com.WeatherProxy.java Source code

Introduction

Here is the source code for com.WeatherProxy.java

Source

/**
 * Adapted from 2 sources by Russ Tuck, 2016:
 *  - Google App Engine "helloworld" example app.
 *  - http://www.mkyong.com/webservices/jax-rs/restfull-java-client-with-java-net-url/
 */
/**
 * Copyright 2015 Google Inc. All Rights Reserved.
 *
 * 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 com;

// Client side:
import com.google.appengine.api.memcache.stdimpl.GCacheFactory;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

// Server side:
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.json.JSONObject;
import javax.cache.Cache;

@SuppressWarnings("serial")
public class WeatherProxy extends HttpServlet {

    Cache cache;

    @Override
    public void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException {
        resp.setContentType("application/json; charset=utf-8");
        resp.setHeader("Access-Control-Allow-Origin", "*");
        PrintWriter out = resp.getWriter();
        String wenhamLat = "42.589611";
        String wenhamLng = "-70.819806";
        // Retrieve lat and lng form url
        String lat = req.getParameter("lat");
        String lng = req.getParameter("lng");

        // Get weather data
        this.getWeather(lat, lng);

        out.println(weatherNow);
    }

    /* Hold cached weather data in JSON format from forecast.io.
     * Note that it contains a timestamp indicating when it was fetched.
     */
    private String weatherNow;

    private void getWeather(String lat, String lng) {
        weatherNow = "";
        String apiUrl = "https://api.forecast.io/forecast/";
        String apiKey = "fad007e59cd36e504fa337d946feb7d2";
        String urlString = apiUrl + apiKey + "/" + lat + "," + lng;

        try {
            URL url = new URL(urlString);
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.setRequestMethod("GET");
            conn.setRequestProperty("Accept", "application/json");
            conn.connect();

            if (conn.getResponseCode() != 200) {
                throw new RuntimeException("Failed : HTTP error code : " + conn.getResponseCode());
            }

            // The body of the response is available as an input stream.
            // Using BufferedReader is good practice for efficient I/O, because it
            // takes lots of little reads and does fewer larger actual I/O
            // operations.  It doesn't make much difference in this case,
            // since we only do one I/O.  But it's still good practice.
            BufferedReader br = new BufferedReader(new InputStreamReader((conn.getInputStream())));
            // api.forecast.io returns a single (very long) line of JSON.
            weatherNow += br.readLine();

        } catch (MalformedURLException e) {
            e.printStackTrace();
            this.weatherNow = "{ 'error': 'MalformedURLException' }";
        } catch (IOException e) {
            e.printStackTrace();
            this.weatherNow = "{ 'error': 'IOException' }";
        }
    }
}