/*
* Copyright 2012 Google Inc.
*
* Licensed 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.
*/
package org.vitaliyl.monitoring.server;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.URL;
import java.net.URLConnection;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.vitaliyl.monitoring.server.beans.MessageDescriptor;
import org.vitaliyl.monitoring.server.beans.ServerDescriptor;
import org.vitaliyl.monitoring.server.dao.AMessageDAO;
import org.vitaliyl.monitoring.server.dao.AServerDescriptorDAO;
import com.google.appengine.api.taskqueue.Queue;
import com.google.appengine.api.taskqueue.QueueFactory;
import com.google.appengine.api.taskqueue.TaskOptions;
import com.google.appengine.api.taskqueue.TaskOptions.Method;
import com.google.gson.Gson;
/**
* Servlet that adds display number of devices and button to send a message.
* <p>
* This servlet is used just by the browser (i.e., not device) and contains the
* main page of the demo app.
*/
@SuppressWarnings("serial")
public class CheckerServlet extends BaseServlet {
static final String ATTRIBUTE_STATUS = "status";
static final Pattern ACTIVE_CONNECTIONS_PATTERN = Pattern.compile("Active connections: (\\d+)");
/**
* Displays the existing messages and offer the option to send a new one.
*/
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException {
resp.setContentType("application/json");
logger.fine("CheckerServlet fired!");
List<MessageDescriptor> statusList = new ArrayList<MessageDescriptor>();
List<ServerDescriptor> servers = AServerDescriptorDAO.getServerDescriptors();
for (int i = 0; i < servers.size(); i++) {
MessageDescriptor md = new MessageDescriptor(servers.get(i));
try {
String rawContent = getRawContent(md.getServerUrl());
Matcher m = ACTIVE_CONNECTIONS_PATTERN.matcher(rawContent);
if (m.find()) {
md.setCurrentConnections(Integer.parseInt(m.group(1)));
}
} catch (IOException e) {
md.setDown(true);
}
statusList.add(md);
if (md.hasProblem()) {
md.setWhen(new Date());
String key = AMessageDAO.createMessageDescriptor(md);
Queue queue = QueueFactory.getQueue("serverError");
TaskOptions taskOptions = TaskOptions.Builder.withUrl("/sendAll").param(SendMessageServlet.PARAMETER_SERVER, key).method(Method.POST);
queue.add(taskOptions);
}
}
writeStatusListToResponse(resp, statusList);
resp.setStatus(HttpServletResponse.SC_OK);
}
private void writeStatusListToResponse(HttpServletResponse resp, List<MessageDescriptor> list) throws IOException {
Gson gson = new Gson();
PrintWriter writer = resp.getWriter();
writer.print(gson.toJson(list));
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws IOException {
doGet(req, resp);
}
public static String getRawContent(String url) throws IOException {
URL website = new URL(url);
URLConnection connection = website.openConnection();
BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
StringBuilder response = new StringBuilder();
String inputLine;
while ((inputLine = in.readLine()) != null)
response.append(inputLine);
in.close();
return response.toString();
}
}