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Java example source code file (FtpCommandHandler.java)

This example Java source code file (FtpCommandHandler.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

auth, command, cwd, epsv, ioexception, net, network, pasv, port, prot, regex, security, socket, ssl, sslsocket, string, type, user

The FtpCommandHandler.java Java example source code

/*
 * Copyright (c) 2006, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

import java.net.*;
import java.io.*;
import java.util.regex.*;
import java.security.*;
import javax.net.ssl.*;

/*
 * This class handles one client connection. It will interpret and act on the
 * commands (like USER, GET, PUT etc...) sent through the socket passed to
 * the constructor.
 *
 * To function it needs to be provided 2 handlers, one for the filesystem
 * and one for authentication.
 * @see FileSystemHandler
 * @see AuthHandler
 * @see #setHandlers(FtpFileSystemHandler,FtpAuthHandler)
 */

public class FtpCommandHandler extends Thread {
    private FtpServer parent = null;
    private Socket cmd = null;
    private Socket oldCmd = null;
    private InetAddress clientAddr = null;
    private ServerSocket pasv = null;

    private BufferedReader in = null;

    private PrintStream out = null;

    private FtpFileSystemHandler fsh = null;
    private FtpAuthHandler auth = null;

    private boolean done = false;

    private String username = null;
    private String password = null;
    private String account = null;
    private boolean logged = false;
    private boolean epsvAll = false;
    private int dataPort = 0;
    private InetAddress dataAddress = null;
    private boolean pasvEnabled = true;
    private boolean portEnabled = true;
    private boolean extendedEnabled = true;
    private boolean binary = true;
    private String renameFrom = null;
    private long restart = 0;
    private boolean useCrypto = false;
    private boolean useDataCrypto = false;
    private SSLSocketFactory sslFact = null;

    private final int ERROR = -1;
    private final int QUIT = 0;
    private final int USER = 1;
    private final int PASS = 2;
    private final int CWD = 3;
    private final int CDUP = 4;
    private final int PWD = 5;
    private final int TYPE = 6;
    private final int NOOP = 7;
    private final int RETR = 8;
    private final int PORT = 9;
    private final int PASV = 10;
    private final int EPSV = 11;
    private final int EPRT = 12;
    private final int SYST = 13;
    private final int STOR = 14;
    private final int STOU = 15;
    private final int LIST = 16;
    private final int NLST = 17;
    private final int RNFR = 18;
    private final int RNTO = 19;
    private final int DELE = 20;
    private final int REST = 21;
    private final int AUTH = 22;
    private final int FEAT = 23;
    private final int CCC = 24;
    private final int PROT = 25;
    private final int PBSZ = 26;

    private String[] commands =
    { "QUIT", "USER", "PASS", "CWD", "CDUP", "PWD", "TYPE", "NOOP", "RETR",
      "PORT", "PASV", "EPSV", "EPRT", "SYST", "STOR", "STOU", "LIST", "NLST",
      "RNFR", "RNTO", "DELE", "REST", "AUTH", "FEAT", "CCC", "PROT", "PBSZ"
    };

    private boolean isPasvSet() {
        if (pasv != null && !pasvEnabled) {
            try {
                pasv.close();
            } catch ( IOException e) {

            }
            pasv = null;
        }
        if (pasvEnabled && pasv != null)
            return true;
        return false;
    }

    private OutputStream getOutDataStream() throws IOException {
        if (isPasvSet()) {
            Socket s = pasv.accept();
            if (useCrypto && useDataCrypto) {
                SSLSocket ssl = (SSLSocket) sslFact.createSocket(s, clientAddr.getHostName(), s.getPort(), true);
                ssl.setUseClientMode(false);
                s = ssl;
            }
            return s.getOutputStream();
        }
        if (dataAddress != null) {
            Socket s;
            if (useCrypto) {
                s = sslFact.createSocket(dataAddress, dataPort);
            } else
                s = new Socket(dataAddress, dataPort);
            dataAddress = null;
            dataPort = 0;
            return s.getOutputStream();
        }
        return null;
    }

    private InputStream getInDataStream() throws IOException {
        if (isPasvSet()) {
            Socket s = pasv.accept();
            if (useCrypto && useDataCrypto) {
                SSLSocket ssl = (SSLSocket) sslFact.createSocket(s, clientAddr.getHostName(), s.getPort(), true);
                ssl.setUseClientMode(false);
                s = ssl;
            }
            return s.getInputStream();
        }
        if (dataAddress != null) {
            Socket s;
            if (useCrypto) {
                s = sslFact.createSocket(dataAddress, dataPort);
            } else
                s = new Socket(dataAddress, dataPort);
            dataAddress = null;
            dataPort = 0;
            return s.getInputStream();
        }
        return null;
    }

    private void parsePort(String port_arg) throws IOException {
        if (epsvAll) {
            out.println("501 PORT not allowed after EPSV ALL.");
            return;
        }
        if (!portEnabled) {
            out.println("500 PORT command is disabled, please use PASV.");
            return;
        }
        StringBuffer host;
        int i = 0, j = 4;
        while (j > 0) {
            i = port_arg.indexOf(',', i + 1);
            if (i < 0)
                break;
            j--;
        }
        if (j != 0) {
            out.println("500 '" + port_arg + "': command not understood.");
            return;
        }
        try {
            host = new StringBuffer(port_arg.substring(0, i));
            for (j = 0; j < host.length(); j++)
                if (host.charAt(j) == ',')
                    host.setCharAt(j, '.');
            String ports = port_arg.substring(i + 1);
            i = ports.indexOf(',');
            dataPort = Integer.parseInt(ports.substring(0, i)) << 8;
            dataPort += (Integer.parseInt(ports.substring(i + 1)));
            dataAddress = InetAddress.getByName(host.toString());
            out.println("200 Command okay.");
        } catch (Exception ex3) {
            dataPort = 0;
            dataAddress = null;
            out.println("500 '" + port_arg + "': command not understood.");
        }
    }

    private void parseEprt(String arg) {
        if (epsvAll) {
            out.println("501 PORT not allowed after EPSV ALL");
            return;
        }
        if (!extendedEnabled || !portEnabled) {
            out.println("500 EPRT is disabled, use PASV instead");
            return;
        }
        Pattern p = Pattern.compile("\\|(\\d)\\|(.*)\\|(\\d+)\\|");
        Matcher m = p.matcher(arg);
        if (!m.find()) {
            out.println("500 '" + arg + "': command not understood.");
            return;
        }
        try {
            dataAddress = InetAddress.getByName(m.group(2));
        } catch (UnknownHostException e) {
            out.println("500 " + arg + ": invalid address.");
            dataAddress = null;
            return;
        }
        dataPort = Integer.parseInt(m.group(3));
        out.println("200 Command okay.");
    }

    private void doPasv() {
        if (!pasvEnabled) {
            out.println("500 PASV is disabled, use PORT.");
            return;
        }
        try {
            if (pasv == null)
                pasv = new ServerSocket(0);
            int port = pasv.getLocalPort();
            InetAddress rAddress = cmd.getLocalAddress();
            if (rAddress instanceof Inet6Address) {
                out.println("500 PASV illegal over IPv6 addresses, use EPSV.");
                return;
            }
            byte[] a = rAddress.getAddress();
            out.println("227 Entering Passive Mode " + a[0] + "," + a[1] + "," + a[2] + "," + a[3] + "," +
                        (port >> 8) + "," + (port & 0xff) );
        } catch (IOException e) {
            out.println("425 can't build data connection: Connection refused.");
        }
    }

    private void doEpsv(String arg) {
        if (!extendedEnabled || !pasvEnabled) {
            out.println("500 EPSV disabled, use PORT or PASV.");
            return;
        }
        if ("all".equalsIgnoreCase(arg)) {
            out.println("200 EPSV ALL Command successful.");
            epsvAll = true;
            return;
        }
        try {
            if (pasv == null)
                pasv = new ServerSocket(0);
            int port = pasv.getLocalPort();
            out.println("229 Entering Extended Passive Mode (|||" + port + "|)");
        } catch (IOException e) {
            out.println("500 Can't create data connection.");
        }
    }

    private void doRetr(String arg) {
        try {
            OutputStream dOut = getOutDataStream();
            if (dOut != null) {
                InputStream dIn = fsh.getFile(arg);
                if (dIn == null) {
                    out.println("550 File not found.");
                    dOut.close();
                    return;
                }
                out.println("150 Opening " + (binary ? "BINARY " : "ASCII ") + " data connection for file " + arg +
                            "(" + fsh.getFileSize(arg) + " bytes).");
                if (binary) {
                    byte[] buf = new byte[2048];
                    dOut = new BufferedOutputStream(dOut);
                    int count;
                    if (restart > 0) {
                        dIn.skip(restart);
                        restart = 0;
                    }
                    do {
                        count = dIn.read(buf);
                        if (count > 0)
                            dOut.write(buf, 0, count);
                    } while (count >= 0);
                    dOut.close();
                    dIn.close();
                    out.println("226 Transfer complete.");
                }
            }
        } catch (IOException e) {

        }
    }

    private void doStor(String arg, boolean unique) {
        try {
            InputStream dIn = getInDataStream();
            if (dIn != null) {
                OutputStream dOut = fsh.putFile(arg);
                if (dOut == null) {
                    out.println("500 Can't create file " + arg);
                    dIn.close();
                    return;
                }
                out.println("150 Opening " + (binary ? "BINARY " : "ASCII ") + " data connection for file " + arg);
                if (binary) {
                    byte[] buf = new byte[2048];
                    dOut = new BufferedOutputStream(dOut);
                    int count;
                    do {
                        count = dIn.read(buf);
                        if (count > 0)
                            dOut.write(buf, 0, count);
                    } while (count >= 0);
                    dOut.close();
                    dIn.close();
                    out.println("226 Transfer complete.");
                }
            }
        } catch (IOException e) {

        }
    }

    private void doList() {
        try {
            OutputStream dOut = getOutDataStream();
            if (dOut != null) {
                InputStream dIn = fsh.listCurrentDir();
                if (dIn == null) {
                    out.println("550 File not found.");
                    dOut.close();
                    return;
                }
                out.println("150 Opening ASCII data connection for file list");
                byte[] buf = new byte[2048];
                dOut = new BufferedOutputStream(dOut);
                int count;
                do {
                    count = dIn.read(buf);
                    if (count > 0)
                        dOut.write(buf, 0, count);
                } while (count >= 0);
                dOut.close();
                dIn.close();
                out.println("226 Transfer complete.");
            }
        } catch (IOException e) {

        }
    }

    private boolean useTLS() {
        if (sslFact == null) {
            sslFact = (SSLSocketFactory) SSLSocketFactory.getDefault();
        }
        if (sslFact == null)
            return false;
        return true;
    }

    private void stopTLS() {
        if (useCrypto) {
            SSLSocket ssl = (SSLSocket) cmd;
            try {
                ssl.close();
            } catch (IOException e) {
                // nada
            }
            cmd = oldCmd;
            oldCmd = null;
            try {
                in = new BufferedReader(new InputStreamReader(cmd.getInputStream()));
                out = new PrintStream(cmd.getOutputStream(), true, "ISO8859_1");
            } catch (Exception ex) {

            }
        }
    }

    public void setHandlers(FtpFileSystemHandler f, FtpAuthHandler a) {
        fsh = f;
        auth = a;
    }

    public FtpCommandHandler(Socket cl, FtpServer p) {
        parent = p;
        cmd = cl;
        clientAddr = cl.getInetAddress();
    }

    public void terminate() {
        done = true;
    }

    private int parseCmd(StringBuffer cmd) {

        if (cmd == null || cmd.length() < 3) // Shortest command is 3 char long
            return ERROR;
        int blank = cmd.indexOf(" ");
        if (blank < 0)
            blank = cmd.length();
        if (blank < 3)
            return ERROR;
        String s = cmd.substring(0,blank);
        cmd.delete(0, blank + 1);
        System.out.println("parse: cmd = " + s + " arg = " +cmd.toString());
        for (int i = 0; i < commands.length; i++)
            if (s.equalsIgnoreCase(commands[i]))
                return i;
        // Unknown command
        return ERROR;
    }

    private boolean checkLogged() {
        if (!logged) {
            out.println("530 Not logged in.");
            return false;
        }
        return true;
    }

    public void run() {
        try {
            // cmd.setSoTimeout(2000);
            in = new BufferedReader(new InputStreamReader(cmd.getInputStream()));
            out = new PrintStream(cmd.getOutputStream(), true, "ISO8859_1");
            out.println("220 Java FTP test server (j2se 6.0) ready.");
            out.flush();
            if (auth.authType() == 0) // No auth needed
                logged = true;
        } catch (IOException e) {
            e.printStackTrace();
            return;
        }

        String str;
        StringBuffer buf;
        int res;
        while (!done) {
            try {
                str = in.readLine();
                System.out.println("line: " + str);
                buf = new StringBuffer(str);
                res = parseCmd(buf);
                switch (res) {
                case ERROR:
                    out.println("500 '" + str +"': command not understood.");
                    break;
                case QUIT:
                    out.println("221 Goodbye.");
                    done = true;
                    break;
                case USER:
                    logged = false;
                    username = buf.toString();
                    if (auth.authType() > 1)
                        out.println("331 User name okay, need password.");
                    else {
                        if (auth.authenticate(username, null)) {
                            out.println("230 User logged in, proceed.");
                            logged = true;
                        } else {
                            out.println("331 User name okay, need password.");
                        }
                    }
                    break;
                case PASS:
                    if (logged || (username == null)) {
                        out.println("503 Login with USER first.");
                        break;
                    }
                    password = buf.toString();
                    if (auth.authType() == 3) {
                        out.println("332 Need account for login.");
                        break;
                    }
                    if (auth.authenticate(username, password)) {
                        logged = true;
                        out.println("230 User " + username + " logged in.");
                        break;
                    }
                    out.println("530 Login incorrect.");
                    username = null;
                    break;
                case CWD:
                    if (checkLogged()) {
                        String path = buf.toString();
                        if (fsh.cd(path)) {
                            out.println("250 CWD command successful.");
                        } else {
                            out.println("550 " + path + ": no such file or directory.");
                        }
                    }
                    break;
                case CDUP:
                    if (checkLogged()) {
                        if (fsh.cdUp())
                            out.println("250 CWD command successful.");
                        else
                            out.println("550 invalid path.");
                    }
                    break;
                case PWD:
                    if (checkLogged()) {
                        String s = fsh.pwd();
                        out.println("257 \"" + s + "\" is current directory");
                    }
                    break;
                case NOOP:
                    if (checkLogged()) {
                        out.println("200 NOOP command successful.");
                    }
                    break;
                case PORT:
                    if (checkLogged()) {
                        parsePort(buf.toString());
                    }
                    break;
                case EPRT:
                    if (checkLogged()) {
                        parseEprt(buf.toString());
                    }
                    break;
                case PASV:
                    if (checkLogged())
                        doPasv();
                    break;
                case EPSV:
                    if (checkLogged())
                        doEpsv(buf.toString());
                    break;
                case RETR:
                    if (checkLogged()) {
                        doRetr(buf.toString());
                    }
                    break;
                case SYST:
                    if (checkLogged()) {
                        out.println("215 UNIX Type: L8 Version: Java 6.0");
                    }
                    break;
                case TYPE:
                    if (checkLogged()) {
                        String arg = buf.toString();
                        if (arg.length() != 1 || "AIE".indexOf(arg.charAt(0)) < 0) {
                            out.println("500 'TYPE " + arg + "' command not understood.");
                            continue;
                        }
                        out.println("200 Type set to " + buf.toString() + ".");
                        if (arg.charAt(0) == 'I')
                            binary = true;
                        else
                            binary = false;
                    }
                    break;
                case STOR:
                case STOU:
                    // TODO: separate STOR and STOU (Store Unique)
                    if (checkLogged()) {
                        doStor(buf.toString(), false);
                    }
                    break;
                case LIST:
                    if (checkLogged()) {
                        doList();
                    }
                    break;
                case NLST:
                    // TODO: implememt
                    break;
                case DELE:
                    if (checkLogged()) {
                        String arg = buf.toString();
                        if (fsh.removeFile(arg)) {
                            out.println("250 file " + arg + " deleted.");
                            break;
                        }
                        out.println("550 " + arg + ": no such file or directory.");
                    }
                    break;
                case RNFR:
                    if (checkLogged()) {
                        if (renameFrom != null) {
                            out.println("503 Bad sequence of commands.");
                            break;
                        }
                        renameFrom = buf.toString();
                        if (fsh.fileExists(renameFrom)) {
                            out.println("350 File or directory exists, ready for destination name.");
                        } else {
                            out.println("550 " + renameFrom + ": no such file or directory");
                            renameFrom = null;
                        }
                    }
                    break;
                case RNTO:
                    if (checkLogged()) {
                        if (renameFrom == null) {
                            out.println("503 Bad sequence of commands.");
                            break;
                        }
                        if (fsh.rename(renameFrom, buf.toString())) {
                            out.println("250 Rename successful");
                        } else {
                            out.println("550 Rename ");
                        }
                        renameFrom = null;
                    }
                    break;
                case REST:
                    if (checkLogged()) {
                        String arg = buf.toString();
                        restart = Long.parseLong(arg);
                        if (restart > 0)
                            out.println("350 Restarting at " + restart + ". Send STORE or RETRIEVE to initiate transfer");
                        else
                            out.println("501 Syntax error in command of arguments.");
                    }
                    break;
                case FEAT:
                    out.println("211-Features:");
                    out.println(" REST STREAM");
                    out.println(" PBSZ");
                    out.println(" AUTH TLS");
                    out.println(" PROT P");
                    out.println(" CCC");
                    out.println("211 End");
                    break;
                case AUTH:
                    if ("TLS".equalsIgnoreCase(buf.toString()) && useTLS()) {
                        out.println("234 TLS Authentication OK.");
                        out.flush();
                        SSLSocket ssl;
                        String[] suites = sslFact.getSupportedCipherSuites();
                        try {
                            ssl = (SSLSocket) sslFact.createSocket(cmd, cmd.getInetAddress().getHostName(), cmd.getPort(), false);
                            ssl.setUseClientMode(false);
                            ssl.setEnabledCipherSuites(suites);
                            ssl.startHandshake();
                        } catch (IOException ioe) {
                            ioe.printStackTrace();
                            out.println("550 Unable to create secure channel.");
                            break;
                        }
                        oldCmd = cmd;
                        cmd = ssl;
                        out = new PrintStream(cmd.getOutputStream(), true, "ISO8859_1");
                        in = new BufferedReader(new InputStreamReader(cmd.getInputStream()));
                        System.out.println("Secure socket created!");
                        useCrypto = true;
                        break;
                    }
                    out.println("501 Unknown or unsupported AUTH type");
                    break;
                case CCC:
                    out.println("200 Command OK.");
                    stopTLS();
                    break;
                case PROT:
                    String arg = buf.toString();
                    if ("C".equalsIgnoreCase(arg)) {
                        // PROT C : Clear protection level
                        // No protection on data channel;
                        useDataCrypto = false;
                        out.println("200 Command OK.");
                        break;
                    }
                    if ("P".equalsIgnoreCase(arg)) {
                        // PROT P : Private protection level
                        // Data channel is integrity and confidentiality protected
                        useDataCrypto = true;
                        out.println("200 Command OK.");
                        break;
                    }
                    out.println("537 Requested PROT level not supported by security mechanism.");
                    break;
                case PBSZ:
                    // TODO: finish
                    out.println("200 Command OK.");
                    break;

                }

            } catch (InterruptedIOException ie) {
                // loop
            } catch (IOException e) {
                e.printStackTrace();
                return;
            }
        }
        try {
            in.close();
            out.close();
            cmd.close();
        } catch (IOException e) {
        }
        parent.removeClient(this);
    }
}

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