io.netty.resolver.DefaultHostsFileEntriesResolver Maven / Gradle / Ivy
/*
* Copyright 2015 The Netty Project
*
* The Netty Project licenses this file to you under the Apache License,
* version 2.0 (the "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
package io.netty.resolver;
import io.netty.util.CharsetUtil;
import io.netty.util.internal.PlatformDependent;
import java.net.Inet4Address;
import java.net.Inet6Address;
import java.net.InetAddress;
import java.nio.charset.Charset;
import java.util.Locale;
import java.util.Map;
/**
* Default {@link HostsFileEntriesResolver} that resolves hosts file entries only once.
*/
public final class DefaultHostsFileEntriesResolver implements HostsFileEntriesResolver {
private final Map inet4Entries;
private final Map inet6Entries;
public DefaultHostsFileEntriesResolver() {
this(parseEntries());
}
// for testing purpose only
DefaultHostsFileEntriesResolver(HostsFileEntries entries) {
inet4Entries = entries.inet4Entries();
inet6Entries = entries.inet6Entries();
}
@Override
public InetAddress address(String inetHost, ResolvedAddressTypes resolvedAddressTypes) {
String normalized = normalize(inetHost);
switch (resolvedAddressTypes) {
case IPV4_ONLY:
return inet4Entries.get(normalized);
case IPV6_ONLY:
return inet6Entries.get(normalized);
case IPV4_PREFERRED:
Inet4Address inet4Address = inet4Entries.get(normalized);
return inet4Address != null? inet4Address : inet6Entries.get(normalized);
case IPV6_PREFERRED:
Inet6Address inet6Address = inet6Entries.get(normalized);
return inet6Address != null? inet6Address : inet4Entries.get(normalized);
default:
throw new IllegalArgumentException("Unknown ResolvedAddressTypes " + resolvedAddressTypes);
}
}
// package-private for testing purposes
String normalize(String inetHost) {
return inetHost.toLowerCase(Locale.ENGLISH);
}
private static HostsFileEntries parseEntries() {
if (PlatformDependent.isWindows()) {
// Ony windows there seems to be no standard for the encoding used for the hosts file, so let us
// try multiple until we either were able to parse it or there is none left and so we return an
// empty intstance.
return HostsFileParser.parseSilently(Charset.defaultCharset(), CharsetUtil.UTF_16, CharsetUtil.UTF_8);
}
return HostsFileParser.parseSilently();
}
}