FlickrPOIProvider.java

package org.osmdroid.bonuspack.location;

import android.util.Log;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import org.osmdroid.bonuspack.utils.BonusPackHelper;
import org.osmdroid.util.BoundingBox;
import org.osmdroid.util.GeoPoint;

import java.util.ArrayList;

/**
 * POI Provider using Flickr service to get geolocalized photos. 
 * @see <a href="http://www.flickr.com/services/api/flickr.photos.search.html">Flickr API</a>
 * @author M.Kergall
 */
public class FlickrPOIProvider {

	protected String mApiKey;
	
	/**
	 * @param apiKey the registered API key to give to Flickr service. 
	 * @see <a href="http://www.flickr.com/help/api/">Flickr registration</a>
	 */
	public FlickrPOIProvider(String apiKey){
		mApiKey = apiKey;
	}
	
	private String getUrlInside(BoundingBox boundingBox, int maxResults){
		StringBuilder url = new StringBuilder("https://api.flickr.com/services/rest/?method=flickr.photos.search");
		url.append("&api_key="+mApiKey);
		url.append("&bbox="+boundingBox.getLonWest());
		url.append(","+boundingBox.getLatSouth());
		url.append(","+boundingBox.getLonEast());
		url.append(","+boundingBox.getLatNorth());
		url.append("&has_geo=1");
		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=" + photoId
			+ "&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){
		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");
				POI poi = new POI(POI.POI_SERVICE_FLICKR);
				poi.mLocation = new GeoPoint(
						jPhoto.getDouble("latitude"), 
						jPhoto.getDouble("longitude"));
				poi.mId = Long.parseLong(photoId);
				poi.mType = jPhoto.getString("title");
				poi.mThumbnailPath = jPhoto.getString("url_sq");
				String owner = jPhoto.getString("owner");
				poi.mUrl = "https://www.flickr.com/photos/"+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, int maxResults){
		String url = getUrlInside(boundingBox, maxResults);
		return getThem(url);
	}
	

}