org.commoncrawl.service.listcrawler.RequestLogServlet.java Source code

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Here is the source code for org.commoncrawl.service.listcrawler.RequestLogServlet.java

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/**
 * Copyright 2008 - CommonCrawl Foundation
 * 
 *    This program 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.
 *
 *    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 General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 **/

package org.commoncrawl.service.listcrawler;

import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.commoncrawl.util.LogFileUtils;

/** 
 * 
 * A custom servlet used to serve up this crawler's cache request log  
 * 
 * @author rana
 *
 */
public class RequestLogServlet extends HttpServlet {

    public static final String servletPath = "/requestLog";
    private static final Log LOG = LogFactory.getLog(RequestLogServlet.class);

    private static final int DEFAULT_MAX_LINES = 25;

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        int maxLines = DEFAULT_MAX_LINES;

        if (req.getParameter("maxLines") == null) {
            resp.sendRedirect(resp.encodeRedirectURL(servletPath + "?maxLines=25"));
        } else {
            try {
                maxLines = Integer.parseInt(req.getParameter("maxLines"));
            } catch (NumberFormatException e) {

            }

            File requestLogFile = new File(ProxyServer.getSingleton().getLogDirectory(),
                    ProxyServer.getRequestLogFileName());

            List<String> tailList = LogFileUtils.tail(requestLogFile, maxLines);

            resp.setContentType("text/plain");
            PrintWriter writer = resp.getWriter();
            try {
                for (String line : tailList) {
                    writer.println(line);
                }
            } finally {
                writer.flush();
                writer.close();
            }
        }
    }

}