TcpProxySocket.java

package org.mariadb.jdbc.failover;

import org.mariadb.jdbc.internal.logging.Logger;
import org.mariadb.jdbc.internal.logging.LoggerFactory;

import java.io.*;
import java.net.BindException;
import java.net.ServerSocket;
import java.net.Socket;

public class TcpProxySocket implements Runnable {
    private static Logger logger = LoggerFactory.getLogger(TcpProxy.class);

    String host;
    int remoteport;
    int localport;
    boolean stop = false;
    Socket client = null;
    Socket server = null;
    ServerSocket ss;

    /**
     * Creation of proxy.
     *
     * @param host       database host
     * @param remoteport database port
     * @throws IOException exception
     */
    public TcpProxySocket(String host, int remoteport) throws IOException {
        this.host = host;
        this.remoteport = remoteport;
        ss = new ServerSocket(0);
        this.localport = ss.getLocalPort();
    }

    public int getLocalPort() {
        return ss.getLocalPort();
    }

    public boolean isClosed() {
        return ss.isClosed();
    }

    /**
     * Kill proxy.
     */
    public void kill() {
        stop = true;
        try {
            if (server != null) {
                server.close();
            }
        } catch (IOException e) {
            //eat Exception
        }
        try {
            if (client != null) {
                client.close();
            }
        } catch (IOException e) {
            //eat Exception
        }
        try {
            ss.close();
        } catch (IOException e) {
            //eat Exception
        }
    }

    @Override
    public void run() {

        logger.trace("host proxy port " + this.localport + " for " + host + " started");
        stop = false;
        try {
            try {
                if (ss.isClosed()) {
                    ss = new ServerSocket(localport);
                }
            } catch (BindException b) {
                //in case for testing crash and reopen too quickly
                try {
                    Thread.sleep(100);
                } catch (InterruptedException i) {
                    //eat Exception
                }
                if (ss.isClosed()) {
                    ss = new ServerSocket(localport);
                }
            }
            final byte[] request = new byte[1024];
            byte[] reply = new byte[4096];
            while (!stop) {
                try {
                    client = ss.accept();
                    final InputStream fromClient = client.getInputStream();
                    final OutputStream toClient = client.getOutputStream();
                    try {
                        server = new Socket(host, remoteport);
                    } catch (IOException e) {
                        PrintWriter out = new PrintWriter(new OutputStreamWriter(toClient));
                        out.println("Proxy server cannot connect to " + host + ":"
                                + remoteport + ":\n" + e);
                        out.flush();
                        client.close();
                        continue;
                    }
                    final InputStream fromServer = server.getInputStream();
                    final OutputStream toServer = server.getOutputStream();
                    new Thread() {
                        public void run() {
                            int bytesRead;
                            try {
                                while ((bytesRead = fromClient.read(request)) != -1) {
                                    toServer.write(request, 0, bytesRead);
                                    toServer.flush();
                                }
                            } catch (IOException e) {
                                //eat exception
                            }
                            try {
                                toServer.close();
                            } catch (IOException e) {
                                //eat exception
                            }
                        }
                    }.start();
                    int bytesRead;
                    try {
                        while ((bytesRead = fromServer.read(reply)) != -1) {
                            try {
                                Thread.sleep(1);
                            } catch (InterruptedException e) {
                                e.printStackTrace();
                            }
                            toClient.write(reply, 0, bytesRead);
                            toClient.flush();
                        }
                    } catch (IOException e) {
                        //eat exception
                    }
                    toClient.close();
                } catch (IOException e) {
                    //System.err.println("ERROR socket : "+e);
                } finally {
                    try {
                        if (server != null) {
                            server.close();
                        }
                        if (client != null) {
                            client.close();
                        }
                    } catch (IOException e) {
                        //eat exception
                    }
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}