001 package com.nimbusds.oauth2.sdk.util;
002
003
004 import java.io.UnsupportedEncodingException;
005 import java.net.MalformedURLException;
006 import java.net.URL;
007 import java.net.URLDecoder;
008 import java.net.URLEncoder;
009 import java.util.HashMap;
010 import java.util.Iterator;
011 import java.util.Map;
012 import java.util.StringTokenizer;
013
014
015 /**
016 * URL operations.
017 *
018 * @author Vladimir Dzhuvinov
019 */
020 public class URLUtils {
021
022
023 /**
024 * The default UTF-8 character set.
025 */
026 public static final String CHARSET = "utf-8";
027
028
029 /**
030 * Gets the base part (protocol, host, port and path) of the specified
031 * URL.
032 *
033 * @param url The URL. May be {@code null}.
034 *
035 * @return The base part of the URL, {@code null} if the original URL
036 * is {@code null} or doesn't specify a protocol.
037 */
038 public static URL getBaseURL(final URL url) {
039
040 if (url == null)
041 return null;
042
043 try {
044 return new URL(url.getProtocol(), url.getHost(), url.getPort(), url.getPath());
045
046 } catch (MalformedURLException e) {
047
048 return null;
049 }
050 }
051
052
053 /**
054 * Serialises the specified map of parameters into a URL query string.
055 * The parameter keys and values are
056 * {@code application/x-www-form-urlencoded} encoded.
057 *
058 * <p>Note that the '?' character preceding the query string in GET
059 * requests is not included in the returned string.
060 *
061 * <p>Example query string:
062 *
063 * <pre>
064 * response_type=code
065 * &client_id=s6BhdRkqt3
066 * &state=xyz
067 * &redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb
068 * </pre>
069 *
070 * <p>The opposite method is {@link #parseParameters}.
071 *
072 * @param params A map of the URL query parameters. May be empty or
073 * {@code null}.
074 *
075 * @return The serialised URL query string, empty if no parameters.
076 */
077 public static String serializeParameters(final Map<String,String> params) {
078
079 if (params == null || params.isEmpty())
080 return "";
081
082 StringBuilder sb = new StringBuilder();
083
084 Iterator <Map.Entry<String,String>> it = params.entrySet().iterator();
085
086 while (it.hasNext()) {
087
088 Map.Entry<String,String> entry = it.next();
089
090 if (entry.getKey() == null || entry.getValue() == null)
091 continue;
092
093 try {
094 String encodedKey = URLEncoder.encode(entry.getKey(), CHARSET);
095 String encodedValue = URLEncoder.encode(entry.getValue(), CHARSET);
096
097 if (sb.length() > 0)
098 sb.append('&');
099
100 sb.append(encodedKey);
101 sb.append('=');
102 sb.append(encodedValue);
103
104 } catch (UnsupportedEncodingException e) {
105
106 // UTF-8 should always be supported
107 }
108 }
109
110 return sb.toString();
111 }
112
113
114 /**
115 * Parses the specified URL query string into a parameter map. If a
116 * parameter has multiple values only the first one will be saved. The
117 * parameter keys and values are
118 * {@code application/x-www-form-urlencoded} decoded.
119 *
120 * <p>Note that the '?' character preceding the query string in GET
121 * requests must not be included.
122 *
123 * <p>Example query string:
124 *
125 * <pre>
126 * response_type=code
127 * &client_id=s6BhdRkqt3
128 * &state=xyz
129 * &redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb
130 * </pre>
131 *
132 * <p>The opposite method {@link #serializeParameters}.
133 *
134 * @param query The URL query string to parse. May be {@code null}.
135 *
136 * @return A map of the URL query parameters, empty if none are found.
137 */
138 public static Map<String,String> parseParameters(final String query) {
139
140 Map<String,String> params = new HashMap<String, String>();
141
142 if (query == null)
143 return params; // empty map
144
145 try {
146 StringTokenizer st = new StringTokenizer(query, "&");
147
148 while(st.hasMoreTokens()) {
149
150 String param = st.nextToken();
151
152 String pair[] = param.split("=");
153
154 String key = URLDecoder.decode(pair[0], CHARSET);
155
156 // Save the first value only
157 if (params.containsKey(key))
158 continue;
159
160 String value = "";
161
162 if (pair.length > 1)
163 value = URLDecoder.decode(pair[1], CHARSET);
164
165 params.put(key, value);
166 }
167
168 } catch (UnsupportedEncodingException e) {
169
170 // UTF-8 should always be supported
171 }
172
173 return params;
174 }
175
176
177 /**
178 * Prevents instantiation.
179 */
180 private URLUtils() {
181
182 // do nothing
183 }
184 }