001/*
002 * Copyright (C) 2011 The Guava Authors
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
005 * in compliance with the License. You may obtain a copy of the License at
006 *
007 * http://www.apache.org/licenses/LICENSE-2.0
008 *
009 * Unless required by applicable law or agreed to in writing, software distributed under the License
010 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
011 * or implied. See the License for the specific language governing permissions and limitations under
012 * the License.
013 */
014
015package com.google.common.net;
016
017import static com.google.common.base.Preconditions.checkArgument;
018import static com.google.common.base.Preconditions.checkNotNull;
019import static com.google.common.base.Preconditions.checkState;
020
021import com.google.common.annotations.Beta;
022import com.google.common.annotations.GwtCompatible;
023import com.google.common.base.Objects;
024import com.google.common.base.Strings;
025import com.google.errorprone.annotations.Immutable;
026import java.io.Serializable;
027import org.checkerframework.checker.nullness.compatqual.NullableDecl;
028
029/**
030 * An immutable representation of a host and port.
031 *
032 * <p>Example usage:
033 *
034 * <pre>
035 * HostAndPort hp = HostAndPort.fromString("[2001:db8::1]")
036 *     .withDefaultPort(80)
037 *     .requireBracketsForIPv6();
038 * hp.getHost();   // returns "2001:db8::1"
039 * hp.getPort();   // returns 80
040 * hp.toString();  // returns "[2001:db8::1]:80"
041 * </pre>
042 *
043 * <p>Here are some examples of recognized formats:
044 *
045 * <ul>
046 *   <li>example.com
047 *   <li>example.com:80
048 *   <li>192.0.2.1
049 *   <li>192.0.2.1:80
050 *   <li>[2001:db8::1] - {@link #getHost()} omits brackets
051 *   <li>[2001:db8::1]:80 - {@link #getHost()} omits brackets
052 *   <li>2001:db8::1 - Use {@link #requireBracketsForIPv6()} to prohibit this
053 * </ul>
054 *
055 * <p>Note that this is not an exhaustive list, because these methods are only concerned with
056 * brackets, colons, and port numbers. Full validation of the host field (if desired) is the
057 * caller's responsibility.
058 *
059 * @author Paul Marks
060 * @since 10.0
061 */
062@Beta
063@Immutable
064@GwtCompatible
065public final class HostAndPort implements Serializable {
066  /** Magic value indicating the absence of a port number. */
067  private static final int NO_PORT = -1;
068
069  /** Hostname, IPv4/IPv6 literal, or unvalidated nonsense. */
070  private final String host;
071
072  /** Validated port number in the range [0..65535], or NO_PORT */
073  private final int port;
074
075  /** True if the parsed host has colons, but no surrounding brackets. */
076  private final boolean hasBracketlessColons;
077
078  private HostAndPort(String host, int port, boolean hasBracketlessColons) {
079    this.host = host;
080    this.port = port;
081    this.hasBracketlessColons = hasBracketlessColons;
082  }
083
084  /**
085   * Returns the portion of this {@code HostAndPort} instance that should represent the hostname or
086   * IPv4/IPv6 literal.
087   *
088   * <p>A successful parse does not imply any degree of sanity in this field. For additional
089   * validation, see the {@link HostSpecifier} class.
090   *
091   * @since 20.0 (since 10.0 as {@code getHostText})
092   */
093  public String getHost() {
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 {@link #withDefaultPort(int)}
107   *     to prevent this from occurring.
108   */
109  public int getPort() {
110    checkState(hasPort());
111    return port;
112  }
113
114  /** Returns the current port number, with a default if no port is defined. */
115  public int getPortOrDefault(int defaultPort) {
116    return hasPort() ? port : defaultPort;
117  }
118
119  /**
120   * Build a HostAndPort instance from separate host and port values.
121   *
122   * <p>Note: Non-bracketed IPv6 literals are allowed. Use {@link #requireBracketsForIPv6()} to
123   * prohibit these.
124   *
125   * @param host the host string to parse. Must not contain a port number.
126   * @param port a port number from [0..65535]
127   * @return if parsing was successful, a populated HostAndPort object.
128   * @throws IllegalArgumentException if {@code host} contains a port number, or {@code port} is out
129   *     of range.
130   */
131  public static HostAndPort fromParts(String host, int port) {
132    checkArgument(isValidPort(port), "Port out of range: %s", port);
133    HostAndPort parsedHost = fromString(host);
134    checkArgument(!parsedHost.hasPort(), "Host has a port: %s", host);
135    return new HostAndPort(parsedHost.host, port, parsedHost.hasBracketlessColons);
136  }
137
138  /**
139   * Build a HostAndPort instance from a host only.
140   *
141   * <p>Note: Non-bracketed IPv6 literals are allowed. Use {@link #requireBracketsForIPv6()} to
142   * prohibit these.
143   *
144   * @param host the host-only string to parse. Must not contain a port number.
145   * @return if parsing was successful, a populated HostAndPort object.
146   * @throws IllegalArgumentException if {@code host} contains a port number.
147   * @since 17.0
148   */
149  public static HostAndPort fromHost(String host) {
150    HostAndPort parsedHost = fromString(host);
151    checkArgument(!parsedHost.hasPort(), "Host has a port: %s", host);
152    return parsedHost;
153  }
154
155  /**
156   * Split a freeform string into a host and port, without strict validation.
157   *
158   * <p>Note that the host-only formats will leave the port field undefined. You can use {@link
159   * #withDefaultPort(int)} to patch in a default value.
160   *
161   * @param hostPortString the input string to parse.
162   * @return if parsing was successful, a populated HostAndPort object.
163   * @throws IllegalArgumentException if nothing meaningful could be parsed.
164   */
165  public static HostAndPort fromString(String hostPortString) {
166    checkNotNull(hostPortString);
167    String host;
168    String portString = null;
169    boolean hasBracketlessColons = false;
170
171    if (hostPortString.startsWith("[")) {
172      String[] hostAndPort = getHostAndPortFromBracketedHost(hostPortString);
173      host = hostAndPort[0];
174      portString = hostAndPort[1];
175    } else {
176      int colonPos = hostPortString.indexOf(':');
177      if (colonPos >= 0 && hostPortString.indexOf(':', colonPos + 1) == -1) {
178        // Exactly 1 colon. Split into host:port.
179        host = hostPortString.substring(0, colonPos);
180        portString = hostPortString.substring(colonPos + 1);
181      } else {
182        // 0 or 2+ colons. Bare hostname or IPv6 literal.
183        host = hostPortString;
184        hasBracketlessColons = (colonPos >= 0);
185      }
186    }
187
188    int port = NO_PORT;
189    if (!Strings.isNullOrEmpty(portString)) {
190      // Try to parse the whole port string as a number.
191      // JDK7 accepts leading plus signs. We don't want to.
192      checkArgument(!portString.startsWith("+"), "Unparseable port number: %s", hostPortString);
193      try {
194        port = Integer.parseInt(portString);
195      } catch (NumberFormatException e) {
196        throw new IllegalArgumentException("Unparseable port number: " + hostPortString);
197      }
198      checkArgument(isValidPort(port), "Port number out of range: %s", hostPortString);
199    }
200
201    return new HostAndPort(host, port, hasBracketlessColons);
202  }
203
204  /**
205   * Parses a bracketed host-port string, throwing IllegalArgumentException if parsing fails.
206   *
207   * @param hostPortString the full bracketed host-port specification. Post might not be specified.
208   * @return an array with 2 strings: host and port, in that order.
209   * @throws IllegalArgumentException if parsing the bracketed host-port string fails.
210   */
211  private static String[] getHostAndPortFromBracketedHost(String hostPortString) {
212    int colonIndex = 0;
213    int closeBracketIndex = 0;
214    checkArgument(
215        hostPortString.charAt(0) == '[',
216        "Bracketed host-port string must start with a bracket: %s",
217        hostPortString);
218    colonIndex = hostPortString.indexOf(':');
219    closeBracketIndex = hostPortString.lastIndexOf(']');
220    checkArgument(
221        colonIndex > -1 && closeBracketIndex > colonIndex,
222        "Invalid bracketed host/port: %s",
223        hostPortString);
224
225    String host = hostPortString.substring(1, closeBracketIndex);
226    if (closeBracketIndex + 1 == hostPortString.length()) {
227      return new String[] {host, ""};
228    } else {
229      checkArgument(
230          hostPortString.charAt(closeBracketIndex + 1) == ':',
231          "Only a colon may follow a close bracket: %s",
232          hostPortString);
233      for (int i = closeBracketIndex + 2; i < hostPortString.length(); ++i) {
234        checkArgument(
235            Character.isDigit(hostPortString.charAt(i)),
236            "Port must be numeric: %s",
237            hostPortString);
238      }
239      return new String[] {host, hostPortString.substring(closeBracketIndex + 2)};
240    }
241  }
242
243  /**
244   * Provide a default port if the parsed string contained only a host.
245   *
246   * <p>You can chain this after {@link #fromString(String)} to include a port in case the port was
247   * omitted from the input string. If a port was already provided, then this method is a no-op.
248   *
249   * @param defaultPort a port number, from [0..65535]
250   * @return a HostAndPort instance, guaranteed to have a defined port.
251   */
252  public HostAndPort withDefaultPort(int defaultPort) {
253    checkArgument(isValidPort(defaultPort));
254    if (hasPort()) {
255      return this;
256    }
257    return new HostAndPort(host, defaultPort, hasBracketlessColons);
258  }
259
260  /**
261   * Generate an error if the host might be a non-bracketed IPv6 literal.
262   *
263   * <p>URI formatting requires that IPv6 literals be surrounded by brackets, like "[2001:db8::1]".
264   * Chain this call after {@link #fromString(String)} to increase the strictness of the parser, and
265   * disallow IPv6 literals that don't contain these brackets.
266   *
267   * <p>Note that this parser identifies IPv6 literals solely based on the presence of a colon. To
268   * perform actual validation of IP addresses, see the {@link InetAddresses#forString(String)}
269   * method.
270   *
271   * @return {@code this}, to enable chaining of calls.
272   * @throws IllegalArgumentException if bracketless IPv6 is detected.
273   */
274  public HostAndPort requireBracketsForIPv6() {
275    checkArgument(!hasBracketlessColons, "Possible bracketless IPv6 literal: %s", host);
276    return this;
277  }
278
279  @Override
280  public boolean equals(@NullableDecl Object other) {
281    if (this == other) {
282      return true;
283    }
284    if (other instanceof HostAndPort) {
285      HostAndPort that = (HostAndPort) other;
286      return Objects.equal(this.host, that.host) && this.port == that.port;
287    }
288    return false;
289  }
290
291  @Override
292  public int hashCode() {
293    return Objects.hashCode(host, port);
294  }
295
296  /** Rebuild the host:port string, including brackets if necessary. */
297  @Override
298  public String toString() {
299    // "[]:12345" requires 8 extra bytes.
300    StringBuilder builder = new StringBuilder(host.length() + 8);
301    if (host.indexOf(':') >= 0) {
302      builder.append('[').append(host).append(']');
303    } else {
304      builder.append(host);
305    }
306    if (hasPort()) {
307      builder.append(':').append(port);
308    }
309    return builder.toString();
310  }
311
312  /** Return true for valid port numbers. */
313  private static boolean isValidPort(int port) {
314    return port >= 0 && port <= 65535;
315  }
316
317  private static final long serialVersionUID = 0;
318}