    001    /*
    002     * Licensed to the Apache Software Foundation (ASF) under one or more
    003     * contributor license agreements.  See the NOTICE file distributed with
    004     * this work for additional information regarding copyright ownership.
    005     * The ASF licenses this file to You under the Apache License, Version 2.0
    006     * (the "License"); you may not use this file except in compliance with
    007     * the License.  You may obtain a copy of the License at
    008     *
    009     *      http://www.apache.org/licenses/LICENSE-2.0
    010     *
    011     * Unless required by applicable law or agreed to in writing, software
    012     * distributed under the License is distributed on an "AS IS" BASIS,
    013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014     * See the License for the specific language governing permissions and
    015     * limitations under the License.
    016     */
    017
    018    package org.apache.commons.net.ftp;
    019
    020    import java.io.BufferedReader;
    021    import java.io.IOException;
    022    import java.io.InputStream;
    023    import java.io.InputStreamReader;
    024    import java.io.OutputStream;
    025    import java.io.UnsupportedEncodingException;
    026    import java.net.Inet6Address;
    027    import java.net.Socket;
    028    import java.net.SocketException;
    029    import java.util.ArrayList;
    030    import java.util.List;
    031
    032    import org.apache.commons.net.util.Base64;
    033
    034    /**
    035     * Experimental attempt at FTP client that tunnels over an HTTP proxy connection.
    036     *
    037     * @since 2.2
    038     */
    039    public class FTPHTTPClient extends FTPClient {
    040        private final String proxyHost;
    041        private final int proxyPort;
    042        private final String proxyUsername;
    043        private final String proxyPassword;
    044
    045        private static final byte[] CRLF={'\r', '\n'};
    046        private final Base64 base64 = new Base64();
    047
    048        public FTPHTTPClient(String proxyHost, int proxyPort, String proxyUser, String proxyPass) {
    049            this.proxyHost = proxyHost;
    050            this.proxyPort = proxyPort;
    051            this.proxyUsername = proxyUser;
    052            this.proxyPassword = proxyPass;
    053        }
    054
    055        public FTPHTTPClient(String proxyHost, int proxyPort) {
    056            this(proxyHost, proxyPort, null, null);
    057        }
    058
    059
    060        /**
    061         * {@inheritDoc}
    062         *
    063         * @throws IllegalStateException if connection mode is not passive
    064         */
    065        // Kept to maintain binary compatibility
    066        // Not strictly necessary, but Clirr complains even though there is a super-impl
    067        @Override
    068        protected Socket _openDataConnection_(int command, String arg)
    069        throws IOException {
    070            return super._openDataConnection_(command, arg);
    071        }
    072
    073        /**
    074         * {@inheritDoc}
    075         *
    076         * @throws IllegalStateException if connection mode is not passive
    077         */
    078        @Override
    079        protected Socket _openDataConnection_(String command, String arg)
    080        throws IOException {
    081            //Force local passive mode, active mode not supported by through proxy
    082            if (getDataConnectionMode() != PASSIVE_LOCAL_DATA_CONNECTION_MODE) {
    083                throw new IllegalStateException("Only passive connection mode supported");
    084            }
    085
    086            final boolean isInet6Address = getRemoteAddress() instanceof Inet6Address;
    087
    088            boolean attemptEPSV = isUseEPSVwithIPv4() || isInet6Address;
    089            if (attemptEPSV && epsv() == FTPReply.ENTERING_EPSV_MODE) {
    090                _parseExtendedPassiveModeReply(_replyLines.get(0));
    091            } else {
    092                if (isInet6Address) {
    093                    return null; // Must use EPSV for IPV6
    094                }
    095                // If EPSV failed on IPV4, revert to PASV
    096                if (pasv() != FTPReply.ENTERING_PASSIVE_MODE) {
    097                    return null;
    098                }
    099                _parsePassiveModeReply(_replyLines.get(0));
    100            }
    101
    102            Socket socket = new Socket(proxyHost, proxyPort);
    103            InputStream is = socket.getInputStream();
    104            OutputStream os = socket.getOutputStream();
    105            tunnelHandshake(this.getPassiveHost(), this.getPassivePort(), is, os);
    106            if ((getRestartOffset() > 0) && !restart(getRestartOffset())) {
    107                socket.close();
    108                return null;
    109            }
    110
    111            if (!FTPReply.isPositivePreliminary(sendCommand(command, arg))) {
    112                socket.close();
    113                return null;
    114            }
    115
    116            return socket;
    117        }
    118
    119        @Override
    120        public void connect(String host, int port) throws SocketException, IOException {
    121
    122            _socket_ = new Socket(proxyHost, proxyPort);
    123            _input_ = _socket_.getInputStream();
    124            _output_ = _socket_.getOutputStream();
    125            try {
    126                tunnelHandshake(host, port, _input_, _output_);
    127            }
    128            catch (Exception e) {
    129                IOException ioe = new IOException("Could not connect to " + host+ " using port " + port);
    130                ioe.initCause(e);
    131                throw ioe;
    132            }
    133            super._connectAction_();
    134        }
    135
    136        private void tunnelHandshake(String host, int port, InputStream input, OutputStream output) throws IOException,
    137        UnsupportedEncodingException {
    138            final String connectString = "CONNECT "  + host + ":" + port  + " HTTP/1.1";
    139            final String hostString = "Host: " + host + ":" + port;
    140
    141            output.write(connectString.getBytes("UTF-8")); // TODO what is the correct encoding?
    142            output.write(CRLF);
    143            output.write(hostString.getBytes("UTF-8"));
    144            output.write(CRLF);
    145
    146            if (proxyUsername != null && proxyPassword != null) {
    147                final String auth = proxyUsername + ":" + proxyPassword;
    148                final String header = "Proxy-Authorization: Basic "
    149                    + base64.encodeToString(auth.getBytes("UTF-8"));
    150                output.write(header.getBytes("UTF-8"));
    151            }
    152            output.write(CRLF);
    153
    154            List<String> response = new ArrayList<String>();
    155            BufferedReader reader = new BufferedReader(
    156                    new InputStreamReader(input));
    157
    158            for (String line = reader.readLine(); line != null
    159            && line.length() > 0; line = reader.readLine()) {
    160                response.add(line);
    161            }
    162
    163            int size = response.size();
    164            if (size == 0) {
    165                throw new IOException("No response from proxy");
    166            }
    167
    168            String code = null;
    169            String resp = response.get(0);
    170            if (resp.startsWith("HTTP/") && resp.length() >= 12) {
    171                code = resp.substring(9, 12);
    172            } else {
    173                throw new IOException("Invalid response from proxy: " + resp);
    174            }
    175
    176            if (!"200".equals(code)) {
    177                StringBuilder msg = new StringBuilder();
    178                msg.append("HTTPTunnelConnector: connection failed\r\n");
    179                msg.append("Response received from the proxy:\r\n");
    180                for (String line : response) {
    181                    msg.append(line);
    182                    msg.append("\r\n");
    183                }
    184                throw new IOException(msg.toString());
    185            }
    186        }
    187    }
    188
    189