentType, conn.getInputStream(), 255 false, uri.getProtocol()); 256 } else { 257 retval = new InputSource(XmlReader.createReader(conn.getInputStream())); 258 } 259 retval.setSystemId(conn.getURL().toString()); 260 return retval; 261 } 262 263 264 /** 265 * Creates an input source from a given file, autodetecting 266 * the character encoding. 267 */ 268 static public InputSource createInputSource(File file) 269 throws IOException { 270 InputSource retval; 271 String path; 272 273 retval = new InputSource(XmlReader.createReader(new FileInputStream(file))); 274 275 // On JDK 1.2 and later, simplify this: 276 // "path = file.toURL ().toString ()". 277 path = file.getAbsolutePath(); 278 if (File.separatorChar != '/') 279 path = path.replace(File.separatorChar, '/'); 280 if (!path.startsWith("/")) 281 path = "/" + path; 282 if (!path.endsWith("/") && file.isDirectory()) 283 path = path + "/"; 284 285 retval.setSystemId("file:" + path); 286 return retval; 287 } 288 289 290 /** 291 * <b>SAX:</b> 292 * Resolve the given entity into an input source. If the name can't 293 * be mapped to a preferred form of the entity, the URI is used. To 294 * resolve the entity, first a local catalog mapping names to URIs is 295 * consulted. If no mapping is found there, a catalog mapping names 296 * to java resources is consulted. Finally, if neither mapping found 297 * a copy of the entity, the specified URI is used. 298 * <p/> 299 * <P> When a URI is used, <a href="#createInputSource"> 300 * createInputSource</a> is used to correctly deduce the character 301 * encoding used by this entity. No MIME type checking is done. 302 * 303 * @param name Used to find alternate copies of the entity, when 304 * this value is non-null; this is the XML "public ID". 305 * @param uri Used when no alternate copy of the entity is found; 306 * this is the XML "system ID", normally a URI. 307 */ 308 public InputSource resolveEntity(String name, String uri) 309 throws IOException { 310 InputSource retval; 311 String mappedURI = name2uri(name); 312 InputStream stream; 313 314 // prefer explicit URI mappings, then bundled resources... 315 if (mappedURI == null && (stream = mapResource(name)) != null) { 316 uri = "java:resource:" + (String) id2resource.get(name); 317 retval = new InputSource(XmlReader.createReader(stream)); 318 319 // ...and treat all URIs the same (as URLs for now). 320 } else { 321 URL url; 322 URLConnection conn; 323 324 if (mappedURI != null) 325 uri = mappedURI; 326 else if (uri == null) 327 return null; 328 329 url = new URL(uri); 330 conn = url.openConnection(); 331 uri = conn.getURL().toString(); 332 // System.out.println ("++ URI: " + url); 333 if (ignoringMIME) 334 retval = new InputSource(XmlReader.createReader(conn.getInputStream())); 335 else { 336 String contentType = conn.getContentType(); 337 retval = createInputSource(contentType, 338 conn.getInputStream(), 339 false, url.getProtocol()); 340 } 341 } 342 retval.setSystemId(uri); 343 retval.setPublicId(name); 344 return retval; 345 } 346 347 348 /** 349 * Returns true if this resolver is ignoring MIME types in the documents 350 * it returns, to work around bugs in how servers have reported the 351 * documents' MIME types. 352 */ 353 public boolean isIgnoringMIME() { 354 return ignoringMIME; 355 } 356 357 /** 358 * Tells the resolver whether to ignore MIME types in the documents it 359 * retrieves. Many web servers incorrectly assign text documents a 360 * default character encoding, even when that is incorrect. For example, 361 * all HTTP text documents default to use ISO-8859-1 (used for Western 362 * European languages), and other MIME sources default text documents 363 * to use US-ASCII (a seven bit encoding). For XML documents which 364 * include text encoding declarations (as most should do), these server 365 * bugs can be worked around by ignoring the MIME type entirely. 366 */ 367 public void setIgnoringMIME(boolean value) { 368 ignoringMIME = value; 369 } 370 371 372 // maps the public ID to an alternate URI, if one is registered 373 private String name2uri(String publicId) { 374 if (publicId == null || id2uri == null) 375 return null; 376 return (String) id2uri.get(publicId); 377 } 378 379 380 /** 381 * Registers the given public ID as corresponding to a particular 382 * URI, typically a local copy. This URI will be used in preference 383 * to ones provided as system IDs in XML entity declarations. This 384 * mechanism would most typically be used for Document Type Definitions 385 * (DTDs), where the public IDs are formally managed and versioned. 386 * 387 * @param publicId The managed public ID being mapped 388 * @param uri The URI of the preferred copy of that entity 389 */ 390 public void registerCatalogEntry(String publicId, 391 String uri) { 392 if (id2uri == null) 393 id2uri = new Hashtable(17); 394 id2uri.put(publicId, uri); 395 } 396 397 398 // return the resource as a stream 399 private InputStream mapResource(String publicId) { 400 // System.out.println ("++ PUBLIC: " + publicId); 401 if (publicId == null || id2resource == null) 402 return null; 403 404 String resourceName = (String) id2resource.get(publicId); 405 ClassLoader loader = null; 406 407 if (resourceName == null) 408 return null; 409 // System.out.println ("++ Resource: " + resourceName); 410 411 if (id2loader != null) 412 loader = (ClassLoader) id2loader.get(publicId); 413 // System.out.println ("++ Loader: " + loader); 414 if (loader == null) 415 return ClassLoader.getSystemResourceAsStream(resourceName); 416 return loader.getResourceAsStream(resourceName); 417 } 418 419 /** 420 * Registers a given public ID as corresponding to a particular Java 421 * resource in a given class loader, typically distributed with a 422 * software package. This resource will be preferred over system IDs 423 * included in XML documents. This mechanism should most typically be 424 * used for Document Type Definitions (DTDs), where the public IDs are 425 * formally managed and versioned. 426 * <p/> 427 * <P> If a mapping to a URI has been provided, that mapping takes 428 * precedence over this one. 429 * 430 * @param publicId The managed public ID being mapped 431 * @param resourceName The name of the Java resource 432 * @param loader The class loader holding the resource, or null if 433 * it is a system resource. 434 */ 435 public void registerCatalogEntry(String publicId, 436 String resourceName, 437 ClassLoader loader) { 438 if (id2resource == null) 439 id2resource = new Hashtable(17); 440 id2resource.put(publicId, resourceName); 441 442 if (loader != null) { 443 if (id2loader == null) 444 id2loader = new Hashtable(17); 445 id2loader.put(publicId, loader); 446 } 447 } 448 }