WeatherServlet.java

/**
 * Copyright (c) 2010-2016 by the respective copyright holders.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 */
package org.openhab.binding.weather.internal.gfx;

import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.Enumeration;
import java.util.Hashtable;

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

import org.apache.commons.io.IOUtils;
import org.apache.commons.lang.StringUtils;
import org.openhab.binding.weather.internal.common.WeatherContext;
import org.openhab.binding.weather.internal.model.Weather;
import org.openhab.io.net.http.SecureHttpContext;
import org.osgi.service.http.HttpContext;
import org.osgi.service.http.HttpService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * The weather servlet serves the Html code based on the weather layouts.
 * Example layouts and icons can be downloaded from the wiki page.
 *
 * @author Gerhard Riegler
 * @since 1.6.0
 */
public class WeatherServlet extends HttpServlet {
    private static final long serialVersionUID = -8254216127563270956L;
    private static final Logger logger = LoggerFactory.getLogger(WeatherServlet.class);

    private static final String SERVLET_NAME = "/weather";
    private static final String WEBAPP_LOCATION = "./webapps/weather-data";
    private static final String LAYOUTS_LOCATION = WEBAPP_LOCATION + "/layouts";

    private HttpService httpService;

    public void setHttpService(HttpService httpService) {
        this.httpService = httpService;
    }

    public void unsetHttpService(HttpService httpService) {
        this.httpService = null;
    }

    /**
     * Activates the weather servlet.
     */
    protected void activate() {
        try {
            logger.debug("Starting up weather servlet at " + SERVLET_NAME);

            Hashtable<String, String> props = new Hashtable<String, String>();
            httpService.registerServlet(SERVLET_NAME, this, props, createHttpContext());

        } catch (Exception ex) {
            logger.error("Error during weather servlet startup", ex);
        }
    }

    /**
     * Deactivates the weather servlet.
     */
    protected void deactivate() {
        httpService.unregister(SERVLET_NAME);
    }

    /**
     * Creates a SecureHttpContext which handles the security for this servlet.
     */
    private HttpContext createHttpContext() {
        HttpContext defaultHttpContext = httpService.createDefaultHttpContext();
        return new SecureHttpContext(defaultHttpContext, "openHAB.org");
    }

    /**
     * {@inheritDoc}
     */
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        logger.debug("Received incoming weather request");

        String locationId = request.getParameter("locationId");
        if (StringUtils.isBlank(locationId)) {
            throw new ServletException("Weather locationId required, please add parameter locationId to the request");
        }

        Weather weather = WeatherContext.getInstance().getWeather(locationId);
        if (weather == null) {
            throw new ServletException("Weather locationId '" + locationId + "' does not exist");
        }

        String layout = request.getParameter("layout");
        if (StringUtils.isBlank(layout)) {
            throw new ServletException("Weather layout required, please add parameter layout to the request");
        }

        layout += ".html";

        File layoutFile = new File(LAYOUTS_LOCATION + "/" + layout);
        if (!layoutFile.exists()) {
            throw new ServletException("File with weather layout '" + layout
                    + "' does not exist, make sure it is in the layouts folder " + LAYOUTS_LOCATION);
        }

        WeatherTokenResolver tokenResolver = new WeatherTokenResolver(weather, locationId);
        Enumeration<String> parameter = request.getParameterNames();
        while (parameter.hasMoreElements()) {
            String parameterName = parameter.nextElement();
            tokenResolver.addParameter(parameterName, request.getParameter(parameterName));
        }

        if (request.getParameter("iconset") == null) {
            tokenResolver.addParameter("iconset", "colorful");
        }

        TokenReplacingReader replReader = new TokenReplacingReader(new FileReader(layoutFile), tokenResolver);
        IOUtils.copy(replReader, response.getOutputStream());
    }

}