gsn.wrappers.general.HttpGetWrapper.java Source code

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Here is the source code for gsn.wrappers.general.HttpGetWrapper.java

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/**
* Global Sensor Networks (GSN) Source Code
* Copyright (c) 2006-2014, Ecole Polytechnique Federale de Lausanne (EPFL)
* 
* This file is part of GSN.
* 
* GSN 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.
* 
* GSN 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 GSN.  If not, see <http://www.gnu.org/licenses/>.
* 
* File: src/gsn/wrappers/general/HttpGetWrapper.java
*
* @author Ali Salehi
* @author Mehdi Riahi
*
*/

package gsn.wrappers.general;

import gsn.beans.AddressBean;
import gsn.beans.DataField;
import gsn.wrappers.AbstractWrapper;

import java.io.BufferedInputStream;
import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

import org.apache.commons.io.output.ByteArrayOutputStream;
import org.slf4j.LoggerFactory;
import org.slf4j.Logger;

public class HttpGetWrapper extends AbstractWrapper {

    private int DEFAULT_RATE = 2000;

    private static int threadCounter = 0;

    private final transient Logger logger = LoggerFactory.getLogger(HttpGetWrapper.class);

    private String urlPath;

    private HttpURLConnection httpURLConnection;

    private URL url;

    private AddressBean addressBean;

    private String inputRate;

    private int rate;

    private transient final DataField[] outputStructure = new DataField[] {
            new DataField("data", "binary:image/jpeg", "JPEG image from the remote networked camera.") };

    /**
     * From XML file it needs the followings :
     * <ul>
     * <li>url</li> The full url for retriving the binary data.
     * <li>rate</li> The interval in msec for updating/asking for new information.
     * <li>mime</li> Type of the binary data.
     * </ul>
     */
    public boolean initialize() {
        this.addressBean = getActiveAddressBean();
        urlPath = this.addressBean.getPredicateValue("url");
        try {
            url = new URL(urlPath);
        } catch (MalformedURLException e) {
            logger.error("Loading the http wrapper failed : " + e.getMessage(), e);
            return false;
        }
        inputRate = this.addressBean.getPredicateValue("rate");
        if (inputRate == null || inputRate.trim().length() == 0)
            rate = DEFAULT_RATE;
        else
            rate = Integer.parseInt(inputRate);
        logger.debug("AXISWirelessCameraWrapper is now running @" + rate + " Rate.");
        return true;
    }

    public void run() {
        ByteArrayOutputStream arrayOutputStream = new ByteArrayOutputStream(1024 * 20);
        byte[] buffer = new byte[16 * 1024];
        BufferedInputStream content;
        while (isActive()) {
            try {
                Thread.sleep(rate);
                httpURLConnection = (HttpURLConnection) url.openConnection();
                httpURLConnection.connect();
                if (httpURLConnection.getResponseCode() == HttpURLConnection.HTTP_ACCEPTED)
                    continue;
                content = new BufferedInputStream(httpURLConnection.getInputStream(), 4096);
                arrayOutputStream.reset();
                int readIndex = -1;
                while ((readIndex = content.read(buffer)) != -1)
                    arrayOutputStream.write(buffer, 0, readIndex);
                postStreamElement(arrayOutputStream.toByteArray());
            } catch (InterruptedException e) {
                logger.error(e.getMessage(), e);
            } catch (IOException e) {
                logger.error(e.getMessage(), e);
            }
        }
    }

    public String getWrapperName() {
        return "Http Receiver";
    }

    public void dispose() {
        threadCounter--;
    }

    public DataField[] getOutputFormat() {
        return outputStructure;
    }

}