com.envirover.rockblock.RockBlockHttpHandler.java Source code

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Here is the source code for com.envirover.rockblock.RockBlockHttpHandler.java

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/*
This file is part of SPLGroundControl application.
    
SPLGroundControl is a MAVLink proxy server for ArduPilot rovers with
RockBLOCK satellite communication.
    
See http://www.rock7mobile.com/downloads/RockBLOCK-Web-Services-User-Guide.pdf
    
Copyright (C) 2017 Envirover
    
SPLGroundControl is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
    
SPLGroundControl 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 for more details.
    
You should have received a copy of the GNU General Public License
along with SPLGroundControl.  If not, see <http://www.gnu.org/licenses/>.
*/

package com.envirover.rockblock;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.StringWriter;
import java.nio.charset.Charset;
import java.text.MessageFormat;
import java.util.List;

import org.apache.commons.codec.DecoderException;
import org.apache.commons.codec.binary.Hex;

import org.apache.commons.io.IOUtils;
import org.apache.http.NameValuePair;
import org.apache.http.client.utils.URLEncodedUtils;
import org.apache.log4j.Level;
import org.apache.log4j.Logger;

import com.MAVLink.MAVLinkPacket;
import com.MAVLink.Parser;
import com.envirover.mavlink.MAVLinkChannel;
import com.envirover.mavlink.MAVLinkLogger;
import com.sun.net.httpserver.HttpExchange;
import com.sun.net.httpserver.HttpHandler;

/**
 * Handles HTTP requests with messages sent by RockBLOCK.
 *
 */
@SuppressWarnings("restriction")
public class RockBlockHttpHandler implements HttpHandler {

    private final static Logger logger = Logger.getLogger(RockBlockHttpHandler.class);

    private final MAVLinkChannel dst;
    private final String imei;

    /**
     * Constructs instance of RockBlockHttpHandler.
     * 
     * @param dst MAVLink message handler
     * @param imei RockBLOCK imei
     */
    public RockBlockHttpHandler(MAVLinkChannel dst, String imei) {
        this.dst = dst;
        this.imei = imei;
    }

    @Override
    public void handle(HttpExchange t) throws IOException {
        try {
            InputStream is = t.getRequestBody();
            StringWriter writer = new StringWriter();
            IOUtils.copy(is, writer, "UTF-8");
            String theString = writer.toString();

            List<NameValuePair> params = URLEncodedUtils.parse(theString, Charset.forName("UTF-8"));

            IridiumMessage message = new IridiumMessage(params);

            logger.debug(message);

            if (message.data == null || message.data.isEmpty()) {
                logger.info(MessageFormat.format("Empty MO message received ''{0}''.", message.toString()));
            } else if (message.imei.equalsIgnoreCase(imei)) {
                MAVLinkPacket packet = message.getPacket();

                if (packet != null) {
                    MAVLinkLogger.log(Level.INFO, "MO", packet);

                    dst.sendMessage(packet);
                } else {
                    logger.warn(MessageFormat.format("Invalid MAVLink message ''{0}''.", message.toString()));
                }
            } else {
                logger.warn(MessageFormat.format("Invalid IMEI ''{0}''.", message.imei));
            }

            //Send response
            String response = "";
            t.sendResponseHeaders(200, response.length());
            OutputStream os = t.getResponseBody();
            os.write(response.getBytes());
            os.close();
        } catch (DecoderException e) {
            logger.error(e.getMessage());
            throw new IOException(e.getMessage());
        }
    }

    class IridiumMessage {
        // HTTP POST request parameters

        // IMEI of the RockBLOCK
        private final static String PARAM_IMEI = "imei";
        // Message Sequence Number
        private final static String PARAM_MOMSN = "momsn";
        // UTC date & time
        private final static String PARAM_TRANSMIT_TIME = "transmit_time";
        // Approximate latitude of the RockBLOCK
        private final static String PARAM_IRIDIUM_LATITUDE = "iridium_latitude";
        // Approximate longitude of the RockBLOCK
        private final static String PARAM_IRIDIUM_LONGITUDE = "iridium_longitude";
        // Estimate of the accuracy (in km) of the position
        private final static String PARAM_IRIDIUM_CEP = "iridium_cep";
        // Hex-encoded message.
        private final static String PARAM_DATA = "data";

        private String imei = null;
        private String momsn = null;
        private String transmitTime = null;
        private String iridiumLatitude = null;
        private String iridiumLongitude = null;
        private String iridiumCep = null;
        private String data = null;

        public IridiumMessage(List<NameValuePair> params) {
            for (NameValuePair param : params) {
                switch (param.getName()) {
                case PARAM_IMEI:
                    imei = param.getValue();
                    break;
                case PARAM_MOMSN:
                    momsn = param.getValue();
                    break;
                case PARAM_TRANSMIT_TIME:
                    transmitTime = param.getValue();
                    break;
                case PARAM_IRIDIUM_LATITUDE:
                    iridiumLatitude = param.getValue();
                    break;
                case PARAM_IRIDIUM_LONGITUDE:
                    iridiumLongitude = param.getValue();
                    break;
                case PARAM_IRIDIUM_CEP:
                    iridiumCep = param.getValue();
                    break;
                case PARAM_DATA:
                    data = param.getValue();
                    break;
                }
            }
        }

        public MAVLinkPacket getPacket() throws DecoderException {
            Parser parser = new Parser();
            MAVLinkPacket packet = null;

            for (byte b : Hex.decodeHex(data.toCharArray())) {
                packet = parser.mavlink_parse_char(b & 0xFF);
            }

            return packet;
        }

        @Override
        public String toString() {
            return String.format("%s %s %s %s %s %s %s", imei, momsn, transmitTime, iridiumLatitude,
                    iridiumLongitude, iridiumCep, data);
        }
    }

}