package com.splout.db.examples;
/*
* #%L
* Splout SQL Hadoop library
* %%
* Copyright (C) 2012 Datasalt Systems S.L.
* %%
* 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.
* #L%
*/
import java.io.IOException;
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 com.google.api.client.http.GenericUrl;
import com.google.api.client.http.HttpRequest;
import com.google.api.client.http.HttpRequestFactory;
import com.google.api.client.http.HttpTransport;
import com.google.api.client.http.javanet.NetHttpTransport;
import com.splout.db.common.SploutClient;
/**
* Servlet that caches and returns the trending wikipedia articles from: http://www.trendingtopics.org/pages.xml?page=1
*/
@SuppressWarnings("serial")
public class PageCountsTrendingServlet extends HttpServlet {
private final static Log log = LogFactory.getLog(PageCountsServlet.class);
private HttpRequestFactory requestFactory;
public PageCountsTrendingServlet() {
HttpTransport transport = new NetHttpTransport();
requestFactory = transport.createRequestFactory();
}
private long cachedFrom;
private String cachedString = null;
public final static long CACHE_FOR = 1000 * 60 * 5; // 5 minutes cache
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException,
IOException {
long now = System.currentTimeMillis();
if(cachedString != null && (now - cachedFrom) < CACHE_FOR) {
resp.getWriter().write(cachedString);
log.info("Returning XML content from cache.");
return;
}
HttpRequest trendReq = requestFactory.buildGetRequest(new GenericUrl("http://www.trendingtopics.org/pages.xml?page=1"));
cachedString = SploutClient.asString(trendReq.execute().getContent());
log.info("Got XML content from trendingtopics: " + cachedString);
cachedFrom = System.currentTimeMillis();
resp.getWriter().write(cachedString);
}
}