001/*
002 * Copyright (C) 2011 The Guava Authors
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package com.google.common.net;
018
019import static com.google.common.base.Preconditions.checkArgument;
020import static com.google.common.base.Preconditions.checkNotNull;
021import static com.google.common.base.Preconditions.checkState;
022
023import com.google.common.annotations.Beta;
024import com.google.common.annotations.GwtCompatible;
025import com.google.common.base.Objects;
026import com.google.common.base.Strings;
027
028import java.io.Serializable;
029
030import javax.annotation.Nullable;
031import javax.annotation.concurrent.Immutable;
032
033/**
034 * An immutable representation of a host and port.
035 *
036 * <p>Example usage:
037 * <pre>
038 * HostAndPort hp = HostAndPort.fromString("[2001:db8::1]")
039 *     .withDefaultPort(80)
040 *     .requireBracketsForIPv6();
041 * hp.getHostText();  // returns "2001:db8::1"
042 * hp.getPort();      // returns 80
043 * hp.toString();     // returns "[2001:db8::1]:80"
044 * </pre>
045 *
046 * <p>Here are some examples of recognized formats:
047 * <ul>
048 *   <li>example.com
049 *   <li>example.com:80
050 *   <li>192.0.2.1
051 *   <li>192.0.2.1:80
052 *   <li>[2001:db8::1]     - {@link #getHostText()} omits brackets
053 *   <li>[2001:db8::1]:80  - {@link #getHostText()} omits brackets
054 *   <li>2001:db8::1       - Use {@link #requireBracketsForIPv6()} to prohibit this
055 * </ul>
056 *
057 * <p>Note that this is not an exhaustive list, because these methods are only
058 * concerned with brackets, colons, and port numbers.  Full validation of the
059 * host field (if desired) is the caller's responsibility.
060 *
061 * @author Paul Marks
062 * @since 10.0
063 */
064@Beta
065@Immutable
066@GwtCompatible
067public final class HostAndPort implements Serializable {
068  /** Magic value indicating the absence of a port number. */
069  private static final int NO_PORT = -1;
070
071  /** Hostname, IPv4/IPv6 literal, or unvalidated nonsense. */
072  private final String host;
073
074  /** Validated port number in the range [0..65535], or NO_PORT */
075  private final int port;
076
077  /** True if the parsed host has colons, but no surrounding brackets. */
078  private final boolean hasBracketlessColons;
079
080  private HostAndPort(String host, int port, boolean hasBracketlessColons) {
081    this.host = host;
082    this.port = port;
083    this.hasBracketlessColons = hasBracketlessColons;
084  }
085
086  /**
087   * Returns the portion of this {@code HostAndPort} instance that should
088   * represent the hostname or IPv4/IPv6 literal.
089   *
090   * <p>A successful parse does not imply any degree of sanity in this field.
091   * For additional validation, see the {@link HostSpecifier} class.
092   */
093  public String getHostText() {
094    return host;
095  }
096
097  /** Return true if this instance has a defined port. */
098  public boolean hasPort() {
099    return port >= 0;
100  }
101
102  /**
103   * Get the current port number, failing if no port is defined.
104   *
105   * @return a validated port number, in the range [0..65535]
106   * @throws IllegalStateException if no port is defined.  You can use
107   *         {@link #withDefaultPort(int)} to prevent this from occurring.
108   */
109  public int getPort() {
110    checkState(hasPort());
111    return port;
112  }
113
114  /**
115   * Returns the current port number, with a default if no port is defined.
116   */
117  public int getPortOrDefault(int defaultPort) {
118    return hasPort() ? port : defaultPort;
119  }
120
121  /**
122   * Build a HostAndPort instance from separate host and port values.
123   *
124   * <p>Note: Non-bracketed IPv6 literals are allowed.
125   * Use {@link #requireBracketsForIPv6()} to prohibit these.
126   *
127   * @param host the host string to parse.  Must not contain a port number.
128   * @param port a port number from [0..65535]
129   * @return if parsing was successful, a populated HostAndPort object.
130   * @throws IllegalArgumentException if {@code host} contains a port number,
131   *     or {@code port} is out of range.
132   */
133  public static HostAndPort fromParts(String host, int port) {
134    checkArgument(isValidPort(port), "Port out of range: %s", port);
135    HostAndPort parsedHost = fromString(host);
136    checkArgument(!parsedHost.hasPort(), "Host has a port: %s", host);
137    return new HostAndPort(parsedHost.host, port, parsedHost.hasBracketlessColons);
138  }
139
140  /**
141   * Build a HostAndPort instance from a host only.
142   *
143   * <p>Note: Non-bracketed IPv6 literals are allowed.
144   * Use {@link #requireBracketsForIPv6()} to prohibit these.
145   *
146   * @param host the host-only string to parse.  Must not contain a port number.
147   * @return if parsing was successful, a populated HostAndPort object.
148   * @throws IllegalArgumentException if {@code host} contains a port number.
149   * @since 17.0
150   */
151  public static HostAndPort fromHost(String host) {
152    HostAndPort parsedHost = fromString(host);
153    checkArgument(!parsedHost.hasPort(), "Host has a port: %s", host);
154    return parsedHost;
155  }
156
157  /**
158   * Split a freeform string into a host and port, without strict validation.
159   *
160   * Note that the host-only formats will leave the port field undefined.  You
161   * can use {@link #withDefaultPort(int)} to patch in a default value.
162   *
163   * @param hostPortString the input string to parse.
164   * @return if parsing was successful, a populated HostAndPort object.
165   * @throws IllegalArgumentException if nothing meaningful could be parsed.
166   */
167  public static HostAndPort fromString(String hostPortString) {
168    checkNotNull(hostPortString);
169    String host;
170    String portString = null;
171    boolean hasBracketlessColons = false;
172
173    if (hostPortString.startsWith("[")) {
174      String[] hostAndPort = getHostAndPortFromBracketedHost(hostPortString);
175      host = hostAndPort[0];
176      portString = hostAndPort[1];
177    } else {
178      int colonPos = hostPortString.indexOf(':');
179      if (colonPos >= 0 && hostPortString.indexOf(':', colonPos + 1) == -1) {
180        // Exactly 1 colon.  Split into host:port.
181        host = hostPortString.substring(0, colonPos);
182        portString = hostPortString.substring(colonPos + 1);
183      } else {
184        // 0 or 2+ colons.  Bare hostname or IPv6 literal.
185        host = hostPortString;
186        hasBracketlessColons = (colonPos >= 0);
187      }
188    }
189
190    int port = NO_PORT;
191    if (!Strings.isNullOrEmpty(portString)) {
192      // Try to parse the whole port string as a number.
193      // JDK7 accepts leading plus signs. We don't want to.
194      checkArgument(!portString.startsWith("+"), "Unparseable port number: %s", hostPortString);
195      try {
196        port = Integer.parseInt(portString);
197      } catch (NumberFormatException e) {
198        throw new IllegalArgumentException("Unparseable port number: " + hostPortString);
199      }
200      checkArgument(isValidPort(port), "Port number out of range: %s", hostPortString);
201    }
202
203    return new HostAndPort(host, port, hasBracketlessColons);
204  }
205
206  /**
207   * Parses a bracketed host-port string, throwing IllegalArgumentException if parsing fails.
208   *
209   * @param hostPortString the full bracketed host-port specification. Post might not be specified.
210   * @return an array with 2 strings: host and port, in that order.
211   * @throws IllegalArgumentException if parsing the bracketed host-port string fails.
212   */
213  private static String[] getHostAndPortFromBracketedHost(String hostPortString) {
214    int colonIndex = 0;
215    int closeBracketIndex = 0;
216    boolean hasPort = false;
217    checkArgument(hostPortString.charAt(0) == '[',
218        "Bracketed host-port string must start with a bracket: %s", hostPortString);
219    colonIndex = hostPortString.indexOf(':');
220    closeBracketIndex = hostPortString.lastIndexOf(']');
221    checkArgument(colonIndex > -1 && closeBracketIndex > colonIndex,
222        "Invalid bracketed host/port: %s", hostPortString);
223
224    String host = hostPortString.substring(1, closeBracketIndex);
225    if (closeBracketIndex + 1 == hostPortString.length()) {
226      return new String[] { host, "" };
227    } else {
228      checkArgument(hostPortString.charAt(closeBracketIndex + 1) == ':',
229          "Only a colon may follow a close bracket: %s", hostPortString);
230      for (int i = closeBracketIndex + 2; i < hostPortString.length(); ++i) {
231        checkArgument(Character.isDigit(hostPortString.charAt(i)),
232            "Port must be numeric: %s", hostPortString);
233      }
234      return new String[] { host, hostPortString.substring(closeBracketIndex + 2) };
235    }
236  }
237
238  /**
239   * Provide a default port if the parsed string contained only a host.
240   *
241   * You can chain this after {@link #fromString(String)} to include a port in
242   * case the port was omitted from the input string.  If a port was already
243   * provided, then this method is a no-op.
244   *
245   * @param defaultPort a port number, from [0..65535]
246   * @return a HostAndPort instance, guaranteed to have a defined port.
247   */
248  public HostAndPort withDefaultPort(int defaultPort) {
249    checkArgument(isValidPort(defaultPort));
250    if (hasPort() || port == defaultPort) {
251      return this;
252    }
253    return new HostAndPort(host, defaultPort, hasBracketlessColons);
254  }
255
256  /**
257   * Generate an error if the host might be a non-bracketed IPv6 literal.
258   *
259   * <p>URI formatting requires that IPv6 literals be surrounded by brackets,
260   * like "[2001:db8::1]".  Chain this call after {@link #fromString(String)}
261   * to increase the strictness of the parser, and disallow IPv6 literals
262   * that don't contain these brackets.
263   *
264   * <p>Note that this parser identifies IPv6 literals solely based on the
265   * presence of a colon.  To perform actual validation of IP addresses, see
266   * the {@link InetAddresses#forString(String)} method.
267   *
268   * @return {@code this}, to enable chaining of calls.
269   * @throws IllegalArgumentException if bracketless IPv6 is detected.
270   */
271  public HostAndPort requireBracketsForIPv6() {
272    checkArgument(!hasBracketlessColons, "Possible bracketless IPv6 literal: %s", host);
273    return this;
274  }
275
276  @Override
277  public boolean equals(@Nullable Object other) {
278    if (this == other) {
279      return true;
280    }
281    if (other instanceof HostAndPort) {
282      HostAndPort that = (HostAndPort) other;
283      return Objects.equal(this.host, that.host)
284          && this.port == that.port
285          && this.hasBracketlessColons == that.hasBracketlessColons;
286    }
287    return false;
288  }
289
290  @Override
291  public int hashCode() {
292    return Objects.hashCode(host, port, hasBracketlessColons);
293  }
294
295  /** Rebuild the host:port string, including brackets if necessary. */
296  @Override
297  public String toString() {
298    // "[]:12345" requires 8 extra bytes.
299    StringBuilder builder = new StringBuilder(host.length() + 8);
300    if (host.indexOf(':') >= 0) {
301      builder.append('[').append(host).append(']');
302    } else {
303      builder.append(host);
304    }
305    if (hasPort()) {
306      builder.append(':').append(port);
307    }
308    return builder.toString();
309  }
310
311  /** Return true for valid port numbers. */
312  private static boolean isValidPort(int port) {
313    return port >= 0 && port <= 65535;
314  }
315
316  private static final long serialVersionUID = 0;
317}