org.vsearchd.crawler.backend.BackendSessionHTTP.java Source code

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Here is the source code for org.vsearchd.crawler.backend.BackendSessionHTTP.java

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/*
 * vsearchd - a focused crawler
 *
 * Copyright (C) 2012-2014  Michael Kassnel 
 * 
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License (Version 3) as published
 * by the Free Software Foundation.
 * 
 * This program 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 Lesser General Public License for more details:
 * http://www.gnu.org/licenses/lgpl.txt
 *
 */

package org.vsearchd.crawler.backend;

import java.io.IOException;
import java.io.InputStream;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URLEncoder;
import java.util.ArrayList;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.HttpVersion;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.params.BasicHttpParams;
import org.apache.http.params.HttpConnectionParams;
import org.apache.http.params.HttpParams;
import org.apache.http.params.HttpProtocolParams;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.vsearchd.crawler.outmessage.OutputField;
import org.vsearchd.crawler.outmessage.OutputMessage;
import org.vsearchd.crawler.outmessage.OutputMessageFactory;
import org.vsearchd.crawler.outmessage.OutputMessageReader;

public class BackendSessionHTTP extends BackendSessionBase implements IBackendSession {

    private Logger log = LoggerFactory.getLogger(getClass().getName());

    private OutputMessageReader reader = new OutputMessageReader();
    private OutputMessage message = null;
    private HttpClient httpclient = null;
    private HttpPost httppost = null;
    private HttpParams params = new BasicHttpParams();
    private ArrayList<NameValuePair> para = new ArrayList<NameValuePair>();
    private UrlEncodedFormEntity formEntity = null;
    private HttpResponse response = null;
    private InputStream instr = null;
    private HttpEntity entity = null;

    public BackendSessionHTTP(BackendServer srv) {
        super(srv);
    }

    public synchronized void connect() {
        httpclient = new DefaultHttpClient();
        httppost = new HttpPost();

        HttpProtocolParams.setVersion(params, HttpVersion.HTTP_1_1);
        HttpProtocolParams.setContentCharset(params, "UTF-8");
        HttpProtocolParams.setUseExpectContinue(params, false);
        HttpProtocolParams.setUserAgent(params, "vsearchd::backend-worker");
        HttpConnectionParams.setStaleCheckingEnabled(params, false);

        httppost.setParams(params);
    }

    public synchronized void disconnect() {
        httpclient.getConnectionManager().shutdown();
    }

    public synchronized void sendMessage(String msg) {

        try {
            this.reader.Read(msg);
        } catch (Exception e) {
            log.error(e.getMessage());
            return;
        }
        this.message = reader.getOutputMessage();
        this.handleOutputMessage();
        this.message.Reset();

        OutputMessageFactory.getInstance().Reset(this.message.getId());
    }

    private void handleOutputMessage() {

        try {
            para.clear();

            for (OutputField field : this.message.getFields()) {
                para.add(new BasicNameValuePair(field.getName(), URLEncoder.encode(field.getValue(), "UTF-8")));
            }

            formEntity = new UrlEncodedFormEntity(para);
            httppost.setURI(new URI("http://" + this.getBackendServer().getHost() + ":"
                    + String.valueOf(this.getBackendServer().getPort()) + "/"
                    + this.getBackendServer().getFilePath()));

            httppost.setEntity(formEntity);
            response = httpclient.execute(httppost);

            entity = response.getEntity();
            instr = entity.getContent();

            while (instr.read() > -1)
                ;
            instr.close();

        } catch (ClientProtocolException e) {
            log.error(e.getMessage());
        } catch (IOException e) {
            log.error(e.getMessage());
        } catch (URISyntaxException e) {
            log.error(e.getMessage());
        }
    }
}