1 /*
2 * ====================================================================
3 * Licensed to the Apache Software Foundation (ASF) under one
4 * or more contributor license agreements. See the NOTICE file
5 * distributed with this work for additional information
6 * regarding copyright ownership. The ASF licenses this file
7 * to you under the Apache License, Version 2.0 (the
8 * "License"); you may not use this file except in compliance
9 * with the License. You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing,
14 * software distributed under the License is distributed on an
15 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
16 * KIND, either express or implied. See the License for the
17 * specific language governing permissions and limitations
18 * under the License.
19 * ====================================================================
20 *
21 * This software consists of voluntary contributions made by many
22 * individuals on behalf of the Apache Software Foundation. For more
23 * information on the Apache Software Foundation, please see
24 * <http://www.apache.org/>.
25 *
26 */
27 package org.apache.hc.client5.http.impl;
28
29 import java.net.InetAddress;
30 import java.net.UnknownHostException;
31 import java.util.Arrays;
32 import java.util.Map;
33 import java.util.concurrent.ConcurrentHashMap;
34
35 import org.apache.hc.client5.http.DnsResolver;
36 import org.apache.hc.core5.annotation.Contract;
37 import org.apache.hc.core5.annotation.ThreadingBehavior;
38 import org.apache.hc.core5.util.Args;
39 import org.slf4j.Logger;
40 import org.slf4j.LoggerFactory;
41
42 /**
43 * In-memory {@link DnsResolver} implementation.
44 *
45 * @since 4.2
46 */
47 @Contract(threading = ThreadingBehavior.STATELESS)
48 public class InMemoryDnsResolver implements DnsResolver {
49
50 /** Logger associated to this class. */
51 private static final Logger LOG = LoggerFactory.getLogger(InMemoryDnsResolver.class);
52
53 /**
54 * In-memory collection that will hold the associations between a host name
55 * and an array of InetAddress instances.
56 */
57 private final Map<String, InetAddress[]> dnsMap;
58
59 /**
60 * Builds a DNS resolver that will resolve the host names against a
61 * collection held in-memory.
62 */
63 public InMemoryDnsResolver() {
64 dnsMap = new ConcurrentHashMap<>();
65 }
66
67 /**
68 * Associates the given array of IP addresses to the given host in this DNS overrider.
69 * The IP addresses are assumed to be already resolved.
70 *
71 * @param host
72 * The host name to be associated with the given IP.
73 * @param ips
74 * array of IP addresses to be resolved by this DNS overrider to the given
75 * host name.
76 */
77 public void add(final String host, final InetAddress... ips) {
78 Args.notNull(host, "Host name");
79 Args.notNull(ips, "Array of IP addresses");
80 dnsMap.put(host, ips);
81 }
82
83 /**
84 * {@inheritDoc}
85 */
86 @Override
87 public InetAddress[] resolve(final String host) throws UnknownHostException {
88 final InetAddress[] resolvedAddresses = dnsMap.get(host);
89 if (LOG.isInfoEnabled()) {
90 LOG.info("Resolving {} to {}", host, Arrays.deepToString(resolvedAddresses));
91 }
92 if(resolvedAddresses == null){
93 throw new UnknownHostException(host + " cannot be resolved");
94 }
95 return resolvedAddresses;
96 }
97
98 @Override
99 public String resolveCanonicalHostname(final String host) throws UnknownHostException {
100 final InetAddress[] resolvedAddresses = resolve(host);
101 if (resolvedAddresses.length > 0) {
102 return resolvedAddresses[0].getCanonicalHostName();
103 }
104 return host;
105 }
106 }