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1   /*
2    * ====================================================================
3    * Licensed to the Apache Software Foundation (ASF) under one
4    * or more contributor license agreements.  See the NOTICE file
5    * distributed with this work for additional information
6    * regarding copyright ownership.  The ASF licenses this file
7    * to you under the Apache License, Version 2.0 (the
8    * "License"); you may not use this file except in compliance
9    * with the License.  You may obtain a copy of the License at
10   *
11   *   http://www.apache.org/licenses/LICENSE-2.0
12   *
13   * Unless required by applicable law or agreed to in writing,
14   * software distributed under the License is distributed on an
15   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
16   * KIND, either express or implied.  See the License for the
17   * specific language governing permissions and limitations
18   * under the License.
19   * ====================================================================
20   *
21   * This software consists of voluntary contributions made by many
22   * individuals on behalf of the Apache Software Foundation.  For more
23   * information on the Apache Software Foundation, please see
24   * <http://www.apache.org/>.
25   *
26   */
27  package org.apache.http.client.utils;
28  
29  import java.net.URI;
30  import java.net.URISyntaxException;
31  import java.util.List;
32  import java.util.Locale;
33  import java.util.Stack;
34  
35  import org.apache.http.HttpHost;
36  import org.apache.http.conn.routing.RouteInfo;
37  import org.apache.http.util.Args;
38  import org.apache.http.util.TextUtils;
39  
40  /**
41   * A collection of utilities for {@link URI URIs}, to workaround
42   * bugs within the class or for ease-of-use features.
43   *
44   * @since 4.0
45   */
46  public class URIUtils {
47  
48       /**
49           * Constructs a {@link URI} using all the parameters. This should be
50           * used instead of
51           * {@link URI#URI(String, String, String, int, String, String, String)}
52           * or any of the other URI multi-argument URI constructors.
53           *
54           * @param scheme
55           *            Scheme name
56           * @param host
57           *            Host name
58           * @param port
59           *            Port number
60           * @param path
61           *            Path
62           * @param query
63           *            Query
64           * @param fragment
65           *            Fragment
66           *
67           * @throws URISyntaxException
68           *             If both a scheme and a path are given but the path is
69           *             relative, if the URI string constructed from the given
70           *             components violates RFC&nbsp;2396, or if the authority
71           *             component of the string is present but cannot be parsed
72           *             as a server-based authority
73           *
74           * @deprecated (4.2) use {@link URIBuilder}.
75           */
76      @Deprecated
77      public static URI createURI(
78              final String scheme,
79              final String host,
80              final int port,
81              final String path,
82              final String query,
83              final String fragment) throws URISyntaxException {
84          final StringBuilder buffer = new StringBuilder();
85          if (host != null) {
86              if (scheme != null) {
87                  buffer.append(scheme);
88                  buffer.append("://");
89              }
90              buffer.append(host);
91              if (port > 0) {
92                  buffer.append(':');
93                  buffer.append(port);
94              }
95          }
96          if (path == null || !path.startsWith("/")) {
97              buffer.append('/');
98          }
99          if (path != null) {
100             buffer.append(path);
101         }
102         if (query != null) {
103             buffer.append('?');
104             buffer.append(query);
105         }
106         if (fragment != null) {
107             buffer.append('#');
108             buffer.append(fragment);
109         }
110         return new URI(buffer.toString());
111     }
112 
113     /**
114      * A convenience method for creating a new {@link URI} whose scheme, host
115      * and port are taken from the target host, but whose path, query and
116      * fragment are taken from the existing URI. The fragment is only used if
117      * dropFragment is false. The path is set to "/" if not explicitly specified.
118      *
119      * @param uri
120      *            Contains the path, query and fragment to use.
121      * @param target
122      *            Contains the scheme, host and port to use.
123      * @param dropFragment
124      *            True if the fragment should not be copied.
125      *
126      * @throws URISyntaxException
127      *             If the resulting URI is invalid.
128      */
129     public static URI rewriteURI(
130             final URI uri,
131             final HttpHost target,
132             final boolean dropFragment) throws URISyntaxException {
133         Args.notNull(uri, "URI");
134         if (uri.isOpaque()) {
135             return uri;
136         }
137         final URIBuilder uribuilder = new URIBuilder(uri);
138         if (target != null) {
139             uribuilder.setScheme(target.getSchemeName());
140             uribuilder.setHost(target.getHostName());
141             uribuilder.setPort(target.getPort());
142         } else {
143             uribuilder.setScheme(null);
144             uribuilder.setHost(null);
145             uribuilder.setPort(-1);
146         }
147         if (dropFragment) {
148             uribuilder.setFragment(null);
149         }
150         if (TextUtils.isEmpty(uribuilder.getPath())) {
151             uribuilder.setPath("/");
152         }
153         return uribuilder.build();
154     }
155 
156     /**
157      * A convenience method for
158      * {@link URIUtils#rewriteURI(URI, HttpHost, boolean)} that always keeps the
159      * fragment.
160      */
161     public static URI rewriteURI(
162             final URI uri,
163             final HttpHost target) throws URISyntaxException {
164         return rewriteURI(uri, target, false);
165     }
166 
167     /**
168      * A convenience method that creates a new {@link URI} whose scheme, host, port, path,
169      * query are taken from the existing URI, dropping any fragment or user-information.
170      * The path is set to "/" if not explicitly specified. The existing URI is returned
171      * unmodified if it has no fragment or user-information and has a path.
172      *
173      * @param uri
174      *            original URI.
175      * @throws URISyntaxException
176      *             If the resulting URI is invalid.
177      */
178     public static URI rewriteURI(final URI uri) throws URISyntaxException {
179         Args.notNull(uri, "URI");
180         if (uri.isOpaque()) {
181             return uri;
182         }
183         final URIBuilder uribuilder = new URIBuilder(uri);
184         if (uribuilder.getUserInfo() != null) {
185             uribuilder.setUserInfo(null);
186         }
187         if (TextUtils.isEmpty(uribuilder.getPath())) {
188             uribuilder.setPath("/");
189         }
190         if (uribuilder.getHost() != null) {
191             uribuilder.setHost(uribuilder.getHost().toLowerCase(Locale.ROOT));
192         }
193         uribuilder.setFragment(null);
194         return uribuilder.build();
195     }
196 
197     /**
198      * A convenience method that optionally converts the original {@link java.net.URI} either
199      * to a relative or an absolute form as required by the specified route.
200      *
201      * @param uri
202      *            original URI.
203      * @throws URISyntaxException
204      *             If the resulting URI is invalid.
205      *
206      * @since 4.4
207      */
208     public static URI rewriteURIForRoute(final URI uri, final RouteInfo route) throws URISyntaxException {
209         if (uri == null) {
210             return null;
211         }
212         if (route.getProxyHost() != null && !route.isTunnelled()) {
213             // Make sure the request URI is absolute
214             if (!uri.isAbsolute()) {
215                 final HttpHost target = route.getTargetHost();
216                 return rewriteURI(uri, target, true);
217             } else {
218                 return rewriteURI(uri);
219             }
220         } else {
221             // Make sure the request URI is relative
222             if (uri.isAbsolute()) {
223                 return rewriteURI(uri, null, true);
224             } else {
225                 return rewriteURI(uri);
226             }
227         }
228     }
229 
230     /**
231      * Resolves a URI reference against a base URI. Work-around for bug in
232      * java.net.URI (http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4708535)
233      *
234      * @param baseURI the base URI
235      * @param reference the URI reference
236      * @return the resulting URI
237      */
238     public static URI resolve(final URI baseURI, final String reference) {
239         return resolve(baseURI, URI.create(reference));
240     }
241 
242     /**
243      * Resolves a URI reference against a base URI. Work-around for bugs in
244      * java.net.URI (e.g. http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4708535)
245      *
246      * @param baseURI the base URI
247      * @param reference the URI reference
248      * @return the resulting URI
249      */
250     public static URI resolve(final URI baseURI, final URI reference){
251         Args.notNull(baseURI, "Base URI");
252         Args.notNull(reference, "Reference URI");
253         final String s = reference.toASCIIString();
254         if (s.startsWith("?")) {
255             String baseUri = baseURI.toASCIIString();
256             final int i = baseUri.indexOf('?');
257             baseUri = i > -1 ? baseUri.substring(0, i) : baseUri;
258             return URI.create(baseUri + s);
259         }
260         final boolean emptyReference = s.isEmpty();
261         URI resolved;
262         if (emptyReference) {
263             resolved = baseURI.resolve(URI.create("#"));
264             final String resolvedString = resolved.toASCIIString();
265             resolved = URI.create(resolvedString.substring(0, resolvedString.indexOf('#')));
266         } else {
267             resolved = baseURI.resolve(reference);
268         }
269         try {
270             return normalizeSyntax(resolved);
271         } catch (final URISyntaxException ex) {
272             throw new IllegalArgumentException(ex);
273         }
274     }
275 
276     /**
277      * Removes dot segments according to RFC 3986, section 5.2.4 and
278      * Syntax-Based Normalization according to RFC 3986, section 6.2.2.
279      *
280      * @param uri the original URI
281      * @return the URI without dot segments
282      */
283     static URI normalizeSyntax(final URI uri) throws URISyntaxException {
284         if (uri.isOpaque() || uri.getAuthority() == null) {
285             // opaque and file: URIs
286             return uri;
287         }
288         Args.check(uri.isAbsolute(), "Base URI must be absolute");
289         final URIBuilder builder = new URIBuilder(uri);
290         final String path = builder.getPath();
291         if (path != null && !path.equals("/")) {
292             final String[] inputSegments = path.split("/");
293             final Stack<String> outputSegments = new Stack<String>();
294             for (final String inputSegment : inputSegments) {
295                 if ((inputSegment.isEmpty()) || (".".equals(inputSegment))) {
296                     // Do nothing
297                 } else if ("..".equals(inputSegment)) {
298                     if (!outputSegments.isEmpty()) {
299                         outputSegments.pop();
300                     }
301                 } else {
302                     outputSegments.push(inputSegment);
303                 }
304             }
305             final StringBuilder outputBuffer = new StringBuilder();
306             for (final String outputSegment : outputSegments) {
307                 outputBuffer.append('/').append(outputSegment);
308             }
309             if (path.lastIndexOf('/') == path.length() - 1) {
310                 // path.endsWith("/") || path.equals("")
311                 outputBuffer.append('/');
312             }
313             builder.setPath(outputBuffer.toString());
314         }
315         if (builder.getScheme() != null) {
316             builder.setScheme(builder.getScheme().toLowerCase(Locale.ROOT));
317         }
318         if (builder.getHost() != null) {
319             builder.setHost(builder.getHost().toLowerCase(Locale.ROOT));
320         }
321         return builder.build();
322     }
323 
324     /**
325      * Extracts target host from the given {@link URI}.
326      *
327      * @param uri
328      * @return the target host if the URI is absolute or {@code null} if the URI is
329      * relative or does not contain a valid host name.
330      *
331      * @since 4.1
332      */
333     public static HttpHost extractHost(final URI uri) {
334         if (uri == null) {
335             return null;
336         }
337         HttpHost target = null;
338         if (uri.isAbsolute()) {
339             int port = uri.getPort(); // may be overridden later
340             String host = uri.getHost();
341             if (host == null) { // normal parse failed; let's do it ourselves
342                 // authority does not seem to care about the valid character-set for host names
343                 host = uri.getAuthority();
344                 if (host != null) {
345                     // Strip off any leading user credentials
346                     final int at = host.indexOf('@');
347                     if (at >= 0) {
348                         if (host.length() > at+1 ) {
349                             host = host.substring(at+1);
350                         } else {
351                             host = null; // @ on its own
352                         }
353                     }
354                     // Extract the port suffix, if present
355                     if (host != null) {
356                         final int colon = host.indexOf(':');
357                         if (colon >= 0) {
358                             final int pos = colon + 1;
359                             int len = 0;
360                             for (int i = pos; i < host.length(); i++) {
361                                 if (Character.isDigit(host.charAt(i))) {
362                                     len++;
363                                 } else {
364                                     break;
365                                 }
366                             }
367                             if (len > 0) {
368                                 try {
369                                     port = Integer.parseInt(host.substring(pos, pos + len));
370                                 } catch (final NumberFormatException ex) {
371                                 }
372                             }
373                             host = host.substring(0, colon);
374                         }
375                     }
376                 }
377             }
378             final String scheme = uri.getScheme();
379             if (!TextUtils.isBlank(host)) {
380                 try {
381                     target = new HttpHost(host, port, scheme);
382                 } catch (final IllegalArgumentException ignore) {
383                 }
384             }
385         }
386         return target;
387     }
388 
389     /**
390      * Derives the interpreted (absolute) URI that was used to generate the last
391      * request. This is done by extracting the request-uri and target origin for
392      * the last request and scanning all the redirect locations for the last
393      * fragment identifier, then combining the result into a {@link URI}.
394      *
395      * @param originalURI
396      *            original request before any redirects
397      * @param target
398      *            if the last URI is relative, it is resolved against this target,
399      *            or {@code null} if not available.
400      * @param redirects
401      *            collection of redirect locations since the original request
402      *            or {@code null} if not available.
403      * @return interpreted (absolute) URI
404      */
405     public static URI resolve(
406             final URI originalURI,
407             final HttpHost target,
408             final List<URI> redirects) throws URISyntaxException {
409         Args.notNull(originalURI, "Request URI");
410         final URIBuilder uribuilder;
411         if (redirects == null || redirects.isEmpty()) {
412             uribuilder = new URIBuilder(originalURI);
413         } else {
414             uribuilder = new URIBuilder(redirects.get(redirects.size() - 1));
415             String frag = uribuilder.getFragment();
416             // read interpreted fragment identifier from redirect locations
417             for (int i = redirects.size() - 1; frag == null && i >= 0; i--) {
418                 frag = redirects.get(i).getFragment();
419             }
420             uribuilder.setFragment(frag);
421         }
422         // read interpreted fragment identifier from original request
423         if (uribuilder.getFragment() == null) {
424             uribuilder.setFragment(originalURI.getFragment());
425         }
426         // last target origin
427         if (target != null && !uribuilder.isAbsolute()) {
428             uribuilder.setScheme(target.getSchemeName());
429             uribuilder.setHost(target.getHostName());
430             uribuilder.setPort(target.getPort());
431         }
432         return uribuilder.build();
433     }
434 
435     /**
436      * This class should not be instantiated.
437      */
438     private URIUtils() {
439     }
440 
441 }