FlickrPOIProvider.java

package org.osmdroid.location;

import java.util.ArrayList;
import java.util.HashMap;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import org.oscim.core.BoundingBox;
import org.oscim.core.GeoPoint;
import org.osmdroid.utils.BonusPackHelper;

import android.util.Log;

/**
 * POI Provider using Flickr service to get geolocalized photos.
 * @see "http://www.flickr.com/services/api/flickr.photos.search.html"
 * @author M.Kergall
 */
public class FlickrPOIProvider implements POIProvider {

	protected String mApiKey;
	private final static String PHOTO_URL = "http://www.flickr.com/photos/%s/%s/sizes/o/in/photostream/";

	/**
	 * @param apiKey
	 *            the registered API key to give to Flickr service.
	 * @see "http://www.flickr.com/help/api/"
	 */
	public FlickrPOIProvider(String apiKey) {
		mApiKey = apiKey;
	}

	private String getUrlInside(BoundingBox boundingBox, int maxResults) {
		StringBuffer url = new StringBuffer(
				"http://api.flickr.com/services/rest/?method=flickr.photos.search");
		url.append("&api_key=" + mApiKey);
		url.append("&bbox=" + boundingBox.getMinLongitude());
		url.append("," + boundingBox.getMinLatitude());
		url.append("," + boundingBox.getMaxLongitude());
		url.append("," + boundingBox.getMaxLatitude());
		url.append("&has_geo=1");
		// url.append("&geo_context=2");
		// url.append("&is_commons=true");
		url.append("&format=json&nojsoncallback=1");
		url.append("&per_page=" + maxResults);
		// From Flickr doc:
		// "Geo queries require some sort of limiting agent in order to prevent the database from crying."
		// And min_date_upload is considered as a limiting agent. So:
		url.append("&min_upload_date=2005/01/01");

		// Ask to provide some additional attributes we will need:
		url.append("&extras=geo,url_sq");
		url.append("&sort=interestingness-desc");
		return url.toString();
	}

	/* public POI getPhoto(String photoId){ String url =
	 * "http://api.flickr.com/services/rest/?method=flickr.photos.getInfo"
	 * +
	 * "&api_key=" + mApiKey + "&photo_id=" + photo Id +
	 * "&format=json&nojsoncallback=1"; Log.d(BonusPackHelper.LOG_TAG,
	 * "getPhoto:"+url); String jString =
	 * BonusPackHelper.requestStringFromUrl(url); if (jString == null)
	 * {
	 * Log.e(BonusPackHelper.LOG_TAG,
	 * "FlickrPOIProvider: request failed.");
	 * return null; } try { POI poi = new POI(POI.POI_SERVICE_FLICKR);
	 * JSONObject jRoot = new JSONObject(jString); JSONObject jPhoto =
	 * jRoot.getJSONObject("photo"); JSONObject jLocation =
	 * jPhoto.getJSONObject("location"); poi.mLocation = new GeoPoint(
	 * jLocation.getDouble("latitude"),
	 * jLocation.getDouble("longitude"));
	 * poi.mId = Long.parseLong(photoId); JSONObject jTitle =
	 * jPhoto.getJSONObject("title"); poi.mType =
	 * jTitle.getString("_content");
	 * JSONObject jDescription = jPhoto.getJSONObject("description");
	 * poi.mDescription = jDescription.getString("_content");
	 * //truncate
	 * description if too long: if (poi.mDescription.length() > 300){
	 * poi.mDescription = poi.mDescription.substring(0, 300) +
	 * " (...)"; }
	 * String farm = jPhoto.getString("farm"); String server =
	 * jPhoto.getString("server"); String secret =
	 * jPhoto.getString("secret");
	 * JSONObject jOwner = jPhoto.getJSONObject("owner"); String nsid
	 * =
	 * jOwner.getString("nsid"); poi.mThumbnailPath =
	 * "http://farm"+farm+".staticflickr.com/"
	 * +server+"/"+photoId+"_"+secret+"_s.jpg"; poi.mUrl =
	 * "http://www.flickr.com/photos/"+nsid+"/"+photoId; return poi;
	 * }catch
	 * (JSONException e) { e.printStackTrace(); return null; } } */

	/**
	 * @param fullUrl
	 *            ...
	 * @return the list of POI
	 */
	public ArrayList<POI> getThem(String fullUrl) {
		// for local debug: fullUrl = "http://10.0.2.2/flickr_mockup.json";
		Log.d(BonusPackHelper.LOG_TAG, "FlickrPOIProvider:get:" + fullUrl);
		String jString = BonusPackHelper.requestStringFromUrl(fullUrl);
		if (jString == null) {
			Log.e(BonusPackHelper.LOG_TAG, "FlickrPOIProvider: request failed.");
			return null;
		}
		try {
			JSONObject jRoot = new JSONObject(jString);
			JSONObject jPhotos = jRoot.getJSONObject("photos");
			JSONArray jPhotoArray = jPhotos.getJSONArray("photo");
			int n = jPhotoArray.length();
			ArrayList<POI> pois = new ArrayList<POI>(n);
			for (int i = 0; i < n; i++) {
				JSONObject jPhoto = jPhotoArray.getJSONObject(i);

				String photoId = jPhoto.getString("id");
				if (mPrevious != null && mPrevious.containsKey(photoId))
					continue;

				POI poi = new POI(POI.POI_SERVICE_FLICKR);
				poi.location = new GeoPoint(
						jPhoto.getDouble("latitude"),
						jPhoto.getDouble("longitude"));
				poi.id = photoId; //Long.parseLong(photoId);
				poi.type = jPhoto.getString("title");
				poi.thumbnailPath = jPhoto.getString("url_sq");
				String owner = jPhoto.getString("owner");
				// the default flickr link viewer doesnt work with mobile browsers... 
				//	poi.url = "http://www.flickr.com/photos/" + owner + "/" + photoId + "/sizes/o/in/photostream/";

				poi.url = String.format(PHOTO_URL, owner, photoId);

				pois.add(poi);
			}
			//			int total = jPhotos.getInt("total");
			//			Log.d(BonusPackHelper.LOG_TAG, "done:" + n + " got, on a total of:" + total);
			return pois;
		} catch (JSONException e) {
			e.printStackTrace();
			return null;
		}
	}

	/**
	 * @param boundingBox
	 *            ...
	 * @param maxResults
	 *            ...
	 * @return list of POI, Flickr photos inside the bounding box.
	 *         Null if
	 *         technical issue.
	 */
	public ArrayList<POI> getPOIInside(BoundingBox boundingBox, String query, int maxResults) {
		String url = getUrlInside(boundingBox, maxResults);
		return getThem(url);
	}

	HashMap<String, POI> mPrevious;

	public void setPrevious(HashMap<String, POI> previous) {
		mPrevious = previous;
	}

}