001 package com.nimbusds.oauth2.sdk.util;
002
003
004 import java.io.UnsupportedEncodingException;
005
006 import java.net.MalformedURLException;
007 import java.net.URL;
008 import java.net.URLDecoder;
009 import java.net.URLEncoder;
010
011 import java.util.HashMap;
012 import java.util.Iterator;
013 import java.util.Map;
014
015
016 /**
017 * URL operations.
018 *
019 * @author Vladimir Dzhuvinov
020 * @version $version$ (2012-05-07)
021 */
022 public class URLUtils {
023
024
025 /**
026 * The default character set.
027 */
028 public static final String CHARSET = "utf-8";
029
030
031 /**
032 * Gets the base part (protocol, host, port and path) of the specified
033 * URL.
034 *
035 * @param url The URL. May be {@code null}.
036 *
037 * @return The base part of the URL, {@code null} if the original URL
038 * is {@code null} or doesn't specify a protocol.
039 */
040 public static URL getBaseURL(final URL url) {
041
042 if (url == null)
043 return null;
044
045 try {
046 return new URL(url.getProtocol(), url.getHost(), url.getPort(), url.getPath());
047
048 } catch (MalformedURLException e) {
049
050 return null;
051 }
052 }
053
054
055 /**
056 * Serialises the specified map of parameters into a URL query string.
057 * The parameter keys and values are
058 * {@code application/x-www-form-urlencoded} encoded.
059 *
060 * <p>Note that the '?' character preceding the query string in GET
061 * requests is not included in the returned string.
062 *
063 * <p>Example query string:
064 *
065 * <pre>
066 * response_type=code
067 * &client_id=s6BhdRkqt3
068 * &state=xyz
069 * &redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb
070 * </pre>
071 *
072 * <p>The opposite method is {@link #parseParameters}.
073 *
074 * @param params A map of the URL query parameters. May be empty or
075 * {@code null}.
076 *
077 * @return The serialised URL query string, empty if no parameters.
078 */
079 public static String serializeParameters(final Map<String,String> params) {
080
081 if (params == null || params.isEmpty())
082 return "";
083
084 StringBuilder sb = new StringBuilder();
085
086 Iterator <Map.Entry<String,String>> it = params.entrySet().iterator();
087
088 while (it.hasNext()) {
089
090 Map.Entry<String,String> entry = it.next();
091
092 if (entry.getKey() == null || entry.getValue() == null)
093 continue;
094
095 try {
096 String encodedKey = URLEncoder.encode(entry.getKey(), CHARSET);
097 String encodedValue = URLEncoder.encode(entry.getValue(), CHARSET);
098
099 if (sb.length() > 0)
100 sb.append('&');
101
102 sb.append(encodedKey);
103 sb.append('=');
104 sb.append(encodedValue);
105
106 } catch (UnsupportedEncodingException e) {
107
108 // UTF-8 should always be supported
109 }
110 }
111
112 return sb.toString();
113 }
114
115
116 /**
117 * Parses the specified URL query string into a parameter map. If a
118 * parameter has multiple values only the first one will be saved. The
119 * parameter keys and values are
120 * {@code application/x-www-form-urlencoded} decoded.
121 *
122 * <p>Note that the '?' character preceding the query string in GET
123 * requests must not be included.
124 *
125 * <p>Example query string:
126 *
127 * <pre>
128 * response_type=code
129 * &client_id=s6BhdRkqt3
130 * &state=xyz
131 * &redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb
132 * </pre>
133 *
134 * <p>The opposite method {@link #serializeParameters}.
135 *
136 * @param query The URL query string to parse. May be {@code null}.
137 *
138 * @return A map of the URL query parameters, empty if none are found.
139 */
140 public static Map<String,String> parseParameters(final String query) {
141
142 Map<String,String> params = new HashMap<String, String>();
143
144 if (query == null)
145 return params; // empty map
146
147 try {
148 for (String param : query.split("&")) {
149
150 String pair[] = param.split("=");
151
152 String key = URLDecoder.decode(pair[0], CHARSET);
153
154 // Save the first value only
155 if (params.containsKey(key))
156 continue;
157
158 String value = "";
159
160 if (pair.length > 1)
161 value = URLDecoder.decode(pair[1], CHARSET);
162
163 params.put(key, value);
164 }
165
166 } catch (UnsupportedEncodingException e) {
167
168 // UTF-8 should always be supported
169 }
170
171 return params;
172 }
173
174
175 /**
176 * Prevents instantiation.
177 */
178 private URLUtils() {
179
180 // do nothing
181 }
182 }