AbstractWeatherProvider.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.provider;

import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.util.Calendar;

import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpStatus;
import org.apache.commons.httpclient.HttpVersion;
import org.apache.commons.httpclient.MultiThreadedHttpConnectionManager;
import org.apache.commons.httpclient.cookie.CookiePolicy;
import org.apache.commons.httpclient.methods.GetMethod;
import org.apache.commons.httpclient.params.HttpClientParams;
import org.apache.commons.lang.StringUtils;
import org.openhab.binding.weather.internal.common.LocationConfig;
import org.openhab.binding.weather.internal.common.ProviderConfig;
import org.openhab.binding.weather.internal.common.WeatherConfig;
import org.openhab.binding.weather.internal.common.WeatherContext;
import org.openhab.binding.weather.internal.model.Forecast;
import org.openhab.binding.weather.internal.model.ProviderName;
import org.openhab.binding.weather.internal.model.Weather;
import org.openhab.binding.weather.internal.parser.WeatherParser;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Common base class for all weather providers. Retrieves, parses and returns
 * weather data.
 *
 * @author Gerhard Riegler
 * @since 1.6.0
 */
public abstract class AbstractWeatherProvider implements WeatherProvider {
    private static final Logger logger = LoggerFactory.getLogger(AbstractWeatherProvider.class);
    private static HttpClient httpClient = null;

    private WeatherConfig config = WeatherContext.getInstance().getConfig();
    private WeatherParser parser;

    static {
        httpClient = new HttpClient(new MultiThreadedHttpConnectionManager());
        HttpClientParams params = httpClient.getParams();
        params.setConnectionManagerTimeout(15000);
        params.setSoTimeout(30000);
        params.setContentCharset("UTF-8");
        params.setCookiePolicy(CookiePolicy.IGNORE_COOKIES);
        params.setVersion(HttpVersion.HTTP_1_0);
    }

    public AbstractWeatherProvider(WeatherParser parser) {
        this.parser = parser;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public Weather getWeather(LocationConfig locationConfig) throws Exception {
        Weather weather = new Weather(getProviderName());
        executeRequest(weather, prepareUrl(getWeatherUrl(), locationConfig), locationConfig);

        String forecastUrl = getForecastUrl();
        if (forecastUrl != null && !weather.hasError()) {
            executeRequest(weather, prepareUrl(forecastUrl, locationConfig), locationConfig);
        }
        if (logger.isDebugEnabled()) {
            logger.debug("{}[{}]: {}", getProviderName(), locationConfig.getLocationId(), weather.toString());
            for (Weather fc : weather.getForecast()) {
                logger.debug("{}[{}]: {}", getProviderName(), locationConfig.getLocationId(), fc.toString());
            }
        }

        return weather;
    }

    /**
     * Prepares the provider URL by setting the config.
     */
    private String prepareUrl(String url, LocationConfig locationConfig) {
        ProviderConfig providerConfig = config.getProviderConfig(getProviderName());
        if (providerConfig != null) {
            url = StringUtils.replace(url, "[API_KEY]", providerConfig.getApiKey());
            url = StringUtils.replace(url, "[API_KEY_2]", providerConfig.getApiKey2());
        }
        if (locationConfig.getLatitude() != null) {
            url = StringUtils.replace(url, "[LATITUDE]", locationConfig.getLatitude().toString());
        }
        if (locationConfig.getLongitude() != null) {
            url = StringUtils.replace(url, "[LONGITUDE]", locationConfig.getLongitude().toString());
        }
        if (locationConfig.getMeasurementUnits() != null) {
            url = StringUtils.replace(url, "[UNITS]", locationConfig.getMeasurementUnits());
        }
        url = StringUtils.replace(url, "[LANGUAGE]", locationConfig.getLanguage());
        url = StringUtils.replace(url, "[WOEID]", locationConfig.getWoeid());
        return url;
    }

    /**
     * Executes the http request and parses the returned stream.
     */
    private void executeRequest(Weather weather, String url, LocationConfig locationConfig) throws Exception {
        GetMethod get = null;
        try {
            logger.trace("{}[{}]: request : {}", getProviderName(), locationConfig.getLocationId(), url);

            get = new GetMethod(url);
            httpClient.executeMethod(get);

            InputStream is = null;
            if (logger.isTraceEnabled()) {
                String response = get.getResponseBodyAsString(100000);
                response = StringUtils.remove(response, "\n");
                response = StringUtils.trim(response);
                logger.trace("{}[{}]: response: {}", getProviderName(), locationConfig.getLocationId(), response);
                is = new ByteArrayInputStream(response.getBytes(get.getResponseCharSet()));
            } else {
                is = get.getResponseBodyAsStream();
            }

            if (get.getStatusCode() == HttpStatus.SC_OK) {
                parser.parseInto(is, weather);
            }
            // special handling because of bad OpenWeatherMap json structure
            if (weather.getProvider() == ProviderName.OPENWEATHERMAP && weather.getResponseCode() != null
                    && weather.getResponseCode() == 200) {
                weather.setError(null);
            }

            if (!weather.hasError() && get.getStatusCode() != HttpStatus.SC_OK) {
                weather.setError(get.getStatusLine().toString());
            }

            if (weather.hasError()) {
                logger.error("{}[{}]: Can't retreive weather data: {}", getProviderName(),
                        locationConfig.getLocationId(), weather.getError());
            } else {
                setLastUpdate(weather);
            }
        } catch (Exception ex) {
            logger.error(getProviderName() + ": " + ex.getMessage());
            weather.setError(ex.getClass().getSimpleName() + ": " + ex.getMessage());
            throw ex;
        } finally {
            if (get != null) {
                get.releaseConnection();
            }
        }
    }

    /**
     * Sets the current timestamp in every weather object.
     */
    private void setLastUpdate(Weather weather) {
        Calendar cal = Calendar.getInstance();
        weather.getCondition().setLastUpdate(cal);
        for (Forecast forecast : weather.getForecast()) {
            forecast.getCondition().setLastUpdate(cal);
        }
    }

    /**
     * Returns the provider weather url.
     */
    protected abstract String getWeatherUrl();

    /**
     * Returns the provider forecast url, some providers needs a second http
     * request.
     */
    protected String getForecastUrl() {
        return null;
    }

}