src/main/java/org/apache/sling/tail/impl/LogTailerWebConsolePlugin.java - sling-org-apache-sling-tail - Git at Google

 package org.apache.sling.tail.impl;

 /*
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information
  * regarding copyright ownership.  The ASF licenses this file
  * to you under the Apache License, Version 2.0 (the
  * "License"); you may not use this file except in compliance
  * with the License.  You may obtain a copy of the License at
  *
  *   http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing,
  * software distributed under the License is distributed on an
  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  * KIND, either express or implied.  See the License for the
  * specific language governing permissions and limitations
  * under the License.
  */

 import ch.qos.logback.classic.LoggerContext;
 import ch.qos.logback.classic.spi.ILoggingEvent;
 import ch.qos.logback.core.Appender;
 import ch.qos.logback.core.FileAppender;
 import org.apache.felix.scr.annotations.*;
 import org.apache.felix.scr.annotations.Properties;
 import org.apache.felix.webconsole.AbstractWebConsolePlugin;
 import org.apache.felix.webconsole.WebConsoleConstants;
 import org.apache.sling.commons.json.io.JSONWriter;
 import org.apache.sling.tail.LogFilter;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;

 import javax.servlet.Servlet;
 import javax.servlet.ServletException;
 import javax.servlet.http.Cookie;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import java.io.File;
 import java.io.IOException;
 import java.io.PrintWriter;
 import java.io.RandomAccessFile;
 import java.util.*;

 /**
  *
  */
 @Component
 @Service(value = { Servlet.class })
 @Properties({
         @Property(name=org.osgi.framework.Constants.SERVICE_DESCRIPTION,
                 value="Apache Sling Web Console Plugin to tail log(s) of this Sling instance"),
         @Property(name= WebConsoleConstants.PLUGIN_LABEL, value=LogTailerWebConsolePlugin.LABEL),
         @Property(name=WebConsoleConstants.PLUGIN_TITLE, value=LogTailerWebConsolePlugin.TITLE),
         @Property(name="felix.webconsole.configprinter.modes", value={"always"})
 })
 public class LogTailerWebConsolePlugin extends AbstractWebConsolePlugin {
     public static final String LABEL = "tail";
     public static final String TITLE = "Tail Logs";

     private final Logger log = LoggerFactory.getLogger(this.getClass());

     private static final int LINES_TO_TAIL = 100;
     private static final String POSITION_COOKIE = "log.tail.position";
     private static final String FILTER_COOKIE = "log.tail.filter";
     private static final String MODIFIED_COOKIE = "log.modified";
     private static final String CREATED_COOKIE = "log.created";

     private String fileName = "";
     private File errLog;

     @Override
     protected void renderContent(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
         if(isAjaxRequest(request)) {

             parseCommand(request, response);

             RandomAccessFile randomAccessFile = null;

             try {

                 try {
                     randomAccessFile = new RandomAccessFile(errLog, "r");
                     log.debug("Tailing file " + fileName + " of length " + randomAccessFile.length());
                 } catch (Exception e) {
                     log.error("Error reading " + fileName, e);
                     response.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
                     return;
                 }

                 JSONWriter json = new JSONWriter(response.getWriter());
                 json.setTidy(true);
                 json.object();

                 boolean reverse = false;
                 //long created = getCreatedTimestampFromCookie(request);
             /*long modified = getModifiedTimestampFromCookie(request);
             if(errLog.lastModified() == modified) {
                 json.endObject();
                 return;
             }
             else {
                  persistCookie(response, MODIFIED_COOKIE, String.valueOf(errLog.lastModified()));
             }*/
                 long pos = getPositionFromCookie(request);
                 if(pos < 0) {
                     pos = randomAccessFile.length()-1;
                     reverse = true;
                 }
                 else if(pos > randomAccessFile.length()) {//file rotated
                     pos = 0;
                 }
                 LogFilter[] query = getQueryFromCookie(request);

                 if(reverse) {
                     randomAccessFile.seek(pos);
                     if(randomAccessFile.read() == '\n') {
                         pos--;
                         randomAccessFile.seek(pos);
                         if(randomAccessFile.read() == '\r') {
                             pos--;
                         }
                     }

                     json.key("content").array();
                     int found = 0;
                     StringBuilder sb = new StringBuilder();
                     String line = null;
                     List<String> lines = new ArrayList<String>();
                     while(found != LINES_TO_TAIL && pos > 0) {
                         boolean eol = false;
                         randomAccessFile.seek(pos);
                         int c = randomAccessFile.read();
                         if(c == '\n') {
                             found++;
                             sb = sb.reverse();
                             line = sb.toString();
                             sb = new StringBuilder();
                             eol = true;
                             pos--;
                             if(pos > 0) {
                                 randomAccessFile.seek(pos);
                                 if(randomAccessFile.read() == '\r') {
                                     pos--;
                                 }
                             }
                         }
                         else {
                             sb.append((char)c);
                             pos--;
                         }

                         if(eol) {
                             if(filter(line, query)){
                                 lines.add(line);
                             }
                         }
                     }

                     if(pos < 0) {
                         if(filter(line, query)){
                             lines.add(line);
                         }
                     }
                     for(int i=lines.size()-1; i > -1; i--) {
                         json.object().key("line").value(lines.get(i)).endObject();
                     }
                     json.endArray();
                     json.endObject();
                 }
                 else {
                     randomAccessFile.seek(pos);
                     String line = null;
                     int lineCount = 0;
                     json.key("content").array();
                     boolean read = true;
                     while(read) {
                         StringBuilder input = new StringBuilder();
                         int c = -1;
                         boolean eol = false;

                         while (!eol) {
                             switch (c = randomAccessFile.read()) {
                                 case -1:
                                 case '\n':
                                     eol = true;
                                     break;
                                 case '\r':
                                     eol = true;
                                     long cur = randomAccessFile.getFilePointer();
                                     if ((randomAccessFile.read()) != '\n') {
                                         randomAccessFile.seek(cur);
                                     }
                                     break;
                                 default:
                                     input.append((char)c);
                                     break;
                             }
                         }

                         if ((c == -1) && (input.length() == 0)) {
                             read = false;
                             continue;
                         }
                         line = input.toString();
                         lineCount++;
                         if(lineCount == LINES_TO_TAIL) {
                             read = false;
                         }
                         pos = randomAccessFile.getFilePointer();

                         if(filter(line, query)){
                             json.object().key("line").value(line).endObject();
                         }
                     }
                     json.endArray();
                     json.endObject();
                 }

                 persistCookie(response, POSITION_COOKIE, String.valueOf(randomAccessFile.getFilePointer()));

             } catch (Exception e) {
                 log.error("Error tailing " + fileName, e);
                 response.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
             }
             finally {
                 try {
                     if(randomAccessFile != null) {
                         randomAccessFile.close();
                     }
                 }
                 catch (Exception e) {
                     log.error("Error closing " + fileName, e);
                 }
             }
         }
         else {
             PrintWriter printWriter = response.getWriter();
             printWriter.println("<script type=\"text/javascript\" src=\"/libs/sling/logtail-plugin/js/tail.js\"></script>");
             printWriter.println("<link href=\"/libs/sling/logtail-plugin/css/tail.css\" rel=\"stylesheet\" type=\"text/css\"></link>");
             printWriter.println("<div class=\"header-cont\">");
             printWriter.println("   <div class=\"header\" style=\"display:none;\">");
             printWriter.println("       <table>");
             printWriter.println("           <tr>");
             printWriter.println("               <td><button class=\"numbering\" title=\"Show Line Numbers\" data-numbers=\"false\">Show Line No.</button></td>");
             printWriter.println("               <td><button class=\"pause\" title=\"Pause\">Pause</button></td>");
             printWriter.println("               <td class=\"longer\"><label>Sync frequency(msec)</label>");
             printWriter.println("                   <button class=\"faster\" title=\"Sync Faster\">-</button>");
             printWriter.println("                   <input id=\"speed\" type=\"text\" value=\"3000\"/>");
             printWriter.println("                   <button class=\"slower\" title=\"Sync Slower\">+</button></td>");
             printWriter.println("               <td><button class=\"tail\" title=\"Unfollow Tail\" data-following=\"true\">Unfollow</button></td>");
             printWriter.println("               <td><button class=\"highlighting\" title=\"Highlight\">Highlight</button></td>");
             printWriter.println("               <td><button class=\"clear\" title=\"Clear Display\">Clear</button></td>");
             printWriter.println("               <td class=\"longer\"><input id=\"filter\" type=\"text\"/><span class=\"filterClear ui-icon ui-icon-close\" title=\"Clear Filter\">&nbsp;</span><button class=\"filter\" title=\"Filter Logs\">Filter</button></td>");
             printWriter.println("               <td><button class=\"refresh\" title=\"Reload Logs\">Reload</button></td>");
             printWriter.println("               <td><button class=\"sizeplus\" title=\"Bigger\">a->A</button></td>");
             printWriter.println("               <td><button class=\"sizeminus\" title=\"Smaller\">A->a</button></td>");
             printWriter.println("               <td><button class=\"top\" title=\"Scroll to Top\">Top</button></td>");
             printWriter.println("               <td><button class=\"bottom\" title=\"Scroll to Bottom\">Bottom</button></td>");
             printWriter.println("           </tr>");
             printWriter.println("           <tr>");
             printWriter.println("               <td class=\"loadingstatus\" colspan=\"2\" data-status=\"inactive\"><ul><li></li></ul></td>");
             printWriter.println("               <td>Tailing &nbsp; <select id=\"logfiles\">" + getOptions() + "</select></td>");
             printWriter.println("           </tr>");
             printWriter.println("       </table>");
             printWriter.println("   </div>");
             printWriter.println("   <div class=\"pulldown\" title=\"Click to show options\">&nbsp;==&nbsp;</div>");
             printWriter.println("</div>");
             printWriter.println("");
             printWriter.println("   <div class=\"content\">");
             printWriter.println("");
             printWriter.println("       <div id=\"logarea\"></div>");
             printWriter.println("");
             printWriter.println("   </div>");
         }
     }

     protected void parseCommand(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
         String cmd = request.getParameter("command");
         if(cmd == null) {
             return;
         }

         if(cmd.equals("reset")) {
             deleteCookie(response, FILTER_COOKIE);
         }
         else if(cmd.startsWith("filter:")) {
             String queryStr = cmd.substring(7);
             if(queryStr.length()==0) {
                 deleteCookie(response, FILTER_COOKIE);
             }
             else {
                 persistCookie(response, FILTER_COOKIE, queryStr);
                 log.info("Filtering on : " + queryStr);
             }
         }
         else if(cmd.startsWith("file:")) {
             if(!fileName.equals(cmd.substring(5))) {
                 deleteCookie(response, FILTER_COOKIE);
                 deleteCookie(response, POSITION_COOKIE);
                 fileName = cmd.substring(5);
                 errLog = new File(filePathMap.get(fileName));
                 if(!errLog.exists()) {
                     throw new ServletException("File " + fileName + " doesn't exist");
                 }
                 if(!errLog.canRead()) {
                     throw new ServletException("Cannot read file " + fileName);
                 }
             }
         }
     }

     @Override
     public String getLabel() {
         return LABEL;
     }

     @Override
     public String getTitle() {
         return TITLE;
     }

     private HashMap<String, String> filePathMap = new HashMap<String, String>();

     private String getKey(File file) {
         if(!filePathMap.containsKey(file.getName())) {
             filePathMap.put(file.getName(), file.getAbsolutePath());
         }
         return file.getName();
     }

     private String getOptions() {
         Set<String> logFiles = new HashSet<String>();
         LoggerContext context = (LoggerContext)LoggerFactory.getILoggerFactory();
         for (ch.qos.logback.classic.Logger logger : context.getLoggerList()) {
             for (Iterator<Appender<ILoggingEvent>> index = logger.iteratorForAppenders(); index.hasNext();) {
                 Appender<ILoggingEvent> appender = index.next();
                 if(appender instanceof FileAppender) {
                     FileAppender fileAppender = (FileAppender) appender;
                     String logfilePath = fileAppender.getFile();
                     logFiles.add(logfilePath);
                 }
             }
         }

         String logFilesHtml = "<option value=\"\"> - Select file - </option>";
         for(String logFile : logFiles) {
             File file = new File(logFile);
             logFilesHtml += "<option value=\"" + getKey(file) + "\">" + file.getName() + "</option>";
         }
         return logFilesHtml;
     }

     @Override
     protected boolean isHtmlRequest( final HttpServletRequest request ) {
         return !isAjaxRequest(request);
     }

     private boolean isAjaxRequest( final HttpServletRequest request) {
         return "XMLHttpRequest".equals(request.getHeader("X-Requested-With"));
     }

     private boolean filter(String str, LogFilter[] query) {
         if(query != null) {
             for(LogFilter q : query) {
                 if(!q.eval(str)) {
                     return false;
                 }
             }
         }
         return true;
     }

     private void deleteCookie(HttpServletResponse response, String name) {
         Cookie cookie = new Cookie(name, "");
         cookie.setMaxAge(0);
         response.addCookie(cookie);
         log.debug("Deleting cookie :: " + cookie.getName());
     }

     private void persistCookie(HttpServletResponse response, String name, String value) {
         Cookie cookie = new Cookie(name , value);
         //cookie.setPath("/system/console/" + LABEL);
         response.addCookie(cookie);
         log.debug("Adding cookie :: " + cookie.getName() + " " + cookie.getValue());
     }

     private LogFilter[] getQueryFromCookie(HttpServletRequest request) {
         try {
             for(Cookie cookie : request.getCookies()) {
                 if(cookie.getName().equals(FILTER_COOKIE)) {
                     String[] parts = cookie.getValue().split("&&");
                     LogFilter[] conditions = new LogFilter[parts.length];
                     for(int i=0; i<parts.length; i++) {
                         final String part = parts[i];
                         conditions[i] = new LogFilter() {
                             public boolean eval(String input) {
                                 return input.contains(part);
                             }

                             public String toString() {
                                 return part;
                             }
                         };
                     }
                     return conditions;
                 }
             }
         }
         catch (Exception e) {

         }
         return null;
     }

     private long getCreatedTimestampFromCookie(HttpServletRequest request) {
         try {
             for(Cookie cookie : request.getCookies()) {
                 if(cookie.getName().equals(CREATED_COOKIE)) {
                     return Long.parseLong(cookie.getValue());
                 }
             }
         }
         catch (Exception e) {

         }
         return -1;
     }

     private long getModifiedTimestampFromCookie(HttpServletRequest request) {
         try {
             for(Cookie cookie : request.getCookies()) {
                 if(cookie.getName().equals(MODIFIED_COOKIE)) {
                     return Long.parseLong(cookie.getValue());
                 }
             }
         }
         catch (Exception e) {

         }
         return -1;
     }

     private long getPositionFromCookie(HttpServletRequest request) {
         try {
             for(Cookie cookie : request.getCookies()) {
                 if(cookie.getName().equals(POSITION_COOKIE)) {
                     return Long.parseLong(cookie.getValue());
                 }
             }
         }
         catch (Exception e) {
             log.debug("Position specified is invalid, Tailing from beginning of the file.", e);
         }
         return -1;
     }
 }
	package org.apache.sling.tail.impl;

	/*
	* Licensed to the Apache Software Foundation (ASF) under one
	* or more contributor license agreements. See the NOTICE file
	* distributed with this work for additional information
	* regarding copyright ownership. The ASF licenses this file
	* to you under the Apache License, Version 2.0 (the
	* "License"); you may not use this file except in compliance
	* with the License. You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing,
	* software distributed under the License is distributed on an
	* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
	* KIND, either express or implied. See the License for the
	* specific language governing permissions and limitations
	* under the License.
	*/

	import ch.qos.logback.classic.LoggerContext;
	import ch.qos.logback.classic.spi.ILoggingEvent;
	import ch.qos.logback.core.Appender;
	import ch.qos.logback.core.FileAppender;
	import org.apache.felix.scr.annotations.*;
	import org.apache.felix.scr.annotations.Properties;
	import org.apache.felix.webconsole.AbstractWebConsolePlugin;
	import org.apache.felix.webconsole.WebConsoleConstants;
	import org.apache.sling.commons.json.io.JSONWriter;
	import org.apache.sling.tail.LogFilter;
	import org.slf4j.Logger;
	import org.slf4j.LoggerFactory;

	import javax.servlet.Servlet;
	import javax.servlet.ServletException;
	import javax.servlet.http.Cookie;
	import javax.servlet.http.HttpServletRequest;
	import javax.servlet.http.HttpServletResponse;
	import java.io.File;
	import java.io.IOException;
	import java.io.PrintWriter;
	import java.io.RandomAccessFile;
	import java.util.*;

	/**
	*
	*/
	@Component
	@Service(value = { Servlet.class })
	@Properties({
	@Property(name=org.osgi.framework.Constants.SERVICE_DESCRIPTION,
	value="Apache Sling Web Console Plugin to tail log(s) of this Sling instance"),
	@Property(name= WebConsoleConstants.PLUGIN_LABEL, value=LogTailerWebConsolePlugin.LABEL),
	@Property(name=WebConsoleConstants.PLUGIN_TITLE, value=LogTailerWebConsolePlugin.TITLE),
	@Property(name="felix.webconsole.configprinter.modes", value={"always"})
	})
	public class LogTailerWebConsolePlugin extends AbstractWebConsolePlugin {
	public static final String LABEL = "tail";
	public static final String TITLE = "Tail Logs";

	private final Logger log = LoggerFactory.getLogger(this.getClass());

	private static final int LINES_TO_TAIL = 100;
	private static final String POSITION_COOKIE = "log.tail.position";
	private static final String FILTER_COOKIE = "log.tail.filter";
	private static final String MODIFIED_COOKIE = "log.modified";
	private static final String CREATED_COOKIE = "log.created";

	private String fileName = "";
	private File errLog;

	@Override
	protected void renderContent(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
	if(isAjaxRequest(request)) {

	parseCommand(request, response);

	RandomAccessFile randomAccessFile = null;

	try {

	try {
	randomAccessFile = new RandomAccessFile(errLog, "r");
	log.debug("Tailing file " + fileName + " of length " + randomAccessFile.length());
	} catch (Exception e) {
	log.error("Error reading " + fileName, e);
	response.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
	return;
	}

	JSONWriter json = new JSONWriter(response.getWriter());
	json.setTidy(true);
	json.object();

	boolean reverse = false;
	//long created = getCreatedTimestampFromCookie(request);
	/*long modified = getModifiedTimestampFromCookie(request);
	if(errLog.lastModified() == modified) {
	json.endObject();
	return;
	}
	else {
	persistCookie(response, MODIFIED_COOKIE, String.valueOf(errLog.lastModified()));
	}*/
	long pos = getPositionFromCookie(request);
	if(pos < 0) {
	pos = randomAccessFile.length()-1;
	reverse = true;
	}
	else if(pos > randomAccessFile.length()) {//file rotated
	pos = 0;
	}
	LogFilter[] query = getQueryFromCookie(request);

	if(reverse) {
	randomAccessFile.seek(pos);
	if(randomAccessFile.read() == '\n') {
	pos--;
	randomAccessFile.seek(pos);
	if(randomAccessFile.read() == '\r') {
	pos--;
	}
	}

	json.key("content").array();
	int found = 0;
	StringBuilder sb = new StringBuilder();
	String line = null;
	List<String> lines = new ArrayList<String>();
	while(found != LINES_TO_TAIL && pos > 0) {
	boolean eol = false;
	randomAccessFile.seek(pos);
	int c = randomAccessFile.read();
	if(c == '\n') {
	found++;
	sb = sb.reverse();
	line = sb.toString();
	sb = new StringBuilder();
	eol = true;
	pos--;
	if(pos > 0) {
	randomAccessFile.seek(pos);
	if(randomAccessFile.read() == '\r') {
	pos--;
	}
	}
	}
	else {
	sb.append((char)c);
	pos--;
	}

	if(eol) {
	if(filter(line, query)){
	lines.add(line);
	}
	}
	}

	if(pos < 0) {
	if(filter(line, query)){
	lines.add(line);
	}
	}
	for(int i=lines.size()-1; i > -1; i--) {
	json.object().key("line").value(lines.get(i)).endObject();
	}
	json.endArray();
	json.endObject();
	}
	else {
	randomAccessFile.seek(pos);
	String line = null;
	int lineCount = 0;
	json.key("content").array();
	boolean read = true;
	while(read) {
	StringBuilder input = new StringBuilder();
	int c = -1;
	boolean eol = false;

	while (!eol) {
	switch (c = randomAccessFile.read()) {
	case -1:
	case '\n':
	eol = true;
	break;
	case '\r':
	eol = true;
	long cur = randomAccessFile.getFilePointer();
	if ((randomAccessFile.read()) != '\n') {
	randomAccessFile.seek(cur);
	}
	break;
	default:
	input.append((char)c);
	break;
	}
	}

	if ((c == -1) && (input.length() == 0)) {
	read = false;
	continue;
	}
	line = input.toString();
	lineCount++;
	if(lineCount == LINES_TO_TAIL) {
	read = false;
	}
	pos = randomAccessFile.getFilePointer();

	if(filter(line, query)){
	json.object().key("line").value(line).endObject();
	}
	}
	json.endArray();
	json.endObject();
	}

	persistCookie(response, POSITION_COOKIE, String.valueOf(randomAccessFile.getFilePointer()));

	} catch (Exception e) {
	log.error("Error tailing " + fileName, e);
	response.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
	}
	finally {
	try {
	if(randomAccessFile != null) {
	randomAccessFile.close();
	}
	}
	catch (Exception e) {
	log.error("Error closing " + fileName, e);
	}
	}
	}
	else {
	PrintWriter printWriter = response.getWriter();
	printWriter.println("<script type=\"text/javascript\" src=\"/libs/sling/logtail-plugin/js/tail.js\"></script>");
	printWriter.println("<link href=\"/libs/sling/logtail-plugin/css/tail.css\" rel=\"stylesheet\" type=\"text/css\"></link>");
	printWriter.println("<div class=\"header-cont\">");
	printWriter.println(" <div class=\"header\" style=\"display:none;\">");
	printWriter.println(" <table>");
	printWriter.println(" <tr>");
	printWriter.println(" <td><button class=\"numbering\" title=\"Show Line Numbers\" data-numbers=\"false\">Show Line No.</button></td>");
	printWriter.println(" <td><button class=\"pause\" title=\"Pause\">Pause</button></td>");
	printWriter.println(" <td class=\"longer\"><label>Sync frequency(msec)</label>");
	printWriter.println(" <button class=\"faster\" title=\"Sync Faster\">-</button>");
	printWriter.println(" <input id=\"speed\" type=\"text\" value=\"3000\"/>");
	printWriter.println(" <button class=\"slower\" title=\"Sync Slower\">+</button></td>");
	printWriter.println(" <td><button class=\"tail\" title=\"Unfollow Tail\" data-following=\"true\">Unfollow</button></td>");
	printWriter.println(" <td><button class=\"highlighting\" title=\"Highlight\">Highlight</button></td>");
	printWriter.println(" <td><button class=\"clear\" title=\"Clear Display\">Clear</button></td>");
	printWriter.println(" <td class=\"longer\"><input id=\"filter\" type=\"text\"/><span class=\"filterClear ui-icon ui-icon-close\" title=\"Clear Filter\"> </span><button class=\"filter\" title=\"Filter Logs\">Filter</button></td>");
	printWriter.println(" <td><button class=\"refresh\" title=\"Reload Logs\">Reload</button></td>");
	printWriter.println(" <td><button class=\"sizeplus\" title=\"Bigger\">a->A</button></td>");
	printWriter.println(" <td><button class=\"sizeminus\" title=\"Smaller\">A->a</button></td>");
	printWriter.println(" <td><button class=\"top\" title=\"Scroll to Top\">Top</button></td>");
	printWriter.println(" <td><button class=\"bottom\" title=\"Scroll to Bottom\">Bottom</button></td>");
	printWriter.println(" </tr>");
	printWriter.println(" <tr>");
	printWriter.println(" <td class=\"loadingstatus\" colspan=\"2\" data-status=\"inactive\"><ul><li></li></ul></td>");
	printWriter.println(" <td>Tailing   <select id=\"logfiles\">" + getOptions() + "</select></td>");
	printWriter.println(" </tr>");
	printWriter.println(" </table>");
	printWriter.println(" </div>");
	printWriter.println(" <div class=\"pulldown\" title=\"Click to show options\"> == </div>");
	printWriter.println("</div>");
	printWriter.println("");
	printWriter.println(" <div class=\"content\">");
	printWriter.println("");
	printWriter.println(" <div id=\"logarea\"></div>");
	printWriter.println("");
	printWriter.println(" </div>");
	}
	}

	protected void parseCommand(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
	String cmd = request.getParameter("command");
	if(cmd == null) {
	return;
	}

	if(cmd.equals("reset")) {
	deleteCookie(response, FILTER_COOKIE);
	}
	else if(cmd.startsWith("filter:")) {
	String queryStr = cmd.substring(7);
	if(queryStr.length()==0) {
	deleteCookie(response, FILTER_COOKIE);
	}
	else {
	persistCookie(response, FILTER_COOKIE, queryStr);
	log.info("Filtering on : " + queryStr);
	}
	}
	else if(cmd.startsWith("file:")) {
	if(!fileName.equals(cmd.substring(5))) {
	deleteCookie(response, FILTER_COOKIE);
	deleteCookie(response, POSITION_COOKIE);
	fileName = cmd.substring(5);
	errLog = new File(filePathMap.get(fileName));
	if(!errLog.exists()) {
	throw new ServletException("File " + fileName + " doesn't exist");
	}
	if(!errLog.canRead()) {
	throw new ServletException("Cannot read file " + fileName);
	}
	}
	}
	}

	@Override
	public String getLabel() {
	return LABEL;
	}

	@Override
	public String getTitle() {
	return TITLE;
	}

	private HashMap<String, String> filePathMap = new HashMap<String, String>();

	private String getKey(File file) {
	if(!filePathMap.containsKey(file.getName())) {
	filePathMap.put(file.getName(), file.getAbsolutePath());
	}
	return file.getName();
	}

	private String getOptions() {
	Set<String> logFiles = new HashSet<String>();
	LoggerContext context = (LoggerContext)LoggerFactory.getILoggerFactory();
	for (ch.qos.logback.classic.Logger logger : context.getLoggerList()) {
	for (Iterator<Appender<ILoggingEvent>> index = logger.iteratorForAppenders(); index.hasNext();) {
	Appender<ILoggingEvent> appender = index.next();
	if(appender instanceof FileAppender) {
	FileAppender fileAppender = (FileAppender) appender;
	String logfilePath = fileAppender.getFile();
	logFiles.add(logfilePath);
	}
	}
	}

	String logFilesHtml = "<option value=\"\"> - Select file - </option>";
	for(String logFile : logFiles) {
	File file = new File(logFile);
	logFilesHtml += "<option value=\"" + getKey(file) + "\">" + file.getName() + "</option>";
	}
	return logFilesHtml;
	}

	@Override
	protected boolean isHtmlRequest( final HttpServletRequest request ) {
	return !isAjaxRequest(request);
	}

	private boolean isAjaxRequest( final HttpServletRequest request) {
	return "XMLHttpRequest".equals(request.getHeader("X-Requested-With"));
	}

	private boolean filter(String str, LogFilter[] query) {
	if(query != null) {
	for(LogFilter q : query) {
	if(!q.eval(str)) {
	return false;
	}
	}
	}
	return true;
	}

	private void deleteCookie(HttpServletResponse response, String name) {
	Cookie cookie = new Cookie(name, "");
	cookie.setMaxAge(0);
	response.addCookie(cookie);
	log.debug("Deleting cookie :: " + cookie.getName());
	}

	private void persistCookie(HttpServletResponse response, String name, String value) {
	Cookie cookie = new Cookie(name , value);
	//cookie.setPath("/system/console/" + LABEL);
	response.addCookie(cookie);
	log.debug("Adding cookie :: " + cookie.getName() + " " + cookie.getValue());
	}

	private LogFilter[] getQueryFromCookie(HttpServletRequest request) {
	try {
	for(Cookie cookie : request.getCookies()) {
	if(cookie.getName().equals(FILTER_COOKIE)) {
	String[] parts = cookie.getValue().split("&&");
	LogFilter[] conditions = new LogFilter[parts.length];
	for(int i=0; i<parts.length; i++) {
	final String part = parts[i];
	conditions[i] = new LogFilter() {
	public boolean eval(String input) {
	return input.contains(part);
	}

	public String toString() {
	return part;
	}
	};
	}
	return conditions;
	}
	}
	}
	catch (Exception e) {

	}
	return null;
	}

	private long getCreatedTimestampFromCookie(HttpServletRequest request) {
	try {
	for(Cookie cookie : request.getCookies()) {
	if(cookie.getName().equals(CREATED_COOKIE)) {
	return Long.parseLong(cookie.getValue());
	}
	}
	}
	catch (Exception e) {

	}
	return -1;
	}

	private long getModifiedTimestampFromCookie(HttpServletRequest request) {
	try {
	for(Cookie cookie : request.getCookies()) {
	if(cookie.getName().equals(MODIFIED_COOKIE)) {
	return Long.parseLong(cookie.getValue());
	}
	}
	}
	catch (Exception e) {

	}
	return -1;
	}

	private long getPositionFromCookie(HttpServletRequest request) {
	try {
	for(Cookie cookie : request.getCookies()) {
	if(cookie.getName().equals(POSITION_COOKIE)) {
	return Long.parseLong(cookie.getValue());
	}
	}
	}
	catch (Exception e) {
	log.debug("Position specified is invalid, Tailing from beginning of the file.", e);
	}
	return -1;
	}
	}