1 /*
2 * Copyright (c) 1995, 2011, 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 java.net;
27
28 import java.io.IOException;
29 import java.io.InputStream;
30 import java.io.OutputStream;
31 import java.util.Hashtable;
32 import java.util.Date;
33 import java.util.StringTokenizer;
34 import java.util.Collections;
35 import java.util.Map;
36 import java.util.List;
37 import java.security.Permission;
38 import java.security.AccessController;
39 import sun.security.util.SecurityConstants;
40 import sun.net.www.MessageHeader;
41
42 /**
43 * The abstract class <code>URLConnection</code> is the superclass
44 * of all classes that represent a communications link between the
45 * application and a URL. Instances of this class can be used both to
46 * read from and to write to the resource referenced by the URL. In
47 * general, creating a connection to a URL is a multistep process:
48 * <p>
49 * <center><table border=2 summary="Describes the process of creating a connection to a URL: openConnection() and connect() over time.">
50 * <tr><th><code>openConnection()</code></th>
51 * <th><code>connect()</code></th></tr>
52 * <tr><td>Manipulate parameters that affect the connection to the remote
53 * resource.</td>
54 * <td>Interact with the resource; query header fields and
55 * contents.</td></tr>
56 * </table>
57 * ---------------------------->
58 * <br>time</center>
59 *
60 * <ol>
61 * <li>The connection object is created by invoking the
62 * <code>openConnection</code> method on a URL.
63 * <li>The setup parameters and general request properties are manipulated.
64 * <li>The actual connection to the remote object is made, using the
65 * <code>connect</code> method.
66 * <li>The remote object becomes available. The header fields and the contents
67 * of the remote object can be accessed.
68 * </ol>
69 * <p>
70 * The setup parameters are modified using the following methods:
71 * <ul>
72 * <li><code>setAllowUserInteraction</code>
73 * <li><code>setDoInput</code>
74 * <li><code>setDoOutput</code>
75 * <li><code>setIfModifiedSince</code>
76 * <li><code>setUseCaches</code>
77 * </ul>
78 * <p>
79 * and the general request properties are modified using the method:
80 * <ul>
81 * <li><code>setRequestProperty</code>
82 * </ul>
83 * <p>
84 * Default values for the <code>AllowUserInteraction</code> and
85 * <code>UseCaches</code> parameters can be set using the methods
86 * <code>setDefaultAllowUserInteraction</code> and
87 * <code>setDefaultUseCaches</code>.
88 * <p>
89 * Each of the above <code>set</code> methods has a corresponding
90 * <code>get</code> method to retrieve the value of the parameter or
91 * general request property. The specific parameters and general
92 * request properties that are applicable are protocol specific.
93 * <p>
94 * The following methods are used to access the header fields and
95 * the contents after the connection is made to the remote object:
96 * <ul>
97 * <li><code>getContent</code>
98 * <li><code>getHeaderField</code>
99 * <li><code>getInputStream</code>
100 * <li><code>getOutputStream</code>
101 * </ul>
102 * <p>
103 * Certain header fields are accessed frequently. The methods:
104 * <ul>
105 * <li><code>getContentEncoding</code>
106 * <li><code>getContentLength</code>
107 * <li><code>getContentType</code>
108 * <li><code>getDate</code>
109 * <li><code>getExpiration</code>
110 * <li><code>getLastModifed</code>
111 * </ul>
112 * <p>
113 * provide convenient access to these fields. The
114 * <code>getContentType</code> method is used by the
115 * <code>getContent</code> method to determine the type of the remote
116 * object; subclasses may find it convenient to override the
117 * <code>getContentType</code> method.
118 * <p>
119 * In the common case, all of the pre-connection parameters and
120 * general request properties can be ignored: the pre-connection
121 * parameters and request properties default to sensible values. For
122 * most clients of this interface, there are only two interesting
123 * methods: <code>getInputStream</code> and <code>getContent</code>,
124 * which are mirrored in the <code>URL</code> class by convenience methods.
125 * <p>
126 * More information on the request properties and header fields of
127 * an <code>http</code> connection can be found at:
128 * <blockquote><pre>
129 * <a href="http://www.ietf.org/rfc/rfc2616.txt">http://www.ietf.org/rfc/rfc2616.txt</a>
130 * </pre></blockquote>
131 *
132 * Note about <code>fileNameMap</code>: In versions prior to JDK 1.1.6,
133 * field <code>fileNameMap</code> of <code>URLConnection</code> was public.
134 * In JDK 1.1.6 and later, <code>fileNameMap</code> is private; accessor
135 * and mutator methods {@link #getFileNameMap() getFileNameMap} and
136 * {@link #setFileNameMap(java.net.FileNameMap) setFileNameMap} are added
137 * to access it. This change is also described on the <a href=
138 * "http://java.sun.com/products/jdk/1.2/compatibility.html">
139 * Compatibility</a> page.
140 *
141 * Invoking the <tt>close()</tt> methods on the <tt>InputStream</tt> or <tt>OutputStream</tt> of an
142 * <tt>URLConnection</tt> after a request may free network resources associated with this
143 * instance, unless particular protocol specifications specify different behaviours
144 * for it.
145 *
146 * @author James Gosling
147 * @see java.net.URL#openConnection()
148 * @see java.net.URLConnection#connect()
149 * @see java.net.URLConnection#getContent()
150 * @see java.net.URLConnection#getContentEncoding()
151 * @see java.net.URLConnection#getContentLength()
152 * @see java.net.URLConnection#getContentType()
153 * @see java.net.URLConnection#getDate()
154 * @see java.net.URLConnection#getExpiration()
155 * @see java.net.URLConnection#getHeaderField(int)
156 * @see java.net.URLConnection#getHeaderField(java.lang.String)
157 * @see java.net.URLConnection#getInputStream()
158 * @see java.net.URLConnection#getLastModified()
159 * @see java.net.URLConnection#getOutputStream()
160 * @see java.net.URLConnection#setAllowUserInteraction(boolean)
161 * @see java.net.URLConnection#setDefaultUseCaches(boolean)
162 * @see java.net.URLConnection#setDoInput(boolean)
163 * @see java.net.URLConnection#setDoOutput(boolean)
164 * @see java.net.URLConnection#setIfModifiedSince(long)
165 * @see java.net.URLConnection#setRequestProperty(java.lang.String, java.lang.String)
166 * @see java.net.URLConnection#setUseCaches(boolean)
167 * @since JDK1.0
168 */
169 public abstract class URLConnection {
170
171 /**
172 * The URL represents the remote object on the World Wide Web to
173 * which this connection is opened.
174 * <p>
175 * The value of this field can be accessed by the
176 * <code>getURL</code> method.
177 * <p>
178 * The default value of this variable is the value of the URL
179 * argument in the <code>URLConnection</code> constructor.
180 *
181 * @see java.net.URLConnection#getURL()
182 * @see java.net.URLConnection#url
183 */
184 protected URL url;
185
186 /**
187 * This variable is set by the <code>setDoInput</code> method. Its
188 * value is returned by the <code>getDoInput</code> method.
189 * <p>
190 * A URL connection can be used for input and/or output. Setting the
191 * <code>doInput</code> flag to <code>true</code> indicates that
192 * the application intends to read data from the URL connection.
193 * <p>
194 * The default value of this field is <code>true</code>.
195 *
196 * @see java.net.URLConnection#getDoInput()
197 * @see java.net.URLConnection#setDoInput(boolean)
198 */
199 protected boolean doInput = true;
200
201 /**
202 * This variable is set by the <code>setDoOutput</code> method. Its
203 * value is returned by the <code>getDoOutput</code> method.
204 * <p>
205 * A URL connection can be used for input and/or output. Setting the
206 * <code>doOutput</code> flag to <code>true</code> indicates
207 * that the application intends to write data to the URL connection.
208 * <p>
209 * The default value of this field is <code>false</code>.
210 *
211 * @see java.net.URLConnection#getDoOutput()
212 * @see java.net.URLConnection#setDoOutput(boolean)
213 */
214 protected boolean doOutput = false;
215
216 private static boolean defaultAllowUserInteraction = false;
217
218 /**
219 * If <code>true</code>, this <code>URL</code> is being examined in
220 * a context in which it makes sense to allow user interactions such
221 * as popping up an authentication dialog. If <code>false</code>,
222 * then no user interaction is allowed.
223 * <p>
224 * The value of this field can be set by the
225 * <code>setAllowUserInteraction</code> method.
226 * Its value is returned by the
227 * <code>getAllowUserInteraction</code> method.
228 * Its default value is the value of the argument in the last invocation
229 * of the <code>setDefaultAllowUserInteraction</code> method.
230 *
231 * @see java.net.URLConnection#getAllowUserInteraction()
232 * @see java.net.URLConnection#setAllowUserInteraction(boolean)
233 * @see java.net.URLConnection#setDefaultAllowUserInteraction(boolean)
234 */
235 protected boolean allowUserInteraction = defaultAllowUserInteraction;
236
237 private static boolean defaultUseCaches = true;
238
239 /**
240 * If <code>true</code>, the protocol is allowed to use caching
241 * whenever it can. If <code>false</code>, the protocol must always
242 * try to get a fresh copy of the object.
243 * <p>
244 * This field is set by the <code>setUseCaches</code> method. Its
245 * value is returned by the <code>getUseCaches</code> method.
246 * <p>
247 * Its default value is the value given in the last invocation of the
248 * <code>setDefaultUseCaches</code> method.
249 *
250 * @see java.net.URLConnection#setUseCaches(boolean)
251 * @see java.net.URLConnection#getUseCaches()
252 * @see java.net.URLConnection#setDefaultUseCaches(boolean)
253 */
254 protected boolean useCaches = defaultUseCaches;
255
256 /**
257 * Some protocols support skipping the fetching of the object unless
258 * the object has been modified more recently than a certain time.
259 * <p>
260 * A nonzero value gives a time as the number of milliseconds since
261 * January 1, 1970, GMT. The object is fetched only if it has been
262 * modified more recently than that time.
263 * <p>
264 * This variable is set by the <code>setIfModifiedSince</code>
265 * method. Its value is returned by the
266 * <code>getIfModifiedSince</code> method.
267 * <p>
268 * The default value of this field is <code>0</code>, indicating
269 * that the fetching must always occur.
270 *
271 * @see java.net.URLConnection#getIfModifiedSince()
272 * @see java.net.URLConnection#setIfModifiedSince(long)
273 */
274 protected long ifModifiedSince = 0;
275
276 /**
277 * If <code>false</code>, this connection object has not created a
278 * communications link to the specified URL. If <code>true</code>,
279 * the communications link has been established.
280 */
281 protected boolean connected = false;
282
283 /**
284 * @since 1.5
285 */
286 private int connectTimeout;
287 private int readTimeout;
288
289 /**
290 * @since 1.6
291 */
292 private MessageHeader requests;
293
294 /**
295 * @since JDK1.1
296 */
297 private static FileNameMap fileNameMap;
298
299 /**
300 * @since 1.2.2
301 */
302 private static boolean fileNameMapLoaded = false;
303
304 /**
305 * Loads filename map (a mimetable) from a data file. It will
306 * first try to load the user-specific table, defined
307 * by "content.types.user.table" property. If that fails,
308 * it tries to load the default built-in table at
309 * lib/content-types.properties under java home.
310 *
311 * @return the FileNameMap
312 * @since 1.2
313 * @see #setFileNameMap(java.net.FileNameMap)
314 */
315 public static synchronized FileNameMap getFileNameMap() {
316 if ((fileNameMap == null) && !fileNameMapLoaded) {
317 fileNameMap = sun.net.www.MimeTable.loadTable();
318 fileNameMapLoaded = true;
319 }
320
321 return new FileNameMap() {
322 private FileNameMap map = fileNameMap;
323 public String getContentTypeFor(String fileName) {
324 return map.getContentTypeFor(fileName);
325 }
326 };
327 }
328
329 /**
330 * Sets the FileNameMap.
331 * <p>
332 * If there is a security manager, this method first calls
333 * the security manager's <code>checkSetFactory</code> method
334 * to ensure the operation is allowed.
335 * This could result in a SecurityException.
336 *
337 * @param map the FileNameMap to be set
338 * @exception SecurityException if a security manager exists and its
339 * <code>checkSetFactory</code> method doesn't allow the operation.
340 * @see SecurityManager#checkSetFactory
341 * @see #getFileNameMap()
342 * @since 1.2
343 */
344 public static void setFileNameMap(FileNameMap map) {
345 SecurityManager sm = System.getSecurityManager();
346 if (sm != null) sm.checkSetFactory();
347 fileNameMap = map;
348 }
349
350 /**
351 * Opens a communications link to the resource referenced by this
352 * URL, if such a connection has not already been established.
353 * <p>
354 * If the <code>connect</code> method is called when the connection
355 * has already been opened (indicated by the <code>connected</code>
356 * field having the value <code>true</code>), the call is ignored.
357 * <p>
358 * URLConnection objects go through two phases: first they are
359 * created, then they are connected. After being created, and
360 * before being connected, various options can be specified
361 * (e.g., doInput and UseCaches). After connecting, it is an
362 * error to try to set them. Operations that depend on being
363 * connected, like getContentLength, will implicitly perform the
364 * connection, if necessary.
365 *
366 * @throws SocketTimeoutException if the timeout expires before
367 * the connection can be established
368 * @exception IOException if an I/O error occurs while opening the
369 * connection.
370 * @see java.net.URLConnection#connected
371 * @see #getConnectTimeout()
372 * @see #setConnectTimeout(int)
373 */
374 abstract public void connect() throws IOException;
375
376 /**
377 * Sets a specified timeout value, in milliseconds, to be used
378 * when opening a communications link to the resource referenced
379 * by this URLConnection. If the timeout expires before the
380 * connection can be established, a
381 * java.net.SocketTimeoutException is raised. A timeout of zero is
382 * interpreted as an infinite timeout.
383
384 * <p> Some non-standard implmentation of this method may ignore
385 * the specified timeout. To see the connect timeout set, please
386 * call getConnectTimeout().
387 *
388 * @param timeout an <code>int</code> that specifies the connect
389 * timeout value in milliseconds
390 * @throws IllegalArgumentException if the timeout parameter is negative
391 *
392 * @see #getConnectTimeout()
393 * @see #connect()
394 * @since 1.5
395 */
396 public void setConnectTimeout(int timeout) {
397 if (timeout < 0) {
398 throw new IllegalArgumentException("timeout can not be negative");
399 }
400 connectTimeout = timeout;
401 }
402
403 /**
404 * Returns setting for connect timeout.
405 * <p>
406 * 0 return implies that the option is disabled
407 * (i.e., timeout of infinity).
408 *
409 * @return an <code>int</code> that indicates the connect timeout
410 * value in milliseconds
411 * @see #setConnectTimeout(int)
412 * @see #connect()
413 * @since 1.5
414 */
415 public int getConnectTimeout() {
416 return connectTimeout;
417 }
418
419 /**
420 * Sets the read timeout to a specified timeout, in
421 * milliseconds. A non-zero value specifies the timeout when
422 * reading from Input stream when a connection is established to a
423 * resource. If the timeout expires before there is data available
424 * for read, a java.net.SocketTimeoutException is raised. A
425 * timeout of zero is interpreted as an infinite timeout.
426 *
427 *<p> Some non-standard implementation of this method ignores the
428 * specified timeout. To see the read timeout set, please call
429 * getReadTimeout().
430 *
431 * @param timeout an <code>int</code> that specifies the timeout
432 * value to be used in milliseconds
433 * @throws IllegalArgumentException if the timeout parameter is negative
434 *
435 * @see #getReadTimeout()
436 * @see InputStream#read()
437 * @since 1.5
438 */
439 public void setReadTimeout(int timeout) {
440 if (timeout < 0) {
441 throw new IllegalArgumentException("timeout can not be negative");
442 }
443 readTimeout = timeout;
444 }
445
446 /**
447 * Returns setting for read timeout. 0 return implies that the
448 * option is disabled (i.e., timeout of infinity).
449 *
450 * @return an <code>int</code> that indicates the read timeout
451 * value in milliseconds
452 *
453 * @see #setReadTimeout(int)
454 * @see InputStream#read()
455 * @since 1.5
456 */
457 public int getReadTimeout() {
458 return readTimeout;
459 }
460
461 /**
462 * Constructs a URL connection to the specified URL. A connection to
463 * the object referenced by the URL is not created.
464 *
465 * @param url the specified URL.
466 */
467 protected URLConnection(URL url) {
468 this.url = url;
469 }
470
471 /**
472 * Returns the value of this <code>URLConnection</code>'s <code>URL</code>
473 * field.
474 *
475 * @return the value of this <code>URLConnection</code>'s <code>URL</code>
476 * field.
477 * @see java.net.URLConnection#url
478 */
479 public URL getURL() {
480 return url;
481 }
482
483 /**
484 * Returns the value of the <code>content-length</code> header field.
485 * <P>
486 * <B>Note</B>: {@link #getContentLengthLong() getContentLengthLong()}
487 * should be preferred over this method, since it returns a {@code long}
488 * instead and is therefore more portable.</P>
489 *
490 * @return the content length of the resource that this connection's URL
491 * references, {@code -1} if the content length is not known,
492 * or if the content length is greater than Integer.MAX_VALUE.
493 */
494 public int getContentLength() {
495 long l = getContentLengthLong();
496 if (l > Integer.MAX_VALUE)
497 return -1;
498 return (int) l;
499 }
500
501 /**
502 * Returns the value of the <code>content-length</code> header field as a
503 * long.
504 *
505 * @return the content length of the resource that this connection's URL
506 * references, or <code>-1</code> if the content length is
507 * not known.
508 * @since 7.0
509 */
510 public long getContentLengthLong() {
511 return getHeaderFieldLong("content-length", -1);
512 }
513
514 /**
515 * Returns the value of the <code>content-type</code> header field.
516 *
517 * @return the content type of the resource that the URL references,
518 * or <code>null</code> if not known.
519 * @see java.net.URLConnection#getHeaderField(java.lang.String)
520 */
521 public String getContentType() {
522 return getHeaderField("content-type");
523 }
524
525 /**
526 * Returns the value of the <code>content-encoding</code> header field.
527 *
528 * @return the content encoding of the resource that the URL references,
529 * or <code>null</code> if not known.
530 * @see java.net.URLConnection#getHeaderField(java.lang.String)
531 */
532 public String getContentEncoding() {
533 return getHeaderField("content-encoding");
534 }
535
536 /**
537 * Returns the value of the <code>expires</code> header field.
538 *
539 * @return the expiration date of the resource that this URL references,
540 * or 0 if not known. The value is the number of milliseconds since
541 * January 1, 1970 GMT.
542 * @see java.net.URLConnection#getHeaderField(java.lang.String)
543 */
544 public long getExpiration() {
545 return getHeaderFieldDate("expires", 0);
546 }
547
548 /**
549 * Returns the value of the <code>date</code> header field.
550 *
551 * @return the sending date of the resource that the URL references,
552 * or <code>0</code> if not known. The value returned is the
553 * number of milliseconds since January 1, 1970 GMT.
554 * @see java.net.URLConnection#getHeaderField(java.lang.String)
555 */
556 public long getDate() {
557 return getHeaderFieldDate("date", 0);
558 }
559
560 /**
561 * Returns the value of the <code>last-modified</code> header field.
562 * The result is the number of milliseconds since January 1, 1970 GMT.
563 *
564 * @return the date the resource referenced by this
565 * <code>URLConnection</code> was last modified, or 0 if not known.
566 * @see java.net.URLConnection#getHeaderField(java.lang.String)
567 */
568 public long getLastModified() {
569 return getHeaderFieldDate("last-modified", 0);
570 }
571
572 /**
573 * Returns the value of the named header field.
574 * <p>
575 * If called on a connection that sets the same header multiple times
576 * with possibly different values, only the last value is returned.
577 *
578 *
579 * @param name the name of a header field.
580 * @return the value of the named header field, or <code>null</code>
581 * if there is no such field in the header.
582 */
583 public String getHeaderField(String name) {
584 return null;
585 }
586
587 /**
588 * Returns an unmodifiable Map of the header fields.
589 * The Map keys are Strings that represent the
590 * response-header field names. Each Map value is an
591 * unmodifiable List of Strings that represents
592 * the corresponding field values.
593 *
594 * @return a Map of header fields
595 * @since 1.4
596 */
597 public Map<String,List<String>> getHeaderFields() {
598 return Collections.emptyMap();
599 }
600
601 /**
602 * Returns the value of the named field parsed as a number.
603 * <p>
604 * This form of <code>getHeaderField</code> exists because some
605 * connection types (e.g., <code>http-ng</code>) have pre-parsed
606 * headers. Classes for that connection type can override this method
607 * and short-circuit the parsing.
608 *
609 * @param name the name of the header field.
610 * @param Default the default value.
611 * @return the value of the named field, parsed as an integer. The
612 * <code>Default</code> value is returned if the field is
613 * missing or malformed.
614 */
615 public int getHeaderFieldInt(String name, int Default) {
616 String value = getHeaderField(name);
617 try {
618 return Integer.parseInt(value);
619 } catch (Exception e) { }
620 return Default;
621 }
622
623 /**
624 * Returns the value of the named field parsed as a number.
625 * <p>
626 * This form of <code>getHeaderField</code> exists because some
627 * connection types (e.g., <code>http-ng</code>) have pre-parsed
628 * headers. Classes for that connection type can override this method
629 * and short-circuit the parsing.
630 *
631 * @param name the name of the header field.
632 * @param Default the default value.
633 * @return the value of the named field, parsed as a long. The
634 * <code>Default</code> value is returned if the field is
635 * missing or malformed.
636 * @since 7.0
637 */
638 public long getHeaderFieldLong(String name, long Default) {
639 String value = getHeaderField(name);
640 try {
641 return Long.parseLong(value);
642 } catch (Exception e) { }
643 return Default;
644 }
645
646 /**
647 * Returns the value of the named field parsed as date.
648 * The result is the number of milliseconds since January 1, 1970 GMT
649 * represented by the named field.
650 * <p>
651 * This form of <code>getHeaderField</code> exists because some
652 * connection types (e.g., <code>http-ng</code>) have pre-parsed
653 * headers. Classes for that connection type can override this method
654 * and short-circuit the parsing.
655 *
656 * @param name the name of the header field.
657 * @param Default a default value.
658 * @return the value of the field, parsed as a date. The value of the
659 * <code>Default</code> argument is returned if the field is
660 * missing or malformed.
661 */
662 @SuppressWarnings("deprecation")
663 public long getHeaderFieldDate(String name, long Default) {
664 String value = getHeaderField(name);
665 try {
666 return Date.parse(value);
667 } catch (Exception e) { }
668 return Default;
669 }
670
671 /**
672 * Returns the key for the <code>n</code><sup>th</sup> header field.
673 * It returns <code>null</code> if there are fewer than <code>n+1</code> fields.
674 *
675 * @param n an index, where n>=0
676 * @return the key for the <code>n</code><sup>th</sup> header field,
677 * or <code>null</code> if there are fewer than <code>n+1</code>
678 * fields.
679 */
680 public String getHeaderFieldKey(int n) {
681 return null;
682 }
683
684 /**
685 * Returns the value for the <code>n</code><sup>th</sup> header field.
686 * It returns <code>null</code> if there are fewer than
687 * <code>n+1</code>fields.
688 * <p>
689 * This method can be used in conjunction with the
690 * {@link #getHeaderFieldKey(int) getHeaderFieldKey} method to iterate through all
691 * the headers in the message.
692 *
693 * @param n an index, where n>=0
694 * @return the value of the <code>n</code><sup>th</sup> header field
695 * or <code>null</code> if there are fewer than <code>n+1</code> fields
696 * @see java.net.URLConnection#getHeaderFieldKey(int)
697 */
698 public String getHeaderField(int n) {
699 return null;
700 }
701
702 /**
703 * Retrieves the contents of this URL connection.
704 * <p>
705 * This method first determines the content type of the object by
706 * calling the <code>getContentType</code> method. If this is
707 * the first time that the application has seen that specific content
708 * type, a content handler for that content type is created:
709 * <ol>
710 * <li>If the application has set up a content handler factory instance
711 * using the <code>setContentHandlerFactory</code> method, the
712 * <code>createContentHandler</code> method of that instance is called
713 * with the content type as an argument; the result is a content
714 * handler for that content type.
715 * <li>If no content handler factory has yet been set up, or if the
716 * factory's <code>createContentHandler</code> method returns
717 * <code>null</code>, then the application loads the class named:
718 * <blockquote><pre>
719 * sun.net.www.content.<<i>contentType</i>>
720 * </pre></blockquote>
721 * where <<i>contentType</i>> is formed by taking the
722 * content-type string, replacing all slash characters with a
723 * <code>period</code> ('.'), and all other non-alphanumeric characters
724 * with the underscore character '<code>_</code>'. The alphanumeric
725 * characters are specifically the 26 uppercase ASCII letters
726 * '<code>A</code>' through '<code>Z</code>', the 26 lowercase ASCII
727 * letters '<code>a</code>' through '<code>z</code>', and the 10 ASCII
728 * digits '<code>0</code>' through '<code>9</code>'. If the specified
729 * class does not exist, or is not a subclass of
730 * <code>ContentHandler</code>, then an
731 * <code>UnknownServiceException</code> is thrown.
732 * </ol>
733 *
734 * @return the object fetched. The <code>instanceof</code> operator
735 * should be used to determine the specific kind of object
736 * returned.
737 * @exception IOException if an I/O error occurs while
738 * getting the content.
739 * @exception UnknownServiceException if the protocol does not support
740 * the content type.
741 * @see java.net.ContentHandlerFactory#createContentHandler(java.lang.String)
742 * @see java.net.URLConnection#getContentType()
743 * @see java.net.URLConnection#setContentHandlerFactory(java.net.ContentHandlerFactory)
744 */
745 public Object getContent() throws IOException {
746 // Must call getInputStream before GetHeaderField gets called
747 // so that FileNotFoundException has a chance to be thrown up
748 // from here without being caught.
749 getInputStream();
750 return getContentHandler().getContent(this);
751 }
752
753 /**
754 * Retrieves the contents of this URL connection.
755 *
756 * @param classes the <code>Class</code> array
757 * indicating the requested types
758 * @return the object fetched that is the first match of the type
759 * specified in the classes array. null if none of
760 * the requested types are supported.
761 * The <code>instanceof</code> operator should be used to
762 * determine the specific kind of object returned.
763 * @exception IOException if an I/O error occurs while
764 * getting the content.
765 * @exception UnknownServiceException if the protocol does not support
766 * the content type.
767 * @see java.net.URLConnection#getContent()
768 * @see java.net.ContentHandlerFactory#createContentHandler(java.lang.String)
769 * @see java.net.URLConnection#getContent(java.lang.Class[])
770 * @see java.net.URLConnection#setContentHandlerFactory(java.net.ContentHandlerFactory)
771 * @since 1.3
772 */
773 public Object getContent(Class[] classes) throws IOException {
774 // Must call getInputStream before GetHeaderField gets called
775 // so that FileNotFoundException has a chance to be thrown up
776 // from here without being caught.
777 getInputStream();
778 return getContentHandler().getContent(this, classes);
779 }
780
781 /**
782 * Returns a permission object representing the permission
783 * necessary to make the connection represented by this
784 * object. This method returns null if no permission is
785 * required to make the connection. By default, this method
786 * returns <code>java.security.AllPermission</code>. Subclasses
787 * should override this method and return the permission
788 * that best represents the permission required to make a
789 * a connection to the URL. For example, a <code>URLConnection</code>
790 * representing a <code>file:</code> URL would return a
791 * <code>java.io.FilePermission</code> object.
792 *
793 * <p>The permission returned may dependent upon the state of the
794 * connection. For example, the permission before connecting may be
795 * different from that after connecting. For example, an HTTP
796 * sever, say foo.com, may redirect the connection to a different
797 * host, say bar.com. Before connecting the permission returned by
798 * the connection will represent the permission needed to connect
799 * to foo.com, while the permission returned after connecting will
800 * be to bar.com.
801 *
802 * <p>Permissions are generally used for two purposes: to protect
803 * caches of objects obtained through URLConnections, and to check
804 * the right of a recipient to learn about a particular URL. In
805 * the first case, the permission should be obtained
806 * <em>after</em> the object has been obtained. For example, in an
807 * HTTP connection, this will represent the permission to connect
808 * to the host from which the data was ultimately fetched. In the
809 * second case, the permission should be obtained and tested
810 * <em>before</em> connecting.
811 *
812 * @return the permission object representing the permission
813 * necessary to make the connection represented by this
814 * URLConnection.
815 *
816 * @exception IOException if the computation of the permission
817 * requires network or file I/O and an exception occurs while
818 * computing it.
819 */
820 public Permission getPermission() throws IOException {
821 return SecurityConstants.ALL_PERMISSION;
822 }
823
824 /**
825 * Returns an input stream that reads from this open connection.
826 *
827 * A SocketTimeoutException can be thrown when reading from the
828 * returned input stream if the read timeout expires before data
829 * is available for read.
830 *
831 * @return an input stream that reads from this open connection.
832 * @exception IOException if an I/O error occurs while
833 * creating the input stream.
834 * @exception UnknownServiceException if the protocol does not support
835 * input.
836 * @see #setReadTimeout(int)
837 * @see #getReadTimeout()
838 */
839 public InputStream getInputStream() throws IOException {
840 throw new UnknownServiceException("protocol doesn't support input");
841 }
842
843 /**
844 * Returns an output stream that writes to this connection.
845 *
846 * @return an output stream that writes to this connection.
847 * @exception IOException if an I/O error occurs while
848 * creating the output stream.
849 * @exception UnknownServiceException if the protocol does not support
850 * output.
851 */
852 public OutputStream getOutputStream() throws IOException {
853 throw new UnknownServiceException("protocol doesn't support output");
854 }
855
856 /**
857 * Returns a <code>String</code> representation of this URL connection.
858 *
859 * @return a string representation of this <code>URLConnection</code>.
860 */
861 public String toString() {
862 return this.getClass().getName() + ":" + url;
863 }
864
865 /**
866 * Sets the value of the <code>doInput</code> field for this
867 * <code>URLConnection</code> to the specified value.
868 * <p>
869 * A URL connection can be used for input and/or output. Set the DoInput
870 * flag to true if you intend to use the URL connection for input,
871 * false if not. The default is true.
872 *
873 * @param doinput the new value.
874 * @throws IllegalStateException if already connected
875 * @see java.net.URLConnection#doInput
876 * @see #getDoInput()
877 */
878 public void setDoInput(boolean doinput) {
879 if (connected)
880 throw new IllegalStateException("Already connected");
881 doInput = doinput;
882 }
883
884 /**
885 * Returns the value of this <code>URLConnection</code>'s
886 * <code>doInput</code> flag.
887 *
888 * @return the value of this <code>URLConnection</code>'s
889 * <code>doInput</code> flag.
890 * @see #setDoInput(boolean)
891 */
892 public boolean getDoInput() {
893 return doInput;
894 }
895
896 /**
897 * Sets the value of the <code>doOutput</code> field for this
898 * <code>URLConnection</code> to the specified value.
899 * <p>
900 * A URL connection can be used for input and/or output. Set the DoOutput
901 * flag to true if you intend to use the URL connection for output,
902 * false if not. The default is false.
903 *
904 * @param dooutput the new value.
905 * @throws IllegalStateException if already connected
906 * @see #getDoOutput()
907 */
908 public void setDoOutput(boolean dooutput) {
909 if (connected)
910 throw new IllegalStateException("Already connected");
911 doOutput = dooutput;
912 }
913
914 /**
915 * Returns the value of this <code>URLConnection</code>'s
916 * <code>doOutput</code> flag.
917 *
918 * @return the value of this <code>URLConnection</code>'s
919 * <code>doOutput</code> flag.
920 * @see #setDoOutput(boolean)
921 */
922 public boolean getDoOutput() {
923 return doOutput;
924 }
925
926 /**
927 * Set the value of the <code>allowUserInteraction</code> field of
928 * this <code>URLConnection</code>.
929 *
930 * @param allowuserinteraction the new value.
931 * @throws IllegalStateException if already connected
932 * @see #getAllowUserInteraction()
933 */
934 public void setAllowUserInteraction(boolean allowuserinteraction) {
935 if (connected)
936 throw new IllegalStateException("Already connected");
937 allowUserInteraction = allowuserinteraction;
938 }
939
940 /**
941 * Returns the value of the <code>allowUserInteraction</code> field for
942 * this object.
943 *
944 * @return the value of the <code>allowUserInteraction</code> field for
945 * this object.
946 * @see #setAllowUserInteraction(boolean)
947 */
948 public boolean getAllowUserInteraction() {
949 return allowUserInteraction;
950 }
951
952 /**
953 * Sets the default value of the
954 * <code>allowUserInteraction</code> field for all future
955 * <code>URLConnection</code> objects to the specified value.
956 *
957 * @param defaultallowuserinteraction the new value.
958 * @see #getDefaultAllowUserInteraction()
959 */
960 public static void setDefaultAllowUserInteraction(boolean defaultallowuserinteraction) {
961 defaultAllowUserInteraction = defaultallowuserinteraction;
962 }
963
964 /**
965 * Returns the default value of the <code>allowUserInteraction</code>
966 * field.
967 * <p>
968 * Ths default is "sticky", being a part of the static state of all
969 * URLConnections. This flag applies to the next, and all following
970 * URLConnections that are created.
971 *
972 * @return the default value of the <code>allowUserInteraction</code>
973 * field.
974 * @see #setDefaultAllowUserInteraction(boolean)
975 */
976 public static boolean getDefaultAllowUserInteraction() {
977 return defaultAllowUserInteraction;
978 }
979
980 /**
981 * Sets the value of the <code>useCaches</code> field of this
982 * <code>URLConnection</code> to the specified value.
983 * <p>
984 * Some protocols do caching of documents. Occasionally, it is important
985 * to be able to "tunnel through" and ignore the caches (e.g., the
986 * "reload" button in a browser). If the UseCaches flag on a connection
987 * is true, the connection is allowed to use whatever caches it can.
988 * If false, caches are to be ignored.
989 * The default value comes from DefaultUseCaches, which defaults to
990 * true.
991 *
992 * @param usecaches a <code>boolean</code> indicating whether
993 * or not to allow caching
994 * @throws IllegalStateException if already connected
995 * @see #getUseCaches()
996 */
997 public void setUseCaches(boolean usecaches) {
998 if (connected)
999 throw new IllegalStateException("Already connected");
1000 useCaches = usecaches;
1001 }
1002
1003 /**
1004 * Returns the value of this <code>URLConnection</code>'s
1005 * <code>useCaches</code> field.
1006 *
1007 * @return the value of this <code>URLConnection</code>'s
1008 * <code>useCaches</code> field.
1009 * @see #setUseCaches(boolean)
1010 */
1011 public boolean getUseCaches() {
1012 return useCaches;
1013 }
1014
1015 /**
1016 * Sets the value of the <code>ifModifiedSince</code> field of
1017 * this <code>URLConnection</code> to the specified value.
1018 *
1019 * @param ifmodifiedsince the new value.
1020 * @throws IllegalStateException if already connected
1021 * @see #getIfModifiedSince()
1022 */
1023 public void setIfModifiedSince(long ifmodifiedsince) {
1024 if (connected)
1025 throw new IllegalStateException("Already connected");
1026 ifModifiedSince = ifmodifiedsince;
1027 }
1028
1029 /**
1030 * Returns the value of this object's <code>ifModifiedSince</code> field.
1031 *
1032 * @return the value of this object's <code>ifModifiedSince</code> field.
1033 * @see #setIfModifiedSince(long)
1034 */
1035 public long getIfModifiedSince() {
1036 return ifModifiedSince;
1037 }
1038
1039 /**
1040 * Returns the default value of a <code>URLConnection</code>'s
1041 * <code>useCaches</code> flag.
1042 * <p>
1043 * Ths default is "sticky", being a part of the static state of all
1044 * URLConnections. This flag applies to the next, and all following
1045 * URLConnections that are created.
1046 *
1047 * @return the default value of a <code>URLConnection</code>'s
1048 * <code>useCaches</code> flag.
1049 * @see #setDefaultUseCaches(boolean)
1050 */
1051 public boolean getDefaultUseCaches() {
1052 return defaultUseCaches;
1053 }
1054
1055 /**
1056 * Sets the default value of the <code>useCaches</code> field to the
1057 * specified value.
1058 *
1059 * @param defaultusecaches the new value.
1060 * @see #getDefaultUseCaches()
1061 */
1062 public void setDefaultUseCaches(boolean defaultusecaches) {
1063 defaultUseCaches = defaultusecaches;
1064 }
1065
1066 /**
1067 * Sets the general request property. If a property with the key already
1068 * exists, overwrite its value with the new value.
1069 *
1070 * <p> NOTE: HTTP requires all request properties which can
1071 * legally have multiple instances with the same key
1072 * to use a comma-seperated list syntax which enables multiple
1073 * properties to be appended into a single property.
1074 *
1075 * @param key the keyword by which the request is known
1076 * (e.g., "<code>Accept</code>").
1077 * @param value the value associated with it.
1078 * @throws IllegalStateException if already connected
1079 * @throws NullPointerException if key is <CODE>null</CODE>
1080 * @see #getRequestProperty(java.lang.String)
1081 */
1082 public void setRequestProperty(String key, String value) {
1083 if (connected)
1084 throw new IllegalStateException("Already connected");
1085 if (key == null)
1086 throw new NullPointerException ("key is null");
1087
1088 if (requests == null)
1089 requests = new MessageHeader();
1090
1091 requests.set(key, value);
1092 }
1093
1094 /**
1095 * Adds a general request property specified by a
1096 * key-value pair. This method will not overwrite
1097 * existing values associated with the same key.
1098 *
1099 * @param key the keyword by which the request is known
1100 * (e.g., "<code>Accept</code>").
1101 * @param value the value associated with it.
1102 * @throws IllegalStateException if already connected
1103 * @throws NullPointerException if key is null
1104 * @see #getRequestProperties()
1105 * @since 1.4
1106 */
1107 public void addRequestProperty(String key, String value) {
1108 if (connected)
1109 throw new IllegalStateException("Already connected");
1110 if (key == null)
1111 throw new NullPointerException ("key is null");
1112
1113 if (requests == null)
1114 requests = new MessageHeader();
1115
1116 requests.add(key, value);
1117 }
1118
1119
1120 /**
1121 * Returns the value of the named general request property for this
1122 * connection.
1123 *
1124 * @param key the keyword by which the request is known (e.g., "Accept").
1125 * @return the value of the named general request property for this
1126 * connection. If key is null, then null is returned.
1127 * @throws IllegalStateException if already connected
1128 * @see #setRequestProperty(java.lang.String, java.lang.String)
1129 */
1130 public String getRequestProperty(String key) {
1131 if (connected)
1132 throw new IllegalStateException("Already connected");
1133
1134 if (requests == null)
1135 return null;
1136
1137 return requests.findValue(key);
1138 }
1139
1140 /**
1141 * Returns an unmodifiable Map of general request
1142 * properties for this connection. The Map keys
1143 * are Strings that represent the request-header
1144 * field names. Each Map value is a unmodifiable List
1145 * of Strings that represents the corresponding
1146 * field values.
1147 *
1148 * @return a Map of the general request properties for this connection.
1149 * @throws IllegalStateException if already connected
1150 * @since 1.4
1151 */
1152 public Map<String,List<String>> getRequestProperties() {
1153 if (connected)
1154 throw new IllegalStateException("Already connected");
1155
1156 if (requests == null)
1157 return Collections.emptyMap();
1158
1159 return requests.getHeaders(null);
1160 }
1161
1162 /**
1163 * Sets the default value of a general request property. When a
1164 * <code>URLConnection</code> is created, it is initialized with
1165 * these properties.
1166 *
1167 * @param key the keyword by which the request is known
1168 * (e.g., "<code>Accept</code>").
1169 * @param value the value associated with the key.
1170 *
1171 * @see java.net.URLConnection#setRequestProperty(java.lang.String,java.lang.String)
1172 *
1173 * @deprecated The instance specific setRequestProperty method
1174 * should be used after an appropriate instance of URLConnection
1175 * is obtained. Invoking this method will have no effect.
1176 *
1177 * @see #getDefaultRequestProperty(java.lang.String)
1178 */
1179 @Deprecated
1180 public static void setDefaultRequestProperty(String key, String value) {
1181 }
1182
1183 /**
1184 * Returns the value of the default request property. Default request
1185 * properties are set for every connection.
1186 *
1187 * @param key the keyword by which the request is known (e.g., "Accept").
1188 * @return the value of the default request property
1189 * for the specified key.
1190 *
1191 * @see java.net.URLConnection#getRequestProperty(java.lang.String)
1192 *
1193 * @deprecated The instance specific getRequestProperty method
1194 * should be used after an appropriate instance of URLConnection
1195 * is obtained.
1196 *
1197 * @see #setDefaultRequestProperty(java.lang.String, java.lang.String)
1198 */
1199 @Deprecated
1200 public static String getDefaultRequestProperty(String key) {
1201 return null;
1202 }
1203
1204 /**
1205 * The ContentHandler factory.
1206 */
1207 static ContentHandlerFactory factory;
1208
1209 /**
1210 * Sets the <code>ContentHandlerFactory</code> of an
1211 * application. It can be called at most once by an application.
1212 * <p>
1213 * The <code>ContentHandlerFactory</code> instance is used to
1214 * construct a content handler from a content type
1215 * <p>
1216 * If there is a security manager, this method first calls
1217 * the security manager's <code>checkSetFactory</code> method
1218 * to ensure the operation is allowed.
1219 * This could result in a SecurityException.
1220 *
1221 * @param fac the desired factory.
1222 * @exception Error if the factory has already been defined.
1223 * @exception SecurityException if a security manager exists and its
1224 * <code>checkSetFactory</code> method doesn't allow the operation.
1225 * @see java.net.ContentHandlerFactory
1226 * @see java.net.URLConnection#getContent()
1227 * @see SecurityManager#checkSetFactory
1228 */
1229 public static synchronized void setContentHandlerFactory(ContentHandlerFactory fac) {
1230 if (factory != null) {
1231 throw new Error("factory already defined");
1232 }
1233 SecurityManager security = System.getSecurityManager();
1234 if (security != null) {
1235 security.checkSetFactory();
1236 }
1237 factory = fac;
1238 }
1239
1240 private static Hashtable<String, ContentHandler> handlers = new Hashtable<>();
1241
1242 /**
1243 * Gets the Content Handler appropriate for this connection.
1244 */
1245 synchronized ContentHandler getContentHandler()
1246 throws UnknownServiceException
1247 {
1248 String contentType = stripOffParameters(getContentType());
1249 ContentHandler handler = null;
1250 if (contentType == null)
1251 throw new UnknownServiceException("no content-type");
1252 try {
1253 handler = handlers.get(contentType);
1254 if (handler != null)
1255 return handler;
1256 } catch(Exception e) {
1257 }
1258
1259 if (factory != null)
1260 handler = factory.createContentHandler(contentType);
1261 if (handler == null) {
1262 try {
1263 handler = lookupContentHandlerClassFor(contentType);
1264 } catch(Exception e) {
1265 e.printStackTrace();
1266 handler = UnknownContentHandler.INSTANCE;
1267 }
1268 handlers.put(contentType, handler);
1269 }
1270 return handler;
1271 }
1272
1273 /*
1274 * Media types are in the format: type/subtype*(; parameter).
1275 * For looking up the content handler, we should ignore those
1276 * parameters.
1277 */
1278 private String stripOffParameters(String contentType)
1279 {
1280 if (contentType == null)
1281 return null;
1282 int index = contentType.indexOf(';');
1283
1284 if (index > 0)
1285 return contentType.substring(0, index);
1286 else
1287 return contentType;
1288 }
1289
1290 private static final String contentClassPrefix = "sun.net.www.content";
1291 private static final String contentPathProp = "java.content.handler.pkgs";
1292
1293 /**
1294 * Looks for a content handler in a user-defineable set of places.
1295 * By default it looks in sun.net.www.content, but users can define a
1296 * vertical-bar delimited set of class prefixes to search through in
1297 * addition by defining the java.content.handler.pkgs property.
1298 * The class name must be of the form:
1299 * <pre>
1300 * {package-prefix}.{major}.{minor}
1301 * e.g.
1302 * YoyoDyne.experimental.text.plain
1303 * </pre>
1304 */
1305 private ContentHandler lookupContentHandlerClassFor(String contentType)
1306 throws InstantiationException, IllegalAccessException, ClassNotFoundException {
1307 String contentHandlerClassName = typeToPackageName(contentType);
1308
1309 String contentHandlerPkgPrefixes =getContentHandlerPkgPrefixes();
1310
1311 StringTokenizer packagePrefixIter =
1312 new StringTokenizer(contentHandlerPkgPrefixes, "|");
1313
1314 while (packagePrefixIter.hasMoreTokens()) {
1315 String packagePrefix = packagePrefixIter.nextToken().trim();
1316
1317 try {
1318 String clsName = packagePrefix + "." + contentHandlerClassName;
1319 Class<?> cls = null;
1320 try {
1321 cls = Class.forName(clsName);
1322 } catch (ClassNotFoundException e) {
1323 ClassLoader cl = ClassLoader.getSystemClassLoader();
1324 if (cl != null) {
1325 cls = cl.loadClass(clsName);
1326 }
1327 }
1328 if (cls != null) {
1329 ContentHandler handler =
1330 (ContentHandler)cls.newInstance();
1331 return handler;
1332 }
1333 } catch(Exception e) {
1334 }
1335 }
1336
1337 return UnknownContentHandler.INSTANCE;
1338 }
1339
1340 /**
1341 * Utility function to map a MIME content type into an equivalent
1342 * pair of class name components. For example: "text/html" would
1343 * be returned as "text.html"
1344 */
1345 private String typeToPackageName(String contentType) {
1346 // make sure we canonicalize the class name: all lower case
1347 contentType = contentType.toLowerCase();
1348 int len = contentType.length();
1349 char nm[] = new char[len];
1350 contentType.getChars(0, len, nm, 0);
1351 for (int i = 0; i < len; i++) {
1352 char c = nm[i];
1353 if (c == '/') {
1354 nm[i] = '.';
1355 } else if (!('A' <= c && c <= 'Z' ||
1356 'a' <= c && c <= 'z' ||
1357 '0' <= c && c <= '9')) {
1358 nm[i] = '_';
1359 }
1360 }
1361 return new String(nm);
1362 }
1363
1364
1365 /**
1366 * Returns a vertical bar separated list of package prefixes for potential
1367 * content handlers. Tries to get the java.content.handler.pkgs property
1368 * to use as a set of package prefixes to search. Whether or not
1369 * that property has been defined, the sun.net.www.content is always
1370 * the last one on the returned package list.
1371 */
1372 private String getContentHandlerPkgPrefixes() {
1373 String packagePrefixList = AccessController.doPrivileged(
1374 new sun.security.action.GetPropertyAction(contentPathProp, ""));
1375
1376 if (packagePrefixList != "") {
1377 packagePrefixList += "|";
1378 }
1379
1380 return packagePrefixList + contentClassPrefix;
1381 }
1382
1383 /**
1384 * Tries to determine the content type of an object, based
1385 * on the specified "file" component of a URL.
1386 * This is a convenience method that can be used by
1387 * subclasses that override the <code>getContentType</code> method.
1388 *
1389 * @param fname a filename.
1390 * @return a guess as to what the content type of the object is,
1391 * based upon its file name.
1392 * @see java.net.URLConnection#getContentType()
1393 */
1394 public static String guessContentTypeFromName(String fname) {
1395 return getFileNameMap().getContentTypeFor(fname);
1396 }
1397
1398 /**
1399 * Tries to determine the type of an input stream based on the
1400 * characters at the beginning of the input stream. This method can
1401 * be used by subclasses that override the
1402 * <code>getContentType</code> method.
1403 * <p>
1404 * Ideally, this routine would not be needed. But many
1405 * <code>http</code> servers return the incorrect content type; in
1406 * addition, there are many nonstandard extensions. Direct inspection
1407 * of the bytes to determine the content type is often more accurate
1408 * than believing the content type claimed by the <code>http</code> server.
1409 *
1410 * @param is an input stream that supports marks.
1411 * @return a guess at the content type, or <code>null</code> if none
1412 * can be determined.
1413 * @exception IOException if an I/O error occurs while reading the
1414 * input stream.
1415 * @see java.io.InputStream#mark(int)
1416 * @see java.io.InputStream#markSupported()
1417 * @see java.net.URLConnection#getContentType()
1418 */
1419 static public String guessContentTypeFromStream(InputStream is)
1420 throws IOException {
1421 // If we can't read ahead safely, just give up on guessing
1422 if (!is.markSupported())
1423 return null;
1424
1425 is.mark(16);
1426 int c1 = is.read();
1427 int c2 = is.read();
1428 int c3 = is.read();
1429 int c4 = is.read();
1430 int c5 = is.read();
1431 int c6 = is.read();
1432 int c7 = is.read();
1433 int c8 = is.read();
1434 int c9 = is.read();
1435 int c10 = is.read();
1436 int c11 = is.read();
1437 int c12 = is.read();
1438 int c13 = is.read();
1439 int c14 = is.read();
1440 int c15 = is.read();
1441 int c16 = is.read();
1442 is.reset();
1443
1444 if (c1 == 0xCA && c2 == 0xFE && c3 == 0xBA && c4 == 0xBE) {
1445 return "application/java-vm";
1446 }
1447
1448 if (c1 == 0xAC && c2 == 0xED) {
1449 // next two bytes are version number, currently 0x00 0x05
1450 return "application/x-java-serialized-object";
1451 }
1452
1453 if (c1 == '<') {
1454 if (c2 == '!'
1455 || ((c2 == 'h' && (c3 == 't' && c4 == 'm' && c5 == 'l' ||
1456 c3 == 'e' && c4 == 'a' && c5 == 'd') ||
1457 (c2 == 'b' && c3 == 'o' && c4 == 'd' && c5 == 'y'))) ||
1458 ((c2 == 'H' && (c3 == 'T' && c4 == 'M' && c5 == 'L' ||
1459 c3 == 'E' && c4 == 'A' && c5 == 'D') ||
1460 (c2 == 'B' && c3 == 'O' && c4 == 'D' && c5 == 'Y')))) {
1461 return "text/html";
1462 }
1463
1464 if (c2 == '?' && c3 == 'x' && c4 == 'm' && c5 == 'l' && c6 == ' ') {
1465 return "application/xml";
1466 }
1467 }
1468
1469 // big and little (identical) endian UTF-8 encodings, with BOM
1470 if (c1 == 0xef && c2 == 0xbb && c3 == 0xbf) {
1471 if (c4 == '<' && c5 == '?' && c6 == 'x') {
1472 return "application/xml";
1473 }
1474 }
1475
1476 // big and little endian UTF-16 encodings, with byte order mark
1477 if (c1 == 0xfe && c2 == 0xff) {
1478 if (c3 == 0 && c4 == '<' && c5 == 0 && c6 == '?' &&
1479 c7 == 0 && c8 == 'x') {
1480 return "application/xml";
1481 }
1482 }
1483
1484 if (c1 == 0xff && c2 == 0xfe) {
1485 if (c3 == '<' && c4 == 0 && c5 == '?' && c6 == 0 &&
1486 c7 == 'x' && c8 == 0) {
1487 return "application/xml";
1488 }
1489 }
1490
1491 // big and little endian UTF-32 encodings, with BOM
1492 if (c1 == 0x00 && c2 == 0x00 && c3 == 0xfe && c4 == 0xff) {
1493 if (c5 == 0 && c6 == 0 && c7 == 0 && c8 == '<' &&
1494 c9 == 0 && c10 == 0 && c11 == 0 && c12 == '?' &&
1495 c13 == 0 && c14 == 0 && c15 == 0 && c16 == 'x') {
1496 return "application/xml";
1497 }
1498 }
1499
1500 if (c1 == 0xff && c2 == 0xfe && c3 == 0x00 && c4 == 0x00) {
1501 if (c5 == '<' && c6 == 0 && c7 == 0 && c8 == 0 &&
1502 c9 == '?' && c10 == 0 && c11 == 0 && c12 == 0 &&
1503 c13 == 'x' && c14 == 0 && c15 == 0 && c16 == 0) {
1504 return "application/xml";
1505 }
1506 }
1507
1508 if (c1 == 'G' && c2 == 'I' && c3 == 'F' && c4 == '8') {
1509 return "image/gif";
1510 }
1511
1512 if (c1 == '#' && c2 == 'd' && c3 == 'e' && c4 == 'f') {
1513 return "image/x-bitmap";
1514 }
1515
1516 if (c1 == '!' && c2 == ' ' && c3 == 'X' && c4 == 'P' &&
1517 c5 == 'M' && c6 == '2') {
1518 return "image/x-pixmap";
1519 }
1520
1521 if (c1 == 137 && c2 == 80 && c3 == 78 &&
1522 c4 == 71 && c5 == 13 && c6 == 10 &&
1523 c7 == 26 && c8 == 10) {
1524 return "image/png";
1525 }
1526
1527 if (c1 == 0xFF && c2 == 0xD8 && c3 == 0xFF) {
1528 if (c4 == 0xE0) {
1529 return "image/jpeg";
1530 }
1531
1532 /**
1533 * File format used by digital cameras to store images.
1534 * Exif Format can be read by any application supporting
1535 * JPEG. Exif Spec can be found at:
1536 * http://www.pima.net/standards/it10/PIMA15740/Exif_2-1.PDF
1537 */
1538 if ((c4 == 0xE1) &&
1539 (c7 == 'E' && c8 == 'x' && c9 == 'i' && c10 =='f' &&
1540 c11 == 0)) {
1541 return "image/jpeg";
1542 }
1543
1544 if (c4 == 0xEE) {
1545 return "image/jpg";
1546 }
1547 }
1548
1549 if (c1 == 0xD0 && c2 == 0xCF && c3 == 0x11 && c4 == 0xE0 &&
1550 c5 == 0xA1 && c6 == 0xB1 && c7 == 0x1A && c8 == 0xE1) {
1551
1552 /* Above is signature of Microsoft Structured Storage.
1553 * Below this, could have tests for various SS entities.
1554 * For now, just test for FlashPix.
1555 */
1556 if (checkfpx(is)) {
1557 return "image/vnd.fpx";
1558 }
1559 }
1560
1561 if (c1 == 0x2E && c2 == 0x73 && c3 == 0x6E && c4 == 0x64) {
1562 return "audio/basic"; // .au format, big endian
1563 }
1564
1565 if (c1 == 0x64 && c2 == 0x6E && c3 == 0x73 && c4 == 0x2E) {
1566 return "audio/basic"; // .au format, little endian
1567 }
1568
1569 if (c1 == 'R' && c2 == 'I' && c3 == 'F' && c4 == 'F') {
1570 /* I don't know if this is official but evidence
1571 * suggests that .wav files start with "RIFF" - brown
1572 */
1573 return "audio/x-wav";
1574 }
1575 return null;
1576 }
1577
1578 /**
1579 * Check for FlashPix image data in InputStream is. Return true if
1580 * the stream has FlashPix data, false otherwise. Before calling this
1581 * method, the stream should have already been checked to be sure it
1582 * contains Microsoft Structured Storage data.
1583 */
1584 static private boolean checkfpx(InputStream is) throws IOException {
1585
1586 /* Test for FlashPix image data in Microsoft Structured Storage format.
1587 * In general, should do this with calls to an SS implementation.
1588 * Lacking that, need to dig via offsets to get to the FlashPix
1589 * ClassID. Details:
1590 *
1591 * Offset to Fpx ClsID from beginning of stream should be:
1592 *
1593 * FpxClsidOffset = rootEntryOffset + clsidOffset
1594 *
1595 * where: clsidOffset = 0x50.
1596 * rootEntryOffset = headerSize + sectorSize*sectDirStart
1597 * + 128*rootEntryDirectory
1598 *
1599 * where: headerSize = 0x200 (always)
1600 * sectorSize = 2 raised to power of uSectorShift,
1601 * which is found in the header at
1602 * offset 0x1E.
1603 * sectDirStart = found in the header at offset 0x30.
1604 * rootEntryDirectory = in general, should search for
1605 * directory labelled as root.
1606 * We will assume value of 0 (i.e.,
1607 * rootEntry is in first directory)
1608 */
1609
1610 // Mark the stream so we can reset it. 0x100 is enough for the first
1611 // few reads, but the mark will have to be reset and set again once
1612 // the offset to the root directory entry is computed. That offset
1613 // can be very large and isn't know until the stream has been read from
1614 is.mark(0x100);
1615
1616 // Get the byte ordering located at 0x1E. 0xFE is Intel,
1617 // 0xFF is other
1618 long toSkip = (long)0x1C;
1619 long posn;
1620
1621 if ((posn = skipForward(is, toSkip)) < toSkip) {
1622 is.reset();
1623 return false;
1624 }
1625
1626 int c[] = new int[16];
1627 if (readBytes(c, 2, is) < 0) {
1628 is.reset();
1629 return false;
1630 }
1631
1632 int byteOrder = c[0];
1633
1634 posn+=2;
1635 int uSectorShift;
1636 if (readBytes(c, 2, is) < 0) {
1637 is.reset();
1638 return false;
1639 }
1640
1641 if(byteOrder == 0xFE) {
1642 uSectorShift = c[0];
1643 uSectorShift += c[1] << 8;
1644 }
1645 else {
1646 uSectorShift = c[0] << 8;
1647 uSectorShift += c[1];
1648 }
1649
1650 posn += 2;
1651 toSkip = (long)0x30 - posn;
1652 long skipped = 0;
1653 if ((skipped = skipForward(is, toSkip)) < toSkip) {
1654 is.reset();
1655 return false;
1656 }
1657 posn += skipped;
1658
1659 if (readBytes(c, 4, is) < 0) {
1660 is.reset();
1661 return false;
1662 }
1663
1664 int sectDirStart;
1665 if(byteOrder == 0xFE) {
1666 sectDirStart = c[0];
1667 sectDirStart += c[1] << 8;
1668 sectDirStart += c[2] << 16;
1669 sectDirStart += c[3] << 24;
1670 } else {
1671 sectDirStart = c[0] << 24;
1672 sectDirStart += c[1] << 16;
1673 sectDirStart += c[2] << 8;
1674 sectDirStart += c[3];
1675 }
1676 posn += 4;
1677 is.reset(); // Reset back to the beginning
1678
1679 toSkip = 0x200L + (long)(1<<uSectorShift)*sectDirStart + 0x50L;
1680
1681 // Sanity check!
1682 if (toSkip < 0) {
1683 return false;
1684 }
1685
1686 /*
1687 * How far can we skip? Is there any performance problem here?
1688 * This skip can be fairly long, at least 0x4c650 in at least
1689 * one case. Have to assume that the skip will fit in an int.
1690 * Leave room to read whole root dir
1691 */
1692 is.mark((int)toSkip+0x30);
1693
1694 if ((skipForward(is, toSkip)) < toSkip) {
1695 is.reset();
1696 return false;
1697 }
1698
1699 /* should be at beginning of ClassID, which is as follows
1700 * (in Intel byte order):
1701 * 00 67 61 56 54 C1 CE 11 85 53 00 AA 00 A1 F9 5B
1702 *
1703 * This is stored from Windows as long,short,short,char[8]
1704 * so for byte order changes, the order only changes for
1705 * the first 8 bytes in the ClassID.
1706 *
1707 * Test against this, ignoring second byte (Intel) since
1708 * this could change depending on part of Fpx file we have.
1709 */
1710
1711 if (readBytes(c, 16, is) < 0) {
1712 is.reset();
1713 return false;
1714 }
1715
1716 // intel byte order
1717 if (byteOrder == 0xFE &&
1718 c[0] == 0x00 && c[2] == 0x61 && c[3] == 0x56 &&
1719 c[4] == 0x54 && c[5] == 0xC1 && c[6] == 0xCE &&
1720 c[7] == 0x11 && c[8] == 0x85 && c[9] == 0x53 &&
1721 c[10]== 0x00 && c[11]== 0xAA && c[12]== 0x00 &&
1722 c[13]== 0xA1 && c[14]== 0xF9 && c[15]== 0x5B) {
1723 is.reset();
1724 return true;
1725 }
1726
1727 // non-intel byte order
1728 else if (c[3] == 0x00 && c[1] == 0x61 && c[0] == 0x56 &&
1729 c[5] == 0x54 && c[4] == 0xC1 && c[7] == 0xCE &&
1730 c[6] == 0x11 && c[8] == 0x85 && c[9] == 0x53 &&
1731 c[10]== 0x00 && c[11]== 0xAA && c[12]== 0x00 &&
1732 c[13]== 0xA1 && c[14]== 0xF9 && c[15]== 0x5B) {
1733 is.reset();
1734 return true;
1735 }
1736 is.reset();
1737 return false;
1738 }
1739
1740 /**
1741 * Tries to read the specified number of bytes from the stream
1742 * Returns -1, If EOF is reached before len bytes are read, returns 0
1743 * otherwise
1744 */
1745 static private int readBytes(int c[], int len, InputStream is)
1746 throws IOException {
1747
1748 byte buf[] = new byte[len];
1749 if (is.read(buf, 0, len) < len) {
1750 return -1;
1751 }
1752
1753 // fill the passed in int array
1754 for (int i = 0; i < len; i++) {
1755 c[i] = buf[i] & 0xff;
1756 }
1757 return 0;
1758 }
1759
1760
1761 /**
1762 * Skips through the specified number of bytes from the stream
1763 * until either EOF is reached, or the specified
1764 * number of bytes have been skipped
1765 */
1766 static private long skipForward(InputStream is, long toSkip)
1767 throws IOException {
1768
1769 long eachSkip = 0;
1770 long skipped = 0;
1771
1772 while (skipped != toSkip) {
1773 eachSkip = is.skip(toSkip - skipped);
1774
1775 // check if EOF is reached
1776 if (eachSkip <= 0) {
1777 if (is.read() == -1) {
1778 return skipped ;
1779 } else {
1780 skipped++;
1781 }
1782 }
1783 skipped += eachSkip;
1784 }
1785 return skipped;
1786 }
1787
1788 }
1789
1790
1791 class UnknownContentHandler extends ContentHandler {
1792 static final ContentHandler INSTANCE = new UnknownContentHandler();
1793
1794 public Object getContent(URLConnection uc) throws IOException {
1795 return uc.getInputStream();
1796 }
1797 }