1 /*
2 * Copyright 2009 Red Hat, Inc.
3 *
4 * Red Hat licenses this file to you under the Apache License, version 2.0
5 * (the "License"); you may not use this file except in compliance with the
6 * License. You may obtain a copy of the License at:
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13 * License for the specific language governing permissions and limitations
14 * under the License.
15 */
16 package org.jboss.netty.handler.codec.http;
17
18 import java.io.UnsupportedEncodingException;
19 import java.net.URI;
20 import java.net.URLDecoder;
21 import java.nio.charset.Charset;
22 import java.nio.charset.UnsupportedCharsetException;
23 import java.util.ArrayList;
24 import java.util.Collections;
25 import java.util.LinkedHashMap;
26 import java.util.List;
27 import java.util.Map;
28
29 /**
30 * Splits an HTTP query string into a path string and key-value parameter pairs.
31 * This decoder is for one time use only. Create a new instance for each URI:
32 * <pre>
33 * {@link QueryStringDecoder} decoder = new {@link QueryStringDecoder}("/hello?recipient=world");
34 * assert decoder.getPath().equals("/hello");
35 * assert decoder.getParameters().get("recipient").equals("world");
36 * </pre>
37 *
38 * @author <a href="http://www.jboss.org/netty/">The Netty Project</a>
39 * @author Andy Taylor (andy.taylor@jboss.org)
40 * @author <a href="http://gleamynode.net/">Trustin Lee</a>
41 * @author <a href="http://tsunanet.net/">Benoit Sigoure</a>
42 * @version $Rev: 2302 $, $Date: 2010-06-14 20:07:44 +0900 (Mon, 14 Jun 2010) $
43 *
44 * @see QueryStringEncoder
45 *
46 * @apiviz.stereotype utility
47 * @apiviz.has org.jboss.netty.handler.codec.http.HttpRequest oneway - - decodes
48 */
49 public class QueryStringDecoder {
50
51 private final Charset charset;
52 private final String uri;
53 private String path;
54 private Map<String, List<String>> params;
55
56 /**
57 * Creates a new decoder that decodes the specified URI. The decoder will
58 * assume that the query string is encoded in UTF-8.
59 */
60 public QueryStringDecoder(String uri) {
61 this(uri, HttpCodecUtil.DEFAULT_CHARSET);
62 }
63
64 /**
65 * Creates a new decoder that decodes the specified URI encoded in the
66 * specified charset.
67 */
68 public QueryStringDecoder(String uri, Charset charset) {
69 if (uri == null) {
70 throw new NullPointerException("uri");
71 }
72 if (charset == null) {
73 throw new NullPointerException("charset");
74 }
75
76 this.uri = uri;
77 this.charset = charset;
78 }
79
80 /**
81 * @deprecated Use {@link #QueryStringDecoder(String, Charset)} instead.
82 */
83 @Deprecated
84 public QueryStringDecoder(String uri, String charset) {
85 this(uri, Charset.forName(charset));
86 }
87
88 /**
89 * Creates a new decoder that decodes the specified URI. The decoder will
90 * assume that the query string is encoded in UTF-8.
91 */
92 public QueryStringDecoder(URI uri) {
93 this(uri, HttpCodecUtil.DEFAULT_CHARSET);
94 }
95
96 /**
97 * Creates a new decoder that decodes the specified URI encoded in the
98 * specified charset.
99 */
100 public QueryStringDecoder(URI uri, Charset charset){
101 if (uri == null) {
102 throw new NullPointerException("uri");
103 }
104 if (charset == null) {
105 throw new NullPointerException("charset");
106 }
107
108 this.uri = uri.toASCIIString();
109 this.charset = charset;
110 }
111
112 /**
113 * @deprecated Use {@link #QueryStringDecoder(URI, Charset)} instead.
114 */
115 @Deprecated
116 public QueryStringDecoder(URI uri, String charset){
117 this(uri, Charset.forName(charset));
118 }
119
120 /**
121 * Returns the decoded path string of the URI.
122 */
123 public String getPath() {
124 if (path == null) {
125 int pathEndPos = uri.indexOf('?');
126 if (pathEndPos < 0) {
127 path = uri;
128 }
129 else {
130 return path = uri.substring(0, pathEndPos);
131 }
132 }
133 return path;
134 }
135
136 /**
137 * Returns the decoded key-value parameter pairs of the URI.
138 */
139 public Map<String, List<String>> getParameters() {
140 if (params == null) {
141 int pathLength = getPath().length();
142 if (uri.length() == pathLength) {
143 return Collections.emptyMap();
144 }
145 params = decodeParams(uri.substring(pathLength + 1));
146 }
147 return params;
148 }
149
150 private Map<String, List<String>> decodeParams(String s) {
151 Map<String, List<String>> params = new LinkedHashMap<String, List<String>>();
152 String name = null;
153 int pos = 0; // Beginning of the unprocessed region
154 int i; // End of the unprocessed region
155 char c = 0; // Current character
156 for (i = 0; i < s.length(); i++) {
157 c = s.charAt(i);
158 if (c == '=' && name == null) {
159 if (pos != i) {
160 name = decodeComponent(s.substring(pos, i), charset);
161 }
162 pos = i + 1;
163 } else if (c == '&') {
164 if (name == null && pos != i) {
165 // We haven't seen an `=' so far but moved forward.
166 // Must be a param of the form '&a&' so add it with
167 // an empty value.
168 addParam(params, decodeComponent(s.substring(pos, i), charset), "");
169 } else if (name != null) {
170 addParam(params, name, decodeComponent(s.substring(pos, i), charset));
171 name = null;
172 }
173 pos = i + 1;
174 }
175 }
176
177 if (pos != i) { // Are there characters we haven't dealt with?
178 if (name == null) { // Yes and we haven't seen any `='.
179 addParam(params, decodeComponent(s.substring(pos, i), charset), "");
180 } else { // Yes and this must be the last value.
181 addParam(params, name, decodeComponent(s.substring(pos, i), charset));
182 }
183 } else if (name != null) { // Have we seen a name without value?
184 addParam(params, name, "");
185 }
186
187 return params;
188 }
189
190 private static String decodeComponent(String s, Charset charset) {
191 if (s == null) {
192 return "";
193 }
194
195 try {
196 return URLDecoder.decode(s, charset.name());
197 } catch (UnsupportedEncodingException e) {
198 throw new UnsupportedCharsetException(charset.name());
199 }
200 }
201
202 private static void addParam(Map<String, List<String>> params, String name, String value) {
203 List<String> values = params.get(name);
204 if (values == null) {
205 values = new ArrayList<String>(1); // Often there's only 1 value.
206 params.put(name, values);
207 }
208 values.add(value);
209 }
210 }