Socks4SocketFactory.java

/*
 * Copyright (C) 2018 Square, Inc.
 *
 * Licensed 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 okhttp3.recipes;


import java.io.IOException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.Proxy;
import java.net.Socket;
import javax.net.SocketFactory;

/**
 * Java's built-in SOCKS proxy doesn't do DNS lookups for hostnames, even though that's required
 * when using a SOCKS 4 proxy (it isn't necessary for SOCKS 5).
 *
 * In order to use SOCKS 4 with OkHttp, use this socket factory instead of configuring a proxy in
 * the OkHttpClient.
 *
 * <pre>{@code
 *   ssh -D 4321 proxy.example.com
 * }</pre>
 *
 * <pre>{@code
 *   final OkHttpClient client = new OkHttpClient.Builder()
 *       .socketFactory(new Socks4SocketFactory("localhost", 4321))
 *       .build();
 * }</pre>
 */
public final class Socks4SocketFactory extends SocketFactory {
  private final Proxy proxy;

  public Socks4SocketFactory(String proxyHost, int proxyPort) {
    this.proxy = new Proxy(Proxy.Type.SOCKS, new InetSocketAddress(proxyHost, proxyPort));
  }

  @Override public Socket createSocket() {
    return new Socket(proxy);
  }

  @Override public Socket createSocket(String host, int port) throws IOException {
    Socket result = createSocket();
    result.connect(new InetSocketAddress(host, port));
    return result;
  }

  @Override public Socket createSocket(InetAddress address, int port) throws IOException {
    Socket result = createSocket();
    result.connect(new InetSocketAddress(address, port));
    return result;
  }

  @Override public Socket createSocket(
      String host, int port, InetAddress localAddress, int localPort) throws IOException {
    Socket result = createSocket();
    result.bind(new InetSocketAddress(localAddress, localPort));
    result.connect(new InetSocketAddress(host, port));
    return result;
  }

  @Override public Socket createSocket(
      InetAddress address, int port, InetAddress localAddress, int localPort) throws IOException {
    Socket result = createSocket();
    result.bind(new InetSocketAddress(localAddress, localPort));
    result.connect(new InetSocketAddress(address, port));
    return result;
  }
}