WithingsApiClient.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.withings.internal.api;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.List;

import org.openhab.binding.withings.internal.model.Attribute;
import org.openhab.binding.withings.internal.model.Category;
import org.openhab.binding.withings.internal.model.MeasureGroup;
import org.openhab.binding.withings.internal.model.MeasureResult;
import org.openhab.binding.withings.internal.model.MeasureType;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;

import oauth.signpost.OAuthConsumer;
import oauth.signpost.exception.OAuthException;

/**
 * {@link WithingsApiClient} provides methods for accessing Withings remote API.
 *
 * @see http://www.withings.com/de/api
 * @author Dennis Nobel
 * @since 1.5.0
 */
public class WithingsApiClient {

    private static final String API_ENDPOINT_MEASURE = "measure";

    private static final String API_METHOD_GET_MEASURES = "getmeas";

    private static final String API_URL = "http://wbsapi.withings.net/";

    private final OAuthConsumer consumer;

    private final Gson gson;

    private final JsonParser jsonParser;

    private final String userId;

    public WithingsApiClient(OAuthConsumer consumer, String userId) {
        this.consumer = consumer;
        this.userId = userId;
        this.gson = createGsonBuilder().create();
        this.jsonParser = new JsonParser();
    }

    /**
     * Returns a list of all measures in form {@link MeasureGroup} objects.
     * 
     * @return list of all measures
     * @throws OAuthException
     *             if an error occurs while signing the request
     * @throws WithingsConnectionException
     *             if a connection, server or authorization error occurs
     * @see http://www.withings.com/de/api#bodymetrics
     */
    public List<MeasureGroup> getMeasures() throws OAuthException, WithingsConnectionException {
        return getMeasures(0);
    }

    /**
     * Returns a list of all measures in form {@link MeasureGroup} objects since
     * the given start time.
     * 
     * @param startTime
     *            time after which measures are returned
     * @return list of all measures
     * @throws OAuthException
     *             if an error occurs while signing the request
     * @throws WithingsConnectionException
     *             if a connection, server or authorization error occurs
     * @see http://www.withings.com/de/api#bodymetrics
     */
    public List<MeasureGroup> getMeasures(int startTime) throws OAuthException, WithingsConnectionException {

        String url = getServiceUrl(API_ENDPOINT_MEASURE, API_METHOD_GET_MEASURES);
        if (startTime > 0) {
            url = url + "&startdate=" + startTime;
        }

        try {
            JsonObject jsonObject = call(consumer.sign(url));

            int status = jsonObject.get("status").getAsInt();

            if (status == 0) {
                JsonElement body = jsonObject.get("body");
                return gson.fromJson(body.getAsJsonObject(), MeasureResult.class).measureGroups;
            } else {
                throw new WithingsConnectionException("Withings API call failed: " + status);
            }

        } catch (Exception ex) {
            throw new WithingsConnectionException("Could not connect to URL: " + ex.getMessage(), ex);
        }
    }

    private JsonObject call(String signedUrl)
            throws IOException, MalformedURLException, WithingsConnectionException, UnsupportedEncodingException {

        HttpURLConnection httpURLConnection;
        httpURLConnection = (HttpURLConnection) new URL(signedUrl).openConnection();
        httpURLConnection.connect();

        int responseCode = httpURLConnection.getResponseCode();

        if (responseCode != HttpURLConnection.HTTP_OK) {
            throw new WithingsConnectionException("Illegal response code: " + responseCode);
        }

        Reader reader = null;
        try {
            InputStream inputStream = httpURLConnection.getInputStream();
            reader = new InputStreamReader(inputStream, "UTF-8");
            JsonObject jsonObject = (JsonObject) jsonParser.parse(reader);
            return jsonObject;
        } finally {
            if (reader != null) {
                try {
                    reader.close();
                } catch (IOException ignored) {

                }
            }
        }

    }

    private GsonBuilder createGsonBuilder() {
        GsonBuilder gsonBuilder = new GsonBuilder();
        gsonBuilder.registerTypeAdapter(MeasureType.class, new JsonDeserializers.MeasureTypeJsonDeserializer());
        gsonBuilder.registerTypeAdapter(Category.class, new JsonDeserializers.CategoryJsonDeserializer());
        gsonBuilder.registerTypeAdapter(Attribute.class, new JsonDeserializers.AttributeJsonDeserializer());
        return gsonBuilder;
    }

    private String getServiceUrl(String endpoint, String method) {
        return API_URL + endpoint + "?action=" + method + "&userid=" + this.userId;
    }

}