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